Post on 16-Jan-2016
transcript
NEWER MODES OF VENTILATION
DRPRATHEEBA DURAIRAJMDDA
5122007
Discovery of the potential for mechanical ventilation to produce ventilator-associated lung injury has resulted in the development of new lung protective strategies
AIM
To enhance respiratory muscle rest Prevent deconditioning atrophy of
muscles Improve gas exchange Prevent lung damage Improve patient synchrony Help in weaning process
Volume Ventilation
Stable consistent tidal volume delivery and minute ventilation which is independent of patientrsquos lung mechanics
BUT Pressures variable and difficult to control Resultant high peak pressure Slow rise to peak pressure distribution of ventilation may not be
optimized Set flow rate may not match patientrsquos demand Increased muscle workload from flow asynchrony may compromise patient comfort gas exchange cardiac function
Volume 500 mlPressure 3500 cm H20
Simple Volume System
Volume 500 ml
Volume 2000 mlPressure 3500 cm H20
Pop
Simple Volume System
PressureControl Ventilation
Benefits 1048707 Variable flow capability for patient demand 1048707 Reduced patient inspiratory muscle workload 1048707 Lower peak inspiratory pressures 1048707 Adjustable inspiratory time 1048707 Rapid filling of the alveoli 1048707 Improved gas distribution VQ matchingand
oxygenation
Disadvantages 1048707 Delivered tidal volume is variable and depends
upon the patientrsquos lung mechanics including changes in airway resistance and lung compliance
1048707 May have adverse effects on volume delivery
PRESSURE
VOLUME
NEWER MODES
Clinicians Want the Best of All Possible Worlds
Advantages of both pressure and volume ventilation 10487071048707 ldquoYou canrsquot always get what you wantrdquo (Rolling Stones) sohellipget what you need 10487071048707 Whatrsquos new
Basic principles
Trigger ndashmachine amp patient [flow presssure ]
Flow triggerig ndash less work ndashprefered Too sensitive ndash auto triggering Limit variable [ pressure volume ] Cycle variable ndash
volume flow pressure time
TYPES
INVASIVE APRV BIPAP Self adaptive modes Proportional assist ventilation Independent ventilation High frequency ventilation Extracorporeal membrane oxygenation Liquid ventilation NONINVASIVE
NON INVASIVE VENTILATION Negative pressure ventilators (Tank and
Cuirass ventilators) were the only non-invasive methods of assisting ventilation for many years mainly for ventilating large number of victims of Polio during their acute illness
use of NIMV has increased in last
decade in various conditions to avoid complications of intubation
Types
Positive Pressure Ventilation
Negative Pressure Ventilation
Mechanism of Action Improvement in pulmonary mechanics and oxygenation In COPD oxygen therapy often worsens
hypercarbia and respiratory acidosis Augments alveolar ventilation and oxygenation
without raising PaCO2 Partial unloading of respiratory muscles Reduces trans-diaphragmatic pressure pressure
time index of respiratory muscles and diaphragmatic electromyographic activity -
Alteration in breathing pattern with an increase in tidal volume decrease in respiratory rate and increase in minute ventilation
NIMV also overcomes the effect of intrinsic PEEP
Advantages of NIMV Preservation of airway defense mechanism Early ventilatory support an option
Intermittent ventilation possible
Patient can eat drink and communicate
Ease of application and removal
Patient can cooperate with physiotherapy
Contdhellip
Improved patient comfort Reduced need for sedation Avoidance of complications of
endotracheal intubation upper airway trauma sinusitis otitis nosocomial pneumonia
Ventilation outside hospital possible Correction of hypoxaemia without
worsening hypercarbia Ease to teach paramedics and nurses
Disadvantages
Mask uncomfortableclaustrophobic Time consuming for medical and nursing
staff Facial pressure sores Airway not protected No direct access to bronchial tree for
suction if secretions are excessive Less effective
Indications of NIMV
Hypercapnic acute respiratory failure
Acute exacerbation of COPD
Post extubation Weaning difficulties Post surgical respiratory
failure Thoracic wall deformities Cystic fibrosis Status asthmaticus Obesity hypoventilation
Syndrome
Hypoxaemic acute respiratory failure
Cardiogenic pulmonary oedema
Community acquired pneumonia
Post traumatic respiratory failure
ARDS Weaning difficulties Chronic Respiratory
Failure Immunocompromised
Patients
Contraindications
Respiratory arrest Unstable cardiorespiratory status Uncooperative patients -confused agitated Unable to protect airway- impaired swallowing
and cough Facial Oesophageal or gastric surgery Craniofacial traumaburn Anatomic lesions of upper airway Vomiting Impaired conciousness
Relative Contraindications
Extreme anxiety Massive obesity
Copious secretions
Need for continuous or nearly continuous ventilatory assistance
Prerequisites for successful Non-Invasive support
Patient is able to cooperate Patient can control airway and secretions Adequate cough reflex Patient is able to co-ordinate breathing with ventilator Patient can breathe unaided for several minutes Haemodynamically stable Blood pHgt71 and PaCO2 lt92 mmHg Improvement in gas exchange heart rate and
respiratory rate within first two hours Normal functioning gastrointestinal tract
Interface Interfaces are devices that connect ventilator tubing to
the face allowing the entry of pressurized gas to the upper airway
Nasal and oronasal masks and mouth pieces CPAP helmet are currently available interfaces
Masks - made from a non irritant material such as silicon rubber - minimal dead space and a soft inflatable cuff to provide a seal with the skin
Nasal mask - better tolerated but less effective ndash leak Face masks are more useful in acute respiratory failure Nasal masksMouth piece CPAP helmet are used most
often in chronic respiratory failure
Ventilators - conventional
Advantages FiO2 can be set Alarm amp monitoring
back up Back up ventilation Separate insp amp exp
limbs ndash prevent rebreathing
Inspiratory pressure gt 20 cm H2O can be set
Disadvantages Expensive Less flexible
ampportable Leak compensation
not present ndash requires tight interface
NPPV Ventilators
Advantages cheaper flexible ampportable Leak compensation
present ndash does not requires tight interface
Inspiratory pressure of 20 cm H2Ois maximum available
Disadvantages FiO2 cannot be set
Due to leak ndash high oxygen flows
Single limb ndash rebreathing
Modes of Ventilation CPAP It is not a true ventilator mode as it does not actively
assist inspiration CPAP by nasal mask provides pneumatic splint which
holds the upper airway open in patients with nocturnal hypoxaemia due to episodes of obstructive sleep apnoea
CPAP increases FRC and opens collapsed alveoli CPAP reduces left ventricular transmural pressure
therefore increases cardiac output ndash effective for treatment of pulmonary oedema
Pressures are usually limited to 5-12 cm of H2O - higher pressure tends to result in gastric distension
BILEVEL POSITIVE AIRWAY PRESSURE [ BI LEVEL PAP]
Unique flow triggering ampleak compensation Spontaneous mode ndashcycle between IPAP (Up to 30 cm
H2O)amp EPAP (Up to 15 cm of H2O)- PATIENT TRIGGERED PRESSURE SUPPORTED
IPAP = PEEP +PS EPAP = PEEP in PCVSPECIAL MACHINES Have blower unit to compensate air leaks upto 180 L mt Pressure limited back up Adjustable sensitivities maximum inspiratory
time adjustable FiO2 -available
BI LEVEL PAP[contdhellip] INDICATIONS Worsening
hypoventilation hypoxemia
Chronic ventilatory muscle dysfunction
Post intubation difficulty Upper airway
obstruction ndashlaryngeal oedemastrictures
CONTRA INDICATIONS Unstable
Haemodynamics Vomiting Neurologically abnormal Pneumothorax Deteriorating respiratory
parameters
PSV
Non-invasive PSV can be administered with standard critical care ventilator or bilevel portable devices -patient triggeredpressure limited flow cycled ventilation
PSV mode has unique ability to vary inspiratory time breath by breath permitting close matching with the patients spontaneous breathing pattern
Advantages (a) Patient-ventilator synchrony (b) Improved patient comfort(c) Reduced diaphragmatic work
Volume limited ventilation ventilators are usually set in assist-control mode with
high tidal volume (10-15 mlkg) to compensate for air leak
suitable in obesity or chest wall deformity who need high
inflation pressure neuromuscular diseases who need high tidal
volume for ventilation Proportional assist ventilation (PAV)
This is a newer mode of ventilation In this mode ventilator has capacity of responding
rapidly to the patients ventilatory efforts By adjusting the gain on the flow and volume signals
one can select the proportion of breathing work that is to be assisted
Goals of NIMV
Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival
Protocol for Non Invasive Ventilation
Explain to the patient what you are doing and what to expect
Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the
patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort
Connect humidification system
Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG
Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O
Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts
Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks
Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg
Increase FiO2 to improve O2 saturation to 90
Complications and Side effects
AIR LEAK [80 -100]
MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly
over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction
FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension
MAJOR COMPLICATIONS Aspiration pneumonia - lt
5 Hypotension Pneumothorax
CRITERIA FOR FAILURE OF NPPV
MAJOR Respiratory arrest Loss of
consciousness Psychomotor
agitation Haemodynamic
instability Heart rate lt50 bm
MINOR Respiratory rate gt 35
mt pH lt730 Pao2 lt45mmHg
Intubate when one major two minor criteria
INVASIVE VENTILATION
Pressure RegulatedVolume Control [PVRC]
Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled
assistcontrol
Establishes a ldquolearning periodrdquo to determine
patientrsquos compliance which establishes regulation of pressurevolume
Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration
Pressure RegulatedVolume Control (PRVC)
1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume
The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume
Results in breath-to-breath variation of inspiratory pressure
Limitations Only an AC mode and requires a change to
Volume Support for weaning Only guarantees volume distally and not at
patient airway
TV AIRWAY PRESSURE
PROBLEMS
VCV preset fn of mechpropertyof lungs
lung injury
PCV acc to mecha property of lung
preset hypoventilation
volutrauma
PRVC preset lower paw necessary
Benefits of both
Comparison with established modes
Applications of PRVC
ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high
flow rates In whom VT has to be controlled ndashsurfactant
therapy
Benefits
Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to
mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort
BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]
Pressure controlled ventilation allowing spontaneous ventilation
Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest
airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to
ventilator in VCV
BIPAP -SUBDIVISIONS
CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at
lower level APRV ndash BIPAP - spontaneous breathing
at higher level Genuine BIPAP - spontaneous breathing
at both levels CPAP - spontaneous breathing at single
CPAP level
paw
t
Setting up BIPAP
Adjusted with ABG values High low PaCO2 Normal PaO2
VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2
mean airway pressure without altering VTRR
equidirectional alteration of P high P low
ADVANTAGES OF BIPAP
Less sedation Reduced atelectasis Ideal mode in pts with inadequate
spontaneous effort In face of deteriorating gas exchange
we can increase the invasiveness of ventilation without having to change mode
Airway Pressure Release Ventilation
(APRV) Outlined in 1987 Continuous positive airway pressure with
regular brief intermittent releases in airway pressure
The release phase results in alveolar ventilation and removal of carbon dioxide
APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance
It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation
Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance
APRV ndashCONTDhellip
Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation
APRV commences at an elevated baseline pressure and follows with a measured pressure release
During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels
Available on Draumlger and Puritan Bennett ventilators
APRV ndashCONTDhellip
Elevated baseline airway pressure during APRV may produce near complete recruitment
Minimizes low volume lung injury from cyclic recruitment
APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation
Needs a High flow CPAP circuit with release valve
Advantages of APRV Lower peak airway pressures Lower minute ventilation
Decreased adverse effects upon circulatory function
Spontaneous ventilation the entire ventilatory cycle
Decreased need for sedation
Near elimination of neuromuscular blockade Recruitment of alveoli
Indications for APRV ALI or low-compliance lung disease patients with airway disease
CONTRAINDICATIONS
Patients with Increased airway resistance
When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation
The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation
P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus
accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than
40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0
cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure
Settings of APRV
Pressure support ventilation
Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by
specific amount of positive pressure at airway
PS Terminated when insp Flow falls below a minimum trigger volume
Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau
` ADVANTAGES Less WOB low pressure high volume work similar to
spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is
achieved with PS of 5 cm H2O
Volume AssuredPressure Support (VAPS)
Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure
breath continues to guarantee volume - 1048707 PIP and inspiratory time increase
1048707 Guarantees volume on current breath (no previous breath averaging)
1048707 Combines the advantages of pressure and volume ventilation breath to breath
Characteristics of VAPS 1048707 The ventilator continuously measures the flow and
pressure and calculates delivered volume Depending on the actual settings breath may be flow
volume or time cycled 1048707 If the target tidal volume has been delivered
inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set
flow will persist until the desired volume has been reached (volume cycled breath)
1048707 Safety limits include high pressure and maximum inspiratory time1048707
Used in the Management of acute and recovering lung disease
Benefits of VAPS
1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort
Applications of VAPS 1048707 A patient who requires a substantial level of
ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony
1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change
Limitations 1048707 Will only increase pressure not lower pressure
with changing mechanics 1048707 Increases inspiratory time to assure volume
Volume support ventilation
Support mode Has PVRC as back up mode Allows spontaneous if preset MV is
achieved If fails deliver preset TV MV in lowest
possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure
limitlower amp upper MV alarm
Applications of VSV
Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations
in inspiratory pressure support
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
Discovery of the potential for mechanical ventilation to produce ventilator-associated lung injury has resulted in the development of new lung protective strategies
AIM
To enhance respiratory muscle rest Prevent deconditioning atrophy of
muscles Improve gas exchange Prevent lung damage Improve patient synchrony Help in weaning process
Volume Ventilation
Stable consistent tidal volume delivery and minute ventilation which is independent of patientrsquos lung mechanics
BUT Pressures variable and difficult to control Resultant high peak pressure Slow rise to peak pressure distribution of ventilation may not be
optimized Set flow rate may not match patientrsquos demand Increased muscle workload from flow asynchrony may compromise patient comfort gas exchange cardiac function
Volume 500 mlPressure 3500 cm H20
Simple Volume System
Volume 500 ml
Volume 2000 mlPressure 3500 cm H20
Pop
Simple Volume System
PressureControl Ventilation
Benefits 1048707 Variable flow capability for patient demand 1048707 Reduced patient inspiratory muscle workload 1048707 Lower peak inspiratory pressures 1048707 Adjustable inspiratory time 1048707 Rapid filling of the alveoli 1048707 Improved gas distribution VQ matchingand
oxygenation
Disadvantages 1048707 Delivered tidal volume is variable and depends
upon the patientrsquos lung mechanics including changes in airway resistance and lung compliance
1048707 May have adverse effects on volume delivery
PRESSURE
VOLUME
NEWER MODES
Clinicians Want the Best of All Possible Worlds
Advantages of both pressure and volume ventilation 10487071048707 ldquoYou canrsquot always get what you wantrdquo (Rolling Stones) sohellipget what you need 10487071048707 Whatrsquos new
Basic principles
Trigger ndashmachine amp patient [flow presssure ]
Flow triggerig ndash less work ndashprefered Too sensitive ndash auto triggering Limit variable [ pressure volume ] Cycle variable ndash
volume flow pressure time
TYPES
INVASIVE APRV BIPAP Self adaptive modes Proportional assist ventilation Independent ventilation High frequency ventilation Extracorporeal membrane oxygenation Liquid ventilation NONINVASIVE
NON INVASIVE VENTILATION Negative pressure ventilators (Tank and
Cuirass ventilators) were the only non-invasive methods of assisting ventilation for many years mainly for ventilating large number of victims of Polio during their acute illness
use of NIMV has increased in last
decade in various conditions to avoid complications of intubation
Types
Positive Pressure Ventilation
Negative Pressure Ventilation
Mechanism of Action Improvement in pulmonary mechanics and oxygenation In COPD oxygen therapy often worsens
hypercarbia and respiratory acidosis Augments alveolar ventilation and oxygenation
without raising PaCO2 Partial unloading of respiratory muscles Reduces trans-diaphragmatic pressure pressure
time index of respiratory muscles and diaphragmatic electromyographic activity -
Alteration in breathing pattern with an increase in tidal volume decrease in respiratory rate and increase in minute ventilation
NIMV also overcomes the effect of intrinsic PEEP
Advantages of NIMV Preservation of airway defense mechanism Early ventilatory support an option
Intermittent ventilation possible
Patient can eat drink and communicate
Ease of application and removal
Patient can cooperate with physiotherapy
Contdhellip
Improved patient comfort Reduced need for sedation Avoidance of complications of
endotracheal intubation upper airway trauma sinusitis otitis nosocomial pneumonia
Ventilation outside hospital possible Correction of hypoxaemia without
worsening hypercarbia Ease to teach paramedics and nurses
Disadvantages
Mask uncomfortableclaustrophobic Time consuming for medical and nursing
staff Facial pressure sores Airway not protected No direct access to bronchial tree for
suction if secretions are excessive Less effective
Indications of NIMV
Hypercapnic acute respiratory failure
Acute exacerbation of COPD
Post extubation Weaning difficulties Post surgical respiratory
failure Thoracic wall deformities Cystic fibrosis Status asthmaticus Obesity hypoventilation
Syndrome
Hypoxaemic acute respiratory failure
Cardiogenic pulmonary oedema
Community acquired pneumonia
Post traumatic respiratory failure
ARDS Weaning difficulties Chronic Respiratory
Failure Immunocompromised
Patients
Contraindications
Respiratory arrest Unstable cardiorespiratory status Uncooperative patients -confused agitated Unable to protect airway- impaired swallowing
and cough Facial Oesophageal or gastric surgery Craniofacial traumaburn Anatomic lesions of upper airway Vomiting Impaired conciousness
Relative Contraindications
Extreme anxiety Massive obesity
Copious secretions
Need for continuous or nearly continuous ventilatory assistance
Prerequisites for successful Non-Invasive support
Patient is able to cooperate Patient can control airway and secretions Adequate cough reflex Patient is able to co-ordinate breathing with ventilator Patient can breathe unaided for several minutes Haemodynamically stable Blood pHgt71 and PaCO2 lt92 mmHg Improvement in gas exchange heart rate and
respiratory rate within first two hours Normal functioning gastrointestinal tract
Interface Interfaces are devices that connect ventilator tubing to
the face allowing the entry of pressurized gas to the upper airway
Nasal and oronasal masks and mouth pieces CPAP helmet are currently available interfaces
Masks - made from a non irritant material such as silicon rubber - minimal dead space and a soft inflatable cuff to provide a seal with the skin
Nasal mask - better tolerated but less effective ndash leak Face masks are more useful in acute respiratory failure Nasal masksMouth piece CPAP helmet are used most
often in chronic respiratory failure
Ventilators - conventional
Advantages FiO2 can be set Alarm amp monitoring
back up Back up ventilation Separate insp amp exp
limbs ndash prevent rebreathing
Inspiratory pressure gt 20 cm H2O can be set
Disadvantages Expensive Less flexible
ampportable Leak compensation
not present ndash requires tight interface
NPPV Ventilators
Advantages cheaper flexible ampportable Leak compensation
present ndash does not requires tight interface
Inspiratory pressure of 20 cm H2Ois maximum available
Disadvantages FiO2 cannot be set
Due to leak ndash high oxygen flows
Single limb ndash rebreathing
Modes of Ventilation CPAP It is not a true ventilator mode as it does not actively
assist inspiration CPAP by nasal mask provides pneumatic splint which
holds the upper airway open in patients with nocturnal hypoxaemia due to episodes of obstructive sleep apnoea
CPAP increases FRC and opens collapsed alveoli CPAP reduces left ventricular transmural pressure
therefore increases cardiac output ndash effective for treatment of pulmonary oedema
Pressures are usually limited to 5-12 cm of H2O - higher pressure tends to result in gastric distension
BILEVEL POSITIVE AIRWAY PRESSURE [ BI LEVEL PAP]
Unique flow triggering ampleak compensation Spontaneous mode ndashcycle between IPAP (Up to 30 cm
H2O)amp EPAP (Up to 15 cm of H2O)- PATIENT TRIGGERED PRESSURE SUPPORTED
IPAP = PEEP +PS EPAP = PEEP in PCVSPECIAL MACHINES Have blower unit to compensate air leaks upto 180 L mt Pressure limited back up Adjustable sensitivities maximum inspiratory
time adjustable FiO2 -available
BI LEVEL PAP[contdhellip] INDICATIONS Worsening
hypoventilation hypoxemia
Chronic ventilatory muscle dysfunction
Post intubation difficulty Upper airway
obstruction ndashlaryngeal oedemastrictures
CONTRA INDICATIONS Unstable
Haemodynamics Vomiting Neurologically abnormal Pneumothorax Deteriorating respiratory
parameters
PSV
Non-invasive PSV can be administered with standard critical care ventilator or bilevel portable devices -patient triggeredpressure limited flow cycled ventilation
PSV mode has unique ability to vary inspiratory time breath by breath permitting close matching with the patients spontaneous breathing pattern
Advantages (a) Patient-ventilator synchrony (b) Improved patient comfort(c) Reduced diaphragmatic work
Volume limited ventilation ventilators are usually set in assist-control mode with
high tidal volume (10-15 mlkg) to compensate for air leak
suitable in obesity or chest wall deformity who need high
inflation pressure neuromuscular diseases who need high tidal
volume for ventilation Proportional assist ventilation (PAV)
This is a newer mode of ventilation In this mode ventilator has capacity of responding
rapidly to the patients ventilatory efforts By adjusting the gain on the flow and volume signals
one can select the proportion of breathing work that is to be assisted
Goals of NIMV
Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival
Protocol for Non Invasive Ventilation
Explain to the patient what you are doing and what to expect
Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the
patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort
Connect humidification system
Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG
Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O
Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts
Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks
Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg
Increase FiO2 to improve O2 saturation to 90
Complications and Side effects
AIR LEAK [80 -100]
MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly
over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction
FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension
MAJOR COMPLICATIONS Aspiration pneumonia - lt
5 Hypotension Pneumothorax
CRITERIA FOR FAILURE OF NPPV
MAJOR Respiratory arrest Loss of
consciousness Psychomotor
agitation Haemodynamic
instability Heart rate lt50 bm
MINOR Respiratory rate gt 35
mt pH lt730 Pao2 lt45mmHg
Intubate when one major two minor criteria
INVASIVE VENTILATION
Pressure RegulatedVolume Control [PVRC]
Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled
assistcontrol
Establishes a ldquolearning periodrdquo to determine
patientrsquos compliance which establishes regulation of pressurevolume
Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration
Pressure RegulatedVolume Control (PRVC)
1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume
The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume
Results in breath-to-breath variation of inspiratory pressure
Limitations Only an AC mode and requires a change to
Volume Support for weaning Only guarantees volume distally and not at
patient airway
TV AIRWAY PRESSURE
PROBLEMS
VCV preset fn of mechpropertyof lungs
lung injury
PCV acc to mecha property of lung
preset hypoventilation
volutrauma
PRVC preset lower paw necessary
Benefits of both
Comparison with established modes
Applications of PRVC
ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high
flow rates In whom VT has to be controlled ndashsurfactant
therapy
Benefits
Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to
mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort
BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]
Pressure controlled ventilation allowing spontaneous ventilation
Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest
airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to
ventilator in VCV
BIPAP -SUBDIVISIONS
CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at
lower level APRV ndash BIPAP - spontaneous breathing
at higher level Genuine BIPAP - spontaneous breathing
at both levels CPAP - spontaneous breathing at single
CPAP level
paw
t
Setting up BIPAP
Adjusted with ABG values High low PaCO2 Normal PaO2
VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2
mean airway pressure without altering VTRR
equidirectional alteration of P high P low
ADVANTAGES OF BIPAP
Less sedation Reduced atelectasis Ideal mode in pts with inadequate
spontaneous effort In face of deteriorating gas exchange
we can increase the invasiveness of ventilation without having to change mode
Airway Pressure Release Ventilation
(APRV) Outlined in 1987 Continuous positive airway pressure with
regular brief intermittent releases in airway pressure
The release phase results in alveolar ventilation and removal of carbon dioxide
APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance
It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation
Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance
APRV ndashCONTDhellip
Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation
APRV commences at an elevated baseline pressure and follows with a measured pressure release
During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels
Available on Draumlger and Puritan Bennett ventilators
APRV ndashCONTDhellip
Elevated baseline airway pressure during APRV may produce near complete recruitment
Minimizes low volume lung injury from cyclic recruitment
APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation
Needs a High flow CPAP circuit with release valve
Advantages of APRV Lower peak airway pressures Lower minute ventilation
Decreased adverse effects upon circulatory function
Spontaneous ventilation the entire ventilatory cycle
Decreased need for sedation
Near elimination of neuromuscular blockade Recruitment of alveoli
Indications for APRV ALI or low-compliance lung disease patients with airway disease
CONTRAINDICATIONS
Patients with Increased airway resistance
When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation
The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation
P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus
accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than
40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0
cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure
Settings of APRV
Pressure support ventilation
Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by
specific amount of positive pressure at airway
PS Terminated when insp Flow falls below a minimum trigger volume
Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau
` ADVANTAGES Less WOB low pressure high volume work similar to
spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is
achieved with PS of 5 cm H2O
Volume AssuredPressure Support (VAPS)
Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure
breath continues to guarantee volume - 1048707 PIP and inspiratory time increase
1048707 Guarantees volume on current breath (no previous breath averaging)
1048707 Combines the advantages of pressure and volume ventilation breath to breath
Characteristics of VAPS 1048707 The ventilator continuously measures the flow and
pressure and calculates delivered volume Depending on the actual settings breath may be flow
volume or time cycled 1048707 If the target tidal volume has been delivered
inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set
flow will persist until the desired volume has been reached (volume cycled breath)
1048707 Safety limits include high pressure and maximum inspiratory time1048707
Used in the Management of acute and recovering lung disease
Benefits of VAPS
1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort
Applications of VAPS 1048707 A patient who requires a substantial level of
ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony
1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change
Limitations 1048707 Will only increase pressure not lower pressure
with changing mechanics 1048707 Increases inspiratory time to assure volume
Volume support ventilation
Support mode Has PVRC as back up mode Allows spontaneous if preset MV is
achieved If fails deliver preset TV MV in lowest
possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure
limitlower amp upper MV alarm
Applications of VSV
Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations
in inspiratory pressure support
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
AIM
To enhance respiratory muscle rest Prevent deconditioning atrophy of
muscles Improve gas exchange Prevent lung damage Improve patient synchrony Help in weaning process
Volume Ventilation
Stable consistent tidal volume delivery and minute ventilation which is independent of patientrsquos lung mechanics
BUT Pressures variable and difficult to control Resultant high peak pressure Slow rise to peak pressure distribution of ventilation may not be
optimized Set flow rate may not match patientrsquos demand Increased muscle workload from flow asynchrony may compromise patient comfort gas exchange cardiac function
Volume 500 mlPressure 3500 cm H20
Simple Volume System
Volume 500 ml
Volume 2000 mlPressure 3500 cm H20
Pop
Simple Volume System
PressureControl Ventilation
Benefits 1048707 Variable flow capability for patient demand 1048707 Reduced patient inspiratory muscle workload 1048707 Lower peak inspiratory pressures 1048707 Adjustable inspiratory time 1048707 Rapid filling of the alveoli 1048707 Improved gas distribution VQ matchingand
oxygenation
Disadvantages 1048707 Delivered tidal volume is variable and depends
upon the patientrsquos lung mechanics including changes in airway resistance and lung compliance
1048707 May have adverse effects on volume delivery
PRESSURE
VOLUME
NEWER MODES
Clinicians Want the Best of All Possible Worlds
Advantages of both pressure and volume ventilation 10487071048707 ldquoYou canrsquot always get what you wantrdquo (Rolling Stones) sohellipget what you need 10487071048707 Whatrsquos new
Basic principles
Trigger ndashmachine amp patient [flow presssure ]
Flow triggerig ndash less work ndashprefered Too sensitive ndash auto triggering Limit variable [ pressure volume ] Cycle variable ndash
volume flow pressure time
TYPES
INVASIVE APRV BIPAP Self adaptive modes Proportional assist ventilation Independent ventilation High frequency ventilation Extracorporeal membrane oxygenation Liquid ventilation NONINVASIVE
NON INVASIVE VENTILATION Negative pressure ventilators (Tank and
Cuirass ventilators) were the only non-invasive methods of assisting ventilation for many years mainly for ventilating large number of victims of Polio during their acute illness
use of NIMV has increased in last
decade in various conditions to avoid complications of intubation
Types
Positive Pressure Ventilation
Negative Pressure Ventilation
Mechanism of Action Improvement in pulmonary mechanics and oxygenation In COPD oxygen therapy often worsens
hypercarbia and respiratory acidosis Augments alveolar ventilation and oxygenation
without raising PaCO2 Partial unloading of respiratory muscles Reduces trans-diaphragmatic pressure pressure
time index of respiratory muscles and diaphragmatic electromyographic activity -
Alteration in breathing pattern with an increase in tidal volume decrease in respiratory rate and increase in minute ventilation
NIMV also overcomes the effect of intrinsic PEEP
Advantages of NIMV Preservation of airway defense mechanism Early ventilatory support an option
Intermittent ventilation possible
Patient can eat drink and communicate
Ease of application and removal
Patient can cooperate with physiotherapy
Contdhellip
Improved patient comfort Reduced need for sedation Avoidance of complications of
endotracheal intubation upper airway trauma sinusitis otitis nosocomial pneumonia
Ventilation outside hospital possible Correction of hypoxaemia without
worsening hypercarbia Ease to teach paramedics and nurses
Disadvantages
Mask uncomfortableclaustrophobic Time consuming for medical and nursing
staff Facial pressure sores Airway not protected No direct access to bronchial tree for
suction if secretions are excessive Less effective
Indications of NIMV
Hypercapnic acute respiratory failure
Acute exacerbation of COPD
Post extubation Weaning difficulties Post surgical respiratory
failure Thoracic wall deformities Cystic fibrosis Status asthmaticus Obesity hypoventilation
Syndrome
Hypoxaemic acute respiratory failure
Cardiogenic pulmonary oedema
Community acquired pneumonia
Post traumatic respiratory failure
ARDS Weaning difficulties Chronic Respiratory
Failure Immunocompromised
Patients
Contraindications
Respiratory arrest Unstable cardiorespiratory status Uncooperative patients -confused agitated Unable to protect airway- impaired swallowing
and cough Facial Oesophageal or gastric surgery Craniofacial traumaburn Anatomic lesions of upper airway Vomiting Impaired conciousness
Relative Contraindications
Extreme anxiety Massive obesity
Copious secretions
Need for continuous or nearly continuous ventilatory assistance
Prerequisites for successful Non-Invasive support
Patient is able to cooperate Patient can control airway and secretions Adequate cough reflex Patient is able to co-ordinate breathing with ventilator Patient can breathe unaided for several minutes Haemodynamically stable Blood pHgt71 and PaCO2 lt92 mmHg Improvement in gas exchange heart rate and
respiratory rate within first two hours Normal functioning gastrointestinal tract
Interface Interfaces are devices that connect ventilator tubing to
the face allowing the entry of pressurized gas to the upper airway
Nasal and oronasal masks and mouth pieces CPAP helmet are currently available interfaces
Masks - made from a non irritant material such as silicon rubber - minimal dead space and a soft inflatable cuff to provide a seal with the skin
Nasal mask - better tolerated but less effective ndash leak Face masks are more useful in acute respiratory failure Nasal masksMouth piece CPAP helmet are used most
often in chronic respiratory failure
Ventilators - conventional
Advantages FiO2 can be set Alarm amp monitoring
back up Back up ventilation Separate insp amp exp
limbs ndash prevent rebreathing
Inspiratory pressure gt 20 cm H2O can be set
Disadvantages Expensive Less flexible
ampportable Leak compensation
not present ndash requires tight interface
NPPV Ventilators
Advantages cheaper flexible ampportable Leak compensation
present ndash does not requires tight interface
Inspiratory pressure of 20 cm H2Ois maximum available
Disadvantages FiO2 cannot be set
Due to leak ndash high oxygen flows
Single limb ndash rebreathing
Modes of Ventilation CPAP It is not a true ventilator mode as it does not actively
assist inspiration CPAP by nasal mask provides pneumatic splint which
holds the upper airway open in patients with nocturnal hypoxaemia due to episodes of obstructive sleep apnoea
CPAP increases FRC and opens collapsed alveoli CPAP reduces left ventricular transmural pressure
therefore increases cardiac output ndash effective for treatment of pulmonary oedema
Pressures are usually limited to 5-12 cm of H2O - higher pressure tends to result in gastric distension
BILEVEL POSITIVE AIRWAY PRESSURE [ BI LEVEL PAP]
Unique flow triggering ampleak compensation Spontaneous mode ndashcycle between IPAP (Up to 30 cm
H2O)amp EPAP (Up to 15 cm of H2O)- PATIENT TRIGGERED PRESSURE SUPPORTED
IPAP = PEEP +PS EPAP = PEEP in PCVSPECIAL MACHINES Have blower unit to compensate air leaks upto 180 L mt Pressure limited back up Adjustable sensitivities maximum inspiratory
time adjustable FiO2 -available
BI LEVEL PAP[contdhellip] INDICATIONS Worsening
hypoventilation hypoxemia
Chronic ventilatory muscle dysfunction
Post intubation difficulty Upper airway
obstruction ndashlaryngeal oedemastrictures
CONTRA INDICATIONS Unstable
Haemodynamics Vomiting Neurologically abnormal Pneumothorax Deteriorating respiratory
parameters
PSV
Non-invasive PSV can be administered with standard critical care ventilator or bilevel portable devices -patient triggeredpressure limited flow cycled ventilation
PSV mode has unique ability to vary inspiratory time breath by breath permitting close matching with the patients spontaneous breathing pattern
Advantages (a) Patient-ventilator synchrony (b) Improved patient comfort(c) Reduced diaphragmatic work
Volume limited ventilation ventilators are usually set in assist-control mode with
high tidal volume (10-15 mlkg) to compensate for air leak
suitable in obesity or chest wall deformity who need high
inflation pressure neuromuscular diseases who need high tidal
volume for ventilation Proportional assist ventilation (PAV)
This is a newer mode of ventilation In this mode ventilator has capacity of responding
rapidly to the patients ventilatory efforts By adjusting the gain on the flow and volume signals
one can select the proportion of breathing work that is to be assisted
Goals of NIMV
Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival
Protocol for Non Invasive Ventilation
Explain to the patient what you are doing and what to expect
Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the
patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort
Connect humidification system
Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG
Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O
Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts
Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks
Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg
Increase FiO2 to improve O2 saturation to 90
Complications and Side effects
AIR LEAK [80 -100]
MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly
over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction
FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension
MAJOR COMPLICATIONS Aspiration pneumonia - lt
5 Hypotension Pneumothorax
CRITERIA FOR FAILURE OF NPPV
MAJOR Respiratory arrest Loss of
consciousness Psychomotor
agitation Haemodynamic
instability Heart rate lt50 bm
MINOR Respiratory rate gt 35
mt pH lt730 Pao2 lt45mmHg
Intubate when one major two minor criteria
INVASIVE VENTILATION
Pressure RegulatedVolume Control [PVRC]
Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled
assistcontrol
Establishes a ldquolearning periodrdquo to determine
patientrsquos compliance which establishes regulation of pressurevolume
Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration
Pressure RegulatedVolume Control (PRVC)
1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume
The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume
Results in breath-to-breath variation of inspiratory pressure
Limitations Only an AC mode and requires a change to
Volume Support for weaning Only guarantees volume distally and not at
patient airway
TV AIRWAY PRESSURE
PROBLEMS
VCV preset fn of mechpropertyof lungs
lung injury
PCV acc to mecha property of lung
preset hypoventilation
volutrauma
PRVC preset lower paw necessary
Benefits of both
Comparison with established modes
Applications of PRVC
ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high
flow rates In whom VT has to be controlled ndashsurfactant
therapy
Benefits
Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to
mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort
BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]
Pressure controlled ventilation allowing spontaneous ventilation
Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest
airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to
ventilator in VCV
BIPAP -SUBDIVISIONS
CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at
lower level APRV ndash BIPAP - spontaneous breathing
at higher level Genuine BIPAP - spontaneous breathing
at both levels CPAP - spontaneous breathing at single
CPAP level
paw
t
Setting up BIPAP
Adjusted with ABG values High low PaCO2 Normal PaO2
VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2
mean airway pressure without altering VTRR
equidirectional alteration of P high P low
ADVANTAGES OF BIPAP
Less sedation Reduced atelectasis Ideal mode in pts with inadequate
spontaneous effort In face of deteriorating gas exchange
we can increase the invasiveness of ventilation without having to change mode
Airway Pressure Release Ventilation
(APRV) Outlined in 1987 Continuous positive airway pressure with
regular brief intermittent releases in airway pressure
The release phase results in alveolar ventilation and removal of carbon dioxide
APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance
It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation
Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance
APRV ndashCONTDhellip
Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation
APRV commences at an elevated baseline pressure and follows with a measured pressure release
During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels
Available on Draumlger and Puritan Bennett ventilators
APRV ndashCONTDhellip
Elevated baseline airway pressure during APRV may produce near complete recruitment
Minimizes low volume lung injury from cyclic recruitment
APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation
Needs a High flow CPAP circuit with release valve
Advantages of APRV Lower peak airway pressures Lower minute ventilation
Decreased adverse effects upon circulatory function
Spontaneous ventilation the entire ventilatory cycle
Decreased need for sedation
Near elimination of neuromuscular blockade Recruitment of alveoli
Indications for APRV ALI or low-compliance lung disease patients with airway disease
CONTRAINDICATIONS
Patients with Increased airway resistance
When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation
The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation
P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus
accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than
40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0
cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure
Settings of APRV
Pressure support ventilation
Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by
specific amount of positive pressure at airway
PS Terminated when insp Flow falls below a minimum trigger volume
Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau
` ADVANTAGES Less WOB low pressure high volume work similar to
spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is
achieved with PS of 5 cm H2O
Volume AssuredPressure Support (VAPS)
Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure
breath continues to guarantee volume - 1048707 PIP and inspiratory time increase
1048707 Guarantees volume on current breath (no previous breath averaging)
1048707 Combines the advantages of pressure and volume ventilation breath to breath
Characteristics of VAPS 1048707 The ventilator continuously measures the flow and
pressure and calculates delivered volume Depending on the actual settings breath may be flow
volume or time cycled 1048707 If the target tidal volume has been delivered
inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set
flow will persist until the desired volume has been reached (volume cycled breath)
1048707 Safety limits include high pressure and maximum inspiratory time1048707
Used in the Management of acute and recovering lung disease
Benefits of VAPS
1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort
Applications of VAPS 1048707 A patient who requires a substantial level of
ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony
1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change
Limitations 1048707 Will only increase pressure not lower pressure
with changing mechanics 1048707 Increases inspiratory time to assure volume
Volume support ventilation
Support mode Has PVRC as back up mode Allows spontaneous if preset MV is
achieved If fails deliver preset TV MV in lowest
possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure
limitlower amp upper MV alarm
Applications of VSV
Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations
in inspiratory pressure support
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
Volume Ventilation
Stable consistent tidal volume delivery and minute ventilation which is independent of patientrsquos lung mechanics
BUT Pressures variable and difficult to control Resultant high peak pressure Slow rise to peak pressure distribution of ventilation may not be
optimized Set flow rate may not match patientrsquos demand Increased muscle workload from flow asynchrony may compromise patient comfort gas exchange cardiac function
Volume 500 mlPressure 3500 cm H20
Simple Volume System
Volume 500 ml
Volume 2000 mlPressure 3500 cm H20
Pop
Simple Volume System
PressureControl Ventilation
Benefits 1048707 Variable flow capability for patient demand 1048707 Reduced patient inspiratory muscle workload 1048707 Lower peak inspiratory pressures 1048707 Adjustable inspiratory time 1048707 Rapid filling of the alveoli 1048707 Improved gas distribution VQ matchingand
oxygenation
Disadvantages 1048707 Delivered tidal volume is variable and depends
upon the patientrsquos lung mechanics including changes in airway resistance and lung compliance
1048707 May have adverse effects on volume delivery
PRESSURE
VOLUME
NEWER MODES
Clinicians Want the Best of All Possible Worlds
Advantages of both pressure and volume ventilation 10487071048707 ldquoYou canrsquot always get what you wantrdquo (Rolling Stones) sohellipget what you need 10487071048707 Whatrsquos new
Basic principles
Trigger ndashmachine amp patient [flow presssure ]
Flow triggerig ndash less work ndashprefered Too sensitive ndash auto triggering Limit variable [ pressure volume ] Cycle variable ndash
volume flow pressure time
TYPES
INVASIVE APRV BIPAP Self adaptive modes Proportional assist ventilation Independent ventilation High frequency ventilation Extracorporeal membrane oxygenation Liquid ventilation NONINVASIVE
NON INVASIVE VENTILATION Negative pressure ventilators (Tank and
Cuirass ventilators) were the only non-invasive methods of assisting ventilation for many years mainly for ventilating large number of victims of Polio during their acute illness
use of NIMV has increased in last
decade in various conditions to avoid complications of intubation
Types
Positive Pressure Ventilation
Negative Pressure Ventilation
Mechanism of Action Improvement in pulmonary mechanics and oxygenation In COPD oxygen therapy often worsens
hypercarbia and respiratory acidosis Augments alveolar ventilation and oxygenation
without raising PaCO2 Partial unloading of respiratory muscles Reduces trans-diaphragmatic pressure pressure
time index of respiratory muscles and diaphragmatic electromyographic activity -
Alteration in breathing pattern with an increase in tidal volume decrease in respiratory rate and increase in minute ventilation
NIMV also overcomes the effect of intrinsic PEEP
Advantages of NIMV Preservation of airway defense mechanism Early ventilatory support an option
Intermittent ventilation possible
Patient can eat drink and communicate
Ease of application and removal
Patient can cooperate with physiotherapy
Contdhellip
Improved patient comfort Reduced need for sedation Avoidance of complications of
endotracheal intubation upper airway trauma sinusitis otitis nosocomial pneumonia
Ventilation outside hospital possible Correction of hypoxaemia without
worsening hypercarbia Ease to teach paramedics and nurses
Disadvantages
Mask uncomfortableclaustrophobic Time consuming for medical and nursing
staff Facial pressure sores Airway not protected No direct access to bronchial tree for
suction if secretions are excessive Less effective
Indications of NIMV
Hypercapnic acute respiratory failure
Acute exacerbation of COPD
Post extubation Weaning difficulties Post surgical respiratory
failure Thoracic wall deformities Cystic fibrosis Status asthmaticus Obesity hypoventilation
Syndrome
Hypoxaemic acute respiratory failure
Cardiogenic pulmonary oedema
Community acquired pneumonia
Post traumatic respiratory failure
ARDS Weaning difficulties Chronic Respiratory
Failure Immunocompromised
Patients
Contraindications
Respiratory arrest Unstable cardiorespiratory status Uncooperative patients -confused agitated Unable to protect airway- impaired swallowing
and cough Facial Oesophageal or gastric surgery Craniofacial traumaburn Anatomic lesions of upper airway Vomiting Impaired conciousness
Relative Contraindications
Extreme anxiety Massive obesity
Copious secretions
Need for continuous or nearly continuous ventilatory assistance
Prerequisites for successful Non-Invasive support
Patient is able to cooperate Patient can control airway and secretions Adequate cough reflex Patient is able to co-ordinate breathing with ventilator Patient can breathe unaided for several minutes Haemodynamically stable Blood pHgt71 and PaCO2 lt92 mmHg Improvement in gas exchange heart rate and
respiratory rate within first two hours Normal functioning gastrointestinal tract
Interface Interfaces are devices that connect ventilator tubing to
the face allowing the entry of pressurized gas to the upper airway
Nasal and oronasal masks and mouth pieces CPAP helmet are currently available interfaces
Masks - made from a non irritant material such as silicon rubber - minimal dead space and a soft inflatable cuff to provide a seal with the skin
Nasal mask - better tolerated but less effective ndash leak Face masks are more useful in acute respiratory failure Nasal masksMouth piece CPAP helmet are used most
often in chronic respiratory failure
Ventilators - conventional
Advantages FiO2 can be set Alarm amp monitoring
back up Back up ventilation Separate insp amp exp
limbs ndash prevent rebreathing
Inspiratory pressure gt 20 cm H2O can be set
Disadvantages Expensive Less flexible
ampportable Leak compensation
not present ndash requires tight interface
NPPV Ventilators
Advantages cheaper flexible ampportable Leak compensation
present ndash does not requires tight interface
Inspiratory pressure of 20 cm H2Ois maximum available
Disadvantages FiO2 cannot be set
Due to leak ndash high oxygen flows
Single limb ndash rebreathing
Modes of Ventilation CPAP It is not a true ventilator mode as it does not actively
assist inspiration CPAP by nasal mask provides pneumatic splint which
holds the upper airway open in patients with nocturnal hypoxaemia due to episodes of obstructive sleep apnoea
CPAP increases FRC and opens collapsed alveoli CPAP reduces left ventricular transmural pressure
therefore increases cardiac output ndash effective for treatment of pulmonary oedema
Pressures are usually limited to 5-12 cm of H2O - higher pressure tends to result in gastric distension
BILEVEL POSITIVE AIRWAY PRESSURE [ BI LEVEL PAP]
Unique flow triggering ampleak compensation Spontaneous mode ndashcycle between IPAP (Up to 30 cm
H2O)amp EPAP (Up to 15 cm of H2O)- PATIENT TRIGGERED PRESSURE SUPPORTED
IPAP = PEEP +PS EPAP = PEEP in PCVSPECIAL MACHINES Have blower unit to compensate air leaks upto 180 L mt Pressure limited back up Adjustable sensitivities maximum inspiratory
time adjustable FiO2 -available
BI LEVEL PAP[contdhellip] INDICATIONS Worsening
hypoventilation hypoxemia
Chronic ventilatory muscle dysfunction
Post intubation difficulty Upper airway
obstruction ndashlaryngeal oedemastrictures
CONTRA INDICATIONS Unstable
Haemodynamics Vomiting Neurologically abnormal Pneumothorax Deteriorating respiratory
parameters
PSV
Non-invasive PSV can be administered with standard critical care ventilator or bilevel portable devices -patient triggeredpressure limited flow cycled ventilation
PSV mode has unique ability to vary inspiratory time breath by breath permitting close matching with the patients spontaneous breathing pattern
Advantages (a) Patient-ventilator synchrony (b) Improved patient comfort(c) Reduced diaphragmatic work
Volume limited ventilation ventilators are usually set in assist-control mode with
high tidal volume (10-15 mlkg) to compensate for air leak
suitable in obesity or chest wall deformity who need high
inflation pressure neuromuscular diseases who need high tidal
volume for ventilation Proportional assist ventilation (PAV)
This is a newer mode of ventilation In this mode ventilator has capacity of responding
rapidly to the patients ventilatory efforts By adjusting the gain on the flow and volume signals
one can select the proportion of breathing work that is to be assisted
Goals of NIMV
Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival
Protocol for Non Invasive Ventilation
Explain to the patient what you are doing and what to expect
Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the
patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort
Connect humidification system
Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG
Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O
Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts
Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks
Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg
Increase FiO2 to improve O2 saturation to 90
Complications and Side effects
AIR LEAK [80 -100]
MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly
over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction
FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension
MAJOR COMPLICATIONS Aspiration pneumonia - lt
5 Hypotension Pneumothorax
CRITERIA FOR FAILURE OF NPPV
MAJOR Respiratory arrest Loss of
consciousness Psychomotor
agitation Haemodynamic
instability Heart rate lt50 bm
MINOR Respiratory rate gt 35
mt pH lt730 Pao2 lt45mmHg
Intubate when one major two minor criteria
INVASIVE VENTILATION
Pressure RegulatedVolume Control [PVRC]
Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled
assistcontrol
Establishes a ldquolearning periodrdquo to determine
patientrsquos compliance which establishes regulation of pressurevolume
Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration
Pressure RegulatedVolume Control (PRVC)
1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume
The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume
Results in breath-to-breath variation of inspiratory pressure
Limitations Only an AC mode and requires a change to
Volume Support for weaning Only guarantees volume distally and not at
patient airway
TV AIRWAY PRESSURE
PROBLEMS
VCV preset fn of mechpropertyof lungs
lung injury
PCV acc to mecha property of lung
preset hypoventilation
volutrauma
PRVC preset lower paw necessary
Benefits of both
Comparison with established modes
Applications of PRVC
ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high
flow rates In whom VT has to be controlled ndashsurfactant
therapy
Benefits
Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to
mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort
BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]
Pressure controlled ventilation allowing spontaneous ventilation
Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest
airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to
ventilator in VCV
BIPAP -SUBDIVISIONS
CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at
lower level APRV ndash BIPAP - spontaneous breathing
at higher level Genuine BIPAP - spontaneous breathing
at both levels CPAP - spontaneous breathing at single
CPAP level
paw
t
Setting up BIPAP
Adjusted with ABG values High low PaCO2 Normal PaO2
VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2
mean airway pressure without altering VTRR
equidirectional alteration of P high P low
ADVANTAGES OF BIPAP
Less sedation Reduced atelectasis Ideal mode in pts with inadequate
spontaneous effort In face of deteriorating gas exchange
we can increase the invasiveness of ventilation without having to change mode
Airway Pressure Release Ventilation
(APRV) Outlined in 1987 Continuous positive airway pressure with
regular brief intermittent releases in airway pressure
The release phase results in alveolar ventilation and removal of carbon dioxide
APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance
It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation
Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance
APRV ndashCONTDhellip
Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation
APRV commences at an elevated baseline pressure and follows with a measured pressure release
During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels
Available on Draumlger and Puritan Bennett ventilators
APRV ndashCONTDhellip
Elevated baseline airway pressure during APRV may produce near complete recruitment
Minimizes low volume lung injury from cyclic recruitment
APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation
Needs a High flow CPAP circuit with release valve
Advantages of APRV Lower peak airway pressures Lower minute ventilation
Decreased adverse effects upon circulatory function
Spontaneous ventilation the entire ventilatory cycle
Decreased need for sedation
Near elimination of neuromuscular blockade Recruitment of alveoli
Indications for APRV ALI or low-compliance lung disease patients with airway disease
CONTRAINDICATIONS
Patients with Increased airway resistance
When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation
The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation
P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus
accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than
40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0
cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure
Settings of APRV
Pressure support ventilation
Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by
specific amount of positive pressure at airway
PS Terminated when insp Flow falls below a minimum trigger volume
Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau
` ADVANTAGES Less WOB low pressure high volume work similar to
spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is
achieved with PS of 5 cm H2O
Volume AssuredPressure Support (VAPS)
Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure
breath continues to guarantee volume - 1048707 PIP and inspiratory time increase
1048707 Guarantees volume on current breath (no previous breath averaging)
1048707 Combines the advantages of pressure and volume ventilation breath to breath
Characteristics of VAPS 1048707 The ventilator continuously measures the flow and
pressure and calculates delivered volume Depending on the actual settings breath may be flow
volume or time cycled 1048707 If the target tidal volume has been delivered
inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set
flow will persist until the desired volume has been reached (volume cycled breath)
1048707 Safety limits include high pressure and maximum inspiratory time1048707
Used in the Management of acute and recovering lung disease
Benefits of VAPS
1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort
Applications of VAPS 1048707 A patient who requires a substantial level of
ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony
1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change
Limitations 1048707 Will only increase pressure not lower pressure
with changing mechanics 1048707 Increases inspiratory time to assure volume
Volume support ventilation
Support mode Has PVRC as back up mode Allows spontaneous if preset MV is
achieved If fails deliver preset TV MV in lowest
possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure
limitlower amp upper MV alarm
Applications of VSV
Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations
in inspiratory pressure support
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
Volume 500 mlPressure 3500 cm H20
Simple Volume System
Volume 500 ml
Volume 2000 mlPressure 3500 cm H20
Pop
Simple Volume System
PressureControl Ventilation
Benefits 1048707 Variable flow capability for patient demand 1048707 Reduced patient inspiratory muscle workload 1048707 Lower peak inspiratory pressures 1048707 Adjustable inspiratory time 1048707 Rapid filling of the alveoli 1048707 Improved gas distribution VQ matchingand
oxygenation
Disadvantages 1048707 Delivered tidal volume is variable and depends
upon the patientrsquos lung mechanics including changes in airway resistance and lung compliance
1048707 May have adverse effects on volume delivery
PRESSURE
VOLUME
NEWER MODES
Clinicians Want the Best of All Possible Worlds
Advantages of both pressure and volume ventilation 10487071048707 ldquoYou canrsquot always get what you wantrdquo (Rolling Stones) sohellipget what you need 10487071048707 Whatrsquos new
Basic principles
Trigger ndashmachine amp patient [flow presssure ]
Flow triggerig ndash less work ndashprefered Too sensitive ndash auto triggering Limit variable [ pressure volume ] Cycle variable ndash
volume flow pressure time
TYPES
INVASIVE APRV BIPAP Self adaptive modes Proportional assist ventilation Independent ventilation High frequency ventilation Extracorporeal membrane oxygenation Liquid ventilation NONINVASIVE
NON INVASIVE VENTILATION Negative pressure ventilators (Tank and
Cuirass ventilators) were the only non-invasive methods of assisting ventilation for many years mainly for ventilating large number of victims of Polio during their acute illness
use of NIMV has increased in last
decade in various conditions to avoid complications of intubation
Types
Positive Pressure Ventilation
Negative Pressure Ventilation
Mechanism of Action Improvement in pulmonary mechanics and oxygenation In COPD oxygen therapy often worsens
hypercarbia and respiratory acidosis Augments alveolar ventilation and oxygenation
without raising PaCO2 Partial unloading of respiratory muscles Reduces trans-diaphragmatic pressure pressure
time index of respiratory muscles and diaphragmatic electromyographic activity -
Alteration in breathing pattern with an increase in tidal volume decrease in respiratory rate and increase in minute ventilation
NIMV also overcomes the effect of intrinsic PEEP
Advantages of NIMV Preservation of airway defense mechanism Early ventilatory support an option
Intermittent ventilation possible
Patient can eat drink and communicate
Ease of application and removal
Patient can cooperate with physiotherapy
Contdhellip
Improved patient comfort Reduced need for sedation Avoidance of complications of
endotracheal intubation upper airway trauma sinusitis otitis nosocomial pneumonia
Ventilation outside hospital possible Correction of hypoxaemia without
worsening hypercarbia Ease to teach paramedics and nurses
Disadvantages
Mask uncomfortableclaustrophobic Time consuming for medical and nursing
staff Facial pressure sores Airway not protected No direct access to bronchial tree for
suction if secretions are excessive Less effective
Indications of NIMV
Hypercapnic acute respiratory failure
Acute exacerbation of COPD
Post extubation Weaning difficulties Post surgical respiratory
failure Thoracic wall deformities Cystic fibrosis Status asthmaticus Obesity hypoventilation
Syndrome
Hypoxaemic acute respiratory failure
Cardiogenic pulmonary oedema
Community acquired pneumonia
Post traumatic respiratory failure
ARDS Weaning difficulties Chronic Respiratory
Failure Immunocompromised
Patients
Contraindications
Respiratory arrest Unstable cardiorespiratory status Uncooperative patients -confused agitated Unable to protect airway- impaired swallowing
and cough Facial Oesophageal or gastric surgery Craniofacial traumaburn Anatomic lesions of upper airway Vomiting Impaired conciousness
Relative Contraindications
Extreme anxiety Massive obesity
Copious secretions
Need for continuous or nearly continuous ventilatory assistance
Prerequisites for successful Non-Invasive support
Patient is able to cooperate Patient can control airway and secretions Adequate cough reflex Patient is able to co-ordinate breathing with ventilator Patient can breathe unaided for several minutes Haemodynamically stable Blood pHgt71 and PaCO2 lt92 mmHg Improvement in gas exchange heart rate and
respiratory rate within first two hours Normal functioning gastrointestinal tract
Interface Interfaces are devices that connect ventilator tubing to
the face allowing the entry of pressurized gas to the upper airway
Nasal and oronasal masks and mouth pieces CPAP helmet are currently available interfaces
Masks - made from a non irritant material such as silicon rubber - minimal dead space and a soft inflatable cuff to provide a seal with the skin
Nasal mask - better tolerated but less effective ndash leak Face masks are more useful in acute respiratory failure Nasal masksMouth piece CPAP helmet are used most
often in chronic respiratory failure
Ventilators - conventional
Advantages FiO2 can be set Alarm amp monitoring
back up Back up ventilation Separate insp amp exp
limbs ndash prevent rebreathing
Inspiratory pressure gt 20 cm H2O can be set
Disadvantages Expensive Less flexible
ampportable Leak compensation
not present ndash requires tight interface
NPPV Ventilators
Advantages cheaper flexible ampportable Leak compensation
present ndash does not requires tight interface
Inspiratory pressure of 20 cm H2Ois maximum available
Disadvantages FiO2 cannot be set
Due to leak ndash high oxygen flows
Single limb ndash rebreathing
Modes of Ventilation CPAP It is not a true ventilator mode as it does not actively
assist inspiration CPAP by nasal mask provides pneumatic splint which
holds the upper airway open in patients with nocturnal hypoxaemia due to episodes of obstructive sleep apnoea
CPAP increases FRC and opens collapsed alveoli CPAP reduces left ventricular transmural pressure
therefore increases cardiac output ndash effective for treatment of pulmonary oedema
Pressures are usually limited to 5-12 cm of H2O - higher pressure tends to result in gastric distension
BILEVEL POSITIVE AIRWAY PRESSURE [ BI LEVEL PAP]
Unique flow triggering ampleak compensation Spontaneous mode ndashcycle between IPAP (Up to 30 cm
H2O)amp EPAP (Up to 15 cm of H2O)- PATIENT TRIGGERED PRESSURE SUPPORTED
IPAP = PEEP +PS EPAP = PEEP in PCVSPECIAL MACHINES Have blower unit to compensate air leaks upto 180 L mt Pressure limited back up Adjustable sensitivities maximum inspiratory
time adjustable FiO2 -available
BI LEVEL PAP[contdhellip] INDICATIONS Worsening
hypoventilation hypoxemia
Chronic ventilatory muscle dysfunction
Post intubation difficulty Upper airway
obstruction ndashlaryngeal oedemastrictures
CONTRA INDICATIONS Unstable
Haemodynamics Vomiting Neurologically abnormal Pneumothorax Deteriorating respiratory
parameters
PSV
Non-invasive PSV can be administered with standard critical care ventilator or bilevel portable devices -patient triggeredpressure limited flow cycled ventilation
PSV mode has unique ability to vary inspiratory time breath by breath permitting close matching with the patients spontaneous breathing pattern
Advantages (a) Patient-ventilator synchrony (b) Improved patient comfort(c) Reduced diaphragmatic work
Volume limited ventilation ventilators are usually set in assist-control mode with
high tidal volume (10-15 mlkg) to compensate for air leak
suitable in obesity or chest wall deformity who need high
inflation pressure neuromuscular diseases who need high tidal
volume for ventilation Proportional assist ventilation (PAV)
This is a newer mode of ventilation In this mode ventilator has capacity of responding
rapidly to the patients ventilatory efforts By adjusting the gain on the flow and volume signals
one can select the proportion of breathing work that is to be assisted
Goals of NIMV
Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival
Protocol for Non Invasive Ventilation
Explain to the patient what you are doing and what to expect
Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the
patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort
Connect humidification system
Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG
Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O
Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts
Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks
Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg
Increase FiO2 to improve O2 saturation to 90
Complications and Side effects
AIR LEAK [80 -100]
MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly
over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction
FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension
MAJOR COMPLICATIONS Aspiration pneumonia - lt
5 Hypotension Pneumothorax
CRITERIA FOR FAILURE OF NPPV
MAJOR Respiratory arrest Loss of
consciousness Psychomotor
agitation Haemodynamic
instability Heart rate lt50 bm
MINOR Respiratory rate gt 35
mt pH lt730 Pao2 lt45mmHg
Intubate when one major two minor criteria
INVASIVE VENTILATION
Pressure RegulatedVolume Control [PVRC]
Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled
assistcontrol
Establishes a ldquolearning periodrdquo to determine
patientrsquos compliance which establishes regulation of pressurevolume
Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration
Pressure RegulatedVolume Control (PRVC)
1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume
The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume
Results in breath-to-breath variation of inspiratory pressure
Limitations Only an AC mode and requires a change to
Volume Support for weaning Only guarantees volume distally and not at
patient airway
TV AIRWAY PRESSURE
PROBLEMS
VCV preset fn of mechpropertyof lungs
lung injury
PCV acc to mecha property of lung
preset hypoventilation
volutrauma
PRVC preset lower paw necessary
Benefits of both
Comparison with established modes
Applications of PRVC
ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high
flow rates In whom VT has to be controlled ndashsurfactant
therapy
Benefits
Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to
mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort
BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]
Pressure controlled ventilation allowing spontaneous ventilation
Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest
airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to
ventilator in VCV
BIPAP -SUBDIVISIONS
CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at
lower level APRV ndash BIPAP - spontaneous breathing
at higher level Genuine BIPAP - spontaneous breathing
at both levels CPAP - spontaneous breathing at single
CPAP level
paw
t
Setting up BIPAP
Adjusted with ABG values High low PaCO2 Normal PaO2
VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2
mean airway pressure without altering VTRR
equidirectional alteration of P high P low
ADVANTAGES OF BIPAP
Less sedation Reduced atelectasis Ideal mode in pts with inadequate
spontaneous effort In face of deteriorating gas exchange
we can increase the invasiveness of ventilation without having to change mode
Airway Pressure Release Ventilation
(APRV) Outlined in 1987 Continuous positive airway pressure with
regular brief intermittent releases in airway pressure
The release phase results in alveolar ventilation and removal of carbon dioxide
APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance
It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation
Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance
APRV ndashCONTDhellip
Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation
APRV commences at an elevated baseline pressure and follows with a measured pressure release
During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels
Available on Draumlger and Puritan Bennett ventilators
APRV ndashCONTDhellip
Elevated baseline airway pressure during APRV may produce near complete recruitment
Minimizes low volume lung injury from cyclic recruitment
APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation
Needs a High flow CPAP circuit with release valve
Advantages of APRV Lower peak airway pressures Lower minute ventilation
Decreased adverse effects upon circulatory function
Spontaneous ventilation the entire ventilatory cycle
Decreased need for sedation
Near elimination of neuromuscular blockade Recruitment of alveoli
Indications for APRV ALI or low-compliance lung disease patients with airway disease
CONTRAINDICATIONS
Patients with Increased airway resistance
When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation
The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation
P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus
accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than
40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0
cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure
Settings of APRV
Pressure support ventilation
Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by
specific amount of positive pressure at airway
PS Terminated when insp Flow falls below a minimum trigger volume
Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau
` ADVANTAGES Less WOB low pressure high volume work similar to
spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is
achieved with PS of 5 cm H2O
Volume AssuredPressure Support (VAPS)
Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure
breath continues to guarantee volume - 1048707 PIP and inspiratory time increase
1048707 Guarantees volume on current breath (no previous breath averaging)
1048707 Combines the advantages of pressure and volume ventilation breath to breath
Characteristics of VAPS 1048707 The ventilator continuously measures the flow and
pressure and calculates delivered volume Depending on the actual settings breath may be flow
volume or time cycled 1048707 If the target tidal volume has been delivered
inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set
flow will persist until the desired volume has been reached (volume cycled breath)
1048707 Safety limits include high pressure and maximum inspiratory time1048707
Used in the Management of acute and recovering lung disease
Benefits of VAPS
1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort
Applications of VAPS 1048707 A patient who requires a substantial level of
ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony
1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change
Limitations 1048707 Will only increase pressure not lower pressure
with changing mechanics 1048707 Increases inspiratory time to assure volume
Volume support ventilation
Support mode Has PVRC as back up mode Allows spontaneous if preset MV is
achieved If fails deliver preset TV MV in lowest
possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure
limitlower amp upper MV alarm
Applications of VSV
Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations
in inspiratory pressure support
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
Volume 2000 mlPressure 3500 cm H20
Pop
Simple Volume System
PressureControl Ventilation
Benefits 1048707 Variable flow capability for patient demand 1048707 Reduced patient inspiratory muscle workload 1048707 Lower peak inspiratory pressures 1048707 Adjustable inspiratory time 1048707 Rapid filling of the alveoli 1048707 Improved gas distribution VQ matchingand
oxygenation
Disadvantages 1048707 Delivered tidal volume is variable and depends
upon the patientrsquos lung mechanics including changes in airway resistance and lung compliance
1048707 May have adverse effects on volume delivery
PRESSURE
VOLUME
NEWER MODES
Clinicians Want the Best of All Possible Worlds
Advantages of both pressure and volume ventilation 10487071048707 ldquoYou canrsquot always get what you wantrdquo (Rolling Stones) sohellipget what you need 10487071048707 Whatrsquos new
Basic principles
Trigger ndashmachine amp patient [flow presssure ]
Flow triggerig ndash less work ndashprefered Too sensitive ndash auto triggering Limit variable [ pressure volume ] Cycle variable ndash
volume flow pressure time
TYPES
INVASIVE APRV BIPAP Self adaptive modes Proportional assist ventilation Independent ventilation High frequency ventilation Extracorporeal membrane oxygenation Liquid ventilation NONINVASIVE
NON INVASIVE VENTILATION Negative pressure ventilators (Tank and
Cuirass ventilators) were the only non-invasive methods of assisting ventilation for many years mainly for ventilating large number of victims of Polio during their acute illness
use of NIMV has increased in last
decade in various conditions to avoid complications of intubation
Types
Positive Pressure Ventilation
Negative Pressure Ventilation
Mechanism of Action Improvement in pulmonary mechanics and oxygenation In COPD oxygen therapy often worsens
hypercarbia and respiratory acidosis Augments alveolar ventilation and oxygenation
without raising PaCO2 Partial unloading of respiratory muscles Reduces trans-diaphragmatic pressure pressure
time index of respiratory muscles and diaphragmatic electromyographic activity -
Alteration in breathing pattern with an increase in tidal volume decrease in respiratory rate and increase in minute ventilation
NIMV also overcomes the effect of intrinsic PEEP
Advantages of NIMV Preservation of airway defense mechanism Early ventilatory support an option
Intermittent ventilation possible
Patient can eat drink and communicate
Ease of application and removal
Patient can cooperate with physiotherapy
Contdhellip
Improved patient comfort Reduced need for sedation Avoidance of complications of
endotracheal intubation upper airway trauma sinusitis otitis nosocomial pneumonia
Ventilation outside hospital possible Correction of hypoxaemia without
worsening hypercarbia Ease to teach paramedics and nurses
Disadvantages
Mask uncomfortableclaustrophobic Time consuming for medical and nursing
staff Facial pressure sores Airway not protected No direct access to bronchial tree for
suction if secretions are excessive Less effective
Indications of NIMV
Hypercapnic acute respiratory failure
Acute exacerbation of COPD
Post extubation Weaning difficulties Post surgical respiratory
failure Thoracic wall deformities Cystic fibrosis Status asthmaticus Obesity hypoventilation
Syndrome
Hypoxaemic acute respiratory failure
Cardiogenic pulmonary oedema
Community acquired pneumonia
Post traumatic respiratory failure
ARDS Weaning difficulties Chronic Respiratory
Failure Immunocompromised
Patients
Contraindications
Respiratory arrest Unstable cardiorespiratory status Uncooperative patients -confused agitated Unable to protect airway- impaired swallowing
and cough Facial Oesophageal or gastric surgery Craniofacial traumaburn Anatomic lesions of upper airway Vomiting Impaired conciousness
Relative Contraindications
Extreme anxiety Massive obesity
Copious secretions
Need for continuous or nearly continuous ventilatory assistance
Prerequisites for successful Non-Invasive support
Patient is able to cooperate Patient can control airway and secretions Adequate cough reflex Patient is able to co-ordinate breathing with ventilator Patient can breathe unaided for several minutes Haemodynamically stable Blood pHgt71 and PaCO2 lt92 mmHg Improvement in gas exchange heart rate and
respiratory rate within first two hours Normal functioning gastrointestinal tract
Interface Interfaces are devices that connect ventilator tubing to
the face allowing the entry of pressurized gas to the upper airway
Nasal and oronasal masks and mouth pieces CPAP helmet are currently available interfaces
Masks - made from a non irritant material such as silicon rubber - minimal dead space and a soft inflatable cuff to provide a seal with the skin
Nasal mask - better tolerated but less effective ndash leak Face masks are more useful in acute respiratory failure Nasal masksMouth piece CPAP helmet are used most
often in chronic respiratory failure
Ventilators - conventional
Advantages FiO2 can be set Alarm amp monitoring
back up Back up ventilation Separate insp amp exp
limbs ndash prevent rebreathing
Inspiratory pressure gt 20 cm H2O can be set
Disadvantages Expensive Less flexible
ampportable Leak compensation
not present ndash requires tight interface
NPPV Ventilators
Advantages cheaper flexible ampportable Leak compensation
present ndash does not requires tight interface
Inspiratory pressure of 20 cm H2Ois maximum available
Disadvantages FiO2 cannot be set
Due to leak ndash high oxygen flows
Single limb ndash rebreathing
Modes of Ventilation CPAP It is not a true ventilator mode as it does not actively
assist inspiration CPAP by nasal mask provides pneumatic splint which
holds the upper airway open in patients with nocturnal hypoxaemia due to episodes of obstructive sleep apnoea
CPAP increases FRC and opens collapsed alveoli CPAP reduces left ventricular transmural pressure
therefore increases cardiac output ndash effective for treatment of pulmonary oedema
Pressures are usually limited to 5-12 cm of H2O - higher pressure tends to result in gastric distension
BILEVEL POSITIVE AIRWAY PRESSURE [ BI LEVEL PAP]
Unique flow triggering ampleak compensation Spontaneous mode ndashcycle between IPAP (Up to 30 cm
H2O)amp EPAP (Up to 15 cm of H2O)- PATIENT TRIGGERED PRESSURE SUPPORTED
IPAP = PEEP +PS EPAP = PEEP in PCVSPECIAL MACHINES Have blower unit to compensate air leaks upto 180 L mt Pressure limited back up Adjustable sensitivities maximum inspiratory
time adjustable FiO2 -available
BI LEVEL PAP[contdhellip] INDICATIONS Worsening
hypoventilation hypoxemia
Chronic ventilatory muscle dysfunction
Post intubation difficulty Upper airway
obstruction ndashlaryngeal oedemastrictures
CONTRA INDICATIONS Unstable
Haemodynamics Vomiting Neurologically abnormal Pneumothorax Deteriorating respiratory
parameters
PSV
Non-invasive PSV can be administered with standard critical care ventilator or bilevel portable devices -patient triggeredpressure limited flow cycled ventilation
PSV mode has unique ability to vary inspiratory time breath by breath permitting close matching with the patients spontaneous breathing pattern
Advantages (a) Patient-ventilator synchrony (b) Improved patient comfort(c) Reduced diaphragmatic work
Volume limited ventilation ventilators are usually set in assist-control mode with
high tidal volume (10-15 mlkg) to compensate for air leak
suitable in obesity or chest wall deformity who need high
inflation pressure neuromuscular diseases who need high tidal
volume for ventilation Proportional assist ventilation (PAV)
This is a newer mode of ventilation In this mode ventilator has capacity of responding
rapidly to the patients ventilatory efforts By adjusting the gain on the flow and volume signals
one can select the proportion of breathing work that is to be assisted
Goals of NIMV
Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival
Protocol for Non Invasive Ventilation
Explain to the patient what you are doing and what to expect
Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the
patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort
Connect humidification system
Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG
Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O
Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts
Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks
Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg
Increase FiO2 to improve O2 saturation to 90
Complications and Side effects
AIR LEAK [80 -100]
MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly
over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction
FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension
MAJOR COMPLICATIONS Aspiration pneumonia - lt
5 Hypotension Pneumothorax
CRITERIA FOR FAILURE OF NPPV
MAJOR Respiratory arrest Loss of
consciousness Psychomotor
agitation Haemodynamic
instability Heart rate lt50 bm
MINOR Respiratory rate gt 35
mt pH lt730 Pao2 lt45mmHg
Intubate when one major two minor criteria
INVASIVE VENTILATION
Pressure RegulatedVolume Control [PVRC]
Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled
assistcontrol
Establishes a ldquolearning periodrdquo to determine
patientrsquos compliance which establishes regulation of pressurevolume
Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration
Pressure RegulatedVolume Control (PRVC)
1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume
The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume
Results in breath-to-breath variation of inspiratory pressure
Limitations Only an AC mode and requires a change to
Volume Support for weaning Only guarantees volume distally and not at
patient airway
TV AIRWAY PRESSURE
PROBLEMS
VCV preset fn of mechpropertyof lungs
lung injury
PCV acc to mecha property of lung
preset hypoventilation
volutrauma
PRVC preset lower paw necessary
Benefits of both
Comparison with established modes
Applications of PRVC
ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high
flow rates In whom VT has to be controlled ndashsurfactant
therapy
Benefits
Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to
mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort
BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]
Pressure controlled ventilation allowing spontaneous ventilation
Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest
airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to
ventilator in VCV
BIPAP -SUBDIVISIONS
CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at
lower level APRV ndash BIPAP - spontaneous breathing
at higher level Genuine BIPAP - spontaneous breathing
at both levels CPAP - spontaneous breathing at single
CPAP level
paw
t
Setting up BIPAP
Adjusted with ABG values High low PaCO2 Normal PaO2
VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2
mean airway pressure without altering VTRR
equidirectional alteration of P high P low
ADVANTAGES OF BIPAP
Less sedation Reduced atelectasis Ideal mode in pts with inadequate
spontaneous effort In face of deteriorating gas exchange
we can increase the invasiveness of ventilation without having to change mode
Airway Pressure Release Ventilation
(APRV) Outlined in 1987 Continuous positive airway pressure with
regular brief intermittent releases in airway pressure
The release phase results in alveolar ventilation and removal of carbon dioxide
APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance
It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation
Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance
APRV ndashCONTDhellip
Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation
APRV commences at an elevated baseline pressure and follows with a measured pressure release
During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels
Available on Draumlger and Puritan Bennett ventilators
APRV ndashCONTDhellip
Elevated baseline airway pressure during APRV may produce near complete recruitment
Minimizes low volume lung injury from cyclic recruitment
APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation
Needs a High flow CPAP circuit with release valve
Advantages of APRV Lower peak airway pressures Lower minute ventilation
Decreased adverse effects upon circulatory function
Spontaneous ventilation the entire ventilatory cycle
Decreased need for sedation
Near elimination of neuromuscular blockade Recruitment of alveoli
Indications for APRV ALI or low-compliance lung disease patients with airway disease
CONTRAINDICATIONS
Patients with Increased airway resistance
When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation
The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation
P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus
accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than
40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0
cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure
Settings of APRV
Pressure support ventilation
Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by
specific amount of positive pressure at airway
PS Terminated when insp Flow falls below a minimum trigger volume
Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau
` ADVANTAGES Less WOB low pressure high volume work similar to
spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is
achieved with PS of 5 cm H2O
Volume AssuredPressure Support (VAPS)
Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure
breath continues to guarantee volume - 1048707 PIP and inspiratory time increase
1048707 Guarantees volume on current breath (no previous breath averaging)
1048707 Combines the advantages of pressure and volume ventilation breath to breath
Characteristics of VAPS 1048707 The ventilator continuously measures the flow and
pressure and calculates delivered volume Depending on the actual settings breath may be flow
volume or time cycled 1048707 If the target tidal volume has been delivered
inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set
flow will persist until the desired volume has been reached (volume cycled breath)
1048707 Safety limits include high pressure and maximum inspiratory time1048707
Used in the Management of acute and recovering lung disease
Benefits of VAPS
1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort
Applications of VAPS 1048707 A patient who requires a substantial level of
ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony
1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change
Limitations 1048707 Will only increase pressure not lower pressure
with changing mechanics 1048707 Increases inspiratory time to assure volume
Volume support ventilation
Support mode Has PVRC as back up mode Allows spontaneous if preset MV is
achieved If fails deliver preset TV MV in lowest
possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure
limitlower amp upper MV alarm
Applications of VSV
Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations
in inspiratory pressure support
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
PressureControl Ventilation
Benefits 1048707 Variable flow capability for patient demand 1048707 Reduced patient inspiratory muscle workload 1048707 Lower peak inspiratory pressures 1048707 Adjustable inspiratory time 1048707 Rapid filling of the alveoli 1048707 Improved gas distribution VQ matchingand
oxygenation
Disadvantages 1048707 Delivered tidal volume is variable and depends
upon the patientrsquos lung mechanics including changes in airway resistance and lung compliance
1048707 May have adverse effects on volume delivery
PRESSURE
VOLUME
NEWER MODES
Clinicians Want the Best of All Possible Worlds
Advantages of both pressure and volume ventilation 10487071048707 ldquoYou canrsquot always get what you wantrdquo (Rolling Stones) sohellipget what you need 10487071048707 Whatrsquos new
Basic principles
Trigger ndashmachine amp patient [flow presssure ]
Flow triggerig ndash less work ndashprefered Too sensitive ndash auto triggering Limit variable [ pressure volume ] Cycle variable ndash
volume flow pressure time
TYPES
INVASIVE APRV BIPAP Self adaptive modes Proportional assist ventilation Independent ventilation High frequency ventilation Extracorporeal membrane oxygenation Liquid ventilation NONINVASIVE
NON INVASIVE VENTILATION Negative pressure ventilators (Tank and
Cuirass ventilators) were the only non-invasive methods of assisting ventilation for many years mainly for ventilating large number of victims of Polio during their acute illness
use of NIMV has increased in last
decade in various conditions to avoid complications of intubation
Types
Positive Pressure Ventilation
Negative Pressure Ventilation
Mechanism of Action Improvement in pulmonary mechanics and oxygenation In COPD oxygen therapy often worsens
hypercarbia and respiratory acidosis Augments alveolar ventilation and oxygenation
without raising PaCO2 Partial unloading of respiratory muscles Reduces trans-diaphragmatic pressure pressure
time index of respiratory muscles and diaphragmatic electromyographic activity -
Alteration in breathing pattern with an increase in tidal volume decrease in respiratory rate and increase in minute ventilation
NIMV also overcomes the effect of intrinsic PEEP
Advantages of NIMV Preservation of airway defense mechanism Early ventilatory support an option
Intermittent ventilation possible
Patient can eat drink and communicate
Ease of application and removal
Patient can cooperate with physiotherapy
Contdhellip
Improved patient comfort Reduced need for sedation Avoidance of complications of
endotracheal intubation upper airway trauma sinusitis otitis nosocomial pneumonia
Ventilation outside hospital possible Correction of hypoxaemia without
worsening hypercarbia Ease to teach paramedics and nurses
Disadvantages
Mask uncomfortableclaustrophobic Time consuming for medical and nursing
staff Facial pressure sores Airway not protected No direct access to bronchial tree for
suction if secretions are excessive Less effective
Indications of NIMV
Hypercapnic acute respiratory failure
Acute exacerbation of COPD
Post extubation Weaning difficulties Post surgical respiratory
failure Thoracic wall deformities Cystic fibrosis Status asthmaticus Obesity hypoventilation
Syndrome
Hypoxaemic acute respiratory failure
Cardiogenic pulmonary oedema
Community acquired pneumonia
Post traumatic respiratory failure
ARDS Weaning difficulties Chronic Respiratory
Failure Immunocompromised
Patients
Contraindications
Respiratory arrest Unstable cardiorespiratory status Uncooperative patients -confused agitated Unable to protect airway- impaired swallowing
and cough Facial Oesophageal or gastric surgery Craniofacial traumaburn Anatomic lesions of upper airway Vomiting Impaired conciousness
Relative Contraindications
Extreme anxiety Massive obesity
Copious secretions
Need for continuous or nearly continuous ventilatory assistance
Prerequisites for successful Non-Invasive support
Patient is able to cooperate Patient can control airway and secretions Adequate cough reflex Patient is able to co-ordinate breathing with ventilator Patient can breathe unaided for several minutes Haemodynamically stable Blood pHgt71 and PaCO2 lt92 mmHg Improvement in gas exchange heart rate and
respiratory rate within first two hours Normal functioning gastrointestinal tract
Interface Interfaces are devices that connect ventilator tubing to
the face allowing the entry of pressurized gas to the upper airway
Nasal and oronasal masks and mouth pieces CPAP helmet are currently available interfaces
Masks - made from a non irritant material such as silicon rubber - minimal dead space and a soft inflatable cuff to provide a seal with the skin
Nasal mask - better tolerated but less effective ndash leak Face masks are more useful in acute respiratory failure Nasal masksMouth piece CPAP helmet are used most
often in chronic respiratory failure
Ventilators - conventional
Advantages FiO2 can be set Alarm amp monitoring
back up Back up ventilation Separate insp amp exp
limbs ndash prevent rebreathing
Inspiratory pressure gt 20 cm H2O can be set
Disadvantages Expensive Less flexible
ampportable Leak compensation
not present ndash requires tight interface
NPPV Ventilators
Advantages cheaper flexible ampportable Leak compensation
present ndash does not requires tight interface
Inspiratory pressure of 20 cm H2Ois maximum available
Disadvantages FiO2 cannot be set
Due to leak ndash high oxygen flows
Single limb ndash rebreathing
Modes of Ventilation CPAP It is not a true ventilator mode as it does not actively
assist inspiration CPAP by nasal mask provides pneumatic splint which
holds the upper airway open in patients with nocturnal hypoxaemia due to episodes of obstructive sleep apnoea
CPAP increases FRC and opens collapsed alveoli CPAP reduces left ventricular transmural pressure
therefore increases cardiac output ndash effective for treatment of pulmonary oedema
Pressures are usually limited to 5-12 cm of H2O - higher pressure tends to result in gastric distension
BILEVEL POSITIVE AIRWAY PRESSURE [ BI LEVEL PAP]
Unique flow triggering ampleak compensation Spontaneous mode ndashcycle between IPAP (Up to 30 cm
H2O)amp EPAP (Up to 15 cm of H2O)- PATIENT TRIGGERED PRESSURE SUPPORTED
IPAP = PEEP +PS EPAP = PEEP in PCVSPECIAL MACHINES Have blower unit to compensate air leaks upto 180 L mt Pressure limited back up Adjustable sensitivities maximum inspiratory
time adjustable FiO2 -available
BI LEVEL PAP[contdhellip] INDICATIONS Worsening
hypoventilation hypoxemia
Chronic ventilatory muscle dysfunction
Post intubation difficulty Upper airway
obstruction ndashlaryngeal oedemastrictures
CONTRA INDICATIONS Unstable
Haemodynamics Vomiting Neurologically abnormal Pneumothorax Deteriorating respiratory
parameters
PSV
Non-invasive PSV can be administered with standard critical care ventilator or bilevel portable devices -patient triggeredpressure limited flow cycled ventilation
PSV mode has unique ability to vary inspiratory time breath by breath permitting close matching with the patients spontaneous breathing pattern
Advantages (a) Patient-ventilator synchrony (b) Improved patient comfort(c) Reduced diaphragmatic work
Volume limited ventilation ventilators are usually set in assist-control mode with
high tidal volume (10-15 mlkg) to compensate for air leak
suitable in obesity or chest wall deformity who need high
inflation pressure neuromuscular diseases who need high tidal
volume for ventilation Proportional assist ventilation (PAV)
This is a newer mode of ventilation In this mode ventilator has capacity of responding
rapidly to the patients ventilatory efforts By adjusting the gain on the flow and volume signals
one can select the proportion of breathing work that is to be assisted
Goals of NIMV
Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival
Protocol for Non Invasive Ventilation
Explain to the patient what you are doing and what to expect
Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the
patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort
Connect humidification system
Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG
Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O
Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts
Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks
Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg
Increase FiO2 to improve O2 saturation to 90
Complications and Side effects
AIR LEAK [80 -100]
MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly
over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction
FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension
MAJOR COMPLICATIONS Aspiration pneumonia - lt
5 Hypotension Pneumothorax
CRITERIA FOR FAILURE OF NPPV
MAJOR Respiratory arrest Loss of
consciousness Psychomotor
agitation Haemodynamic
instability Heart rate lt50 bm
MINOR Respiratory rate gt 35
mt pH lt730 Pao2 lt45mmHg
Intubate when one major two minor criteria
INVASIVE VENTILATION
Pressure RegulatedVolume Control [PVRC]
Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled
assistcontrol
Establishes a ldquolearning periodrdquo to determine
patientrsquos compliance which establishes regulation of pressurevolume
Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration
Pressure RegulatedVolume Control (PRVC)
1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume
The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume
Results in breath-to-breath variation of inspiratory pressure
Limitations Only an AC mode and requires a change to
Volume Support for weaning Only guarantees volume distally and not at
patient airway
TV AIRWAY PRESSURE
PROBLEMS
VCV preset fn of mechpropertyof lungs
lung injury
PCV acc to mecha property of lung
preset hypoventilation
volutrauma
PRVC preset lower paw necessary
Benefits of both
Comparison with established modes
Applications of PRVC
ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high
flow rates In whom VT has to be controlled ndashsurfactant
therapy
Benefits
Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to
mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort
BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]
Pressure controlled ventilation allowing spontaneous ventilation
Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest
airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to
ventilator in VCV
BIPAP -SUBDIVISIONS
CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at
lower level APRV ndash BIPAP - spontaneous breathing
at higher level Genuine BIPAP - spontaneous breathing
at both levels CPAP - spontaneous breathing at single
CPAP level
paw
t
Setting up BIPAP
Adjusted with ABG values High low PaCO2 Normal PaO2
VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2
mean airway pressure without altering VTRR
equidirectional alteration of P high P low
ADVANTAGES OF BIPAP
Less sedation Reduced atelectasis Ideal mode in pts with inadequate
spontaneous effort In face of deteriorating gas exchange
we can increase the invasiveness of ventilation without having to change mode
Airway Pressure Release Ventilation
(APRV) Outlined in 1987 Continuous positive airway pressure with
regular brief intermittent releases in airway pressure
The release phase results in alveolar ventilation and removal of carbon dioxide
APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance
It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation
Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance
APRV ndashCONTDhellip
Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation
APRV commences at an elevated baseline pressure and follows with a measured pressure release
During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels
Available on Draumlger and Puritan Bennett ventilators
APRV ndashCONTDhellip
Elevated baseline airway pressure during APRV may produce near complete recruitment
Minimizes low volume lung injury from cyclic recruitment
APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation
Needs a High flow CPAP circuit with release valve
Advantages of APRV Lower peak airway pressures Lower minute ventilation
Decreased adverse effects upon circulatory function
Spontaneous ventilation the entire ventilatory cycle
Decreased need for sedation
Near elimination of neuromuscular blockade Recruitment of alveoli
Indications for APRV ALI or low-compliance lung disease patients with airway disease
CONTRAINDICATIONS
Patients with Increased airway resistance
When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation
The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation
P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus
accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than
40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0
cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure
Settings of APRV
Pressure support ventilation
Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by
specific amount of positive pressure at airway
PS Terminated when insp Flow falls below a minimum trigger volume
Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau
` ADVANTAGES Less WOB low pressure high volume work similar to
spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is
achieved with PS of 5 cm H2O
Volume AssuredPressure Support (VAPS)
Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure
breath continues to guarantee volume - 1048707 PIP and inspiratory time increase
1048707 Guarantees volume on current breath (no previous breath averaging)
1048707 Combines the advantages of pressure and volume ventilation breath to breath
Characteristics of VAPS 1048707 The ventilator continuously measures the flow and
pressure and calculates delivered volume Depending on the actual settings breath may be flow
volume or time cycled 1048707 If the target tidal volume has been delivered
inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set
flow will persist until the desired volume has been reached (volume cycled breath)
1048707 Safety limits include high pressure and maximum inspiratory time1048707
Used in the Management of acute and recovering lung disease
Benefits of VAPS
1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort
Applications of VAPS 1048707 A patient who requires a substantial level of
ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony
1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change
Limitations 1048707 Will only increase pressure not lower pressure
with changing mechanics 1048707 Increases inspiratory time to assure volume
Volume support ventilation
Support mode Has PVRC as back up mode Allows spontaneous if preset MV is
achieved If fails deliver preset TV MV in lowest
possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure
limitlower amp upper MV alarm
Applications of VSV
Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations
in inspiratory pressure support
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
PRESSURE
VOLUME
NEWER MODES
Clinicians Want the Best of All Possible Worlds
Advantages of both pressure and volume ventilation 10487071048707 ldquoYou canrsquot always get what you wantrdquo (Rolling Stones) sohellipget what you need 10487071048707 Whatrsquos new
Basic principles
Trigger ndashmachine amp patient [flow presssure ]
Flow triggerig ndash less work ndashprefered Too sensitive ndash auto triggering Limit variable [ pressure volume ] Cycle variable ndash
volume flow pressure time
TYPES
INVASIVE APRV BIPAP Self adaptive modes Proportional assist ventilation Independent ventilation High frequency ventilation Extracorporeal membrane oxygenation Liquid ventilation NONINVASIVE
NON INVASIVE VENTILATION Negative pressure ventilators (Tank and
Cuirass ventilators) were the only non-invasive methods of assisting ventilation for many years mainly for ventilating large number of victims of Polio during their acute illness
use of NIMV has increased in last
decade in various conditions to avoid complications of intubation
Types
Positive Pressure Ventilation
Negative Pressure Ventilation
Mechanism of Action Improvement in pulmonary mechanics and oxygenation In COPD oxygen therapy often worsens
hypercarbia and respiratory acidosis Augments alveolar ventilation and oxygenation
without raising PaCO2 Partial unloading of respiratory muscles Reduces trans-diaphragmatic pressure pressure
time index of respiratory muscles and diaphragmatic electromyographic activity -
Alteration in breathing pattern with an increase in tidal volume decrease in respiratory rate and increase in minute ventilation
NIMV also overcomes the effect of intrinsic PEEP
Advantages of NIMV Preservation of airway defense mechanism Early ventilatory support an option
Intermittent ventilation possible
Patient can eat drink and communicate
Ease of application and removal
Patient can cooperate with physiotherapy
Contdhellip
Improved patient comfort Reduced need for sedation Avoidance of complications of
endotracheal intubation upper airway trauma sinusitis otitis nosocomial pneumonia
Ventilation outside hospital possible Correction of hypoxaemia without
worsening hypercarbia Ease to teach paramedics and nurses
Disadvantages
Mask uncomfortableclaustrophobic Time consuming for medical and nursing
staff Facial pressure sores Airway not protected No direct access to bronchial tree for
suction if secretions are excessive Less effective
Indications of NIMV
Hypercapnic acute respiratory failure
Acute exacerbation of COPD
Post extubation Weaning difficulties Post surgical respiratory
failure Thoracic wall deformities Cystic fibrosis Status asthmaticus Obesity hypoventilation
Syndrome
Hypoxaemic acute respiratory failure
Cardiogenic pulmonary oedema
Community acquired pneumonia
Post traumatic respiratory failure
ARDS Weaning difficulties Chronic Respiratory
Failure Immunocompromised
Patients
Contraindications
Respiratory arrest Unstable cardiorespiratory status Uncooperative patients -confused agitated Unable to protect airway- impaired swallowing
and cough Facial Oesophageal or gastric surgery Craniofacial traumaburn Anatomic lesions of upper airway Vomiting Impaired conciousness
Relative Contraindications
Extreme anxiety Massive obesity
Copious secretions
Need for continuous or nearly continuous ventilatory assistance
Prerequisites for successful Non-Invasive support
Patient is able to cooperate Patient can control airway and secretions Adequate cough reflex Patient is able to co-ordinate breathing with ventilator Patient can breathe unaided for several minutes Haemodynamically stable Blood pHgt71 and PaCO2 lt92 mmHg Improvement in gas exchange heart rate and
respiratory rate within first two hours Normal functioning gastrointestinal tract
Interface Interfaces are devices that connect ventilator tubing to
the face allowing the entry of pressurized gas to the upper airway
Nasal and oronasal masks and mouth pieces CPAP helmet are currently available interfaces
Masks - made from a non irritant material such as silicon rubber - minimal dead space and a soft inflatable cuff to provide a seal with the skin
Nasal mask - better tolerated but less effective ndash leak Face masks are more useful in acute respiratory failure Nasal masksMouth piece CPAP helmet are used most
often in chronic respiratory failure
Ventilators - conventional
Advantages FiO2 can be set Alarm amp monitoring
back up Back up ventilation Separate insp amp exp
limbs ndash prevent rebreathing
Inspiratory pressure gt 20 cm H2O can be set
Disadvantages Expensive Less flexible
ampportable Leak compensation
not present ndash requires tight interface
NPPV Ventilators
Advantages cheaper flexible ampportable Leak compensation
present ndash does not requires tight interface
Inspiratory pressure of 20 cm H2Ois maximum available
Disadvantages FiO2 cannot be set
Due to leak ndash high oxygen flows
Single limb ndash rebreathing
Modes of Ventilation CPAP It is not a true ventilator mode as it does not actively
assist inspiration CPAP by nasal mask provides pneumatic splint which
holds the upper airway open in patients with nocturnal hypoxaemia due to episodes of obstructive sleep apnoea
CPAP increases FRC and opens collapsed alveoli CPAP reduces left ventricular transmural pressure
therefore increases cardiac output ndash effective for treatment of pulmonary oedema
Pressures are usually limited to 5-12 cm of H2O - higher pressure tends to result in gastric distension
BILEVEL POSITIVE AIRWAY PRESSURE [ BI LEVEL PAP]
Unique flow triggering ampleak compensation Spontaneous mode ndashcycle between IPAP (Up to 30 cm
H2O)amp EPAP (Up to 15 cm of H2O)- PATIENT TRIGGERED PRESSURE SUPPORTED
IPAP = PEEP +PS EPAP = PEEP in PCVSPECIAL MACHINES Have blower unit to compensate air leaks upto 180 L mt Pressure limited back up Adjustable sensitivities maximum inspiratory
time adjustable FiO2 -available
BI LEVEL PAP[contdhellip] INDICATIONS Worsening
hypoventilation hypoxemia
Chronic ventilatory muscle dysfunction
Post intubation difficulty Upper airway
obstruction ndashlaryngeal oedemastrictures
CONTRA INDICATIONS Unstable
Haemodynamics Vomiting Neurologically abnormal Pneumothorax Deteriorating respiratory
parameters
PSV
Non-invasive PSV can be administered with standard critical care ventilator or bilevel portable devices -patient triggeredpressure limited flow cycled ventilation
PSV mode has unique ability to vary inspiratory time breath by breath permitting close matching with the patients spontaneous breathing pattern
Advantages (a) Patient-ventilator synchrony (b) Improved patient comfort(c) Reduced diaphragmatic work
Volume limited ventilation ventilators are usually set in assist-control mode with
high tidal volume (10-15 mlkg) to compensate for air leak
suitable in obesity or chest wall deformity who need high
inflation pressure neuromuscular diseases who need high tidal
volume for ventilation Proportional assist ventilation (PAV)
This is a newer mode of ventilation In this mode ventilator has capacity of responding
rapidly to the patients ventilatory efforts By adjusting the gain on the flow and volume signals
one can select the proportion of breathing work that is to be assisted
Goals of NIMV
Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival
Protocol for Non Invasive Ventilation
Explain to the patient what you are doing and what to expect
Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the
patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort
Connect humidification system
Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG
Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O
Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts
Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks
Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg
Increase FiO2 to improve O2 saturation to 90
Complications and Side effects
AIR LEAK [80 -100]
MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly
over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction
FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension
MAJOR COMPLICATIONS Aspiration pneumonia - lt
5 Hypotension Pneumothorax
CRITERIA FOR FAILURE OF NPPV
MAJOR Respiratory arrest Loss of
consciousness Psychomotor
agitation Haemodynamic
instability Heart rate lt50 bm
MINOR Respiratory rate gt 35
mt pH lt730 Pao2 lt45mmHg
Intubate when one major two minor criteria
INVASIVE VENTILATION
Pressure RegulatedVolume Control [PVRC]
Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled
assistcontrol
Establishes a ldquolearning periodrdquo to determine
patientrsquos compliance which establishes regulation of pressurevolume
Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration
Pressure RegulatedVolume Control (PRVC)
1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume
The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume
Results in breath-to-breath variation of inspiratory pressure
Limitations Only an AC mode and requires a change to
Volume Support for weaning Only guarantees volume distally and not at
patient airway
TV AIRWAY PRESSURE
PROBLEMS
VCV preset fn of mechpropertyof lungs
lung injury
PCV acc to mecha property of lung
preset hypoventilation
volutrauma
PRVC preset lower paw necessary
Benefits of both
Comparison with established modes
Applications of PRVC
ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high
flow rates In whom VT has to be controlled ndashsurfactant
therapy
Benefits
Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to
mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort
BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]
Pressure controlled ventilation allowing spontaneous ventilation
Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest
airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to
ventilator in VCV
BIPAP -SUBDIVISIONS
CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at
lower level APRV ndash BIPAP - spontaneous breathing
at higher level Genuine BIPAP - spontaneous breathing
at both levels CPAP - spontaneous breathing at single
CPAP level
paw
t
Setting up BIPAP
Adjusted with ABG values High low PaCO2 Normal PaO2
VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2
mean airway pressure without altering VTRR
equidirectional alteration of P high P low
ADVANTAGES OF BIPAP
Less sedation Reduced atelectasis Ideal mode in pts with inadequate
spontaneous effort In face of deteriorating gas exchange
we can increase the invasiveness of ventilation without having to change mode
Airway Pressure Release Ventilation
(APRV) Outlined in 1987 Continuous positive airway pressure with
regular brief intermittent releases in airway pressure
The release phase results in alveolar ventilation and removal of carbon dioxide
APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance
It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation
Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance
APRV ndashCONTDhellip
Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation
APRV commences at an elevated baseline pressure and follows with a measured pressure release
During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels
Available on Draumlger and Puritan Bennett ventilators
APRV ndashCONTDhellip
Elevated baseline airway pressure during APRV may produce near complete recruitment
Minimizes low volume lung injury from cyclic recruitment
APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation
Needs a High flow CPAP circuit with release valve
Advantages of APRV Lower peak airway pressures Lower minute ventilation
Decreased adverse effects upon circulatory function
Spontaneous ventilation the entire ventilatory cycle
Decreased need for sedation
Near elimination of neuromuscular blockade Recruitment of alveoli
Indications for APRV ALI or low-compliance lung disease patients with airway disease
CONTRAINDICATIONS
Patients with Increased airway resistance
When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation
The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation
P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus
accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than
40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0
cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure
Settings of APRV
Pressure support ventilation
Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by
specific amount of positive pressure at airway
PS Terminated when insp Flow falls below a minimum trigger volume
Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau
` ADVANTAGES Less WOB low pressure high volume work similar to
spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is
achieved with PS of 5 cm H2O
Volume AssuredPressure Support (VAPS)
Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure
breath continues to guarantee volume - 1048707 PIP and inspiratory time increase
1048707 Guarantees volume on current breath (no previous breath averaging)
1048707 Combines the advantages of pressure and volume ventilation breath to breath
Characteristics of VAPS 1048707 The ventilator continuously measures the flow and
pressure and calculates delivered volume Depending on the actual settings breath may be flow
volume or time cycled 1048707 If the target tidal volume has been delivered
inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set
flow will persist until the desired volume has been reached (volume cycled breath)
1048707 Safety limits include high pressure and maximum inspiratory time1048707
Used in the Management of acute and recovering lung disease
Benefits of VAPS
1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort
Applications of VAPS 1048707 A patient who requires a substantial level of
ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony
1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change
Limitations 1048707 Will only increase pressure not lower pressure
with changing mechanics 1048707 Increases inspiratory time to assure volume
Volume support ventilation
Support mode Has PVRC as back up mode Allows spontaneous if preset MV is
achieved If fails deliver preset TV MV in lowest
possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure
limitlower amp upper MV alarm
Applications of VSV
Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations
in inspiratory pressure support
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
Clinicians Want the Best of All Possible Worlds
Advantages of both pressure and volume ventilation 10487071048707 ldquoYou canrsquot always get what you wantrdquo (Rolling Stones) sohellipget what you need 10487071048707 Whatrsquos new
Basic principles
Trigger ndashmachine amp patient [flow presssure ]
Flow triggerig ndash less work ndashprefered Too sensitive ndash auto triggering Limit variable [ pressure volume ] Cycle variable ndash
volume flow pressure time
TYPES
INVASIVE APRV BIPAP Self adaptive modes Proportional assist ventilation Independent ventilation High frequency ventilation Extracorporeal membrane oxygenation Liquid ventilation NONINVASIVE
NON INVASIVE VENTILATION Negative pressure ventilators (Tank and
Cuirass ventilators) were the only non-invasive methods of assisting ventilation for many years mainly for ventilating large number of victims of Polio during their acute illness
use of NIMV has increased in last
decade in various conditions to avoid complications of intubation
Types
Positive Pressure Ventilation
Negative Pressure Ventilation
Mechanism of Action Improvement in pulmonary mechanics and oxygenation In COPD oxygen therapy often worsens
hypercarbia and respiratory acidosis Augments alveolar ventilation and oxygenation
without raising PaCO2 Partial unloading of respiratory muscles Reduces trans-diaphragmatic pressure pressure
time index of respiratory muscles and diaphragmatic electromyographic activity -
Alteration in breathing pattern with an increase in tidal volume decrease in respiratory rate and increase in minute ventilation
NIMV also overcomes the effect of intrinsic PEEP
Advantages of NIMV Preservation of airway defense mechanism Early ventilatory support an option
Intermittent ventilation possible
Patient can eat drink and communicate
Ease of application and removal
Patient can cooperate with physiotherapy
Contdhellip
Improved patient comfort Reduced need for sedation Avoidance of complications of
endotracheal intubation upper airway trauma sinusitis otitis nosocomial pneumonia
Ventilation outside hospital possible Correction of hypoxaemia without
worsening hypercarbia Ease to teach paramedics and nurses
Disadvantages
Mask uncomfortableclaustrophobic Time consuming for medical and nursing
staff Facial pressure sores Airway not protected No direct access to bronchial tree for
suction if secretions are excessive Less effective
Indications of NIMV
Hypercapnic acute respiratory failure
Acute exacerbation of COPD
Post extubation Weaning difficulties Post surgical respiratory
failure Thoracic wall deformities Cystic fibrosis Status asthmaticus Obesity hypoventilation
Syndrome
Hypoxaemic acute respiratory failure
Cardiogenic pulmonary oedema
Community acquired pneumonia
Post traumatic respiratory failure
ARDS Weaning difficulties Chronic Respiratory
Failure Immunocompromised
Patients
Contraindications
Respiratory arrest Unstable cardiorespiratory status Uncooperative patients -confused agitated Unable to protect airway- impaired swallowing
and cough Facial Oesophageal or gastric surgery Craniofacial traumaburn Anatomic lesions of upper airway Vomiting Impaired conciousness
Relative Contraindications
Extreme anxiety Massive obesity
Copious secretions
Need for continuous or nearly continuous ventilatory assistance
Prerequisites for successful Non-Invasive support
Patient is able to cooperate Patient can control airway and secretions Adequate cough reflex Patient is able to co-ordinate breathing with ventilator Patient can breathe unaided for several minutes Haemodynamically stable Blood pHgt71 and PaCO2 lt92 mmHg Improvement in gas exchange heart rate and
respiratory rate within first two hours Normal functioning gastrointestinal tract
Interface Interfaces are devices that connect ventilator tubing to
the face allowing the entry of pressurized gas to the upper airway
Nasal and oronasal masks and mouth pieces CPAP helmet are currently available interfaces
Masks - made from a non irritant material such as silicon rubber - minimal dead space and a soft inflatable cuff to provide a seal with the skin
Nasal mask - better tolerated but less effective ndash leak Face masks are more useful in acute respiratory failure Nasal masksMouth piece CPAP helmet are used most
often in chronic respiratory failure
Ventilators - conventional
Advantages FiO2 can be set Alarm amp monitoring
back up Back up ventilation Separate insp amp exp
limbs ndash prevent rebreathing
Inspiratory pressure gt 20 cm H2O can be set
Disadvantages Expensive Less flexible
ampportable Leak compensation
not present ndash requires tight interface
NPPV Ventilators
Advantages cheaper flexible ampportable Leak compensation
present ndash does not requires tight interface
Inspiratory pressure of 20 cm H2Ois maximum available
Disadvantages FiO2 cannot be set
Due to leak ndash high oxygen flows
Single limb ndash rebreathing
Modes of Ventilation CPAP It is not a true ventilator mode as it does not actively
assist inspiration CPAP by nasal mask provides pneumatic splint which
holds the upper airway open in patients with nocturnal hypoxaemia due to episodes of obstructive sleep apnoea
CPAP increases FRC and opens collapsed alveoli CPAP reduces left ventricular transmural pressure
therefore increases cardiac output ndash effective for treatment of pulmonary oedema
Pressures are usually limited to 5-12 cm of H2O - higher pressure tends to result in gastric distension
BILEVEL POSITIVE AIRWAY PRESSURE [ BI LEVEL PAP]
Unique flow triggering ampleak compensation Spontaneous mode ndashcycle between IPAP (Up to 30 cm
H2O)amp EPAP (Up to 15 cm of H2O)- PATIENT TRIGGERED PRESSURE SUPPORTED
IPAP = PEEP +PS EPAP = PEEP in PCVSPECIAL MACHINES Have blower unit to compensate air leaks upto 180 L mt Pressure limited back up Adjustable sensitivities maximum inspiratory
time adjustable FiO2 -available
BI LEVEL PAP[contdhellip] INDICATIONS Worsening
hypoventilation hypoxemia
Chronic ventilatory muscle dysfunction
Post intubation difficulty Upper airway
obstruction ndashlaryngeal oedemastrictures
CONTRA INDICATIONS Unstable
Haemodynamics Vomiting Neurologically abnormal Pneumothorax Deteriorating respiratory
parameters
PSV
Non-invasive PSV can be administered with standard critical care ventilator or bilevel portable devices -patient triggeredpressure limited flow cycled ventilation
PSV mode has unique ability to vary inspiratory time breath by breath permitting close matching with the patients spontaneous breathing pattern
Advantages (a) Patient-ventilator synchrony (b) Improved patient comfort(c) Reduced diaphragmatic work
Volume limited ventilation ventilators are usually set in assist-control mode with
high tidal volume (10-15 mlkg) to compensate for air leak
suitable in obesity or chest wall deformity who need high
inflation pressure neuromuscular diseases who need high tidal
volume for ventilation Proportional assist ventilation (PAV)
This is a newer mode of ventilation In this mode ventilator has capacity of responding
rapidly to the patients ventilatory efforts By adjusting the gain on the flow and volume signals
one can select the proportion of breathing work that is to be assisted
Goals of NIMV
Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival
Protocol for Non Invasive Ventilation
Explain to the patient what you are doing and what to expect
Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the
patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort
Connect humidification system
Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG
Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O
Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts
Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks
Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg
Increase FiO2 to improve O2 saturation to 90
Complications and Side effects
AIR LEAK [80 -100]
MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly
over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction
FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension
MAJOR COMPLICATIONS Aspiration pneumonia - lt
5 Hypotension Pneumothorax
CRITERIA FOR FAILURE OF NPPV
MAJOR Respiratory arrest Loss of
consciousness Psychomotor
agitation Haemodynamic
instability Heart rate lt50 bm
MINOR Respiratory rate gt 35
mt pH lt730 Pao2 lt45mmHg
Intubate when one major two minor criteria
INVASIVE VENTILATION
Pressure RegulatedVolume Control [PVRC]
Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled
assistcontrol
Establishes a ldquolearning periodrdquo to determine
patientrsquos compliance which establishes regulation of pressurevolume
Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration
Pressure RegulatedVolume Control (PRVC)
1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume
The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume
Results in breath-to-breath variation of inspiratory pressure
Limitations Only an AC mode and requires a change to
Volume Support for weaning Only guarantees volume distally and not at
patient airway
TV AIRWAY PRESSURE
PROBLEMS
VCV preset fn of mechpropertyof lungs
lung injury
PCV acc to mecha property of lung
preset hypoventilation
volutrauma
PRVC preset lower paw necessary
Benefits of both
Comparison with established modes
Applications of PRVC
ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high
flow rates In whom VT has to be controlled ndashsurfactant
therapy
Benefits
Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to
mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort
BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]
Pressure controlled ventilation allowing spontaneous ventilation
Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest
airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to
ventilator in VCV
BIPAP -SUBDIVISIONS
CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at
lower level APRV ndash BIPAP - spontaneous breathing
at higher level Genuine BIPAP - spontaneous breathing
at both levels CPAP - spontaneous breathing at single
CPAP level
paw
t
Setting up BIPAP
Adjusted with ABG values High low PaCO2 Normal PaO2
VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2
mean airway pressure without altering VTRR
equidirectional alteration of P high P low
ADVANTAGES OF BIPAP
Less sedation Reduced atelectasis Ideal mode in pts with inadequate
spontaneous effort In face of deteriorating gas exchange
we can increase the invasiveness of ventilation without having to change mode
Airway Pressure Release Ventilation
(APRV) Outlined in 1987 Continuous positive airway pressure with
regular brief intermittent releases in airway pressure
The release phase results in alveolar ventilation and removal of carbon dioxide
APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance
It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation
Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance
APRV ndashCONTDhellip
Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation
APRV commences at an elevated baseline pressure and follows with a measured pressure release
During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels
Available on Draumlger and Puritan Bennett ventilators
APRV ndashCONTDhellip
Elevated baseline airway pressure during APRV may produce near complete recruitment
Minimizes low volume lung injury from cyclic recruitment
APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation
Needs a High flow CPAP circuit with release valve
Advantages of APRV Lower peak airway pressures Lower minute ventilation
Decreased adverse effects upon circulatory function
Spontaneous ventilation the entire ventilatory cycle
Decreased need for sedation
Near elimination of neuromuscular blockade Recruitment of alveoli
Indications for APRV ALI or low-compliance lung disease patients with airway disease
CONTRAINDICATIONS
Patients with Increased airway resistance
When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation
The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation
P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus
accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than
40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0
cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure
Settings of APRV
Pressure support ventilation
Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by
specific amount of positive pressure at airway
PS Terminated when insp Flow falls below a minimum trigger volume
Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau
` ADVANTAGES Less WOB low pressure high volume work similar to
spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is
achieved with PS of 5 cm H2O
Volume AssuredPressure Support (VAPS)
Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure
breath continues to guarantee volume - 1048707 PIP and inspiratory time increase
1048707 Guarantees volume on current breath (no previous breath averaging)
1048707 Combines the advantages of pressure and volume ventilation breath to breath
Characteristics of VAPS 1048707 The ventilator continuously measures the flow and
pressure and calculates delivered volume Depending on the actual settings breath may be flow
volume or time cycled 1048707 If the target tidal volume has been delivered
inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set
flow will persist until the desired volume has been reached (volume cycled breath)
1048707 Safety limits include high pressure and maximum inspiratory time1048707
Used in the Management of acute and recovering lung disease
Benefits of VAPS
1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort
Applications of VAPS 1048707 A patient who requires a substantial level of
ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony
1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change
Limitations 1048707 Will only increase pressure not lower pressure
with changing mechanics 1048707 Increases inspiratory time to assure volume
Volume support ventilation
Support mode Has PVRC as back up mode Allows spontaneous if preset MV is
achieved If fails deliver preset TV MV in lowest
possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure
limitlower amp upper MV alarm
Applications of VSV
Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations
in inspiratory pressure support
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
Basic principles
Trigger ndashmachine amp patient [flow presssure ]
Flow triggerig ndash less work ndashprefered Too sensitive ndash auto triggering Limit variable [ pressure volume ] Cycle variable ndash
volume flow pressure time
TYPES
INVASIVE APRV BIPAP Self adaptive modes Proportional assist ventilation Independent ventilation High frequency ventilation Extracorporeal membrane oxygenation Liquid ventilation NONINVASIVE
NON INVASIVE VENTILATION Negative pressure ventilators (Tank and
Cuirass ventilators) were the only non-invasive methods of assisting ventilation for many years mainly for ventilating large number of victims of Polio during their acute illness
use of NIMV has increased in last
decade in various conditions to avoid complications of intubation
Types
Positive Pressure Ventilation
Negative Pressure Ventilation
Mechanism of Action Improvement in pulmonary mechanics and oxygenation In COPD oxygen therapy often worsens
hypercarbia and respiratory acidosis Augments alveolar ventilation and oxygenation
without raising PaCO2 Partial unloading of respiratory muscles Reduces trans-diaphragmatic pressure pressure
time index of respiratory muscles and diaphragmatic electromyographic activity -
Alteration in breathing pattern with an increase in tidal volume decrease in respiratory rate and increase in minute ventilation
NIMV also overcomes the effect of intrinsic PEEP
Advantages of NIMV Preservation of airway defense mechanism Early ventilatory support an option
Intermittent ventilation possible
Patient can eat drink and communicate
Ease of application and removal
Patient can cooperate with physiotherapy
Contdhellip
Improved patient comfort Reduced need for sedation Avoidance of complications of
endotracheal intubation upper airway trauma sinusitis otitis nosocomial pneumonia
Ventilation outside hospital possible Correction of hypoxaemia without
worsening hypercarbia Ease to teach paramedics and nurses
Disadvantages
Mask uncomfortableclaustrophobic Time consuming for medical and nursing
staff Facial pressure sores Airway not protected No direct access to bronchial tree for
suction if secretions are excessive Less effective
Indications of NIMV
Hypercapnic acute respiratory failure
Acute exacerbation of COPD
Post extubation Weaning difficulties Post surgical respiratory
failure Thoracic wall deformities Cystic fibrosis Status asthmaticus Obesity hypoventilation
Syndrome
Hypoxaemic acute respiratory failure
Cardiogenic pulmonary oedema
Community acquired pneumonia
Post traumatic respiratory failure
ARDS Weaning difficulties Chronic Respiratory
Failure Immunocompromised
Patients
Contraindications
Respiratory arrest Unstable cardiorespiratory status Uncooperative patients -confused agitated Unable to protect airway- impaired swallowing
and cough Facial Oesophageal or gastric surgery Craniofacial traumaburn Anatomic lesions of upper airway Vomiting Impaired conciousness
Relative Contraindications
Extreme anxiety Massive obesity
Copious secretions
Need for continuous or nearly continuous ventilatory assistance
Prerequisites for successful Non-Invasive support
Patient is able to cooperate Patient can control airway and secretions Adequate cough reflex Patient is able to co-ordinate breathing with ventilator Patient can breathe unaided for several minutes Haemodynamically stable Blood pHgt71 and PaCO2 lt92 mmHg Improvement in gas exchange heart rate and
respiratory rate within first two hours Normal functioning gastrointestinal tract
Interface Interfaces are devices that connect ventilator tubing to
the face allowing the entry of pressurized gas to the upper airway
Nasal and oronasal masks and mouth pieces CPAP helmet are currently available interfaces
Masks - made from a non irritant material such as silicon rubber - minimal dead space and a soft inflatable cuff to provide a seal with the skin
Nasal mask - better tolerated but less effective ndash leak Face masks are more useful in acute respiratory failure Nasal masksMouth piece CPAP helmet are used most
often in chronic respiratory failure
Ventilators - conventional
Advantages FiO2 can be set Alarm amp monitoring
back up Back up ventilation Separate insp amp exp
limbs ndash prevent rebreathing
Inspiratory pressure gt 20 cm H2O can be set
Disadvantages Expensive Less flexible
ampportable Leak compensation
not present ndash requires tight interface
NPPV Ventilators
Advantages cheaper flexible ampportable Leak compensation
present ndash does not requires tight interface
Inspiratory pressure of 20 cm H2Ois maximum available
Disadvantages FiO2 cannot be set
Due to leak ndash high oxygen flows
Single limb ndash rebreathing
Modes of Ventilation CPAP It is not a true ventilator mode as it does not actively
assist inspiration CPAP by nasal mask provides pneumatic splint which
holds the upper airway open in patients with nocturnal hypoxaemia due to episodes of obstructive sleep apnoea
CPAP increases FRC and opens collapsed alveoli CPAP reduces left ventricular transmural pressure
therefore increases cardiac output ndash effective for treatment of pulmonary oedema
Pressures are usually limited to 5-12 cm of H2O - higher pressure tends to result in gastric distension
BILEVEL POSITIVE AIRWAY PRESSURE [ BI LEVEL PAP]
Unique flow triggering ampleak compensation Spontaneous mode ndashcycle between IPAP (Up to 30 cm
H2O)amp EPAP (Up to 15 cm of H2O)- PATIENT TRIGGERED PRESSURE SUPPORTED
IPAP = PEEP +PS EPAP = PEEP in PCVSPECIAL MACHINES Have blower unit to compensate air leaks upto 180 L mt Pressure limited back up Adjustable sensitivities maximum inspiratory
time adjustable FiO2 -available
BI LEVEL PAP[contdhellip] INDICATIONS Worsening
hypoventilation hypoxemia
Chronic ventilatory muscle dysfunction
Post intubation difficulty Upper airway
obstruction ndashlaryngeal oedemastrictures
CONTRA INDICATIONS Unstable
Haemodynamics Vomiting Neurologically abnormal Pneumothorax Deteriorating respiratory
parameters
PSV
Non-invasive PSV can be administered with standard critical care ventilator or bilevel portable devices -patient triggeredpressure limited flow cycled ventilation
PSV mode has unique ability to vary inspiratory time breath by breath permitting close matching with the patients spontaneous breathing pattern
Advantages (a) Patient-ventilator synchrony (b) Improved patient comfort(c) Reduced diaphragmatic work
Volume limited ventilation ventilators are usually set in assist-control mode with
high tidal volume (10-15 mlkg) to compensate for air leak
suitable in obesity or chest wall deformity who need high
inflation pressure neuromuscular diseases who need high tidal
volume for ventilation Proportional assist ventilation (PAV)
This is a newer mode of ventilation In this mode ventilator has capacity of responding
rapidly to the patients ventilatory efforts By adjusting the gain on the flow and volume signals
one can select the proportion of breathing work that is to be assisted
Goals of NIMV
Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival
Protocol for Non Invasive Ventilation
Explain to the patient what you are doing and what to expect
Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the
patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort
Connect humidification system
Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG
Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O
Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts
Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks
Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg
Increase FiO2 to improve O2 saturation to 90
Complications and Side effects
AIR LEAK [80 -100]
MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly
over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction
FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension
MAJOR COMPLICATIONS Aspiration pneumonia - lt
5 Hypotension Pneumothorax
CRITERIA FOR FAILURE OF NPPV
MAJOR Respiratory arrest Loss of
consciousness Psychomotor
agitation Haemodynamic
instability Heart rate lt50 bm
MINOR Respiratory rate gt 35
mt pH lt730 Pao2 lt45mmHg
Intubate when one major two minor criteria
INVASIVE VENTILATION
Pressure RegulatedVolume Control [PVRC]
Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled
assistcontrol
Establishes a ldquolearning periodrdquo to determine
patientrsquos compliance which establishes regulation of pressurevolume
Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration
Pressure RegulatedVolume Control (PRVC)
1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume
The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume
Results in breath-to-breath variation of inspiratory pressure
Limitations Only an AC mode and requires a change to
Volume Support for weaning Only guarantees volume distally and not at
patient airway
TV AIRWAY PRESSURE
PROBLEMS
VCV preset fn of mechpropertyof lungs
lung injury
PCV acc to mecha property of lung
preset hypoventilation
volutrauma
PRVC preset lower paw necessary
Benefits of both
Comparison with established modes
Applications of PRVC
ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high
flow rates In whom VT has to be controlled ndashsurfactant
therapy
Benefits
Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to
mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort
BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]
Pressure controlled ventilation allowing spontaneous ventilation
Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest
airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to
ventilator in VCV
BIPAP -SUBDIVISIONS
CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at
lower level APRV ndash BIPAP - spontaneous breathing
at higher level Genuine BIPAP - spontaneous breathing
at both levels CPAP - spontaneous breathing at single
CPAP level
paw
t
Setting up BIPAP
Adjusted with ABG values High low PaCO2 Normal PaO2
VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2
mean airway pressure without altering VTRR
equidirectional alteration of P high P low
ADVANTAGES OF BIPAP
Less sedation Reduced atelectasis Ideal mode in pts with inadequate
spontaneous effort In face of deteriorating gas exchange
we can increase the invasiveness of ventilation without having to change mode
Airway Pressure Release Ventilation
(APRV) Outlined in 1987 Continuous positive airway pressure with
regular brief intermittent releases in airway pressure
The release phase results in alveolar ventilation and removal of carbon dioxide
APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance
It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation
Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance
APRV ndashCONTDhellip
Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation
APRV commences at an elevated baseline pressure and follows with a measured pressure release
During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels
Available on Draumlger and Puritan Bennett ventilators
APRV ndashCONTDhellip
Elevated baseline airway pressure during APRV may produce near complete recruitment
Minimizes low volume lung injury from cyclic recruitment
APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation
Needs a High flow CPAP circuit with release valve
Advantages of APRV Lower peak airway pressures Lower minute ventilation
Decreased adverse effects upon circulatory function
Spontaneous ventilation the entire ventilatory cycle
Decreased need for sedation
Near elimination of neuromuscular blockade Recruitment of alveoli
Indications for APRV ALI or low-compliance lung disease patients with airway disease
CONTRAINDICATIONS
Patients with Increased airway resistance
When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation
The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation
P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus
accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than
40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0
cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure
Settings of APRV
Pressure support ventilation
Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by
specific amount of positive pressure at airway
PS Terminated when insp Flow falls below a minimum trigger volume
Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau
` ADVANTAGES Less WOB low pressure high volume work similar to
spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is
achieved with PS of 5 cm H2O
Volume AssuredPressure Support (VAPS)
Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure
breath continues to guarantee volume - 1048707 PIP and inspiratory time increase
1048707 Guarantees volume on current breath (no previous breath averaging)
1048707 Combines the advantages of pressure and volume ventilation breath to breath
Characteristics of VAPS 1048707 The ventilator continuously measures the flow and
pressure and calculates delivered volume Depending on the actual settings breath may be flow
volume or time cycled 1048707 If the target tidal volume has been delivered
inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set
flow will persist until the desired volume has been reached (volume cycled breath)
1048707 Safety limits include high pressure and maximum inspiratory time1048707
Used in the Management of acute and recovering lung disease
Benefits of VAPS
1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort
Applications of VAPS 1048707 A patient who requires a substantial level of
ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony
1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change
Limitations 1048707 Will only increase pressure not lower pressure
with changing mechanics 1048707 Increases inspiratory time to assure volume
Volume support ventilation
Support mode Has PVRC as back up mode Allows spontaneous if preset MV is
achieved If fails deliver preset TV MV in lowest
possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure
limitlower amp upper MV alarm
Applications of VSV
Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations
in inspiratory pressure support
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
TYPES
INVASIVE APRV BIPAP Self adaptive modes Proportional assist ventilation Independent ventilation High frequency ventilation Extracorporeal membrane oxygenation Liquid ventilation NONINVASIVE
NON INVASIVE VENTILATION Negative pressure ventilators (Tank and
Cuirass ventilators) were the only non-invasive methods of assisting ventilation for many years mainly for ventilating large number of victims of Polio during their acute illness
use of NIMV has increased in last
decade in various conditions to avoid complications of intubation
Types
Positive Pressure Ventilation
Negative Pressure Ventilation
Mechanism of Action Improvement in pulmonary mechanics and oxygenation In COPD oxygen therapy often worsens
hypercarbia and respiratory acidosis Augments alveolar ventilation and oxygenation
without raising PaCO2 Partial unloading of respiratory muscles Reduces trans-diaphragmatic pressure pressure
time index of respiratory muscles and diaphragmatic electromyographic activity -
Alteration in breathing pattern with an increase in tidal volume decrease in respiratory rate and increase in minute ventilation
NIMV also overcomes the effect of intrinsic PEEP
Advantages of NIMV Preservation of airway defense mechanism Early ventilatory support an option
Intermittent ventilation possible
Patient can eat drink and communicate
Ease of application and removal
Patient can cooperate with physiotherapy
Contdhellip
Improved patient comfort Reduced need for sedation Avoidance of complications of
endotracheal intubation upper airway trauma sinusitis otitis nosocomial pneumonia
Ventilation outside hospital possible Correction of hypoxaemia without
worsening hypercarbia Ease to teach paramedics and nurses
Disadvantages
Mask uncomfortableclaustrophobic Time consuming for medical and nursing
staff Facial pressure sores Airway not protected No direct access to bronchial tree for
suction if secretions are excessive Less effective
Indications of NIMV
Hypercapnic acute respiratory failure
Acute exacerbation of COPD
Post extubation Weaning difficulties Post surgical respiratory
failure Thoracic wall deformities Cystic fibrosis Status asthmaticus Obesity hypoventilation
Syndrome
Hypoxaemic acute respiratory failure
Cardiogenic pulmonary oedema
Community acquired pneumonia
Post traumatic respiratory failure
ARDS Weaning difficulties Chronic Respiratory
Failure Immunocompromised
Patients
Contraindications
Respiratory arrest Unstable cardiorespiratory status Uncooperative patients -confused agitated Unable to protect airway- impaired swallowing
and cough Facial Oesophageal or gastric surgery Craniofacial traumaburn Anatomic lesions of upper airway Vomiting Impaired conciousness
Relative Contraindications
Extreme anxiety Massive obesity
Copious secretions
Need for continuous or nearly continuous ventilatory assistance
Prerequisites for successful Non-Invasive support
Patient is able to cooperate Patient can control airway and secretions Adequate cough reflex Patient is able to co-ordinate breathing with ventilator Patient can breathe unaided for several minutes Haemodynamically stable Blood pHgt71 and PaCO2 lt92 mmHg Improvement in gas exchange heart rate and
respiratory rate within first two hours Normal functioning gastrointestinal tract
Interface Interfaces are devices that connect ventilator tubing to
the face allowing the entry of pressurized gas to the upper airway
Nasal and oronasal masks and mouth pieces CPAP helmet are currently available interfaces
Masks - made from a non irritant material such as silicon rubber - minimal dead space and a soft inflatable cuff to provide a seal with the skin
Nasal mask - better tolerated but less effective ndash leak Face masks are more useful in acute respiratory failure Nasal masksMouth piece CPAP helmet are used most
often in chronic respiratory failure
Ventilators - conventional
Advantages FiO2 can be set Alarm amp monitoring
back up Back up ventilation Separate insp amp exp
limbs ndash prevent rebreathing
Inspiratory pressure gt 20 cm H2O can be set
Disadvantages Expensive Less flexible
ampportable Leak compensation
not present ndash requires tight interface
NPPV Ventilators
Advantages cheaper flexible ampportable Leak compensation
present ndash does not requires tight interface
Inspiratory pressure of 20 cm H2Ois maximum available
Disadvantages FiO2 cannot be set
Due to leak ndash high oxygen flows
Single limb ndash rebreathing
Modes of Ventilation CPAP It is not a true ventilator mode as it does not actively
assist inspiration CPAP by nasal mask provides pneumatic splint which
holds the upper airway open in patients with nocturnal hypoxaemia due to episodes of obstructive sleep apnoea
CPAP increases FRC and opens collapsed alveoli CPAP reduces left ventricular transmural pressure
therefore increases cardiac output ndash effective for treatment of pulmonary oedema
Pressures are usually limited to 5-12 cm of H2O - higher pressure tends to result in gastric distension
BILEVEL POSITIVE AIRWAY PRESSURE [ BI LEVEL PAP]
Unique flow triggering ampleak compensation Spontaneous mode ndashcycle between IPAP (Up to 30 cm
H2O)amp EPAP (Up to 15 cm of H2O)- PATIENT TRIGGERED PRESSURE SUPPORTED
IPAP = PEEP +PS EPAP = PEEP in PCVSPECIAL MACHINES Have blower unit to compensate air leaks upto 180 L mt Pressure limited back up Adjustable sensitivities maximum inspiratory
time adjustable FiO2 -available
BI LEVEL PAP[contdhellip] INDICATIONS Worsening
hypoventilation hypoxemia
Chronic ventilatory muscle dysfunction
Post intubation difficulty Upper airway
obstruction ndashlaryngeal oedemastrictures
CONTRA INDICATIONS Unstable
Haemodynamics Vomiting Neurologically abnormal Pneumothorax Deteriorating respiratory
parameters
PSV
Non-invasive PSV can be administered with standard critical care ventilator or bilevel portable devices -patient triggeredpressure limited flow cycled ventilation
PSV mode has unique ability to vary inspiratory time breath by breath permitting close matching with the patients spontaneous breathing pattern
Advantages (a) Patient-ventilator synchrony (b) Improved patient comfort(c) Reduced diaphragmatic work
Volume limited ventilation ventilators are usually set in assist-control mode with
high tidal volume (10-15 mlkg) to compensate for air leak
suitable in obesity or chest wall deformity who need high
inflation pressure neuromuscular diseases who need high tidal
volume for ventilation Proportional assist ventilation (PAV)
This is a newer mode of ventilation In this mode ventilator has capacity of responding
rapidly to the patients ventilatory efforts By adjusting the gain on the flow and volume signals
one can select the proportion of breathing work that is to be assisted
Goals of NIMV
Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival
Protocol for Non Invasive Ventilation
Explain to the patient what you are doing and what to expect
Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the
patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort
Connect humidification system
Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG
Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O
Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts
Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks
Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg
Increase FiO2 to improve O2 saturation to 90
Complications and Side effects
AIR LEAK [80 -100]
MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly
over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction
FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension
MAJOR COMPLICATIONS Aspiration pneumonia - lt
5 Hypotension Pneumothorax
CRITERIA FOR FAILURE OF NPPV
MAJOR Respiratory arrest Loss of
consciousness Psychomotor
agitation Haemodynamic
instability Heart rate lt50 bm
MINOR Respiratory rate gt 35
mt pH lt730 Pao2 lt45mmHg
Intubate when one major two minor criteria
INVASIVE VENTILATION
Pressure RegulatedVolume Control [PVRC]
Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled
assistcontrol
Establishes a ldquolearning periodrdquo to determine
patientrsquos compliance which establishes regulation of pressurevolume
Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration
Pressure RegulatedVolume Control (PRVC)
1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume
The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume
Results in breath-to-breath variation of inspiratory pressure
Limitations Only an AC mode and requires a change to
Volume Support for weaning Only guarantees volume distally and not at
patient airway
TV AIRWAY PRESSURE
PROBLEMS
VCV preset fn of mechpropertyof lungs
lung injury
PCV acc to mecha property of lung
preset hypoventilation
volutrauma
PRVC preset lower paw necessary
Benefits of both
Comparison with established modes
Applications of PRVC
ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high
flow rates In whom VT has to be controlled ndashsurfactant
therapy
Benefits
Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to
mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort
BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]
Pressure controlled ventilation allowing spontaneous ventilation
Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest
airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to
ventilator in VCV
BIPAP -SUBDIVISIONS
CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at
lower level APRV ndash BIPAP - spontaneous breathing
at higher level Genuine BIPAP - spontaneous breathing
at both levels CPAP - spontaneous breathing at single
CPAP level
paw
t
Setting up BIPAP
Adjusted with ABG values High low PaCO2 Normal PaO2
VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2
mean airway pressure without altering VTRR
equidirectional alteration of P high P low
ADVANTAGES OF BIPAP
Less sedation Reduced atelectasis Ideal mode in pts with inadequate
spontaneous effort In face of deteriorating gas exchange
we can increase the invasiveness of ventilation without having to change mode
Airway Pressure Release Ventilation
(APRV) Outlined in 1987 Continuous positive airway pressure with
regular brief intermittent releases in airway pressure
The release phase results in alveolar ventilation and removal of carbon dioxide
APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance
It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation
Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance
APRV ndashCONTDhellip
Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation
APRV commences at an elevated baseline pressure and follows with a measured pressure release
During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels
Available on Draumlger and Puritan Bennett ventilators
APRV ndashCONTDhellip
Elevated baseline airway pressure during APRV may produce near complete recruitment
Minimizes low volume lung injury from cyclic recruitment
APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation
Needs a High flow CPAP circuit with release valve
Advantages of APRV Lower peak airway pressures Lower minute ventilation
Decreased adverse effects upon circulatory function
Spontaneous ventilation the entire ventilatory cycle
Decreased need for sedation
Near elimination of neuromuscular blockade Recruitment of alveoli
Indications for APRV ALI or low-compliance lung disease patients with airway disease
CONTRAINDICATIONS
Patients with Increased airway resistance
When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation
The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation
P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus
accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than
40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0
cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure
Settings of APRV
Pressure support ventilation
Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by
specific amount of positive pressure at airway
PS Terminated when insp Flow falls below a minimum trigger volume
Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau
` ADVANTAGES Less WOB low pressure high volume work similar to
spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is
achieved with PS of 5 cm H2O
Volume AssuredPressure Support (VAPS)
Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure
breath continues to guarantee volume - 1048707 PIP and inspiratory time increase
1048707 Guarantees volume on current breath (no previous breath averaging)
1048707 Combines the advantages of pressure and volume ventilation breath to breath
Characteristics of VAPS 1048707 The ventilator continuously measures the flow and
pressure and calculates delivered volume Depending on the actual settings breath may be flow
volume or time cycled 1048707 If the target tidal volume has been delivered
inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set
flow will persist until the desired volume has been reached (volume cycled breath)
1048707 Safety limits include high pressure and maximum inspiratory time1048707
Used in the Management of acute and recovering lung disease
Benefits of VAPS
1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort
Applications of VAPS 1048707 A patient who requires a substantial level of
ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony
1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change
Limitations 1048707 Will only increase pressure not lower pressure
with changing mechanics 1048707 Increases inspiratory time to assure volume
Volume support ventilation
Support mode Has PVRC as back up mode Allows spontaneous if preset MV is
achieved If fails deliver preset TV MV in lowest
possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure
limitlower amp upper MV alarm
Applications of VSV
Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations
in inspiratory pressure support
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
NON INVASIVE VENTILATION Negative pressure ventilators (Tank and
Cuirass ventilators) were the only non-invasive methods of assisting ventilation for many years mainly for ventilating large number of victims of Polio during their acute illness
use of NIMV has increased in last
decade in various conditions to avoid complications of intubation
Types
Positive Pressure Ventilation
Negative Pressure Ventilation
Mechanism of Action Improvement in pulmonary mechanics and oxygenation In COPD oxygen therapy often worsens
hypercarbia and respiratory acidosis Augments alveolar ventilation and oxygenation
without raising PaCO2 Partial unloading of respiratory muscles Reduces trans-diaphragmatic pressure pressure
time index of respiratory muscles and diaphragmatic electromyographic activity -
Alteration in breathing pattern with an increase in tidal volume decrease in respiratory rate and increase in minute ventilation
NIMV also overcomes the effect of intrinsic PEEP
Advantages of NIMV Preservation of airway defense mechanism Early ventilatory support an option
Intermittent ventilation possible
Patient can eat drink and communicate
Ease of application and removal
Patient can cooperate with physiotherapy
Contdhellip
Improved patient comfort Reduced need for sedation Avoidance of complications of
endotracheal intubation upper airway trauma sinusitis otitis nosocomial pneumonia
Ventilation outside hospital possible Correction of hypoxaemia without
worsening hypercarbia Ease to teach paramedics and nurses
Disadvantages
Mask uncomfortableclaustrophobic Time consuming for medical and nursing
staff Facial pressure sores Airway not protected No direct access to bronchial tree for
suction if secretions are excessive Less effective
Indications of NIMV
Hypercapnic acute respiratory failure
Acute exacerbation of COPD
Post extubation Weaning difficulties Post surgical respiratory
failure Thoracic wall deformities Cystic fibrosis Status asthmaticus Obesity hypoventilation
Syndrome
Hypoxaemic acute respiratory failure
Cardiogenic pulmonary oedema
Community acquired pneumonia
Post traumatic respiratory failure
ARDS Weaning difficulties Chronic Respiratory
Failure Immunocompromised
Patients
Contraindications
Respiratory arrest Unstable cardiorespiratory status Uncooperative patients -confused agitated Unable to protect airway- impaired swallowing
and cough Facial Oesophageal or gastric surgery Craniofacial traumaburn Anatomic lesions of upper airway Vomiting Impaired conciousness
Relative Contraindications
Extreme anxiety Massive obesity
Copious secretions
Need for continuous or nearly continuous ventilatory assistance
Prerequisites for successful Non-Invasive support
Patient is able to cooperate Patient can control airway and secretions Adequate cough reflex Patient is able to co-ordinate breathing with ventilator Patient can breathe unaided for several minutes Haemodynamically stable Blood pHgt71 and PaCO2 lt92 mmHg Improvement in gas exchange heart rate and
respiratory rate within first two hours Normal functioning gastrointestinal tract
Interface Interfaces are devices that connect ventilator tubing to
the face allowing the entry of pressurized gas to the upper airway
Nasal and oronasal masks and mouth pieces CPAP helmet are currently available interfaces
Masks - made from a non irritant material such as silicon rubber - minimal dead space and a soft inflatable cuff to provide a seal with the skin
Nasal mask - better tolerated but less effective ndash leak Face masks are more useful in acute respiratory failure Nasal masksMouth piece CPAP helmet are used most
often in chronic respiratory failure
Ventilators - conventional
Advantages FiO2 can be set Alarm amp monitoring
back up Back up ventilation Separate insp amp exp
limbs ndash prevent rebreathing
Inspiratory pressure gt 20 cm H2O can be set
Disadvantages Expensive Less flexible
ampportable Leak compensation
not present ndash requires tight interface
NPPV Ventilators
Advantages cheaper flexible ampportable Leak compensation
present ndash does not requires tight interface
Inspiratory pressure of 20 cm H2Ois maximum available
Disadvantages FiO2 cannot be set
Due to leak ndash high oxygen flows
Single limb ndash rebreathing
Modes of Ventilation CPAP It is not a true ventilator mode as it does not actively
assist inspiration CPAP by nasal mask provides pneumatic splint which
holds the upper airway open in patients with nocturnal hypoxaemia due to episodes of obstructive sleep apnoea
CPAP increases FRC and opens collapsed alveoli CPAP reduces left ventricular transmural pressure
therefore increases cardiac output ndash effective for treatment of pulmonary oedema
Pressures are usually limited to 5-12 cm of H2O - higher pressure tends to result in gastric distension
BILEVEL POSITIVE AIRWAY PRESSURE [ BI LEVEL PAP]
Unique flow triggering ampleak compensation Spontaneous mode ndashcycle between IPAP (Up to 30 cm
H2O)amp EPAP (Up to 15 cm of H2O)- PATIENT TRIGGERED PRESSURE SUPPORTED
IPAP = PEEP +PS EPAP = PEEP in PCVSPECIAL MACHINES Have blower unit to compensate air leaks upto 180 L mt Pressure limited back up Adjustable sensitivities maximum inspiratory
time adjustable FiO2 -available
BI LEVEL PAP[contdhellip] INDICATIONS Worsening
hypoventilation hypoxemia
Chronic ventilatory muscle dysfunction
Post intubation difficulty Upper airway
obstruction ndashlaryngeal oedemastrictures
CONTRA INDICATIONS Unstable
Haemodynamics Vomiting Neurologically abnormal Pneumothorax Deteriorating respiratory
parameters
PSV
Non-invasive PSV can be administered with standard critical care ventilator or bilevel portable devices -patient triggeredpressure limited flow cycled ventilation
PSV mode has unique ability to vary inspiratory time breath by breath permitting close matching with the patients spontaneous breathing pattern
Advantages (a) Patient-ventilator synchrony (b) Improved patient comfort(c) Reduced diaphragmatic work
Volume limited ventilation ventilators are usually set in assist-control mode with
high tidal volume (10-15 mlkg) to compensate for air leak
suitable in obesity or chest wall deformity who need high
inflation pressure neuromuscular diseases who need high tidal
volume for ventilation Proportional assist ventilation (PAV)
This is a newer mode of ventilation In this mode ventilator has capacity of responding
rapidly to the patients ventilatory efforts By adjusting the gain on the flow and volume signals
one can select the proportion of breathing work that is to be assisted
Goals of NIMV
Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival
Protocol for Non Invasive Ventilation
Explain to the patient what you are doing and what to expect
Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the
patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort
Connect humidification system
Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG
Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O
Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts
Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks
Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg
Increase FiO2 to improve O2 saturation to 90
Complications and Side effects
AIR LEAK [80 -100]
MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly
over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction
FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension
MAJOR COMPLICATIONS Aspiration pneumonia - lt
5 Hypotension Pneumothorax
CRITERIA FOR FAILURE OF NPPV
MAJOR Respiratory arrest Loss of
consciousness Psychomotor
agitation Haemodynamic
instability Heart rate lt50 bm
MINOR Respiratory rate gt 35
mt pH lt730 Pao2 lt45mmHg
Intubate when one major two minor criteria
INVASIVE VENTILATION
Pressure RegulatedVolume Control [PVRC]
Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled
assistcontrol
Establishes a ldquolearning periodrdquo to determine
patientrsquos compliance which establishes regulation of pressurevolume
Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration
Pressure RegulatedVolume Control (PRVC)
1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume
The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume
Results in breath-to-breath variation of inspiratory pressure
Limitations Only an AC mode and requires a change to
Volume Support for weaning Only guarantees volume distally and not at
patient airway
TV AIRWAY PRESSURE
PROBLEMS
VCV preset fn of mechpropertyof lungs
lung injury
PCV acc to mecha property of lung
preset hypoventilation
volutrauma
PRVC preset lower paw necessary
Benefits of both
Comparison with established modes
Applications of PRVC
ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high
flow rates In whom VT has to be controlled ndashsurfactant
therapy
Benefits
Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to
mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort
BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]
Pressure controlled ventilation allowing spontaneous ventilation
Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest
airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to
ventilator in VCV
BIPAP -SUBDIVISIONS
CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at
lower level APRV ndash BIPAP - spontaneous breathing
at higher level Genuine BIPAP - spontaneous breathing
at both levels CPAP - spontaneous breathing at single
CPAP level
paw
t
Setting up BIPAP
Adjusted with ABG values High low PaCO2 Normal PaO2
VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2
mean airway pressure without altering VTRR
equidirectional alteration of P high P low
ADVANTAGES OF BIPAP
Less sedation Reduced atelectasis Ideal mode in pts with inadequate
spontaneous effort In face of deteriorating gas exchange
we can increase the invasiveness of ventilation without having to change mode
Airway Pressure Release Ventilation
(APRV) Outlined in 1987 Continuous positive airway pressure with
regular brief intermittent releases in airway pressure
The release phase results in alveolar ventilation and removal of carbon dioxide
APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance
It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation
Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance
APRV ndashCONTDhellip
Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation
APRV commences at an elevated baseline pressure and follows with a measured pressure release
During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels
Available on Draumlger and Puritan Bennett ventilators
APRV ndashCONTDhellip
Elevated baseline airway pressure during APRV may produce near complete recruitment
Minimizes low volume lung injury from cyclic recruitment
APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation
Needs a High flow CPAP circuit with release valve
Advantages of APRV Lower peak airway pressures Lower minute ventilation
Decreased adverse effects upon circulatory function
Spontaneous ventilation the entire ventilatory cycle
Decreased need for sedation
Near elimination of neuromuscular blockade Recruitment of alveoli
Indications for APRV ALI or low-compliance lung disease patients with airway disease
CONTRAINDICATIONS
Patients with Increased airway resistance
When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation
The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation
P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus
accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than
40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0
cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure
Settings of APRV
Pressure support ventilation
Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by
specific amount of positive pressure at airway
PS Terminated when insp Flow falls below a minimum trigger volume
Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau
` ADVANTAGES Less WOB low pressure high volume work similar to
spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is
achieved with PS of 5 cm H2O
Volume AssuredPressure Support (VAPS)
Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure
breath continues to guarantee volume - 1048707 PIP and inspiratory time increase
1048707 Guarantees volume on current breath (no previous breath averaging)
1048707 Combines the advantages of pressure and volume ventilation breath to breath
Characteristics of VAPS 1048707 The ventilator continuously measures the flow and
pressure and calculates delivered volume Depending on the actual settings breath may be flow
volume or time cycled 1048707 If the target tidal volume has been delivered
inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set
flow will persist until the desired volume has been reached (volume cycled breath)
1048707 Safety limits include high pressure and maximum inspiratory time1048707
Used in the Management of acute and recovering lung disease
Benefits of VAPS
1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort
Applications of VAPS 1048707 A patient who requires a substantial level of
ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony
1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change
Limitations 1048707 Will only increase pressure not lower pressure
with changing mechanics 1048707 Increases inspiratory time to assure volume
Volume support ventilation
Support mode Has PVRC as back up mode Allows spontaneous if preset MV is
achieved If fails deliver preset TV MV in lowest
possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure
limitlower amp upper MV alarm
Applications of VSV
Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations
in inspiratory pressure support
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
Types
Positive Pressure Ventilation
Negative Pressure Ventilation
Mechanism of Action Improvement in pulmonary mechanics and oxygenation In COPD oxygen therapy often worsens
hypercarbia and respiratory acidosis Augments alveolar ventilation and oxygenation
without raising PaCO2 Partial unloading of respiratory muscles Reduces trans-diaphragmatic pressure pressure
time index of respiratory muscles and diaphragmatic electromyographic activity -
Alteration in breathing pattern with an increase in tidal volume decrease in respiratory rate and increase in minute ventilation
NIMV also overcomes the effect of intrinsic PEEP
Advantages of NIMV Preservation of airway defense mechanism Early ventilatory support an option
Intermittent ventilation possible
Patient can eat drink and communicate
Ease of application and removal
Patient can cooperate with physiotherapy
Contdhellip
Improved patient comfort Reduced need for sedation Avoidance of complications of
endotracheal intubation upper airway trauma sinusitis otitis nosocomial pneumonia
Ventilation outside hospital possible Correction of hypoxaemia without
worsening hypercarbia Ease to teach paramedics and nurses
Disadvantages
Mask uncomfortableclaustrophobic Time consuming for medical and nursing
staff Facial pressure sores Airway not protected No direct access to bronchial tree for
suction if secretions are excessive Less effective
Indications of NIMV
Hypercapnic acute respiratory failure
Acute exacerbation of COPD
Post extubation Weaning difficulties Post surgical respiratory
failure Thoracic wall deformities Cystic fibrosis Status asthmaticus Obesity hypoventilation
Syndrome
Hypoxaemic acute respiratory failure
Cardiogenic pulmonary oedema
Community acquired pneumonia
Post traumatic respiratory failure
ARDS Weaning difficulties Chronic Respiratory
Failure Immunocompromised
Patients
Contraindications
Respiratory arrest Unstable cardiorespiratory status Uncooperative patients -confused agitated Unable to protect airway- impaired swallowing
and cough Facial Oesophageal or gastric surgery Craniofacial traumaburn Anatomic lesions of upper airway Vomiting Impaired conciousness
Relative Contraindications
Extreme anxiety Massive obesity
Copious secretions
Need for continuous or nearly continuous ventilatory assistance
Prerequisites for successful Non-Invasive support
Patient is able to cooperate Patient can control airway and secretions Adequate cough reflex Patient is able to co-ordinate breathing with ventilator Patient can breathe unaided for several minutes Haemodynamically stable Blood pHgt71 and PaCO2 lt92 mmHg Improvement in gas exchange heart rate and
respiratory rate within first two hours Normal functioning gastrointestinal tract
Interface Interfaces are devices that connect ventilator tubing to
the face allowing the entry of pressurized gas to the upper airway
Nasal and oronasal masks and mouth pieces CPAP helmet are currently available interfaces
Masks - made from a non irritant material such as silicon rubber - minimal dead space and a soft inflatable cuff to provide a seal with the skin
Nasal mask - better tolerated but less effective ndash leak Face masks are more useful in acute respiratory failure Nasal masksMouth piece CPAP helmet are used most
often in chronic respiratory failure
Ventilators - conventional
Advantages FiO2 can be set Alarm amp monitoring
back up Back up ventilation Separate insp amp exp
limbs ndash prevent rebreathing
Inspiratory pressure gt 20 cm H2O can be set
Disadvantages Expensive Less flexible
ampportable Leak compensation
not present ndash requires tight interface
NPPV Ventilators
Advantages cheaper flexible ampportable Leak compensation
present ndash does not requires tight interface
Inspiratory pressure of 20 cm H2Ois maximum available
Disadvantages FiO2 cannot be set
Due to leak ndash high oxygen flows
Single limb ndash rebreathing
Modes of Ventilation CPAP It is not a true ventilator mode as it does not actively
assist inspiration CPAP by nasal mask provides pneumatic splint which
holds the upper airway open in patients with nocturnal hypoxaemia due to episodes of obstructive sleep apnoea
CPAP increases FRC and opens collapsed alveoli CPAP reduces left ventricular transmural pressure
therefore increases cardiac output ndash effective for treatment of pulmonary oedema
Pressures are usually limited to 5-12 cm of H2O - higher pressure tends to result in gastric distension
BILEVEL POSITIVE AIRWAY PRESSURE [ BI LEVEL PAP]
Unique flow triggering ampleak compensation Spontaneous mode ndashcycle between IPAP (Up to 30 cm
H2O)amp EPAP (Up to 15 cm of H2O)- PATIENT TRIGGERED PRESSURE SUPPORTED
IPAP = PEEP +PS EPAP = PEEP in PCVSPECIAL MACHINES Have blower unit to compensate air leaks upto 180 L mt Pressure limited back up Adjustable sensitivities maximum inspiratory
time adjustable FiO2 -available
BI LEVEL PAP[contdhellip] INDICATIONS Worsening
hypoventilation hypoxemia
Chronic ventilatory muscle dysfunction
Post intubation difficulty Upper airway
obstruction ndashlaryngeal oedemastrictures
CONTRA INDICATIONS Unstable
Haemodynamics Vomiting Neurologically abnormal Pneumothorax Deteriorating respiratory
parameters
PSV
Non-invasive PSV can be administered with standard critical care ventilator or bilevel portable devices -patient triggeredpressure limited flow cycled ventilation
PSV mode has unique ability to vary inspiratory time breath by breath permitting close matching with the patients spontaneous breathing pattern
Advantages (a) Patient-ventilator synchrony (b) Improved patient comfort(c) Reduced diaphragmatic work
Volume limited ventilation ventilators are usually set in assist-control mode with
high tidal volume (10-15 mlkg) to compensate for air leak
suitable in obesity or chest wall deformity who need high
inflation pressure neuromuscular diseases who need high tidal
volume for ventilation Proportional assist ventilation (PAV)
This is a newer mode of ventilation In this mode ventilator has capacity of responding
rapidly to the patients ventilatory efforts By adjusting the gain on the flow and volume signals
one can select the proportion of breathing work that is to be assisted
Goals of NIMV
Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival
Protocol for Non Invasive Ventilation
Explain to the patient what you are doing and what to expect
Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the
patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort
Connect humidification system
Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG
Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O
Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts
Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks
Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg
Increase FiO2 to improve O2 saturation to 90
Complications and Side effects
AIR LEAK [80 -100]
MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly
over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction
FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension
MAJOR COMPLICATIONS Aspiration pneumonia - lt
5 Hypotension Pneumothorax
CRITERIA FOR FAILURE OF NPPV
MAJOR Respiratory arrest Loss of
consciousness Psychomotor
agitation Haemodynamic
instability Heart rate lt50 bm
MINOR Respiratory rate gt 35
mt pH lt730 Pao2 lt45mmHg
Intubate when one major two minor criteria
INVASIVE VENTILATION
Pressure RegulatedVolume Control [PVRC]
Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled
assistcontrol
Establishes a ldquolearning periodrdquo to determine
patientrsquos compliance which establishes regulation of pressurevolume
Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration
Pressure RegulatedVolume Control (PRVC)
1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume
The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume
Results in breath-to-breath variation of inspiratory pressure
Limitations Only an AC mode and requires a change to
Volume Support for weaning Only guarantees volume distally and not at
patient airway
TV AIRWAY PRESSURE
PROBLEMS
VCV preset fn of mechpropertyof lungs
lung injury
PCV acc to mecha property of lung
preset hypoventilation
volutrauma
PRVC preset lower paw necessary
Benefits of both
Comparison with established modes
Applications of PRVC
ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high
flow rates In whom VT has to be controlled ndashsurfactant
therapy
Benefits
Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to
mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort
BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]
Pressure controlled ventilation allowing spontaneous ventilation
Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest
airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to
ventilator in VCV
BIPAP -SUBDIVISIONS
CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at
lower level APRV ndash BIPAP - spontaneous breathing
at higher level Genuine BIPAP - spontaneous breathing
at both levels CPAP - spontaneous breathing at single
CPAP level
paw
t
Setting up BIPAP
Adjusted with ABG values High low PaCO2 Normal PaO2
VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2
mean airway pressure without altering VTRR
equidirectional alteration of P high P low
ADVANTAGES OF BIPAP
Less sedation Reduced atelectasis Ideal mode in pts with inadequate
spontaneous effort In face of deteriorating gas exchange
we can increase the invasiveness of ventilation without having to change mode
Airway Pressure Release Ventilation
(APRV) Outlined in 1987 Continuous positive airway pressure with
regular brief intermittent releases in airway pressure
The release phase results in alveolar ventilation and removal of carbon dioxide
APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance
It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation
Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance
APRV ndashCONTDhellip
Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation
APRV commences at an elevated baseline pressure and follows with a measured pressure release
During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels
Available on Draumlger and Puritan Bennett ventilators
APRV ndashCONTDhellip
Elevated baseline airway pressure during APRV may produce near complete recruitment
Minimizes low volume lung injury from cyclic recruitment
APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation
Needs a High flow CPAP circuit with release valve
Advantages of APRV Lower peak airway pressures Lower minute ventilation
Decreased adverse effects upon circulatory function
Spontaneous ventilation the entire ventilatory cycle
Decreased need for sedation
Near elimination of neuromuscular blockade Recruitment of alveoli
Indications for APRV ALI or low-compliance lung disease patients with airway disease
CONTRAINDICATIONS
Patients with Increased airway resistance
When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation
The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation
P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus
accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than
40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0
cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure
Settings of APRV
Pressure support ventilation
Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by
specific amount of positive pressure at airway
PS Terminated when insp Flow falls below a minimum trigger volume
Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau
` ADVANTAGES Less WOB low pressure high volume work similar to
spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is
achieved with PS of 5 cm H2O
Volume AssuredPressure Support (VAPS)
Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure
breath continues to guarantee volume - 1048707 PIP and inspiratory time increase
1048707 Guarantees volume on current breath (no previous breath averaging)
1048707 Combines the advantages of pressure and volume ventilation breath to breath
Characteristics of VAPS 1048707 The ventilator continuously measures the flow and
pressure and calculates delivered volume Depending on the actual settings breath may be flow
volume or time cycled 1048707 If the target tidal volume has been delivered
inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set
flow will persist until the desired volume has been reached (volume cycled breath)
1048707 Safety limits include high pressure and maximum inspiratory time1048707
Used in the Management of acute and recovering lung disease
Benefits of VAPS
1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort
Applications of VAPS 1048707 A patient who requires a substantial level of
ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony
1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change
Limitations 1048707 Will only increase pressure not lower pressure
with changing mechanics 1048707 Increases inspiratory time to assure volume
Volume support ventilation
Support mode Has PVRC as back up mode Allows spontaneous if preset MV is
achieved If fails deliver preset TV MV in lowest
possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure
limitlower amp upper MV alarm
Applications of VSV
Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations
in inspiratory pressure support
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
Mechanism of Action Improvement in pulmonary mechanics and oxygenation In COPD oxygen therapy often worsens
hypercarbia and respiratory acidosis Augments alveolar ventilation and oxygenation
without raising PaCO2 Partial unloading of respiratory muscles Reduces trans-diaphragmatic pressure pressure
time index of respiratory muscles and diaphragmatic electromyographic activity -
Alteration in breathing pattern with an increase in tidal volume decrease in respiratory rate and increase in minute ventilation
NIMV also overcomes the effect of intrinsic PEEP
Advantages of NIMV Preservation of airway defense mechanism Early ventilatory support an option
Intermittent ventilation possible
Patient can eat drink and communicate
Ease of application and removal
Patient can cooperate with physiotherapy
Contdhellip
Improved patient comfort Reduced need for sedation Avoidance of complications of
endotracheal intubation upper airway trauma sinusitis otitis nosocomial pneumonia
Ventilation outside hospital possible Correction of hypoxaemia without
worsening hypercarbia Ease to teach paramedics and nurses
Disadvantages
Mask uncomfortableclaustrophobic Time consuming for medical and nursing
staff Facial pressure sores Airway not protected No direct access to bronchial tree for
suction if secretions are excessive Less effective
Indications of NIMV
Hypercapnic acute respiratory failure
Acute exacerbation of COPD
Post extubation Weaning difficulties Post surgical respiratory
failure Thoracic wall deformities Cystic fibrosis Status asthmaticus Obesity hypoventilation
Syndrome
Hypoxaemic acute respiratory failure
Cardiogenic pulmonary oedema
Community acquired pneumonia
Post traumatic respiratory failure
ARDS Weaning difficulties Chronic Respiratory
Failure Immunocompromised
Patients
Contraindications
Respiratory arrest Unstable cardiorespiratory status Uncooperative patients -confused agitated Unable to protect airway- impaired swallowing
and cough Facial Oesophageal or gastric surgery Craniofacial traumaburn Anatomic lesions of upper airway Vomiting Impaired conciousness
Relative Contraindications
Extreme anxiety Massive obesity
Copious secretions
Need for continuous or nearly continuous ventilatory assistance
Prerequisites for successful Non-Invasive support
Patient is able to cooperate Patient can control airway and secretions Adequate cough reflex Patient is able to co-ordinate breathing with ventilator Patient can breathe unaided for several minutes Haemodynamically stable Blood pHgt71 and PaCO2 lt92 mmHg Improvement in gas exchange heart rate and
respiratory rate within first two hours Normal functioning gastrointestinal tract
Interface Interfaces are devices that connect ventilator tubing to
the face allowing the entry of pressurized gas to the upper airway
Nasal and oronasal masks and mouth pieces CPAP helmet are currently available interfaces
Masks - made from a non irritant material such as silicon rubber - minimal dead space and a soft inflatable cuff to provide a seal with the skin
Nasal mask - better tolerated but less effective ndash leak Face masks are more useful in acute respiratory failure Nasal masksMouth piece CPAP helmet are used most
often in chronic respiratory failure
Ventilators - conventional
Advantages FiO2 can be set Alarm amp monitoring
back up Back up ventilation Separate insp amp exp
limbs ndash prevent rebreathing
Inspiratory pressure gt 20 cm H2O can be set
Disadvantages Expensive Less flexible
ampportable Leak compensation
not present ndash requires tight interface
NPPV Ventilators
Advantages cheaper flexible ampportable Leak compensation
present ndash does not requires tight interface
Inspiratory pressure of 20 cm H2Ois maximum available
Disadvantages FiO2 cannot be set
Due to leak ndash high oxygen flows
Single limb ndash rebreathing
Modes of Ventilation CPAP It is not a true ventilator mode as it does not actively
assist inspiration CPAP by nasal mask provides pneumatic splint which
holds the upper airway open in patients with nocturnal hypoxaemia due to episodes of obstructive sleep apnoea
CPAP increases FRC and opens collapsed alveoli CPAP reduces left ventricular transmural pressure
therefore increases cardiac output ndash effective for treatment of pulmonary oedema
Pressures are usually limited to 5-12 cm of H2O - higher pressure tends to result in gastric distension
BILEVEL POSITIVE AIRWAY PRESSURE [ BI LEVEL PAP]
Unique flow triggering ampleak compensation Spontaneous mode ndashcycle between IPAP (Up to 30 cm
H2O)amp EPAP (Up to 15 cm of H2O)- PATIENT TRIGGERED PRESSURE SUPPORTED
IPAP = PEEP +PS EPAP = PEEP in PCVSPECIAL MACHINES Have blower unit to compensate air leaks upto 180 L mt Pressure limited back up Adjustable sensitivities maximum inspiratory
time adjustable FiO2 -available
BI LEVEL PAP[contdhellip] INDICATIONS Worsening
hypoventilation hypoxemia
Chronic ventilatory muscle dysfunction
Post intubation difficulty Upper airway
obstruction ndashlaryngeal oedemastrictures
CONTRA INDICATIONS Unstable
Haemodynamics Vomiting Neurologically abnormal Pneumothorax Deteriorating respiratory
parameters
PSV
Non-invasive PSV can be administered with standard critical care ventilator or bilevel portable devices -patient triggeredpressure limited flow cycled ventilation
PSV mode has unique ability to vary inspiratory time breath by breath permitting close matching with the patients spontaneous breathing pattern
Advantages (a) Patient-ventilator synchrony (b) Improved patient comfort(c) Reduced diaphragmatic work
Volume limited ventilation ventilators are usually set in assist-control mode with
high tidal volume (10-15 mlkg) to compensate for air leak
suitable in obesity or chest wall deformity who need high
inflation pressure neuromuscular diseases who need high tidal
volume for ventilation Proportional assist ventilation (PAV)
This is a newer mode of ventilation In this mode ventilator has capacity of responding
rapidly to the patients ventilatory efforts By adjusting the gain on the flow and volume signals
one can select the proportion of breathing work that is to be assisted
Goals of NIMV
Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival
Protocol for Non Invasive Ventilation
Explain to the patient what you are doing and what to expect
Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the
patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort
Connect humidification system
Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG
Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O
Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts
Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks
Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg
Increase FiO2 to improve O2 saturation to 90
Complications and Side effects
AIR LEAK [80 -100]
MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly
over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction
FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension
MAJOR COMPLICATIONS Aspiration pneumonia - lt
5 Hypotension Pneumothorax
CRITERIA FOR FAILURE OF NPPV
MAJOR Respiratory arrest Loss of
consciousness Psychomotor
agitation Haemodynamic
instability Heart rate lt50 bm
MINOR Respiratory rate gt 35
mt pH lt730 Pao2 lt45mmHg
Intubate when one major two minor criteria
INVASIVE VENTILATION
Pressure RegulatedVolume Control [PVRC]
Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled
assistcontrol
Establishes a ldquolearning periodrdquo to determine
patientrsquos compliance which establishes regulation of pressurevolume
Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration
Pressure RegulatedVolume Control (PRVC)
1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume
The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume
Results in breath-to-breath variation of inspiratory pressure
Limitations Only an AC mode and requires a change to
Volume Support for weaning Only guarantees volume distally and not at
patient airway
TV AIRWAY PRESSURE
PROBLEMS
VCV preset fn of mechpropertyof lungs
lung injury
PCV acc to mecha property of lung
preset hypoventilation
volutrauma
PRVC preset lower paw necessary
Benefits of both
Comparison with established modes
Applications of PRVC
ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high
flow rates In whom VT has to be controlled ndashsurfactant
therapy
Benefits
Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to
mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort
BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]
Pressure controlled ventilation allowing spontaneous ventilation
Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest
airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to
ventilator in VCV
BIPAP -SUBDIVISIONS
CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at
lower level APRV ndash BIPAP - spontaneous breathing
at higher level Genuine BIPAP - spontaneous breathing
at both levels CPAP - spontaneous breathing at single
CPAP level
paw
t
Setting up BIPAP
Adjusted with ABG values High low PaCO2 Normal PaO2
VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2
mean airway pressure without altering VTRR
equidirectional alteration of P high P low
ADVANTAGES OF BIPAP
Less sedation Reduced atelectasis Ideal mode in pts with inadequate
spontaneous effort In face of deteriorating gas exchange
we can increase the invasiveness of ventilation without having to change mode
Airway Pressure Release Ventilation
(APRV) Outlined in 1987 Continuous positive airway pressure with
regular brief intermittent releases in airway pressure
The release phase results in alveolar ventilation and removal of carbon dioxide
APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance
It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation
Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance
APRV ndashCONTDhellip
Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation
APRV commences at an elevated baseline pressure and follows with a measured pressure release
During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels
Available on Draumlger and Puritan Bennett ventilators
APRV ndashCONTDhellip
Elevated baseline airway pressure during APRV may produce near complete recruitment
Minimizes low volume lung injury from cyclic recruitment
APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation
Needs a High flow CPAP circuit with release valve
Advantages of APRV Lower peak airway pressures Lower minute ventilation
Decreased adverse effects upon circulatory function
Spontaneous ventilation the entire ventilatory cycle
Decreased need for sedation
Near elimination of neuromuscular blockade Recruitment of alveoli
Indications for APRV ALI or low-compliance lung disease patients with airway disease
CONTRAINDICATIONS
Patients with Increased airway resistance
When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation
The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation
P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus
accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than
40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0
cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure
Settings of APRV
Pressure support ventilation
Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by
specific amount of positive pressure at airway
PS Terminated when insp Flow falls below a minimum trigger volume
Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau
` ADVANTAGES Less WOB low pressure high volume work similar to
spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is
achieved with PS of 5 cm H2O
Volume AssuredPressure Support (VAPS)
Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure
breath continues to guarantee volume - 1048707 PIP and inspiratory time increase
1048707 Guarantees volume on current breath (no previous breath averaging)
1048707 Combines the advantages of pressure and volume ventilation breath to breath
Characteristics of VAPS 1048707 The ventilator continuously measures the flow and
pressure and calculates delivered volume Depending on the actual settings breath may be flow
volume or time cycled 1048707 If the target tidal volume has been delivered
inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set
flow will persist until the desired volume has been reached (volume cycled breath)
1048707 Safety limits include high pressure and maximum inspiratory time1048707
Used in the Management of acute and recovering lung disease
Benefits of VAPS
1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort
Applications of VAPS 1048707 A patient who requires a substantial level of
ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony
1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change
Limitations 1048707 Will only increase pressure not lower pressure
with changing mechanics 1048707 Increases inspiratory time to assure volume
Volume support ventilation
Support mode Has PVRC as back up mode Allows spontaneous if preset MV is
achieved If fails deliver preset TV MV in lowest
possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure
limitlower amp upper MV alarm
Applications of VSV
Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations
in inspiratory pressure support
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
Advantages of NIMV Preservation of airway defense mechanism Early ventilatory support an option
Intermittent ventilation possible
Patient can eat drink and communicate
Ease of application and removal
Patient can cooperate with physiotherapy
Contdhellip
Improved patient comfort Reduced need for sedation Avoidance of complications of
endotracheal intubation upper airway trauma sinusitis otitis nosocomial pneumonia
Ventilation outside hospital possible Correction of hypoxaemia without
worsening hypercarbia Ease to teach paramedics and nurses
Disadvantages
Mask uncomfortableclaustrophobic Time consuming for medical and nursing
staff Facial pressure sores Airway not protected No direct access to bronchial tree for
suction if secretions are excessive Less effective
Indications of NIMV
Hypercapnic acute respiratory failure
Acute exacerbation of COPD
Post extubation Weaning difficulties Post surgical respiratory
failure Thoracic wall deformities Cystic fibrosis Status asthmaticus Obesity hypoventilation
Syndrome
Hypoxaemic acute respiratory failure
Cardiogenic pulmonary oedema
Community acquired pneumonia
Post traumatic respiratory failure
ARDS Weaning difficulties Chronic Respiratory
Failure Immunocompromised
Patients
Contraindications
Respiratory arrest Unstable cardiorespiratory status Uncooperative patients -confused agitated Unable to protect airway- impaired swallowing
and cough Facial Oesophageal or gastric surgery Craniofacial traumaburn Anatomic lesions of upper airway Vomiting Impaired conciousness
Relative Contraindications
Extreme anxiety Massive obesity
Copious secretions
Need for continuous or nearly continuous ventilatory assistance
Prerequisites for successful Non-Invasive support
Patient is able to cooperate Patient can control airway and secretions Adequate cough reflex Patient is able to co-ordinate breathing with ventilator Patient can breathe unaided for several minutes Haemodynamically stable Blood pHgt71 and PaCO2 lt92 mmHg Improvement in gas exchange heart rate and
respiratory rate within first two hours Normal functioning gastrointestinal tract
Interface Interfaces are devices that connect ventilator tubing to
the face allowing the entry of pressurized gas to the upper airway
Nasal and oronasal masks and mouth pieces CPAP helmet are currently available interfaces
Masks - made from a non irritant material such as silicon rubber - minimal dead space and a soft inflatable cuff to provide a seal with the skin
Nasal mask - better tolerated but less effective ndash leak Face masks are more useful in acute respiratory failure Nasal masksMouth piece CPAP helmet are used most
often in chronic respiratory failure
Ventilators - conventional
Advantages FiO2 can be set Alarm amp monitoring
back up Back up ventilation Separate insp amp exp
limbs ndash prevent rebreathing
Inspiratory pressure gt 20 cm H2O can be set
Disadvantages Expensive Less flexible
ampportable Leak compensation
not present ndash requires tight interface
NPPV Ventilators
Advantages cheaper flexible ampportable Leak compensation
present ndash does not requires tight interface
Inspiratory pressure of 20 cm H2Ois maximum available
Disadvantages FiO2 cannot be set
Due to leak ndash high oxygen flows
Single limb ndash rebreathing
Modes of Ventilation CPAP It is not a true ventilator mode as it does not actively
assist inspiration CPAP by nasal mask provides pneumatic splint which
holds the upper airway open in patients with nocturnal hypoxaemia due to episodes of obstructive sleep apnoea
CPAP increases FRC and opens collapsed alveoli CPAP reduces left ventricular transmural pressure
therefore increases cardiac output ndash effective for treatment of pulmonary oedema
Pressures are usually limited to 5-12 cm of H2O - higher pressure tends to result in gastric distension
BILEVEL POSITIVE AIRWAY PRESSURE [ BI LEVEL PAP]
Unique flow triggering ampleak compensation Spontaneous mode ndashcycle between IPAP (Up to 30 cm
H2O)amp EPAP (Up to 15 cm of H2O)- PATIENT TRIGGERED PRESSURE SUPPORTED
IPAP = PEEP +PS EPAP = PEEP in PCVSPECIAL MACHINES Have blower unit to compensate air leaks upto 180 L mt Pressure limited back up Adjustable sensitivities maximum inspiratory
time adjustable FiO2 -available
BI LEVEL PAP[contdhellip] INDICATIONS Worsening
hypoventilation hypoxemia
Chronic ventilatory muscle dysfunction
Post intubation difficulty Upper airway
obstruction ndashlaryngeal oedemastrictures
CONTRA INDICATIONS Unstable
Haemodynamics Vomiting Neurologically abnormal Pneumothorax Deteriorating respiratory
parameters
PSV
Non-invasive PSV can be administered with standard critical care ventilator or bilevel portable devices -patient triggeredpressure limited flow cycled ventilation
PSV mode has unique ability to vary inspiratory time breath by breath permitting close matching with the patients spontaneous breathing pattern
Advantages (a) Patient-ventilator synchrony (b) Improved patient comfort(c) Reduced diaphragmatic work
Volume limited ventilation ventilators are usually set in assist-control mode with
high tidal volume (10-15 mlkg) to compensate for air leak
suitable in obesity or chest wall deformity who need high
inflation pressure neuromuscular diseases who need high tidal
volume for ventilation Proportional assist ventilation (PAV)
This is a newer mode of ventilation In this mode ventilator has capacity of responding
rapidly to the patients ventilatory efforts By adjusting the gain on the flow and volume signals
one can select the proportion of breathing work that is to be assisted
Goals of NIMV
Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival
Protocol for Non Invasive Ventilation
Explain to the patient what you are doing and what to expect
Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the
patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort
Connect humidification system
Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG
Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O
Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts
Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks
Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg
Increase FiO2 to improve O2 saturation to 90
Complications and Side effects
AIR LEAK [80 -100]
MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly
over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction
FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension
MAJOR COMPLICATIONS Aspiration pneumonia - lt
5 Hypotension Pneumothorax
CRITERIA FOR FAILURE OF NPPV
MAJOR Respiratory arrest Loss of
consciousness Psychomotor
agitation Haemodynamic
instability Heart rate lt50 bm
MINOR Respiratory rate gt 35
mt pH lt730 Pao2 lt45mmHg
Intubate when one major two minor criteria
INVASIVE VENTILATION
Pressure RegulatedVolume Control [PVRC]
Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled
assistcontrol
Establishes a ldquolearning periodrdquo to determine
patientrsquos compliance which establishes regulation of pressurevolume
Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration
Pressure RegulatedVolume Control (PRVC)
1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume
The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume
Results in breath-to-breath variation of inspiratory pressure
Limitations Only an AC mode and requires a change to
Volume Support for weaning Only guarantees volume distally and not at
patient airway
TV AIRWAY PRESSURE
PROBLEMS
VCV preset fn of mechpropertyof lungs
lung injury
PCV acc to mecha property of lung
preset hypoventilation
volutrauma
PRVC preset lower paw necessary
Benefits of both
Comparison with established modes
Applications of PRVC
ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high
flow rates In whom VT has to be controlled ndashsurfactant
therapy
Benefits
Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to
mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort
BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]
Pressure controlled ventilation allowing spontaneous ventilation
Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest
airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to
ventilator in VCV
BIPAP -SUBDIVISIONS
CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at
lower level APRV ndash BIPAP - spontaneous breathing
at higher level Genuine BIPAP - spontaneous breathing
at both levels CPAP - spontaneous breathing at single
CPAP level
paw
t
Setting up BIPAP
Adjusted with ABG values High low PaCO2 Normal PaO2
VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2
mean airway pressure without altering VTRR
equidirectional alteration of P high P low
ADVANTAGES OF BIPAP
Less sedation Reduced atelectasis Ideal mode in pts with inadequate
spontaneous effort In face of deteriorating gas exchange
we can increase the invasiveness of ventilation without having to change mode
Airway Pressure Release Ventilation
(APRV) Outlined in 1987 Continuous positive airway pressure with
regular brief intermittent releases in airway pressure
The release phase results in alveolar ventilation and removal of carbon dioxide
APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance
It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation
Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance
APRV ndashCONTDhellip
Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation
APRV commences at an elevated baseline pressure and follows with a measured pressure release
During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels
Available on Draumlger and Puritan Bennett ventilators
APRV ndashCONTDhellip
Elevated baseline airway pressure during APRV may produce near complete recruitment
Minimizes low volume lung injury from cyclic recruitment
APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation
Needs a High flow CPAP circuit with release valve
Advantages of APRV Lower peak airway pressures Lower minute ventilation
Decreased adverse effects upon circulatory function
Spontaneous ventilation the entire ventilatory cycle
Decreased need for sedation
Near elimination of neuromuscular blockade Recruitment of alveoli
Indications for APRV ALI or low-compliance lung disease patients with airway disease
CONTRAINDICATIONS
Patients with Increased airway resistance
When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation
The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation
P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus
accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than
40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0
cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure
Settings of APRV
Pressure support ventilation
Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by
specific amount of positive pressure at airway
PS Terminated when insp Flow falls below a minimum trigger volume
Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau
` ADVANTAGES Less WOB low pressure high volume work similar to
spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is
achieved with PS of 5 cm H2O
Volume AssuredPressure Support (VAPS)
Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure
breath continues to guarantee volume - 1048707 PIP and inspiratory time increase
1048707 Guarantees volume on current breath (no previous breath averaging)
1048707 Combines the advantages of pressure and volume ventilation breath to breath
Characteristics of VAPS 1048707 The ventilator continuously measures the flow and
pressure and calculates delivered volume Depending on the actual settings breath may be flow
volume or time cycled 1048707 If the target tidal volume has been delivered
inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set
flow will persist until the desired volume has been reached (volume cycled breath)
1048707 Safety limits include high pressure and maximum inspiratory time1048707
Used in the Management of acute and recovering lung disease
Benefits of VAPS
1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort
Applications of VAPS 1048707 A patient who requires a substantial level of
ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony
1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change
Limitations 1048707 Will only increase pressure not lower pressure
with changing mechanics 1048707 Increases inspiratory time to assure volume
Volume support ventilation
Support mode Has PVRC as back up mode Allows spontaneous if preset MV is
achieved If fails deliver preset TV MV in lowest
possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure
limitlower amp upper MV alarm
Applications of VSV
Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations
in inspiratory pressure support
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
Contdhellip
Improved patient comfort Reduced need for sedation Avoidance of complications of
endotracheal intubation upper airway trauma sinusitis otitis nosocomial pneumonia
Ventilation outside hospital possible Correction of hypoxaemia without
worsening hypercarbia Ease to teach paramedics and nurses
Disadvantages
Mask uncomfortableclaustrophobic Time consuming for medical and nursing
staff Facial pressure sores Airway not protected No direct access to bronchial tree for
suction if secretions are excessive Less effective
Indications of NIMV
Hypercapnic acute respiratory failure
Acute exacerbation of COPD
Post extubation Weaning difficulties Post surgical respiratory
failure Thoracic wall deformities Cystic fibrosis Status asthmaticus Obesity hypoventilation
Syndrome
Hypoxaemic acute respiratory failure
Cardiogenic pulmonary oedema
Community acquired pneumonia
Post traumatic respiratory failure
ARDS Weaning difficulties Chronic Respiratory
Failure Immunocompromised
Patients
Contraindications
Respiratory arrest Unstable cardiorespiratory status Uncooperative patients -confused agitated Unable to protect airway- impaired swallowing
and cough Facial Oesophageal or gastric surgery Craniofacial traumaburn Anatomic lesions of upper airway Vomiting Impaired conciousness
Relative Contraindications
Extreme anxiety Massive obesity
Copious secretions
Need for continuous or nearly continuous ventilatory assistance
Prerequisites for successful Non-Invasive support
Patient is able to cooperate Patient can control airway and secretions Adequate cough reflex Patient is able to co-ordinate breathing with ventilator Patient can breathe unaided for several minutes Haemodynamically stable Blood pHgt71 and PaCO2 lt92 mmHg Improvement in gas exchange heart rate and
respiratory rate within first two hours Normal functioning gastrointestinal tract
Interface Interfaces are devices that connect ventilator tubing to
the face allowing the entry of pressurized gas to the upper airway
Nasal and oronasal masks and mouth pieces CPAP helmet are currently available interfaces
Masks - made from a non irritant material such as silicon rubber - minimal dead space and a soft inflatable cuff to provide a seal with the skin
Nasal mask - better tolerated but less effective ndash leak Face masks are more useful in acute respiratory failure Nasal masksMouth piece CPAP helmet are used most
often in chronic respiratory failure
Ventilators - conventional
Advantages FiO2 can be set Alarm amp monitoring
back up Back up ventilation Separate insp amp exp
limbs ndash prevent rebreathing
Inspiratory pressure gt 20 cm H2O can be set
Disadvantages Expensive Less flexible
ampportable Leak compensation
not present ndash requires tight interface
NPPV Ventilators
Advantages cheaper flexible ampportable Leak compensation
present ndash does not requires tight interface
Inspiratory pressure of 20 cm H2Ois maximum available
Disadvantages FiO2 cannot be set
Due to leak ndash high oxygen flows
Single limb ndash rebreathing
Modes of Ventilation CPAP It is not a true ventilator mode as it does not actively
assist inspiration CPAP by nasal mask provides pneumatic splint which
holds the upper airway open in patients with nocturnal hypoxaemia due to episodes of obstructive sleep apnoea
CPAP increases FRC and opens collapsed alveoli CPAP reduces left ventricular transmural pressure
therefore increases cardiac output ndash effective for treatment of pulmonary oedema
Pressures are usually limited to 5-12 cm of H2O - higher pressure tends to result in gastric distension
BILEVEL POSITIVE AIRWAY PRESSURE [ BI LEVEL PAP]
Unique flow triggering ampleak compensation Spontaneous mode ndashcycle between IPAP (Up to 30 cm
H2O)amp EPAP (Up to 15 cm of H2O)- PATIENT TRIGGERED PRESSURE SUPPORTED
IPAP = PEEP +PS EPAP = PEEP in PCVSPECIAL MACHINES Have blower unit to compensate air leaks upto 180 L mt Pressure limited back up Adjustable sensitivities maximum inspiratory
time adjustable FiO2 -available
BI LEVEL PAP[contdhellip] INDICATIONS Worsening
hypoventilation hypoxemia
Chronic ventilatory muscle dysfunction
Post intubation difficulty Upper airway
obstruction ndashlaryngeal oedemastrictures
CONTRA INDICATIONS Unstable
Haemodynamics Vomiting Neurologically abnormal Pneumothorax Deteriorating respiratory
parameters
PSV
Non-invasive PSV can be administered with standard critical care ventilator or bilevel portable devices -patient triggeredpressure limited flow cycled ventilation
PSV mode has unique ability to vary inspiratory time breath by breath permitting close matching with the patients spontaneous breathing pattern
Advantages (a) Patient-ventilator synchrony (b) Improved patient comfort(c) Reduced diaphragmatic work
Volume limited ventilation ventilators are usually set in assist-control mode with
high tidal volume (10-15 mlkg) to compensate for air leak
suitable in obesity or chest wall deformity who need high
inflation pressure neuromuscular diseases who need high tidal
volume for ventilation Proportional assist ventilation (PAV)
This is a newer mode of ventilation In this mode ventilator has capacity of responding
rapidly to the patients ventilatory efforts By adjusting the gain on the flow and volume signals
one can select the proportion of breathing work that is to be assisted
Goals of NIMV
Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival
Protocol for Non Invasive Ventilation
Explain to the patient what you are doing and what to expect
Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the
patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort
Connect humidification system
Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG
Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O
Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts
Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks
Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg
Increase FiO2 to improve O2 saturation to 90
Complications and Side effects
AIR LEAK [80 -100]
MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly
over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction
FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension
MAJOR COMPLICATIONS Aspiration pneumonia - lt
5 Hypotension Pneumothorax
CRITERIA FOR FAILURE OF NPPV
MAJOR Respiratory arrest Loss of
consciousness Psychomotor
agitation Haemodynamic
instability Heart rate lt50 bm
MINOR Respiratory rate gt 35
mt pH lt730 Pao2 lt45mmHg
Intubate when one major two minor criteria
INVASIVE VENTILATION
Pressure RegulatedVolume Control [PVRC]
Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled
assistcontrol
Establishes a ldquolearning periodrdquo to determine
patientrsquos compliance which establishes regulation of pressurevolume
Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration
Pressure RegulatedVolume Control (PRVC)
1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume
The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume
Results in breath-to-breath variation of inspiratory pressure
Limitations Only an AC mode and requires a change to
Volume Support for weaning Only guarantees volume distally and not at
patient airway
TV AIRWAY PRESSURE
PROBLEMS
VCV preset fn of mechpropertyof lungs
lung injury
PCV acc to mecha property of lung
preset hypoventilation
volutrauma
PRVC preset lower paw necessary
Benefits of both
Comparison with established modes
Applications of PRVC
ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high
flow rates In whom VT has to be controlled ndashsurfactant
therapy
Benefits
Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to
mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort
BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]
Pressure controlled ventilation allowing spontaneous ventilation
Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest
airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to
ventilator in VCV
BIPAP -SUBDIVISIONS
CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at
lower level APRV ndash BIPAP - spontaneous breathing
at higher level Genuine BIPAP - spontaneous breathing
at both levels CPAP - spontaneous breathing at single
CPAP level
paw
t
Setting up BIPAP
Adjusted with ABG values High low PaCO2 Normal PaO2
VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2
mean airway pressure without altering VTRR
equidirectional alteration of P high P low
ADVANTAGES OF BIPAP
Less sedation Reduced atelectasis Ideal mode in pts with inadequate
spontaneous effort In face of deteriorating gas exchange
we can increase the invasiveness of ventilation without having to change mode
Airway Pressure Release Ventilation
(APRV) Outlined in 1987 Continuous positive airway pressure with
regular brief intermittent releases in airway pressure
The release phase results in alveolar ventilation and removal of carbon dioxide
APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance
It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation
Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance
APRV ndashCONTDhellip
Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation
APRV commences at an elevated baseline pressure and follows with a measured pressure release
During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels
Available on Draumlger and Puritan Bennett ventilators
APRV ndashCONTDhellip
Elevated baseline airway pressure during APRV may produce near complete recruitment
Minimizes low volume lung injury from cyclic recruitment
APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation
Needs a High flow CPAP circuit with release valve
Advantages of APRV Lower peak airway pressures Lower minute ventilation
Decreased adverse effects upon circulatory function
Spontaneous ventilation the entire ventilatory cycle
Decreased need for sedation
Near elimination of neuromuscular blockade Recruitment of alveoli
Indications for APRV ALI or low-compliance lung disease patients with airway disease
CONTRAINDICATIONS
Patients with Increased airway resistance
When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation
The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation
P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus
accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than
40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0
cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure
Settings of APRV
Pressure support ventilation
Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by
specific amount of positive pressure at airway
PS Terminated when insp Flow falls below a minimum trigger volume
Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau
` ADVANTAGES Less WOB low pressure high volume work similar to
spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is
achieved with PS of 5 cm H2O
Volume AssuredPressure Support (VAPS)
Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure
breath continues to guarantee volume - 1048707 PIP and inspiratory time increase
1048707 Guarantees volume on current breath (no previous breath averaging)
1048707 Combines the advantages of pressure and volume ventilation breath to breath
Characteristics of VAPS 1048707 The ventilator continuously measures the flow and
pressure and calculates delivered volume Depending on the actual settings breath may be flow
volume or time cycled 1048707 If the target tidal volume has been delivered
inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set
flow will persist until the desired volume has been reached (volume cycled breath)
1048707 Safety limits include high pressure and maximum inspiratory time1048707
Used in the Management of acute and recovering lung disease
Benefits of VAPS
1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort
Applications of VAPS 1048707 A patient who requires a substantial level of
ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony
1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change
Limitations 1048707 Will only increase pressure not lower pressure
with changing mechanics 1048707 Increases inspiratory time to assure volume
Volume support ventilation
Support mode Has PVRC as back up mode Allows spontaneous if preset MV is
achieved If fails deliver preset TV MV in lowest
possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure
limitlower amp upper MV alarm
Applications of VSV
Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations
in inspiratory pressure support
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
Disadvantages
Mask uncomfortableclaustrophobic Time consuming for medical and nursing
staff Facial pressure sores Airway not protected No direct access to bronchial tree for
suction if secretions are excessive Less effective
Indications of NIMV
Hypercapnic acute respiratory failure
Acute exacerbation of COPD
Post extubation Weaning difficulties Post surgical respiratory
failure Thoracic wall deformities Cystic fibrosis Status asthmaticus Obesity hypoventilation
Syndrome
Hypoxaemic acute respiratory failure
Cardiogenic pulmonary oedema
Community acquired pneumonia
Post traumatic respiratory failure
ARDS Weaning difficulties Chronic Respiratory
Failure Immunocompromised
Patients
Contraindications
Respiratory arrest Unstable cardiorespiratory status Uncooperative patients -confused agitated Unable to protect airway- impaired swallowing
and cough Facial Oesophageal or gastric surgery Craniofacial traumaburn Anatomic lesions of upper airway Vomiting Impaired conciousness
Relative Contraindications
Extreme anxiety Massive obesity
Copious secretions
Need for continuous or nearly continuous ventilatory assistance
Prerequisites for successful Non-Invasive support
Patient is able to cooperate Patient can control airway and secretions Adequate cough reflex Patient is able to co-ordinate breathing with ventilator Patient can breathe unaided for several minutes Haemodynamically stable Blood pHgt71 and PaCO2 lt92 mmHg Improvement in gas exchange heart rate and
respiratory rate within first two hours Normal functioning gastrointestinal tract
Interface Interfaces are devices that connect ventilator tubing to
the face allowing the entry of pressurized gas to the upper airway
Nasal and oronasal masks and mouth pieces CPAP helmet are currently available interfaces
Masks - made from a non irritant material such as silicon rubber - minimal dead space and a soft inflatable cuff to provide a seal with the skin
Nasal mask - better tolerated but less effective ndash leak Face masks are more useful in acute respiratory failure Nasal masksMouth piece CPAP helmet are used most
often in chronic respiratory failure
Ventilators - conventional
Advantages FiO2 can be set Alarm amp monitoring
back up Back up ventilation Separate insp amp exp
limbs ndash prevent rebreathing
Inspiratory pressure gt 20 cm H2O can be set
Disadvantages Expensive Less flexible
ampportable Leak compensation
not present ndash requires tight interface
NPPV Ventilators
Advantages cheaper flexible ampportable Leak compensation
present ndash does not requires tight interface
Inspiratory pressure of 20 cm H2Ois maximum available
Disadvantages FiO2 cannot be set
Due to leak ndash high oxygen flows
Single limb ndash rebreathing
Modes of Ventilation CPAP It is not a true ventilator mode as it does not actively
assist inspiration CPAP by nasal mask provides pneumatic splint which
holds the upper airway open in patients with nocturnal hypoxaemia due to episodes of obstructive sleep apnoea
CPAP increases FRC and opens collapsed alveoli CPAP reduces left ventricular transmural pressure
therefore increases cardiac output ndash effective for treatment of pulmonary oedema
Pressures are usually limited to 5-12 cm of H2O - higher pressure tends to result in gastric distension
BILEVEL POSITIVE AIRWAY PRESSURE [ BI LEVEL PAP]
Unique flow triggering ampleak compensation Spontaneous mode ndashcycle between IPAP (Up to 30 cm
H2O)amp EPAP (Up to 15 cm of H2O)- PATIENT TRIGGERED PRESSURE SUPPORTED
IPAP = PEEP +PS EPAP = PEEP in PCVSPECIAL MACHINES Have blower unit to compensate air leaks upto 180 L mt Pressure limited back up Adjustable sensitivities maximum inspiratory
time adjustable FiO2 -available
BI LEVEL PAP[contdhellip] INDICATIONS Worsening
hypoventilation hypoxemia
Chronic ventilatory muscle dysfunction
Post intubation difficulty Upper airway
obstruction ndashlaryngeal oedemastrictures
CONTRA INDICATIONS Unstable
Haemodynamics Vomiting Neurologically abnormal Pneumothorax Deteriorating respiratory
parameters
PSV
Non-invasive PSV can be administered with standard critical care ventilator or bilevel portable devices -patient triggeredpressure limited flow cycled ventilation
PSV mode has unique ability to vary inspiratory time breath by breath permitting close matching with the patients spontaneous breathing pattern
Advantages (a) Patient-ventilator synchrony (b) Improved patient comfort(c) Reduced diaphragmatic work
Volume limited ventilation ventilators are usually set in assist-control mode with
high tidal volume (10-15 mlkg) to compensate for air leak
suitable in obesity or chest wall deformity who need high
inflation pressure neuromuscular diseases who need high tidal
volume for ventilation Proportional assist ventilation (PAV)
This is a newer mode of ventilation In this mode ventilator has capacity of responding
rapidly to the patients ventilatory efforts By adjusting the gain on the flow and volume signals
one can select the proportion of breathing work that is to be assisted
Goals of NIMV
Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival
Protocol for Non Invasive Ventilation
Explain to the patient what you are doing and what to expect
Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the
patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort
Connect humidification system
Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG
Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O
Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts
Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks
Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg
Increase FiO2 to improve O2 saturation to 90
Complications and Side effects
AIR LEAK [80 -100]
MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly
over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction
FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension
MAJOR COMPLICATIONS Aspiration pneumonia - lt
5 Hypotension Pneumothorax
CRITERIA FOR FAILURE OF NPPV
MAJOR Respiratory arrest Loss of
consciousness Psychomotor
agitation Haemodynamic
instability Heart rate lt50 bm
MINOR Respiratory rate gt 35
mt pH lt730 Pao2 lt45mmHg
Intubate when one major two minor criteria
INVASIVE VENTILATION
Pressure RegulatedVolume Control [PVRC]
Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled
assistcontrol
Establishes a ldquolearning periodrdquo to determine
patientrsquos compliance which establishes regulation of pressurevolume
Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration
Pressure RegulatedVolume Control (PRVC)
1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume
The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume
Results in breath-to-breath variation of inspiratory pressure
Limitations Only an AC mode and requires a change to
Volume Support for weaning Only guarantees volume distally and not at
patient airway
TV AIRWAY PRESSURE
PROBLEMS
VCV preset fn of mechpropertyof lungs
lung injury
PCV acc to mecha property of lung
preset hypoventilation
volutrauma
PRVC preset lower paw necessary
Benefits of both
Comparison with established modes
Applications of PRVC
ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high
flow rates In whom VT has to be controlled ndashsurfactant
therapy
Benefits
Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to
mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort
BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]
Pressure controlled ventilation allowing spontaneous ventilation
Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest
airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to
ventilator in VCV
BIPAP -SUBDIVISIONS
CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at
lower level APRV ndash BIPAP - spontaneous breathing
at higher level Genuine BIPAP - spontaneous breathing
at both levels CPAP - spontaneous breathing at single
CPAP level
paw
t
Setting up BIPAP
Adjusted with ABG values High low PaCO2 Normal PaO2
VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2
mean airway pressure without altering VTRR
equidirectional alteration of P high P low
ADVANTAGES OF BIPAP
Less sedation Reduced atelectasis Ideal mode in pts with inadequate
spontaneous effort In face of deteriorating gas exchange
we can increase the invasiveness of ventilation without having to change mode
Airway Pressure Release Ventilation
(APRV) Outlined in 1987 Continuous positive airway pressure with
regular brief intermittent releases in airway pressure
The release phase results in alveolar ventilation and removal of carbon dioxide
APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance
It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation
Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance
APRV ndashCONTDhellip
Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation
APRV commences at an elevated baseline pressure and follows with a measured pressure release
During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels
Available on Draumlger and Puritan Bennett ventilators
APRV ndashCONTDhellip
Elevated baseline airway pressure during APRV may produce near complete recruitment
Minimizes low volume lung injury from cyclic recruitment
APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation
Needs a High flow CPAP circuit with release valve
Advantages of APRV Lower peak airway pressures Lower minute ventilation
Decreased adverse effects upon circulatory function
Spontaneous ventilation the entire ventilatory cycle
Decreased need for sedation
Near elimination of neuromuscular blockade Recruitment of alveoli
Indications for APRV ALI or low-compliance lung disease patients with airway disease
CONTRAINDICATIONS
Patients with Increased airway resistance
When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation
The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation
P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus
accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than
40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0
cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure
Settings of APRV
Pressure support ventilation
Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by
specific amount of positive pressure at airway
PS Terminated when insp Flow falls below a minimum trigger volume
Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau
` ADVANTAGES Less WOB low pressure high volume work similar to
spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is
achieved with PS of 5 cm H2O
Volume AssuredPressure Support (VAPS)
Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure
breath continues to guarantee volume - 1048707 PIP and inspiratory time increase
1048707 Guarantees volume on current breath (no previous breath averaging)
1048707 Combines the advantages of pressure and volume ventilation breath to breath
Characteristics of VAPS 1048707 The ventilator continuously measures the flow and
pressure and calculates delivered volume Depending on the actual settings breath may be flow
volume or time cycled 1048707 If the target tidal volume has been delivered
inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set
flow will persist until the desired volume has been reached (volume cycled breath)
1048707 Safety limits include high pressure and maximum inspiratory time1048707
Used in the Management of acute and recovering lung disease
Benefits of VAPS
1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort
Applications of VAPS 1048707 A patient who requires a substantial level of
ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony
1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change
Limitations 1048707 Will only increase pressure not lower pressure
with changing mechanics 1048707 Increases inspiratory time to assure volume
Volume support ventilation
Support mode Has PVRC as back up mode Allows spontaneous if preset MV is
achieved If fails deliver preset TV MV in lowest
possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure
limitlower amp upper MV alarm
Applications of VSV
Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations
in inspiratory pressure support
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
Indications of NIMV
Hypercapnic acute respiratory failure
Acute exacerbation of COPD
Post extubation Weaning difficulties Post surgical respiratory
failure Thoracic wall deformities Cystic fibrosis Status asthmaticus Obesity hypoventilation
Syndrome
Hypoxaemic acute respiratory failure
Cardiogenic pulmonary oedema
Community acquired pneumonia
Post traumatic respiratory failure
ARDS Weaning difficulties Chronic Respiratory
Failure Immunocompromised
Patients
Contraindications
Respiratory arrest Unstable cardiorespiratory status Uncooperative patients -confused agitated Unable to protect airway- impaired swallowing
and cough Facial Oesophageal or gastric surgery Craniofacial traumaburn Anatomic lesions of upper airway Vomiting Impaired conciousness
Relative Contraindications
Extreme anxiety Massive obesity
Copious secretions
Need for continuous or nearly continuous ventilatory assistance
Prerequisites for successful Non-Invasive support
Patient is able to cooperate Patient can control airway and secretions Adequate cough reflex Patient is able to co-ordinate breathing with ventilator Patient can breathe unaided for several minutes Haemodynamically stable Blood pHgt71 and PaCO2 lt92 mmHg Improvement in gas exchange heart rate and
respiratory rate within first two hours Normal functioning gastrointestinal tract
Interface Interfaces are devices that connect ventilator tubing to
the face allowing the entry of pressurized gas to the upper airway
Nasal and oronasal masks and mouth pieces CPAP helmet are currently available interfaces
Masks - made from a non irritant material such as silicon rubber - minimal dead space and a soft inflatable cuff to provide a seal with the skin
Nasal mask - better tolerated but less effective ndash leak Face masks are more useful in acute respiratory failure Nasal masksMouth piece CPAP helmet are used most
often in chronic respiratory failure
Ventilators - conventional
Advantages FiO2 can be set Alarm amp monitoring
back up Back up ventilation Separate insp amp exp
limbs ndash prevent rebreathing
Inspiratory pressure gt 20 cm H2O can be set
Disadvantages Expensive Less flexible
ampportable Leak compensation
not present ndash requires tight interface
NPPV Ventilators
Advantages cheaper flexible ampportable Leak compensation
present ndash does not requires tight interface
Inspiratory pressure of 20 cm H2Ois maximum available
Disadvantages FiO2 cannot be set
Due to leak ndash high oxygen flows
Single limb ndash rebreathing
Modes of Ventilation CPAP It is not a true ventilator mode as it does not actively
assist inspiration CPAP by nasal mask provides pneumatic splint which
holds the upper airway open in patients with nocturnal hypoxaemia due to episodes of obstructive sleep apnoea
CPAP increases FRC and opens collapsed alveoli CPAP reduces left ventricular transmural pressure
therefore increases cardiac output ndash effective for treatment of pulmonary oedema
Pressures are usually limited to 5-12 cm of H2O - higher pressure tends to result in gastric distension
BILEVEL POSITIVE AIRWAY PRESSURE [ BI LEVEL PAP]
Unique flow triggering ampleak compensation Spontaneous mode ndashcycle between IPAP (Up to 30 cm
H2O)amp EPAP (Up to 15 cm of H2O)- PATIENT TRIGGERED PRESSURE SUPPORTED
IPAP = PEEP +PS EPAP = PEEP in PCVSPECIAL MACHINES Have blower unit to compensate air leaks upto 180 L mt Pressure limited back up Adjustable sensitivities maximum inspiratory
time adjustable FiO2 -available
BI LEVEL PAP[contdhellip] INDICATIONS Worsening
hypoventilation hypoxemia
Chronic ventilatory muscle dysfunction
Post intubation difficulty Upper airway
obstruction ndashlaryngeal oedemastrictures
CONTRA INDICATIONS Unstable
Haemodynamics Vomiting Neurologically abnormal Pneumothorax Deteriorating respiratory
parameters
PSV
Non-invasive PSV can be administered with standard critical care ventilator or bilevel portable devices -patient triggeredpressure limited flow cycled ventilation
PSV mode has unique ability to vary inspiratory time breath by breath permitting close matching with the patients spontaneous breathing pattern
Advantages (a) Patient-ventilator synchrony (b) Improved patient comfort(c) Reduced diaphragmatic work
Volume limited ventilation ventilators are usually set in assist-control mode with
high tidal volume (10-15 mlkg) to compensate for air leak
suitable in obesity or chest wall deformity who need high
inflation pressure neuromuscular diseases who need high tidal
volume for ventilation Proportional assist ventilation (PAV)
This is a newer mode of ventilation In this mode ventilator has capacity of responding
rapidly to the patients ventilatory efforts By adjusting the gain on the flow and volume signals
one can select the proportion of breathing work that is to be assisted
Goals of NIMV
Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival
Protocol for Non Invasive Ventilation
Explain to the patient what you are doing and what to expect
Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the
patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort
Connect humidification system
Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG
Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O
Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts
Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks
Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg
Increase FiO2 to improve O2 saturation to 90
Complications and Side effects
AIR LEAK [80 -100]
MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly
over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction
FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension
MAJOR COMPLICATIONS Aspiration pneumonia - lt
5 Hypotension Pneumothorax
CRITERIA FOR FAILURE OF NPPV
MAJOR Respiratory arrest Loss of
consciousness Psychomotor
agitation Haemodynamic
instability Heart rate lt50 bm
MINOR Respiratory rate gt 35
mt pH lt730 Pao2 lt45mmHg
Intubate when one major two minor criteria
INVASIVE VENTILATION
Pressure RegulatedVolume Control [PVRC]
Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled
assistcontrol
Establishes a ldquolearning periodrdquo to determine
patientrsquos compliance which establishes regulation of pressurevolume
Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration
Pressure RegulatedVolume Control (PRVC)
1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume
The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume
Results in breath-to-breath variation of inspiratory pressure
Limitations Only an AC mode and requires a change to
Volume Support for weaning Only guarantees volume distally and not at
patient airway
TV AIRWAY PRESSURE
PROBLEMS
VCV preset fn of mechpropertyof lungs
lung injury
PCV acc to mecha property of lung
preset hypoventilation
volutrauma
PRVC preset lower paw necessary
Benefits of both
Comparison with established modes
Applications of PRVC
ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high
flow rates In whom VT has to be controlled ndashsurfactant
therapy
Benefits
Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to
mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort
BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]
Pressure controlled ventilation allowing spontaneous ventilation
Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest
airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to
ventilator in VCV
BIPAP -SUBDIVISIONS
CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at
lower level APRV ndash BIPAP - spontaneous breathing
at higher level Genuine BIPAP - spontaneous breathing
at both levels CPAP - spontaneous breathing at single
CPAP level
paw
t
Setting up BIPAP
Adjusted with ABG values High low PaCO2 Normal PaO2
VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2
mean airway pressure without altering VTRR
equidirectional alteration of P high P low
ADVANTAGES OF BIPAP
Less sedation Reduced atelectasis Ideal mode in pts with inadequate
spontaneous effort In face of deteriorating gas exchange
we can increase the invasiveness of ventilation without having to change mode
Airway Pressure Release Ventilation
(APRV) Outlined in 1987 Continuous positive airway pressure with
regular brief intermittent releases in airway pressure
The release phase results in alveolar ventilation and removal of carbon dioxide
APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance
It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation
Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance
APRV ndashCONTDhellip
Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation
APRV commences at an elevated baseline pressure and follows with a measured pressure release
During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels
Available on Draumlger and Puritan Bennett ventilators
APRV ndashCONTDhellip
Elevated baseline airway pressure during APRV may produce near complete recruitment
Minimizes low volume lung injury from cyclic recruitment
APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation
Needs a High flow CPAP circuit with release valve
Advantages of APRV Lower peak airway pressures Lower minute ventilation
Decreased adverse effects upon circulatory function
Spontaneous ventilation the entire ventilatory cycle
Decreased need for sedation
Near elimination of neuromuscular blockade Recruitment of alveoli
Indications for APRV ALI or low-compliance lung disease patients with airway disease
CONTRAINDICATIONS
Patients with Increased airway resistance
When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation
The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation
P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus
accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than
40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0
cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure
Settings of APRV
Pressure support ventilation
Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by
specific amount of positive pressure at airway
PS Terminated when insp Flow falls below a minimum trigger volume
Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau
` ADVANTAGES Less WOB low pressure high volume work similar to
spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is
achieved with PS of 5 cm H2O
Volume AssuredPressure Support (VAPS)
Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure
breath continues to guarantee volume - 1048707 PIP and inspiratory time increase
1048707 Guarantees volume on current breath (no previous breath averaging)
1048707 Combines the advantages of pressure and volume ventilation breath to breath
Characteristics of VAPS 1048707 The ventilator continuously measures the flow and
pressure and calculates delivered volume Depending on the actual settings breath may be flow
volume or time cycled 1048707 If the target tidal volume has been delivered
inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set
flow will persist until the desired volume has been reached (volume cycled breath)
1048707 Safety limits include high pressure and maximum inspiratory time1048707
Used in the Management of acute and recovering lung disease
Benefits of VAPS
1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort
Applications of VAPS 1048707 A patient who requires a substantial level of
ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony
1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change
Limitations 1048707 Will only increase pressure not lower pressure
with changing mechanics 1048707 Increases inspiratory time to assure volume
Volume support ventilation
Support mode Has PVRC as back up mode Allows spontaneous if preset MV is
achieved If fails deliver preset TV MV in lowest
possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure
limitlower amp upper MV alarm
Applications of VSV
Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations
in inspiratory pressure support
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
Contraindications
Respiratory arrest Unstable cardiorespiratory status Uncooperative patients -confused agitated Unable to protect airway- impaired swallowing
and cough Facial Oesophageal or gastric surgery Craniofacial traumaburn Anatomic lesions of upper airway Vomiting Impaired conciousness
Relative Contraindications
Extreme anxiety Massive obesity
Copious secretions
Need for continuous or nearly continuous ventilatory assistance
Prerequisites for successful Non-Invasive support
Patient is able to cooperate Patient can control airway and secretions Adequate cough reflex Patient is able to co-ordinate breathing with ventilator Patient can breathe unaided for several minutes Haemodynamically stable Blood pHgt71 and PaCO2 lt92 mmHg Improvement in gas exchange heart rate and
respiratory rate within first two hours Normal functioning gastrointestinal tract
Interface Interfaces are devices that connect ventilator tubing to
the face allowing the entry of pressurized gas to the upper airway
Nasal and oronasal masks and mouth pieces CPAP helmet are currently available interfaces
Masks - made from a non irritant material such as silicon rubber - minimal dead space and a soft inflatable cuff to provide a seal with the skin
Nasal mask - better tolerated but less effective ndash leak Face masks are more useful in acute respiratory failure Nasal masksMouth piece CPAP helmet are used most
often in chronic respiratory failure
Ventilators - conventional
Advantages FiO2 can be set Alarm amp monitoring
back up Back up ventilation Separate insp amp exp
limbs ndash prevent rebreathing
Inspiratory pressure gt 20 cm H2O can be set
Disadvantages Expensive Less flexible
ampportable Leak compensation
not present ndash requires tight interface
NPPV Ventilators
Advantages cheaper flexible ampportable Leak compensation
present ndash does not requires tight interface
Inspiratory pressure of 20 cm H2Ois maximum available
Disadvantages FiO2 cannot be set
Due to leak ndash high oxygen flows
Single limb ndash rebreathing
Modes of Ventilation CPAP It is not a true ventilator mode as it does not actively
assist inspiration CPAP by nasal mask provides pneumatic splint which
holds the upper airway open in patients with nocturnal hypoxaemia due to episodes of obstructive sleep apnoea
CPAP increases FRC and opens collapsed alveoli CPAP reduces left ventricular transmural pressure
therefore increases cardiac output ndash effective for treatment of pulmonary oedema
Pressures are usually limited to 5-12 cm of H2O - higher pressure tends to result in gastric distension
BILEVEL POSITIVE AIRWAY PRESSURE [ BI LEVEL PAP]
Unique flow triggering ampleak compensation Spontaneous mode ndashcycle between IPAP (Up to 30 cm
H2O)amp EPAP (Up to 15 cm of H2O)- PATIENT TRIGGERED PRESSURE SUPPORTED
IPAP = PEEP +PS EPAP = PEEP in PCVSPECIAL MACHINES Have blower unit to compensate air leaks upto 180 L mt Pressure limited back up Adjustable sensitivities maximum inspiratory
time adjustable FiO2 -available
BI LEVEL PAP[contdhellip] INDICATIONS Worsening
hypoventilation hypoxemia
Chronic ventilatory muscle dysfunction
Post intubation difficulty Upper airway
obstruction ndashlaryngeal oedemastrictures
CONTRA INDICATIONS Unstable
Haemodynamics Vomiting Neurologically abnormal Pneumothorax Deteriorating respiratory
parameters
PSV
Non-invasive PSV can be administered with standard critical care ventilator or bilevel portable devices -patient triggeredpressure limited flow cycled ventilation
PSV mode has unique ability to vary inspiratory time breath by breath permitting close matching with the patients spontaneous breathing pattern
Advantages (a) Patient-ventilator synchrony (b) Improved patient comfort(c) Reduced diaphragmatic work
Volume limited ventilation ventilators are usually set in assist-control mode with
high tidal volume (10-15 mlkg) to compensate for air leak
suitable in obesity or chest wall deformity who need high
inflation pressure neuromuscular diseases who need high tidal
volume for ventilation Proportional assist ventilation (PAV)
This is a newer mode of ventilation In this mode ventilator has capacity of responding
rapidly to the patients ventilatory efforts By adjusting the gain on the flow and volume signals
one can select the proportion of breathing work that is to be assisted
Goals of NIMV
Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival
Protocol for Non Invasive Ventilation
Explain to the patient what you are doing and what to expect
Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the
patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort
Connect humidification system
Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG
Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O
Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts
Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks
Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg
Increase FiO2 to improve O2 saturation to 90
Complications and Side effects
AIR LEAK [80 -100]
MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly
over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction
FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension
MAJOR COMPLICATIONS Aspiration pneumonia - lt
5 Hypotension Pneumothorax
CRITERIA FOR FAILURE OF NPPV
MAJOR Respiratory arrest Loss of
consciousness Psychomotor
agitation Haemodynamic
instability Heart rate lt50 bm
MINOR Respiratory rate gt 35
mt pH lt730 Pao2 lt45mmHg
Intubate when one major two minor criteria
INVASIVE VENTILATION
Pressure RegulatedVolume Control [PVRC]
Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled
assistcontrol
Establishes a ldquolearning periodrdquo to determine
patientrsquos compliance which establishes regulation of pressurevolume
Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration
Pressure RegulatedVolume Control (PRVC)
1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume
The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume
Results in breath-to-breath variation of inspiratory pressure
Limitations Only an AC mode and requires a change to
Volume Support for weaning Only guarantees volume distally and not at
patient airway
TV AIRWAY PRESSURE
PROBLEMS
VCV preset fn of mechpropertyof lungs
lung injury
PCV acc to mecha property of lung
preset hypoventilation
volutrauma
PRVC preset lower paw necessary
Benefits of both
Comparison with established modes
Applications of PRVC
ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high
flow rates In whom VT has to be controlled ndashsurfactant
therapy
Benefits
Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to
mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort
BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]
Pressure controlled ventilation allowing spontaneous ventilation
Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest
airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to
ventilator in VCV
BIPAP -SUBDIVISIONS
CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at
lower level APRV ndash BIPAP - spontaneous breathing
at higher level Genuine BIPAP - spontaneous breathing
at both levels CPAP - spontaneous breathing at single
CPAP level
paw
t
Setting up BIPAP
Adjusted with ABG values High low PaCO2 Normal PaO2
VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2
mean airway pressure without altering VTRR
equidirectional alteration of P high P low
ADVANTAGES OF BIPAP
Less sedation Reduced atelectasis Ideal mode in pts with inadequate
spontaneous effort In face of deteriorating gas exchange
we can increase the invasiveness of ventilation without having to change mode
Airway Pressure Release Ventilation
(APRV) Outlined in 1987 Continuous positive airway pressure with
regular brief intermittent releases in airway pressure
The release phase results in alveolar ventilation and removal of carbon dioxide
APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance
It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation
Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance
APRV ndashCONTDhellip
Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation
APRV commences at an elevated baseline pressure and follows with a measured pressure release
During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels
Available on Draumlger and Puritan Bennett ventilators
APRV ndashCONTDhellip
Elevated baseline airway pressure during APRV may produce near complete recruitment
Minimizes low volume lung injury from cyclic recruitment
APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation
Needs a High flow CPAP circuit with release valve
Advantages of APRV Lower peak airway pressures Lower minute ventilation
Decreased adverse effects upon circulatory function
Spontaneous ventilation the entire ventilatory cycle
Decreased need for sedation
Near elimination of neuromuscular blockade Recruitment of alveoli
Indications for APRV ALI or low-compliance lung disease patients with airway disease
CONTRAINDICATIONS
Patients with Increased airway resistance
When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation
The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation
P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus
accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than
40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0
cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure
Settings of APRV
Pressure support ventilation
Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by
specific amount of positive pressure at airway
PS Terminated when insp Flow falls below a minimum trigger volume
Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau
` ADVANTAGES Less WOB low pressure high volume work similar to
spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is
achieved with PS of 5 cm H2O
Volume AssuredPressure Support (VAPS)
Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure
breath continues to guarantee volume - 1048707 PIP and inspiratory time increase
1048707 Guarantees volume on current breath (no previous breath averaging)
1048707 Combines the advantages of pressure and volume ventilation breath to breath
Characteristics of VAPS 1048707 The ventilator continuously measures the flow and
pressure and calculates delivered volume Depending on the actual settings breath may be flow
volume or time cycled 1048707 If the target tidal volume has been delivered
inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set
flow will persist until the desired volume has been reached (volume cycled breath)
1048707 Safety limits include high pressure and maximum inspiratory time1048707
Used in the Management of acute and recovering lung disease
Benefits of VAPS
1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort
Applications of VAPS 1048707 A patient who requires a substantial level of
ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony
1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change
Limitations 1048707 Will only increase pressure not lower pressure
with changing mechanics 1048707 Increases inspiratory time to assure volume
Volume support ventilation
Support mode Has PVRC as back up mode Allows spontaneous if preset MV is
achieved If fails deliver preset TV MV in lowest
possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure
limitlower amp upper MV alarm
Applications of VSV
Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations
in inspiratory pressure support
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
Relative Contraindications
Extreme anxiety Massive obesity
Copious secretions
Need for continuous or nearly continuous ventilatory assistance
Prerequisites for successful Non-Invasive support
Patient is able to cooperate Patient can control airway and secretions Adequate cough reflex Patient is able to co-ordinate breathing with ventilator Patient can breathe unaided for several minutes Haemodynamically stable Blood pHgt71 and PaCO2 lt92 mmHg Improvement in gas exchange heart rate and
respiratory rate within first two hours Normal functioning gastrointestinal tract
Interface Interfaces are devices that connect ventilator tubing to
the face allowing the entry of pressurized gas to the upper airway
Nasal and oronasal masks and mouth pieces CPAP helmet are currently available interfaces
Masks - made from a non irritant material such as silicon rubber - minimal dead space and a soft inflatable cuff to provide a seal with the skin
Nasal mask - better tolerated but less effective ndash leak Face masks are more useful in acute respiratory failure Nasal masksMouth piece CPAP helmet are used most
often in chronic respiratory failure
Ventilators - conventional
Advantages FiO2 can be set Alarm amp monitoring
back up Back up ventilation Separate insp amp exp
limbs ndash prevent rebreathing
Inspiratory pressure gt 20 cm H2O can be set
Disadvantages Expensive Less flexible
ampportable Leak compensation
not present ndash requires tight interface
NPPV Ventilators
Advantages cheaper flexible ampportable Leak compensation
present ndash does not requires tight interface
Inspiratory pressure of 20 cm H2Ois maximum available
Disadvantages FiO2 cannot be set
Due to leak ndash high oxygen flows
Single limb ndash rebreathing
Modes of Ventilation CPAP It is not a true ventilator mode as it does not actively
assist inspiration CPAP by nasal mask provides pneumatic splint which
holds the upper airway open in patients with nocturnal hypoxaemia due to episodes of obstructive sleep apnoea
CPAP increases FRC and opens collapsed alveoli CPAP reduces left ventricular transmural pressure
therefore increases cardiac output ndash effective for treatment of pulmonary oedema
Pressures are usually limited to 5-12 cm of H2O - higher pressure tends to result in gastric distension
BILEVEL POSITIVE AIRWAY PRESSURE [ BI LEVEL PAP]
Unique flow triggering ampleak compensation Spontaneous mode ndashcycle between IPAP (Up to 30 cm
H2O)amp EPAP (Up to 15 cm of H2O)- PATIENT TRIGGERED PRESSURE SUPPORTED
IPAP = PEEP +PS EPAP = PEEP in PCVSPECIAL MACHINES Have blower unit to compensate air leaks upto 180 L mt Pressure limited back up Adjustable sensitivities maximum inspiratory
time adjustable FiO2 -available
BI LEVEL PAP[contdhellip] INDICATIONS Worsening
hypoventilation hypoxemia
Chronic ventilatory muscle dysfunction
Post intubation difficulty Upper airway
obstruction ndashlaryngeal oedemastrictures
CONTRA INDICATIONS Unstable
Haemodynamics Vomiting Neurologically abnormal Pneumothorax Deteriorating respiratory
parameters
PSV
Non-invasive PSV can be administered with standard critical care ventilator or bilevel portable devices -patient triggeredpressure limited flow cycled ventilation
PSV mode has unique ability to vary inspiratory time breath by breath permitting close matching with the patients spontaneous breathing pattern
Advantages (a) Patient-ventilator synchrony (b) Improved patient comfort(c) Reduced diaphragmatic work
Volume limited ventilation ventilators are usually set in assist-control mode with
high tidal volume (10-15 mlkg) to compensate for air leak
suitable in obesity or chest wall deformity who need high
inflation pressure neuromuscular diseases who need high tidal
volume for ventilation Proportional assist ventilation (PAV)
This is a newer mode of ventilation In this mode ventilator has capacity of responding
rapidly to the patients ventilatory efforts By adjusting the gain on the flow and volume signals
one can select the proportion of breathing work that is to be assisted
Goals of NIMV
Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival
Protocol for Non Invasive Ventilation
Explain to the patient what you are doing and what to expect
Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the
patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort
Connect humidification system
Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG
Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O
Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts
Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks
Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg
Increase FiO2 to improve O2 saturation to 90
Complications and Side effects
AIR LEAK [80 -100]
MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly
over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction
FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension
MAJOR COMPLICATIONS Aspiration pneumonia - lt
5 Hypotension Pneumothorax
CRITERIA FOR FAILURE OF NPPV
MAJOR Respiratory arrest Loss of
consciousness Psychomotor
agitation Haemodynamic
instability Heart rate lt50 bm
MINOR Respiratory rate gt 35
mt pH lt730 Pao2 lt45mmHg
Intubate when one major two minor criteria
INVASIVE VENTILATION
Pressure RegulatedVolume Control [PVRC]
Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled
assistcontrol
Establishes a ldquolearning periodrdquo to determine
patientrsquos compliance which establishes regulation of pressurevolume
Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration
Pressure RegulatedVolume Control (PRVC)
1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume
The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume
Results in breath-to-breath variation of inspiratory pressure
Limitations Only an AC mode and requires a change to
Volume Support for weaning Only guarantees volume distally and not at
patient airway
TV AIRWAY PRESSURE
PROBLEMS
VCV preset fn of mechpropertyof lungs
lung injury
PCV acc to mecha property of lung
preset hypoventilation
volutrauma
PRVC preset lower paw necessary
Benefits of both
Comparison with established modes
Applications of PRVC
ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high
flow rates In whom VT has to be controlled ndashsurfactant
therapy
Benefits
Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to
mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort
BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]
Pressure controlled ventilation allowing spontaneous ventilation
Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest
airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to
ventilator in VCV
BIPAP -SUBDIVISIONS
CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at
lower level APRV ndash BIPAP - spontaneous breathing
at higher level Genuine BIPAP - spontaneous breathing
at both levels CPAP - spontaneous breathing at single
CPAP level
paw
t
Setting up BIPAP
Adjusted with ABG values High low PaCO2 Normal PaO2
VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2
mean airway pressure without altering VTRR
equidirectional alteration of P high P low
ADVANTAGES OF BIPAP
Less sedation Reduced atelectasis Ideal mode in pts with inadequate
spontaneous effort In face of deteriorating gas exchange
we can increase the invasiveness of ventilation without having to change mode
Airway Pressure Release Ventilation
(APRV) Outlined in 1987 Continuous positive airway pressure with
regular brief intermittent releases in airway pressure
The release phase results in alveolar ventilation and removal of carbon dioxide
APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance
It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation
Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance
APRV ndashCONTDhellip
Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation
APRV commences at an elevated baseline pressure and follows with a measured pressure release
During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels
Available on Draumlger and Puritan Bennett ventilators
APRV ndashCONTDhellip
Elevated baseline airway pressure during APRV may produce near complete recruitment
Minimizes low volume lung injury from cyclic recruitment
APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation
Needs a High flow CPAP circuit with release valve
Advantages of APRV Lower peak airway pressures Lower minute ventilation
Decreased adverse effects upon circulatory function
Spontaneous ventilation the entire ventilatory cycle
Decreased need for sedation
Near elimination of neuromuscular blockade Recruitment of alveoli
Indications for APRV ALI or low-compliance lung disease patients with airway disease
CONTRAINDICATIONS
Patients with Increased airway resistance
When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation
The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation
P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus
accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than
40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0
cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure
Settings of APRV
Pressure support ventilation
Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by
specific amount of positive pressure at airway
PS Terminated when insp Flow falls below a minimum trigger volume
Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau
` ADVANTAGES Less WOB low pressure high volume work similar to
spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is
achieved with PS of 5 cm H2O
Volume AssuredPressure Support (VAPS)
Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure
breath continues to guarantee volume - 1048707 PIP and inspiratory time increase
1048707 Guarantees volume on current breath (no previous breath averaging)
1048707 Combines the advantages of pressure and volume ventilation breath to breath
Characteristics of VAPS 1048707 The ventilator continuously measures the flow and
pressure and calculates delivered volume Depending on the actual settings breath may be flow
volume or time cycled 1048707 If the target tidal volume has been delivered
inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set
flow will persist until the desired volume has been reached (volume cycled breath)
1048707 Safety limits include high pressure and maximum inspiratory time1048707
Used in the Management of acute and recovering lung disease
Benefits of VAPS
1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort
Applications of VAPS 1048707 A patient who requires a substantial level of
ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony
1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change
Limitations 1048707 Will only increase pressure not lower pressure
with changing mechanics 1048707 Increases inspiratory time to assure volume
Volume support ventilation
Support mode Has PVRC as back up mode Allows spontaneous if preset MV is
achieved If fails deliver preset TV MV in lowest
possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure
limitlower amp upper MV alarm
Applications of VSV
Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations
in inspiratory pressure support
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
Prerequisites for successful Non-Invasive support
Patient is able to cooperate Patient can control airway and secretions Adequate cough reflex Patient is able to co-ordinate breathing with ventilator Patient can breathe unaided for several minutes Haemodynamically stable Blood pHgt71 and PaCO2 lt92 mmHg Improvement in gas exchange heart rate and
respiratory rate within first two hours Normal functioning gastrointestinal tract
Interface Interfaces are devices that connect ventilator tubing to
the face allowing the entry of pressurized gas to the upper airway
Nasal and oronasal masks and mouth pieces CPAP helmet are currently available interfaces
Masks - made from a non irritant material such as silicon rubber - minimal dead space and a soft inflatable cuff to provide a seal with the skin
Nasal mask - better tolerated but less effective ndash leak Face masks are more useful in acute respiratory failure Nasal masksMouth piece CPAP helmet are used most
often in chronic respiratory failure
Ventilators - conventional
Advantages FiO2 can be set Alarm amp monitoring
back up Back up ventilation Separate insp amp exp
limbs ndash prevent rebreathing
Inspiratory pressure gt 20 cm H2O can be set
Disadvantages Expensive Less flexible
ampportable Leak compensation
not present ndash requires tight interface
NPPV Ventilators
Advantages cheaper flexible ampportable Leak compensation
present ndash does not requires tight interface
Inspiratory pressure of 20 cm H2Ois maximum available
Disadvantages FiO2 cannot be set
Due to leak ndash high oxygen flows
Single limb ndash rebreathing
Modes of Ventilation CPAP It is not a true ventilator mode as it does not actively
assist inspiration CPAP by nasal mask provides pneumatic splint which
holds the upper airway open in patients with nocturnal hypoxaemia due to episodes of obstructive sleep apnoea
CPAP increases FRC and opens collapsed alveoli CPAP reduces left ventricular transmural pressure
therefore increases cardiac output ndash effective for treatment of pulmonary oedema
Pressures are usually limited to 5-12 cm of H2O - higher pressure tends to result in gastric distension
BILEVEL POSITIVE AIRWAY PRESSURE [ BI LEVEL PAP]
Unique flow triggering ampleak compensation Spontaneous mode ndashcycle between IPAP (Up to 30 cm
H2O)amp EPAP (Up to 15 cm of H2O)- PATIENT TRIGGERED PRESSURE SUPPORTED
IPAP = PEEP +PS EPAP = PEEP in PCVSPECIAL MACHINES Have blower unit to compensate air leaks upto 180 L mt Pressure limited back up Adjustable sensitivities maximum inspiratory
time adjustable FiO2 -available
BI LEVEL PAP[contdhellip] INDICATIONS Worsening
hypoventilation hypoxemia
Chronic ventilatory muscle dysfunction
Post intubation difficulty Upper airway
obstruction ndashlaryngeal oedemastrictures
CONTRA INDICATIONS Unstable
Haemodynamics Vomiting Neurologically abnormal Pneumothorax Deteriorating respiratory
parameters
PSV
Non-invasive PSV can be administered with standard critical care ventilator or bilevel portable devices -patient triggeredpressure limited flow cycled ventilation
PSV mode has unique ability to vary inspiratory time breath by breath permitting close matching with the patients spontaneous breathing pattern
Advantages (a) Patient-ventilator synchrony (b) Improved patient comfort(c) Reduced diaphragmatic work
Volume limited ventilation ventilators are usually set in assist-control mode with
high tidal volume (10-15 mlkg) to compensate for air leak
suitable in obesity or chest wall deformity who need high
inflation pressure neuromuscular diseases who need high tidal
volume for ventilation Proportional assist ventilation (PAV)
This is a newer mode of ventilation In this mode ventilator has capacity of responding
rapidly to the patients ventilatory efforts By adjusting the gain on the flow and volume signals
one can select the proportion of breathing work that is to be assisted
Goals of NIMV
Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival
Protocol for Non Invasive Ventilation
Explain to the patient what you are doing and what to expect
Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the
patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort
Connect humidification system
Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG
Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O
Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts
Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks
Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg
Increase FiO2 to improve O2 saturation to 90
Complications and Side effects
AIR LEAK [80 -100]
MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly
over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction
FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension
MAJOR COMPLICATIONS Aspiration pneumonia - lt
5 Hypotension Pneumothorax
CRITERIA FOR FAILURE OF NPPV
MAJOR Respiratory arrest Loss of
consciousness Psychomotor
agitation Haemodynamic
instability Heart rate lt50 bm
MINOR Respiratory rate gt 35
mt pH lt730 Pao2 lt45mmHg
Intubate when one major two minor criteria
INVASIVE VENTILATION
Pressure RegulatedVolume Control [PVRC]
Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled
assistcontrol
Establishes a ldquolearning periodrdquo to determine
patientrsquos compliance which establishes regulation of pressurevolume
Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration
Pressure RegulatedVolume Control (PRVC)
1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume
The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume
Results in breath-to-breath variation of inspiratory pressure
Limitations Only an AC mode and requires a change to
Volume Support for weaning Only guarantees volume distally and not at
patient airway
TV AIRWAY PRESSURE
PROBLEMS
VCV preset fn of mechpropertyof lungs
lung injury
PCV acc to mecha property of lung
preset hypoventilation
volutrauma
PRVC preset lower paw necessary
Benefits of both
Comparison with established modes
Applications of PRVC
ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high
flow rates In whom VT has to be controlled ndashsurfactant
therapy
Benefits
Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to
mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort
BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]
Pressure controlled ventilation allowing spontaneous ventilation
Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest
airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to
ventilator in VCV
BIPAP -SUBDIVISIONS
CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at
lower level APRV ndash BIPAP - spontaneous breathing
at higher level Genuine BIPAP - spontaneous breathing
at both levels CPAP - spontaneous breathing at single
CPAP level
paw
t
Setting up BIPAP
Adjusted with ABG values High low PaCO2 Normal PaO2
VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2
mean airway pressure without altering VTRR
equidirectional alteration of P high P low
ADVANTAGES OF BIPAP
Less sedation Reduced atelectasis Ideal mode in pts with inadequate
spontaneous effort In face of deteriorating gas exchange
we can increase the invasiveness of ventilation without having to change mode
Airway Pressure Release Ventilation
(APRV) Outlined in 1987 Continuous positive airway pressure with
regular brief intermittent releases in airway pressure
The release phase results in alveolar ventilation and removal of carbon dioxide
APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance
It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation
Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance
APRV ndashCONTDhellip
Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation
APRV commences at an elevated baseline pressure and follows with a measured pressure release
During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels
Available on Draumlger and Puritan Bennett ventilators
APRV ndashCONTDhellip
Elevated baseline airway pressure during APRV may produce near complete recruitment
Minimizes low volume lung injury from cyclic recruitment
APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation
Needs a High flow CPAP circuit with release valve
Advantages of APRV Lower peak airway pressures Lower minute ventilation
Decreased adverse effects upon circulatory function
Spontaneous ventilation the entire ventilatory cycle
Decreased need for sedation
Near elimination of neuromuscular blockade Recruitment of alveoli
Indications for APRV ALI or low-compliance lung disease patients with airway disease
CONTRAINDICATIONS
Patients with Increased airway resistance
When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation
The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation
P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus
accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than
40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0
cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure
Settings of APRV
Pressure support ventilation
Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by
specific amount of positive pressure at airway
PS Terminated when insp Flow falls below a minimum trigger volume
Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau
` ADVANTAGES Less WOB low pressure high volume work similar to
spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is
achieved with PS of 5 cm H2O
Volume AssuredPressure Support (VAPS)
Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure
breath continues to guarantee volume - 1048707 PIP and inspiratory time increase
1048707 Guarantees volume on current breath (no previous breath averaging)
1048707 Combines the advantages of pressure and volume ventilation breath to breath
Characteristics of VAPS 1048707 The ventilator continuously measures the flow and
pressure and calculates delivered volume Depending on the actual settings breath may be flow
volume or time cycled 1048707 If the target tidal volume has been delivered
inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set
flow will persist until the desired volume has been reached (volume cycled breath)
1048707 Safety limits include high pressure and maximum inspiratory time1048707
Used in the Management of acute and recovering lung disease
Benefits of VAPS
1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort
Applications of VAPS 1048707 A patient who requires a substantial level of
ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony
1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change
Limitations 1048707 Will only increase pressure not lower pressure
with changing mechanics 1048707 Increases inspiratory time to assure volume
Volume support ventilation
Support mode Has PVRC as back up mode Allows spontaneous if preset MV is
achieved If fails deliver preset TV MV in lowest
possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure
limitlower amp upper MV alarm
Applications of VSV
Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations
in inspiratory pressure support
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
Interface Interfaces are devices that connect ventilator tubing to
the face allowing the entry of pressurized gas to the upper airway
Nasal and oronasal masks and mouth pieces CPAP helmet are currently available interfaces
Masks - made from a non irritant material such as silicon rubber - minimal dead space and a soft inflatable cuff to provide a seal with the skin
Nasal mask - better tolerated but less effective ndash leak Face masks are more useful in acute respiratory failure Nasal masksMouth piece CPAP helmet are used most
often in chronic respiratory failure
Ventilators - conventional
Advantages FiO2 can be set Alarm amp monitoring
back up Back up ventilation Separate insp amp exp
limbs ndash prevent rebreathing
Inspiratory pressure gt 20 cm H2O can be set
Disadvantages Expensive Less flexible
ampportable Leak compensation
not present ndash requires tight interface
NPPV Ventilators
Advantages cheaper flexible ampportable Leak compensation
present ndash does not requires tight interface
Inspiratory pressure of 20 cm H2Ois maximum available
Disadvantages FiO2 cannot be set
Due to leak ndash high oxygen flows
Single limb ndash rebreathing
Modes of Ventilation CPAP It is not a true ventilator mode as it does not actively
assist inspiration CPAP by nasal mask provides pneumatic splint which
holds the upper airway open in patients with nocturnal hypoxaemia due to episodes of obstructive sleep apnoea
CPAP increases FRC and opens collapsed alveoli CPAP reduces left ventricular transmural pressure
therefore increases cardiac output ndash effective for treatment of pulmonary oedema
Pressures are usually limited to 5-12 cm of H2O - higher pressure tends to result in gastric distension
BILEVEL POSITIVE AIRWAY PRESSURE [ BI LEVEL PAP]
Unique flow triggering ampleak compensation Spontaneous mode ndashcycle between IPAP (Up to 30 cm
H2O)amp EPAP (Up to 15 cm of H2O)- PATIENT TRIGGERED PRESSURE SUPPORTED
IPAP = PEEP +PS EPAP = PEEP in PCVSPECIAL MACHINES Have blower unit to compensate air leaks upto 180 L mt Pressure limited back up Adjustable sensitivities maximum inspiratory
time adjustable FiO2 -available
BI LEVEL PAP[contdhellip] INDICATIONS Worsening
hypoventilation hypoxemia
Chronic ventilatory muscle dysfunction
Post intubation difficulty Upper airway
obstruction ndashlaryngeal oedemastrictures
CONTRA INDICATIONS Unstable
Haemodynamics Vomiting Neurologically abnormal Pneumothorax Deteriorating respiratory
parameters
PSV
Non-invasive PSV can be administered with standard critical care ventilator or bilevel portable devices -patient triggeredpressure limited flow cycled ventilation
PSV mode has unique ability to vary inspiratory time breath by breath permitting close matching with the patients spontaneous breathing pattern
Advantages (a) Patient-ventilator synchrony (b) Improved patient comfort(c) Reduced diaphragmatic work
Volume limited ventilation ventilators are usually set in assist-control mode with
high tidal volume (10-15 mlkg) to compensate for air leak
suitable in obesity or chest wall deformity who need high
inflation pressure neuromuscular diseases who need high tidal
volume for ventilation Proportional assist ventilation (PAV)
This is a newer mode of ventilation In this mode ventilator has capacity of responding
rapidly to the patients ventilatory efforts By adjusting the gain on the flow and volume signals
one can select the proportion of breathing work that is to be assisted
Goals of NIMV
Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival
Protocol for Non Invasive Ventilation
Explain to the patient what you are doing and what to expect
Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the
patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort
Connect humidification system
Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG
Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O
Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts
Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks
Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg
Increase FiO2 to improve O2 saturation to 90
Complications and Side effects
AIR LEAK [80 -100]
MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly
over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction
FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension
MAJOR COMPLICATIONS Aspiration pneumonia - lt
5 Hypotension Pneumothorax
CRITERIA FOR FAILURE OF NPPV
MAJOR Respiratory arrest Loss of
consciousness Psychomotor
agitation Haemodynamic
instability Heart rate lt50 bm
MINOR Respiratory rate gt 35
mt pH lt730 Pao2 lt45mmHg
Intubate when one major two minor criteria
INVASIVE VENTILATION
Pressure RegulatedVolume Control [PVRC]
Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled
assistcontrol
Establishes a ldquolearning periodrdquo to determine
patientrsquos compliance which establishes regulation of pressurevolume
Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration
Pressure RegulatedVolume Control (PRVC)
1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume
The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume
Results in breath-to-breath variation of inspiratory pressure
Limitations Only an AC mode and requires a change to
Volume Support for weaning Only guarantees volume distally and not at
patient airway
TV AIRWAY PRESSURE
PROBLEMS
VCV preset fn of mechpropertyof lungs
lung injury
PCV acc to mecha property of lung
preset hypoventilation
volutrauma
PRVC preset lower paw necessary
Benefits of both
Comparison with established modes
Applications of PRVC
ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high
flow rates In whom VT has to be controlled ndashsurfactant
therapy
Benefits
Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to
mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort
BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]
Pressure controlled ventilation allowing spontaneous ventilation
Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest
airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to
ventilator in VCV
BIPAP -SUBDIVISIONS
CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at
lower level APRV ndash BIPAP - spontaneous breathing
at higher level Genuine BIPAP - spontaneous breathing
at both levels CPAP - spontaneous breathing at single
CPAP level
paw
t
Setting up BIPAP
Adjusted with ABG values High low PaCO2 Normal PaO2
VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2
mean airway pressure without altering VTRR
equidirectional alteration of P high P low
ADVANTAGES OF BIPAP
Less sedation Reduced atelectasis Ideal mode in pts with inadequate
spontaneous effort In face of deteriorating gas exchange
we can increase the invasiveness of ventilation without having to change mode
Airway Pressure Release Ventilation
(APRV) Outlined in 1987 Continuous positive airway pressure with
regular brief intermittent releases in airway pressure
The release phase results in alveolar ventilation and removal of carbon dioxide
APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance
It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation
Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance
APRV ndashCONTDhellip
Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation
APRV commences at an elevated baseline pressure and follows with a measured pressure release
During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels
Available on Draumlger and Puritan Bennett ventilators
APRV ndashCONTDhellip
Elevated baseline airway pressure during APRV may produce near complete recruitment
Minimizes low volume lung injury from cyclic recruitment
APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation
Needs a High flow CPAP circuit with release valve
Advantages of APRV Lower peak airway pressures Lower minute ventilation
Decreased adverse effects upon circulatory function
Spontaneous ventilation the entire ventilatory cycle
Decreased need for sedation
Near elimination of neuromuscular blockade Recruitment of alveoli
Indications for APRV ALI or low-compliance lung disease patients with airway disease
CONTRAINDICATIONS
Patients with Increased airway resistance
When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation
The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation
P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus
accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than
40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0
cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure
Settings of APRV
Pressure support ventilation
Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by
specific amount of positive pressure at airway
PS Terminated when insp Flow falls below a minimum trigger volume
Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau
` ADVANTAGES Less WOB low pressure high volume work similar to
spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is
achieved with PS of 5 cm H2O
Volume AssuredPressure Support (VAPS)
Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure
breath continues to guarantee volume - 1048707 PIP and inspiratory time increase
1048707 Guarantees volume on current breath (no previous breath averaging)
1048707 Combines the advantages of pressure and volume ventilation breath to breath
Characteristics of VAPS 1048707 The ventilator continuously measures the flow and
pressure and calculates delivered volume Depending on the actual settings breath may be flow
volume or time cycled 1048707 If the target tidal volume has been delivered
inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set
flow will persist until the desired volume has been reached (volume cycled breath)
1048707 Safety limits include high pressure and maximum inspiratory time1048707
Used in the Management of acute and recovering lung disease
Benefits of VAPS
1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort
Applications of VAPS 1048707 A patient who requires a substantial level of
ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony
1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change
Limitations 1048707 Will only increase pressure not lower pressure
with changing mechanics 1048707 Increases inspiratory time to assure volume
Volume support ventilation
Support mode Has PVRC as back up mode Allows spontaneous if preset MV is
achieved If fails deliver preset TV MV in lowest
possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure
limitlower amp upper MV alarm
Applications of VSV
Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations
in inspiratory pressure support
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
Ventilators - conventional
Advantages FiO2 can be set Alarm amp monitoring
back up Back up ventilation Separate insp amp exp
limbs ndash prevent rebreathing
Inspiratory pressure gt 20 cm H2O can be set
Disadvantages Expensive Less flexible
ampportable Leak compensation
not present ndash requires tight interface
NPPV Ventilators
Advantages cheaper flexible ampportable Leak compensation
present ndash does not requires tight interface
Inspiratory pressure of 20 cm H2Ois maximum available
Disadvantages FiO2 cannot be set
Due to leak ndash high oxygen flows
Single limb ndash rebreathing
Modes of Ventilation CPAP It is not a true ventilator mode as it does not actively
assist inspiration CPAP by nasal mask provides pneumatic splint which
holds the upper airway open in patients with nocturnal hypoxaemia due to episodes of obstructive sleep apnoea
CPAP increases FRC and opens collapsed alveoli CPAP reduces left ventricular transmural pressure
therefore increases cardiac output ndash effective for treatment of pulmonary oedema
Pressures are usually limited to 5-12 cm of H2O - higher pressure tends to result in gastric distension
BILEVEL POSITIVE AIRWAY PRESSURE [ BI LEVEL PAP]
Unique flow triggering ampleak compensation Spontaneous mode ndashcycle between IPAP (Up to 30 cm
H2O)amp EPAP (Up to 15 cm of H2O)- PATIENT TRIGGERED PRESSURE SUPPORTED
IPAP = PEEP +PS EPAP = PEEP in PCVSPECIAL MACHINES Have blower unit to compensate air leaks upto 180 L mt Pressure limited back up Adjustable sensitivities maximum inspiratory
time adjustable FiO2 -available
BI LEVEL PAP[contdhellip] INDICATIONS Worsening
hypoventilation hypoxemia
Chronic ventilatory muscle dysfunction
Post intubation difficulty Upper airway
obstruction ndashlaryngeal oedemastrictures
CONTRA INDICATIONS Unstable
Haemodynamics Vomiting Neurologically abnormal Pneumothorax Deteriorating respiratory
parameters
PSV
Non-invasive PSV can be administered with standard critical care ventilator or bilevel portable devices -patient triggeredpressure limited flow cycled ventilation
PSV mode has unique ability to vary inspiratory time breath by breath permitting close matching with the patients spontaneous breathing pattern
Advantages (a) Patient-ventilator synchrony (b) Improved patient comfort(c) Reduced diaphragmatic work
Volume limited ventilation ventilators are usually set in assist-control mode with
high tidal volume (10-15 mlkg) to compensate for air leak
suitable in obesity or chest wall deformity who need high
inflation pressure neuromuscular diseases who need high tidal
volume for ventilation Proportional assist ventilation (PAV)
This is a newer mode of ventilation In this mode ventilator has capacity of responding
rapidly to the patients ventilatory efforts By adjusting the gain on the flow and volume signals
one can select the proportion of breathing work that is to be assisted
Goals of NIMV
Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival
Protocol for Non Invasive Ventilation
Explain to the patient what you are doing and what to expect
Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the
patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort
Connect humidification system
Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG
Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O
Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts
Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks
Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg
Increase FiO2 to improve O2 saturation to 90
Complications and Side effects
AIR LEAK [80 -100]
MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly
over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction
FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension
MAJOR COMPLICATIONS Aspiration pneumonia - lt
5 Hypotension Pneumothorax
CRITERIA FOR FAILURE OF NPPV
MAJOR Respiratory arrest Loss of
consciousness Psychomotor
agitation Haemodynamic
instability Heart rate lt50 bm
MINOR Respiratory rate gt 35
mt pH lt730 Pao2 lt45mmHg
Intubate when one major two minor criteria
INVASIVE VENTILATION
Pressure RegulatedVolume Control [PVRC]
Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled
assistcontrol
Establishes a ldquolearning periodrdquo to determine
patientrsquos compliance which establishes regulation of pressurevolume
Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration
Pressure RegulatedVolume Control (PRVC)
1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume
The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume
Results in breath-to-breath variation of inspiratory pressure
Limitations Only an AC mode and requires a change to
Volume Support for weaning Only guarantees volume distally and not at
patient airway
TV AIRWAY PRESSURE
PROBLEMS
VCV preset fn of mechpropertyof lungs
lung injury
PCV acc to mecha property of lung
preset hypoventilation
volutrauma
PRVC preset lower paw necessary
Benefits of both
Comparison with established modes
Applications of PRVC
ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high
flow rates In whom VT has to be controlled ndashsurfactant
therapy
Benefits
Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to
mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort
BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]
Pressure controlled ventilation allowing spontaneous ventilation
Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest
airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to
ventilator in VCV
BIPAP -SUBDIVISIONS
CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at
lower level APRV ndash BIPAP - spontaneous breathing
at higher level Genuine BIPAP - spontaneous breathing
at both levels CPAP - spontaneous breathing at single
CPAP level
paw
t
Setting up BIPAP
Adjusted with ABG values High low PaCO2 Normal PaO2
VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2
mean airway pressure without altering VTRR
equidirectional alteration of P high P low
ADVANTAGES OF BIPAP
Less sedation Reduced atelectasis Ideal mode in pts with inadequate
spontaneous effort In face of deteriorating gas exchange
we can increase the invasiveness of ventilation without having to change mode
Airway Pressure Release Ventilation
(APRV) Outlined in 1987 Continuous positive airway pressure with
regular brief intermittent releases in airway pressure
The release phase results in alveolar ventilation and removal of carbon dioxide
APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance
It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation
Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance
APRV ndashCONTDhellip
Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation
APRV commences at an elevated baseline pressure and follows with a measured pressure release
During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels
Available on Draumlger and Puritan Bennett ventilators
APRV ndashCONTDhellip
Elevated baseline airway pressure during APRV may produce near complete recruitment
Minimizes low volume lung injury from cyclic recruitment
APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation
Needs a High flow CPAP circuit with release valve
Advantages of APRV Lower peak airway pressures Lower minute ventilation
Decreased adverse effects upon circulatory function
Spontaneous ventilation the entire ventilatory cycle
Decreased need for sedation
Near elimination of neuromuscular blockade Recruitment of alveoli
Indications for APRV ALI or low-compliance lung disease patients with airway disease
CONTRAINDICATIONS
Patients with Increased airway resistance
When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation
The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation
P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus
accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than
40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0
cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure
Settings of APRV
Pressure support ventilation
Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by
specific amount of positive pressure at airway
PS Terminated when insp Flow falls below a minimum trigger volume
Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau
` ADVANTAGES Less WOB low pressure high volume work similar to
spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is
achieved with PS of 5 cm H2O
Volume AssuredPressure Support (VAPS)
Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure
breath continues to guarantee volume - 1048707 PIP and inspiratory time increase
1048707 Guarantees volume on current breath (no previous breath averaging)
1048707 Combines the advantages of pressure and volume ventilation breath to breath
Characteristics of VAPS 1048707 The ventilator continuously measures the flow and
pressure and calculates delivered volume Depending on the actual settings breath may be flow
volume or time cycled 1048707 If the target tidal volume has been delivered
inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set
flow will persist until the desired volume has been reached (volume cycled breath)
1048707 Safety limits include high pressure and maximum inspiratory time1048707
Used in the Management of acute and recovering lung disease
Benefits of VAPS
1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort
Applications of VAPS 1048707 A patient who requires a substantial level of
ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony
1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change
Limitations 1048707 Will only increase pressure not lower pressure
with changing mechanics 1048707 Increases inspiratory time to assure volume
Volume support ventilation
Support mode Has PVRC as back up mode Allows spontaneous if preset MV is
achieved If fails deliver preset TV MV in lowest
possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure
limitlower amp upper MV alarm
Applications of VSV
Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations
in inspiratory pressure support
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
NPPV Ventilators
Advantages cheaper flexible ampportable Leak compensation
present ndash does not requires tight interface
Inspiratory pressure of 20 cm H2Ois maximum available
Disadvantages FiO2 cannot be set
Due to leak ndash high oxygen flows
Single limb ndash rebreathing
Modes of Ventilation CPAP It is not a true ventilator mode as it does not actively
assist inspiration CPAP by nasal mask provides pneumatic splint which
holds the upper airway open in patients with nocturnal hypoxaemia due to episodes of obstructive sleep apnoea
CPAP increases FRC and opens collapsed alveoli CPAP reduces left ventricular transmural pressure
therefore increases cardiac output ndash effective for treatment of pulmonary oedema
Pressures are usually limited to 5-12 cm of H2O - higher pressure tends to result in gastric distension
BILEVEL POSITIVE AIRWAY PRESSURE [ BI LEVEL PAP]
Unique flow triggering ampleak compensation Spontaneous mode ndashcycle between IPAP (Up to 30 cm
H2O)amp EPAP (Up to 15 cm of H2O)- PATIENT TRIGGERED PRESSURE SUPPORTED
IPAP = PEEP +PS EPAP = PEEP in PCVSPECIAL MACHINES Have blower unit to compensate air leaks upto 180 L mt Pressure limited back up Adjustable sensitivities maximum inspiratory
time adjustable FiO2 -available
BI LEVEL PAP[contdhellip] INDICATIONS Worsening
hypoventilation hypoxemia
Chronic ventilatory muscle dysfunction
Post intubation difficulty Upper airway
obstruction ndashlaryngeal oedemastrictures
CONTRA INDICATIONS Unstable
Haemodynamics Vomiting Neurologically abnormal Pneumothorax Deteriorating respiratory
parameters
PSV
Non-invasive PSV can be administered with standard critical care ventilator or bilevel portable devices -patient triggeredpressure limited flow cycled ventilation
PSV mode has unique ability to vary inspiratory time breath by breath permitting close matching with the patients spontaneous breathing pattern
Advantages (a) Patient-ventilator synchrony (b) Improved patient comfort(c) Reduced diaphragmatic work
Volume limited ventilation ventilators are usually set in assist-control mode with
high tidal volume (10-15 mlkg) to compensate for air leak
suitable in obesity or chest wall deformity who need high
inflation pressure neuromuscular diseases who need high tidal
volume for ventilation Proportional assist ventilation (PAV)
This is a newer mode of ventilation In this mode ventilator has capacity of responding
rapidly to the patients ventilatory efforts By adjusting the gain on the flow and volume signals
one can select the proportion of breathing work that is to be assisted
Goals of NIMV
Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival
Protocol for Non Invasive Ventilation
Explain to the patient what you are doing and what to expect
Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the
patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort
Connect humidification system
Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG
Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O
Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts
Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks
Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg
Increase FiO2 to improve O2 saturation to 90
Complications and Side effects
AIR LEAK [80 -100]
MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly
over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction
FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension
MAJOR COMPLICATIONS Aspiration pneumonia - lt
5 Hypotension Pneumothorax
CRITERIA FOR FAILURE OF NPPV
MAJOR Respiratory arrest Loss of
consciousness Psychomotor
agitation Haemodynamic
instability Heart rate lt50 bm
MINOR Respiratory rate gt 35
mt pH lt730 Pao2 lt45mmHg
Intubate when one major two minor criteria
INVASIVE VENTILATION
Pressure RegulatedVolume Control [PVRC]
Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled
assistcontrol
Establishes a ldquolearning periodrdquo to determine
patientrsquos compliance which establishes regulation of pressurevolume
Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration
Pressure RegulatedVolume Control (PRVC)
1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume
The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume
Results in breath-to-breath variation of inspiratory pressure
Limitations Only an AC mode and requires a change to
Volume Support for weaning Only guarantees volume distally and not at
patient airway
TV AIRWAY PRESSURE
PROBLEMS
VCV preset fn of mechpropertyof lungs
lung injury
PCV acc to mecha property of lung
preset hypoventilation
volutrauma
PRVC preset lower paw necessary
Benefits of both
Comparison with established modes
Applications of PRVC
ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high
flow rates In whom VT has to be controlled ndashsurfactant
therapy
Benefits
Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to
mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort
BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]
Pressure controlled ventilation allowing spontaneous ventilation
Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest
airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to
ventilator in VCV
BIPAP -SUBDIVISIONS
CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at
lower level APRV ndash BIPAP - spontaneous breathing
at higher level Genuine BIPAP - spontaneous breathing
at both levels CPAP - spontaneous breathing at single
CPAP level
paw
t
Setting up BIPAP
Adjusted with ABG values High low PaCO2 Normal PaO2
VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2
mean airway pressure without altering VTRR
equidirectional alteration of P high P low
ADVANTAGES OF BIPAP
Less sedation Reduced atelectasis Ideal mode in pts with inadequate
spontaneous effort In face of deteriorating gas exchange
we can increase the invasiveness of ventilation without having to change mode
Airway Pressure Release Ventilation
(APRV) Outlined in 1987 Continuous positive airway pressure with
regular brief intermittent releases in airway pressure
The release phase results in alveolar ventilation and removal of carbon dioxide
APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance
It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation
Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance
APRV ndashCONTDhellip
Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation
APRV commences at an elevated baseline pressure and follows with a measured pressure release
During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels
Available on Draumlger and Puritan Bennett ventilators
APRV ndashCONTDhellip
Elevated baseline airway pressure during APRV may produce near complete recruitment
Minimizes low volume lung injury from cyclic recruitment
APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation
Needs a High flow CPAP circuit with release valve
Advantages of APRV Lower peak airway pressures Lower minute ventilation
Decreased adverse effects upon circulatory function
Spontaneous ventilation the entire ventilatory cycle
Decreased need for sedation
Near elimination of neuromuscular blockade Recruitment of alveoli
Indications for APRV ALI or low-compliance lung disease patients with airway disease
CONTRAINDICATIONS
Patients with Increased airway resistance
When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation
The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation
P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus
accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than
40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0
cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure
Settings of APRV
Pressure support ventilation
Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by
specific amount of positive pressure at airway
PS Terminated when insp Flow falls below a minimum trigger volume
Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau
` ADVANTAGES Less WOB low pressure high volume work similar to
spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is
achieved with PS of 5 cm H2O
Volume AssuredPressure Support (VAPS)
Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure
breath continues to guarantee volume - 1048707 PIP and inspiratory time increase
1048707 Guarantees volume on current breath (no previous breath averaging)
1048707 Combines the advantages of pressure and volume ventilation breath to breath
Characteristics of VAPS 1048707 The ventilator continuously measures the flow and
pressure and calculates delivered volume Depending on the actual settings breath may be flow
volume or time cycled 1048707 If the target tidal volume has been delivered
inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set
flow will persist until the desired volume has been reached (volume cycled breath)
1048707 Safety limits include high pressure and maximum inspiratory time1048707
Used in the Management of acute and recovering lung disease
Benefits of VAPS
1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort
Applications of VAPS 1048707 A patient who requires a substantial level of
ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony
1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change
Limitations 1048707 Will only increase pressure not lower pressure
with changing mechanics 1048707 Increases inspiratory time to assure volume
Volume support ventilation
Support mode Has PVRC as back up mode Allows spontaneous if preset MV is
achieved If fails deliver preset TV MV in lowest
possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure
limitlower amp upper MV alarm
Applications of VSV
Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations
in inspiratory pressure support
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
Modes of Ventilation CPAP It is not a true ventilator mode as it does not actively
assist inspiration CPAP by nasal mask provides pneumatic splint which
holds the upper airway open in patients with nocturnal hypoxaemia due to episodes of obstructive sleep apnoea
CPAP increases FRC and opens collapsed alveoli CPAP reduces left ventricular transmural pressure
therefore increases cardiac output ndash effective for treatment of pulmonary oedema
Pressures are usually limited to 5-12 cm of H2O - higher pressure tends to result in gastric distension
BILEVEL POSITIVE AIRWAY PRESSURE [ BI LEVEL PAP]
Unique flow triggering ampleak compensation Spontaneous mode ndashcycle between IPAP (Up to 30 cm
H2O)amp EPAP (Up to 15 cm of H2O)- PATIENT TRIGGERED PRESSURE SUPPORTED
IPAP = PEEP +PS EPAP = PEEP in PCVSPECIAL MACHINES Have blower unit to compensate air leaks upto 180 L mt Pressure limited back up Adjustable sensitivities maximum inspiratory
time adjustable FiO2 -available
BI LEVEL PAP[contdhellip] INDICATIONS Worsening
hypoventilation hypoxemia
Chronic ventilatory muscle dysfunction
Post intubation difficulty Upper airway
obstruction ndashlaryngeal oedemastrictures
CONTRA INDICATIONS Unstable
Haemodynamics Vomiting Neurologically abnormal Pneumothorax Deteriorating respiratory
parameters
PSV
Non-invasive PSV can be administered with standard critical care ventilator or bilevel portable devices -patient triggeredpressure limited flow cycled ventilation
PSV mode has unique ability to vary inspiratory time breath by breath permitting close matching with the patients spontaneous breathing pattern
Advantages (a) Patient-ventilator synchrony (b) Improved patient comfort(c) Reduced diaphragmatic work
Volume limited ventilation ventilators are usually set in assist-control mode with
high tidal volume (10-15 mlkg) to compensate for air leak
suitable in obesity or chest wall deformity who need high
inflation pressure neuromuscular diseases who need high tidal
volume for ventilation Proportional assist ventilation (PAV)
This is a newer mode of ventilation In this mode ventilator has capacity of responding
rapidly to the patients ventilatory efforts By adjusting the gain on the flow and volume signals
one can select the proportion of breathing work that is to be assisted
Goals of NIMV
Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival
Protocol for Non Invasive Ventilation
Explain to the patient what you are doing and what to expect
Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the
patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort
Connect humidification system
Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG
Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O
Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts
Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks
Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg
Increase FiO2 to improve O2 saturation to 90
Complications and Side effects
AIR LEAK [80 -100]
MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly
over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction
FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension
MAJOR COMPLICATIONS Aspiration pneumonia - lt
5 Hypotension Pneumothorax
CRITERIA FOR FAILURE OF NPPV
MAJOR Respiratory arrest Loss of
consciousness Psychomotor
agitation Haemodynamic
instability Heart rate lt50 bm
MINOR Respiratory rate gt 35
mt pH lt730 Pao2 lt45mmHg
Intubate when one major two minor criteria
INVASIVE VENTILATION
Pressure RegulatedVolume Control [PVRC]
Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled
assistcontrol
Establishes a ldquolearning periodrdquo to determine
patientrsquos compliance which establishes regulation of pressurevolume
Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration
Pressure RegulatedVolume Control (PRVC)
1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume
The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume
Results in breath-to-breath variation of inspiratory pressure
Limitations Only an AC mode and requires a change to
Volume Support for weaning Only guarantees volume distally and not at
patient airway
TV AIRWAY PRESSURE
PROBLEMS
VCV preset fn of mechpropertyof lungs
lung injury
PCV acc to mecha property of lung
preset hypoventilation
volutrauma
PRVC preset lower paw necessary
Benefits of both
Comparison with established modes
Applications of PRVC
ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high
flow rates In whom VT has to be controlled ndashsurfactant
therapy
Benefits
Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to
mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort
BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]
Pressure controlled ventilation allowing spontaneous ventilation
Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest
airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to
ventilator in VCV
BIPAP -SUBDIVISIONS
CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at
lower level APRV ndash BIPAP - spontaneous breathing
at higher level Genuine BIPAP - spontaneous breathing
at both levels CPAP - spontaneous breathing at single
CPAP level
paw
t
Setting up BIPAP
Adjusted with ABG values High low PaCO2 Normal PaO2
VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2
mean airway pressure without altering VTRR
equidirectional alteration of P high P low
ADVANTAGES OF BIPAP
Less sedation Reduced atelectasis Ideal mode in pts with inadequate
spontaneous effort In face of deteriorating gas exchange
we can increase the invasiveness of ventilation without having to change mode
Airway Pressure Release Ventilation
(APRV) Outlined in 1987 Continuous positive airway pressure with
regular brief intermittent releases in airway pressure
The release phase results in alveolar ventilation and removal of carbon dioxide
APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance
It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation
Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance
APRV ndashCONTDhellip
Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation
APRV commences at an elevated baseline pressure and follows with a measured pressure release
During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels
Available on Draumlger and Puritan Bennett ventilators
APRV ndashCONTDhellip
Elevated baseline airway pressure during APRV may produce near complete recruitment
Minimizes low volume lung injury from cyclic recruitment
APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation
Needs a High flow CPAP circuit with release valve
Advantages of APRV Lower peak airway pressures Lower minute ventilation
Decreased adverse effects upon circulatory function
Spontaneous ventilation the entire ventilatory cycle
Decreased need for sedation
Near elimination of neuromuscular blockade Recruitment of alveoli
Indications for APRV ALI or low-compliance lung disease patients with airway disease
CONTRAINDICATIONS
Patients with Increased airway resistance
When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation
The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation
P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus
accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than
40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0
cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure
Settings of APRV
Pressure support ventilation
Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by
specific amount of positive pressure at airway
PS Terminated when insp Flow falls below a minimum trigger volume
Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau
` ADVANTAGES Less WOB low pressure high volume work similar to
spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is
achieved with PS of 5 cm H2O
Volume AssuredPressure Support (VAPS)
Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure
breath continues to guarantee volume - 1048707 PIP and inspiratory time increase
1048707 Guarantees volume on current breath (no previous breath averaging)
1048707 Combines the advantages of pressure and volume ventilation breath to breath
Characteristics of VAPS 1048707 The ventilator continuously measures the flow and
pressure and calculates delivered volume Depending on the actual settings breath may be flow
volume or time cycled 1048707 If the target tidal volume has been delivered
inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set
flow will persist until the desired volume has been reached (volume cycled breath)
1048707 Safety limits include high pressure and maximum inspiratory time1048707
Used in the Management of acute and recovering lung disease
Benefits of VAPS
1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort
Applications of VAPS 1048707 A patient who requires a substantial level of
ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony
1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change
Limitations 1048707 Will only increase pressure not lower pressure
with changing mechanics 1048707 Increases inspiratory time to assure volume
Volume support ventilation
Support mode Has PVRC as back up mode Allows spontaneous if preset MV is
achieved If fails deliver preset TV MV in lowest
possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure
limitlower amp upper MV alarm
Applications of VSV
Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations
in inspiratory pressure support
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
BILEVEL POSITIVE AIRWAY PRESSURE [ BI LEVEL PAP]
Unique flow triggering ampleak compensation Spontaneous mode ndashcycle between IPAP (Up to 30 cm
H2O)amp EPAP (Up to 15 cm of H2O)- PATIENT TRIGGERED PRESSURE SUPPORTED
IPAP = PEEP +PS EPAP = PEEP in PCVSPECIAL MACHINES Have blower unit to compensate air leaks upto 180 L mt Pressure limited back up Adjustable sensitivities maximum inspiratory
time adjustable FiO2 -available
BI LEVEL PAP[contdhellip] INDICATIONS Worsening
hypoventilation hypoxemia
Chronic ventilatory muscle dysfunction
Post intubation difficulty Upper airway
obstruction ndashlaryngeal oedemastrictures
CONTRA INDICATIONS Unstable
Haemodynamics Vomiting Neurologically abnormal Pneumothorax Deteriorating respiratory
parameters
PSV
Non-invasive PSV can be administered with standard critical care ventilator or bilevel portable devices -patient triggeredpressure limited flow cycled ventilation
PSV mode has unique ability to vary inspiratory time breath by breath permitting close matching with the patients spontaneous breathing pattern
Advantages (a) Patient-ventilator synchrony (b) Improved patient comfort(c) Reduced diaphragmatic work
Volume limited ventilation ventilators are usually set in assist-control mode with
high tidal volume (10-15 mlkg) to compensate for air leak
suitable in obesity or chest wall deformity who need high
inflation pressure neuromuscular diseases who need high tidal
volume for ventilation Proportional assist ventilation (PAV)
This is a newer mode of ventilation In this mode ventilator has capacity of responding
rapidly to the patients ventilatory efforts By adjusting the gain on the flow and volume signals
one can select the proportion of breathing work that is to be assisted
Goals of NIMV
Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival
Protocol for Non Invasive Ventilation
Explain to the patient what you are doing and what to expect
Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the
patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort
Connect humidification system
Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG
Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O
Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts
Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks
Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg
Increase FiO2 to improve O2 saturation to 90
Complications and Side effects
AIR LEAK [80 -100]
MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly
over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction
FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension
MAJOR COMPLICATIONS Aspiration pneumonia - lt
5 Hypotension Pneumothorax
CRITERIA FOR FAILURE OF NPPV
MAJOR Respiratory arrest Loss of
consciousness Psychomotor
agitation Haemodynamic
instability Heart rate lt50 bm
MINOR Respiratory rate gt 35
mt pH lt730 Pao2 lt45mmHg
Intubate when one major two minor criteria
INVASIVE VENTILATION
Pressure RegulatedVolume Control [PVRC]
Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled
assistcontrol
Establishes a ldquolearning periodrdquo to determine
patientrsquos compliance which establishes regulation of pressurevolume
Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration
Pressure RegulatedVolume Control (PRVC)
1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume
The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume
Results in breath-to-breath variation of inspiratory pressure
Limitations Only an AC mode and requires a change to
Volume Support for weaning Only guarantees volume distally and not at
patient airway
TV AIRWAY PRESSURE
PROBLEMS
VCV preset fn of mechpropertyof lungs
lung injury
PCV acc to mecha property of lung
preset hypoventilation
volutrauma
PRVC preset lower paw necessary
Benefits of both
Comparison with established modes
Applications of PRVC
ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high
flow rates In whom VT has to be controlled ndashsurfactant
therapy
Benefits
Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to
mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort
BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]
Pressure controlled ventilation allowing spontaneous ventilation
Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest
airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to
ventilator in VCV
BIPAP -SUBDIVISIONS
CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at
lower level APRV ndash BIPAP - spontaneous breathing
at higher level Genuine BIPAP - spontaneous breathing
at both levels CPAP - spontaneous breathing at single
CPAP level
paw
t
Setting up BIPAP
Adjusted with ABG values High low PaCO2 Normal PaO2
VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2
mean airway pressure without altering VTRR
equidirectional alteration of P high P low
ADVANTAGES OF BIPAP
Less sedation Reduced atelectasis Ideal mode in pts with inadequate
spontaneous effort In face of deteriorating gas exchange
we can increase the invasiveness of ventilation without having to change mode
Airway Pressure Release Ventilation
(APRV) Outlined in 1987 Continuous positive airway pressure with
regular brief intermittent releases in airway pressure
The release phase results in alveolar ventilation and removal of carbon dioxide
APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance
It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation
Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance
APRV ndashCONTDhellip
Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation
APRV commences at an elevated baseline pressure and follows with a measured pressure release
During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels
Available on Draumlger and Puritan Bennett ventilators
APRV ndashCONTDhellip
Elevated baseline airway pressure during APRV may produce near complete recruitment
Minimizes low volume lung injury from cyclic recruitment
APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation
Needs a High flow CPAP circuit with release valve
Advantages of APRV Lower peak airway pressures Lower minute ventilation
Decreased adverse effects upon circulatory function
Spontaneous ventilation the entire ventilatory cycle
Decreased need for sedation
Near elimination of neuromuscular blockade Recruitment of alveoli
Indications for APRV ALI or low-compliance lung disease patients with airway disease
CONTRAINDICATIONS
Patients with Increased airway resistance
When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation
The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation
P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus
accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than
40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0
cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure
Settings of APRV
Pressure support ventilation
Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by
specific amount of positive pressure at airway
PS Terminated when insp Flow falls below a minimum trigger volume
Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau
` ADVANTAGES Less WOB low pressure high volume work similar to
spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is
achieved with PS of 5 cm H2O
Volume AssuredPressure Support (VAPS)
Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure
breath continues to guarantee volume - 1048707 PIP and inspiratory time increase
1048707 Guarantees volume on current breath (no previous breath averaging)
1048707 Combines the advantages of pressure and volume ventilation breath to breath
Characteristics of VAPS 1048707 The ventilator continuously measures the flow and
pressure and calculates delivered volume Depending on the actual settings breath may be flow
volume or time cycled 1048707 If the target tidal volume has been delivered
inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set
flow will persist until the desired volume has been reached (volume cycled breath)
1048707 Safety limits include high pressure and maximum inspiratory time1048707
Used in the Management of acute and recovering lung disease
Benefits of VAPS
1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort
Applications of VAPS 1048707 A patient who requires a substantial level of
ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony
1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change
Limitations 1048707 Will only increase pressure not lower pressure
with changing mechanics 1048707 Increases inspiratory time to assure volume
Volume support ventilation
Support mode Has PVRC as back up mode Allows spontaneous if preset MV is
achieved If fails deliver preset TV MV in lowest
possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure
limitlower amp upper MV alarm
Applications of VSV
Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations
in inspiratory pressure support
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
BI LEVEL PAP[contdhellip] INDICATIONS Worsening
hypoventilation hypoxemia
Chronic ventilatory muscle dysfunction
Post intubation difficulty Upper airway
obstruction ndashlaryngeal oedemastrictures
CONTRA INDICATIONS Unstable
Haemodynamics Vomiting Neurologically abnormal Pneumothorax Deteriorating respiratory
parameters
PSV
Non-invasive PSV can be administered with standard critical care ventilator or bilevel portable devices -patient triggeredpressure limited flow cycled ventilation
PSV mode has unique ability to vary inspiratory time breath by breath permitting close matching with the patients spontaneous breathing pattern
Advantages (a) Patient-ventilator synchrony (b) Improved patient comfort(c) Reduced diaphragmatic work
Volume limited ventilation ventilators are usually set in assist-control mode with
high tidal volume (10-15 mlkg) to compensate for air leak
suitable in obesity or chest wall deformity who need high
inflation pressure neuromuscular diseases who need high tidal
volume for ventilation Proportional assist ventilation (PAV)
This is a newer mode of ventilation In this mode ventilator has capacity of responding
rapidly to the patients ventilatory efforts By adjusting the gain on the flow and volume signals
one can select the proportion of breathing work that is to be assisted
Goals of NIMV
Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival
Protocol for Non Invasive Ventilation
Explain to the patient what you are doing and what to expect
Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the
patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort
Connect humidification system
Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG
Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O
Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts
Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks
Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg
Increase FiO2 to improve O2 saturation to 90
Complications and Side effects
AIR LEAK [80 -100]
MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly
over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction
FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension
MAJOR COMPLICATIONS Aspiration pneumonia - lt
5 Hypotension Pneumothorax
CRITERIA FOR FAILURE OF NPPV
MAJOR Respiratory arrest Loss of
consciousness Psychomotor
agitation Haemodynamic
instability Heart rate lt50 bm
MINOR Respiratory rate gt 35
mt pH lt730 Pao2 lt45mmHg
Intubate when one major two minor criteria
INVASIVE VENTILATION
Pressure RegulatedVolume Control [PVRC]
Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled
assistcontrol
Establishes a ldquolearning periodrdquo to determine
patientrsquos compliance which establishes regulation of pressurevolume
Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration
Pressure RegulatedVolume Control (PRVC)
1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume
The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume
Results in breath-to-breath variation of inspiratory pressure
Limitations Only an AC mode and requires a change to
Volume Support for weaning Only guarantees volume distally and not at
patient airway
TV AIRWAY PRESSURE
PROBLEMS
VCV preset fn of mechpropertyof lungs
lung injury
PCV acc to mecha property of lung
preset hypoventilation
volutrauma
PRVC preset lower paw necessary
Benefits of both
Comparison with established modes
Applications of PRVC
ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high
flow rates In whom VT has to be controlled ndashsurfactant
therapy
Benefits
Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to
mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort
BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]
Pressure controlled ventilation allowing spontaneous ventilation
Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest
airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to
ventilator in VCV
BIPAP -SUBDIVISIONS
CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at
lower level APRV ndash BIPAP - spontaneous breathing
at higher level Genuine BIPAP - spontaneous breathing
at both levels CPAP - spontaneous breathing at single
CPAP level
paw
t
Setting up BIPAP
Adjusted with ABG values High low PaCO2 Normal PaO2
VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2
mean airway pressure without altering VTRR
equidirectional alteration of P high P low
ADVANTAGES OF BIPAP
Less sedation Reduced atelectasis Ideal mode in pts with inadequate
spontaneous effort In face of deteriorating gas exchange
we can increase the invasiveness of ventilation without having to change mode
Airway Pressure Release Ventilation
(APRV) Outlined in 1987 Continuous positive airway pressure with
regular brief intermittent releases in airway pressure
The release phase results in alveolar ventilation and removal of carbon dioxide
APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance
It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation
Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance
APRV ndashCONTDhellip
Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation
APRV commences at an elevated baseline pressure and follows with a measured pressure release
During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels
Available on Draumlger and Puritan Bennett ventilators
APRV ndashCONTDhellip
Elevated baseline airway pressure during APRV may produce near complete recruitment
Minimizes low volume lung injury from cyclic recruitment
APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation
Needs a High flow CPAP circuit with release valve
Advantages of APRV Lower peak airway pressures Lower minute ventilation
Decreased adverse effects upon circulatory function
Spontaneous ventilation the entire ventilatory cycle
Decreased need for sedation
Near elimination of neuromuscular blockade Recruitment of alveoli
Indications for APRV ALI or low-compliance lung disease patients with airway disease
CONTRAINDICATIONS
Patients with Increased airway resistance
When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation
The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation
P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus
accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than
40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0
cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure
Settings of APRV
Pressure support ventilation
Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by
specific amount of positive pressure at airway
PS Terminated when insp Flow falls below a minimum trigger volume
Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau
` ADVANTAGES Less WOB low pressure high volume work similar to
spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is
achieved with PS of 5 cm H2O
Volume AssuredPressure Support (VAPS)
Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure
breath continues to guarantee volume - 1048707 PIP and inspiratory time increase
1048707 Guarantees volume on current breath (no previous breath averaging)
1048707 Combines the advantages of pressure and volume ventilation breath to breath
Characteristics of VAPS 1048707 The ventilator continuously measures the flow and
pressure and calculates delivered volume Depending on the actual settings breath may be flow
volume or time cycled 1048707 If the target tidal volume has been delivered
inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set
flow will persist until the desired volume has been reached (volume cycled breath)
1048707 Safety limits include high pressure and maximum inspiratory time1048707
Used in the Management of acute and recovering lung disease
Benefits of VAPS
1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort
Applications of VAPS 1048707 A patient who requires a substantial level of
ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony
1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change
Limitations 1048707 Will only increase pressure not lower pressure
with changing mechanics 1048707 Increases inspiratory time to assure volume
Volume support ventilation
Support mode Has PVRC as back up mode Allows spontaneous if preset MV is
achieved If fails deliver preset TV MV in lowest
possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure
limitlower amp upper MV alarm
Applications of VSV
Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations
in inspiratory pressure support
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
PSV
Non-invasive PSV can be administered with standard critical care ventilator or bilevel portable devices -patient triggeredpressure limited flow cycled ventilation
PSV mode has unique ability to vary inspiratory time breath by breath permitting close matching with the patients spontaneous breathing pattern
Advantages (a) Patient-ventilator synchrony (b) Improved patient comfort(c) Reduced diaphragmatic work
Volume limited ventilation ventilators are usually set in assist-control mode with
high tidal volume (10-15 mlkg) to compensate for air leak
suitable in obesity or chest wall deformity who need high
inflation pressure neuromuscular diseases who need high tidal
volume for ventilation Proportional assist ventilation (PAV)
This is a newer mode of ventilation In this mode ventilator has capacity of responding
rapidly to the patients ventilatory efforts By adjusting the gain on the flow and volume signals
one can select the proportion of breathing work that is to be assisted
Goals of NIMV
Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival
Protocol for Non Invasive Ventilation
Explain to the patient what you are doing and what to expect
Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the
patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort
Connect humidification system
Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG
Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O
Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts
Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks
Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg
Increase FiO2 to improve O2 saturation to 90
Complications and Side effects
AIR LEAK [80 -100]
MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly
over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction
FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension
MAJOR COMPLICATIONS Aspiration pneumonia - lt
5 Hypotension Pneumothorax
CRITERIA FOR FAILURE OF NPPV
MAJOR Respiratory arrest Loss of
consciousness Psychomotor
agitation Haemodynamic
instability Heart rate lt50 bm
MINOR Respiratory rate gt 35
mt pH lt730 Pao2 lt45mmHg
Intubate when one major two minor criteria
INVASIVE VENTILATION
Pressure RegulatedVolume Control [PVRC]
Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled
assistcontrol
Establishes a ldquolearning periodrdquo to determine
patientrsquos compliance which establishes regulation of pressurevolume
Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration
Pressure RegulatedVolume Control (PRVC)
1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume
The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume
Results in breath-to-breath variation of inspiratory pressure
Limitations Only an AC mode and requires a change to
Volume Support for weaning Only guarantees volume distally and not at
patient airway
TV AIRWAY PRESSURE
PROBLEMS
VCV preset fn of mechpropertyof lungs
lung injury
PCV acc to mecha property of lung
preset hypoventilation
volutrauma
PRVC preset lower paw necessary
Benefits of both
Comparison with established modes
Applications of PRVC
ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high
flow rates In whom VT has to be controlled ndashsurfactant
therapy
Benefits
Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to
mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort
BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]
Pressure controlled ventilation allowing spontaneous ventilation
Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest
airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to
ventilator in VCV
BIPAP -SUBDIVISIONS
CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at
lower level APRV ndash BIPAP - spontaneous breathing
at higher level Genuine BIPAP - spontaneous breathing
at both levels CPAP - spontaneous breathing at single
CPAP level
paw
t
Setting up BIPAP
Adjusted with ABG values High low PaCO2 Normal PaO2
VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2
mean airway pressure without altering VTRR
equidirectional alteration of P high P low
ADVANTAGES OF BIPAP
Less sedation Reduced atelectasis Ideal mode in pts with inadequate
spontaneous effort In face of deteriorating gas exchange
we can increase the invasiveness of ventilation without having to change mode
Airway Pressure Release Ventilation
(APRV) Outlined in 1987 Continuous positive airway pressure with
regular brief intermittent releases in airway pressure
The release phase results in alveolar ventilation and removal of carbon dioxide
APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance
It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation
Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance
APRV ndashCONTDhellip
Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation
APRV commences at an elevated baseline pressure and follows with a measured pressure release
During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels
Available on Draumlger and Puritan Bennett ventilators
APRV ndashCONTDhellip
Elevated baseline airway pressure during APRV may produce near complete recruitment
Minimizes low volume lung injury from cyclic recruitment
APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation
Needs a High flow CPAP circuit with release valve
Advantages of APRV Lower peak airway pressures Lower minute ventilation
Decreased adverse effects upon circulatory function
Spontaneous ventilation the entire ventilatory cycle
Decreased need for sedation
Near elimination of neuromuscular blockade Recruitment of alveoli
Indications for APRV ALI or low-compliance lung disease patients with airway disease
CONTRAINDICATIONS
Patients with Increased airway resistance
When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation
The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation
P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus
accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than
40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0
cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure
Settings of APRV
Pressure support ventilation
Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by
specific amount of positive pressure at airway
PS Terminated when insp Flow falls below a minimum trigger volume
Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau
` ADVANTAGES Less WOB low pressure high volume work similar to
spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is
achieved with PS of 5 cm H2O
Volume AssuredPressure Support (VAPS)
Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure
breath continues to guarantee volume - 1048707 PIP and inspiratory time increase
1048707 Guarantees volume on current breath (no previous breath averaging)
1048707 Combines the advantages of pressure and volume ventilation breath to breath
Characteristics of VAPS 1048707 The ventilator continuously measures the flow and
pressure and calculates delivered volume Depending on the actual settings breath may be flow
volume or time cycled 1048707 If the target tidal volume has been delivered
inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set
flow will persist until the desired volume has been reached (volume cycled breath)
1048707 Safety limits include high pressure and maximum inspiratory time1048707
Used in the Management of acute and recovering lung disease
Benefits of VAPS
1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort
Applications of VAPS 1048707 A patient who requires a substantial level of
ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony
1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change
Limitations 1048707 Will only increase pressure not lower pressure
with changing mechanics 1048707 Increases inspiratory time to assure volume
Volume support ventilation
Support mode Has PVRC as back up mode Allows spontaneous if preset MV is
achieved If fails deliver preset TV MV in lowest
possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure
limitlower amp upper MV alarm
Applications of VSV
Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations
in inspiratory pressure support
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
Volume limited ventilation ventilators are usually set in assist-control mode with
high tidal volume (10-15 mlkg) to compensate for air leak
suitable in obesity or chest wall deformity who need high
inflation pressure neuromuscular diseases who need high tidal
volume for ventilation Proportional assist ventilation (PAV)
This is a newer mode of ventilation In this mode ventilator has capacity of responding
rapidly to the patients ventilatory efforts By adjusting the gain on the flow and volume signals
one can select the proportion of breathing work that is to be assisted
Goals of NIMV
Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival
Protocol for Non Invasive Ventilation
Explain to the patient what you are doing and what to expect
Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the
patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort
Connect humidification system
Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG
Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O
Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts
Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks
Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg
Increase FiO2 to improve O2 saturation to 90
Complications and Side effects
AIR LEAK [80 -100]
MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly
over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction
FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension
MAJOR COMPLICATIONS Aspiration pneumonia - lt
5 Hypotension Pneumothorax
CRITERIA FOR FAILURE OF NPPV
MAJOR Respiratory arrest Loss of
consciousness Psychomotor
agitation Haemodynamic
instability Heart rate lt50 bm
MINOR Respiratory rate gt 35
mt pH lt730 Pao2 lt45mmHg
Intubate when one major two minor criteria
INVASIVE VENTILATION
Pressure RegulatedVolume Control [PVRC]
Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled
assistcontrol
Establishes a ldquolearning periodrdquo to determine
patientrsquos compliance which establishes regulation of pressurevolume
Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration
Pressure RegulatedVolume Control (PRVC)
1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume
The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume
Results in breath-to-breath variation of inspiratory pressure
Limitations Only an AC mode and requires a change to
Volume Support for weaning Only guarantees volume distally and not at
patient airway
TV AIRWAY PRESSURE
PROBLEMS
VCV preset fn of mechpropertyof lungs
lung injury
PCV acc to mecha property of lung
preset hypoventilation
volutrauma
PRVC preset lower paw necessary
Benefits of both
Comparison with established modes
Applications of PRVC
ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high
flow rates In whom VT has to be controlled ndashsurfactant
therapy
Benefits
Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to
mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort
BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]
Pressure controlled ventilation allowing spontaneous ventilation
Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest
airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to
ventilator in VCV
BIPAP -SUBDIVISIONS
CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at
lower level APRV ndash BIPAP - spontaneous breathing
at higher level Genuine BIPAP - spontaneous breathing
at both levels CPAP - spontaneous breathing at single
CPAP level
paw
t
Setting up BIPAP
Adjusted with ABG values High low PaCO2 Normal PaO2
VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2
mean airway pressure without altering VTRR
equidirectional alteration of P high P low
ADVANTAGES OF BIPAP
Less sedation Reduced atelectasis Ideal mode in pts with inadequate
spontaneous effort In face of deteriorating gas exchange
we can increase the invasiveness of ventilation without having to change mode
Airway Pressure Release Ventilation
(APRV) Outlined in 1987 Continuous positive airway pressure with
regular brief intermittent releases in airway pressure
The release phase results in alveolar ventilation and removal of carbon dioxide
APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance
It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation
Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance
APRV ndashCONTDhellip
Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation
APRV commences at an elevated baseline pressure and follows with a measured pressure release
During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels
Available on Draumlger and Puritan Bennett ventilators
APRV ndashCONTDhellip
Elevated baseline airway pressure during APRV may produce near complete recruitment
Minimizes low volume lung injury from cyclic recruitment
APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation
Needs a High flow CPAP circuit with release valve
Advantages of APRV Lower peak airway pressures Lower minute ventilation
Decreased adverse effects upon circulatory function
Spontaneous ventilation the entire ventilatory cycle
Decreased need for sedation
Near elimination of neuromuscular blockade Recruitment of alveoli
Indications for APRV ALI or low-compliance lung disease patients with airway disease
CONTRAINDICATIONS
Patients with Increased airway resistance
When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation
The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation
P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus
accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than
40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0
cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure
Settings of APRV
Pressure support ventilation
Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by
specific amount of positive pressure at airway
PS Terminated when insp Flow falls below a minimum trigger volume
Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau
` ADVANTAGES Less WOB low pressure high volume work similar to
spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is
achieved with PS of 5 cm H2O
Volume AssuredPressure Support (VAPS)
Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure
breath continues to guarantee volume - 1048707 PIP and inspiratory time increase
1048707 Guarantees volume on current breath (no previous breath averaging)
1048707 Combines the advantages of pressure and volume ventilation breath to breath
Characteristics of VAPS 1048707 The ventilator continuously measures the flow and
pressure and calculates delivered volume Depending on the actual settings breath may be flow
volume or time cycled 1048707 If the target tidal volume has been delivered
inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set
flow will persist until the desired volume has been reached (volume cycled breath)
1048707 Safety limits include high pressure and maximum inspiratory time1048707
Used in the Management of acute and recovering lung disease
Benefits of VAPS
1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort
Applications of VAPS 1048707 A patient who requires a substantial level of
ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony
1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change
Limitations 1048707 Will only increase pressure not lower pressure
with changing mechanics 1048707 Increases inspiratory time to assure volume
Volume support ventilation
Support mode Has PVRC as back up mode Allows spontaneous if preset MV is
achieved If fails deliver preset TV MV in lowest
possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure
limitlower amp upper MV alarm
Applications of VSV
Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations
in inspiratory pressure support
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
Goals of NIMV
Short Term Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Long Term Improve sleep duration and quality Maximize quality of life Enhance functional status Prolong survival
Protocol for Non Invasive Ventilation
Explain to the patient what you are doing and what to expect
Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the
patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort
Connect humidification system
Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG
Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O
Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts
Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks
Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg
Increase FiO2 to improve O2 saturation to 90
Complications and Side effects
AIR LEAK [80 -100]
MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly
over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction
FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension
MAJOR COMPLICATIONS Aspiration pneumonia - lt
5 Hypotension Pneumothorax
CRITERIA FOR FAILURE OF NPPV
MAJOR Respiratory arrest Loss of
consciousness Psychomotor
agitation Haemodynamic
instability Heart rate lt50 bm
MINOR Respiratory rate gt 35
mt pH lt730 Pao2 lt45mmHg
Intubate when one major two minor criteria
INVASIVE VENTILATION
Pressure RegulatedVolume Control [PVRC]
Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled
assistcontrol
Establishes a ldquolearning periodrdquo to determine
patientrsquos compliance which establishes regulation of pressurevolume
Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration
Pressure RegulatedVolume Control (PRVC)
1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume
The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume
Results in breath-to-breath variation of inspiratory pressure
Limitations Only an AC mode and requires a change to
Volume Support for weaning Only guarantees volume distally and not at
patient airway
TV AIRWAY PRESSURE
PROBLEMS
VCV preset fn of mechpropertyof lungs
lung injury
PCV acc to mecha property of lung
preset hypoventilation
volutrauma
PRVC preset lower paw necessary
Benefits of both
Comparison with established modes
Applications of PRVC
ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high
flow rates In whom VT has to be controlled ndashsurfactant
therapy
Benefits
Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to
mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort
BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]
Pressure controlled ventilation allowing spontaneous ventilation
Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest
airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to
ventilator in VCV
BIPAP -SUBDIVISIONS
CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at
lower level APRV ndash BIPAP - spontaneous breathing
at higher level Genuine BIPAP - spontaneous breathing
at both levels CPAP - spontaneous breathing at single
CPAP level
paw
t
Setting up BIPAP
Adjusted with ABG values High low PaCO2 Normal PaO2
VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2
mean airway pressure without altering VTRR
equidirectional alteration of P high P low
ADVANTAGES OF BIPAP
Less sedation Reduced atelectasis Ideal mode in pts with inadequate
spontaneous effort In face of deteriorating gas exchange
we can increase the invasiveness of ventilation without having to change mode
Airway Pressure Release Ventilation
(APRV) Outlined in 1987 Continuous positive airway pressure with
regular brief intermittent releases in airway pressure
The release phase results in alveolar ventilation and removal of carbon dioxide
APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance
It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation
Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance
APRV ndashCONTDhellip
Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation
APRV commences at an elevated baseline pressure and follows with a measured pressure release
During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels
Available on Draumlger and Puritan Bennett ventilators
APRV ndashCONTDhellip
Elevated baseline airway pressure during APRV may produce near complete recruitment
Minimizes low volume lung injury from cyclic recruitment
APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation
Needs a High flow CPAP circuit with release valve
Advantages of APRV Lower peak airway pressures Lower minute ventilation
Decreased adverse effects upon circulatory function
Spontaneous ventilation the entire ventilatory cycle
Decreased need for sedation
Near elimination of neuromuscular blockade Recruitment of alveoli
Indications for APRV ALI or low-compliance lung disease patients with airway disease
CONTRAINDICATIONS
Patients with Increased airway resistance
When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation
The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation
P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus
accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than
40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0
cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure
Settings of APRV
Pressure support ventilation
Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by
specific amount of positive pressure at airway
PS Terminated when insp Flow falls below a minimum trigger volume
Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau
` ADVANTAGES Less WOB low pressure high volume work similar to
spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is
achieved with PS of 5 cm H2O
Volume AssuredPressure Support (VAPS)
Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure
breath continues to guarantee volume - 1048707 PIP and inspiratory time increase
1048707 Guarantees volume on current breath (no previous breath averaging)
1048707 Combines the advantages of pressure and volume ventilation breath to breath
Characteristics of VAPS 1048707 The ventilator continuously measures the flow and
pressure and calculates delivered volume Depending on the actual settings breath may be flow
volume or time cycled 1048707 If the target tidal volume has been delivered
inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set
flow will persist until the desired volume has been reached (volume cycled breath)
1048707 Safety limits include high pressure and maximum inspiratory time1048707
Used in the Management of acute and recovering lung disease
Benefits of VAPS
1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort
Applications of VAPS 1048707 A patient who requires a substantial level of
ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony
1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change
Limitations 1048707 Will only increase pressure not lower pressure
with changing mechanics 1048707 Increases inspiratory time to assure volume
Volume support ventilation
Support mode Has PVRC as back up mode Allows spontaneous if preset MV is
achieved If fails deliver preset TV MV in lowest
possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure
limitlower amp upper MV alarm
Applications of VSV
Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations
in inspiratory pressure support
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
Protocol for Non Invasive Ventilation
Explain to the patient what you are doing and what to expect
Setup the ventilator by the bed side Keep the head of the patients bed at gt45 degree angle Choose the correct interface Turn on the ventilator and dial in the settings Attach O2 at 2 litres per minute Hold the mask gently over the patients face until the
patient becomes comfortable with it Strap the face mask on using the rubber head strap and minimize air leak without discomfort
Connect humidification system
Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG
Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O
Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts
Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks
Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg
Increase FiO2 to improve O2 saturation to 90
Complications and Side effects
AIR LEAK [80 -100]
MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly
over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction
FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension
MAJOR COMPLICATIONS Aspiration pneumonia - lt
5 Hypotension Pneumothorax
CRITERIA FOR FAILURE OF NPPV
MAJOR Respiratory arrest Loss of
consciousness Psychomotor
agitation Haemodynamic
instability Heart rate lt50 bm
MINOR Respiratory rate gt 35
mt pH lt730 Pao2 lt45mmHg
Intubate when one major two minor criteria
INVASIVE VENTILATION
Pressure RegulatedVolume Control [PVRC]
Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled
assistcontrol
Establishes a ldquolearning periodrdquo to determine
patientrsquos compliance which establishes regulation of pressurevolume
Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration
Pressure RegulatedVolume Control (PRVC)
1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume
The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume
Results in breath-to-breath variation of inspiratory pressure
Limitations Only an AC mode and requires a change to
Volume Support for weaning Only guarantees volume distally and not at
patient airway
TV AIRWAY PRESSURE
PROBLEMS
VCV preset fn of mechpropertyof lungs
lung injury
PCV acc to mecha property of lung
preset hypoventilation
volutrauma
PRVC preset lower paw necessary
Benefits of both
Comparison with established modes
Applications of PRVC
ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high
flow rates In whom VT has to be controlled ndashsurfactant
therapy
Benefits
Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to
mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort
BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]
Pressure controlled ventilation allowing spontaneous ventilation
Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest
airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to
ventilator in VCV
BIPAP -SUBDIVISIONS
CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at
lower level APRV ndash BIPAP - spontaneous breathing
at higher level Genuine BIPAP - spontaneous breathing
at both levels CPAP - spontaneous breathing at single
CPAP level
paw
t
Setting up BIPAP
Adjusted with ABG values High low PaCO2 Normal PaO2
VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2
mean airway pressure without altering VTRR
equidirectional alteration of P high P low
ADVANTAGES OF BIPAP
Less sedation Reduced atelectasis Ideal mode in pts with inadequate
spontaneous effort In face of deteriorating gas exchange
we can increase the invasiveness of ventilation without having to change mode
Airway Pressure Release Ventilation
(APRV) Outlined in 1987 Continuous positive airway pressure with
regular brief intermittent releases in airway pressure
The release phase results in alveolar ventilation and removal of carbon dioxide
APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance
It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation
Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance
APRV ndashCONTDhellip
Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation
APRV commences at an elevated baseline pressure and follows with a measured pressure release
During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels
Available on Draumlger and Puritan Bennett ventilators
APRV ndashCONTDhellip
Elevated baseline airway pressure during APRV may produce near complete recruitment
Minimizes low volume lung injury from cyclic recruitment
APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation
Needs a High flow CPAP circuit with release valve
Advantages of APRV Lower peak airway pressures Lower minute ventilation
Decreased adverse effects upon circulatory function
Spontaneous ventilation the entire ventilatory cycle
Decreased need for sedation
Near elimination of neuromuscular blockade Recruitment of alveoli
Indications for APRV ALI or low-compliance lung disease patients with airway disease
CONTRAINDICATIONS
Patients with Increased airway resistance
When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation
The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation
P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus
accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than
40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0
cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure
Settings of APRV
Pressure support ventilation
Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by
specific amount of positive pressure at airway
PS Terminated when insp Flow falls below a minimum trigger volume
Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau
` ADVANTAGES Less WOB low pressure high volume work similar to
spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is
achieved with PS of 5 cm H2O
Volume AssuredPressure Support (VAPS)
Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure
breath continues to guarantee volume - 1048707 PIP and inspiratory time increase
1048707 Guarantees volume on current breath (no previous breath averaging)
1048707 Combines the advantages of pressure and volume ventilation breath to breath
Characteristics of VAPS 1048707 The ventilator continuously measures the flow and
pressure and calculates delivered volume Depending on the actual settings breath may be flow
volume or time cycled 1048707 If the target tidal volume has been delivered
inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set
flow will persist until the desired volume has been reached (volume cycled breath)
1048707 Safety limits include high pressure and maximum inspiratory time1048707
Used in the Management of acute and recovering lung disease
Benefits of VAPS
1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort
Applications of VAPS 1048707 A patient who requires a substantial level of
ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony
1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change
Limitations 1048707 Will only increase pressure not lower pressure
with changing mechanics 1048707 Increases inspiratory time to assure volume
Volume support ventilation
Support mode Has PVRC as back up mode Allows spontaneous if preset MV is
achieved If fails deliver preset TV MV in lowest
possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure
limitlower amp upper MV alarm
Applications of VSV
Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations
in inspiratory pressure support
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
Monitor- respiratory rate heart rate level of dyspnoea O2 saturation blood pressure minute ventilation exhaled tidal volume abdominal distension and ABG
Initial ventilator setting should be very low ie IPAP of 6 cm H2O and EPAP of 2 cmH2O
Increase EPAP by 1-2 cm increments till the patient triggers the ventilator in all his inspiratory efforts
Increase IPAP in small increments keeping it 4cmH2O above EPAP to a maximum pressure which the patient can tolerate without discomfort and major leaks
Titrate pressure to achieve a respiratory rate of lt25 breathsmin and Vt gt7mlkg
Increase FiO2 to improve O2 saturation to 90
Complications and Side effects
AIR LEAK [80 -100]
MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly
over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction
FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension
MAJOR COMPLICATIONS Aspiration pneumonia - lt
5 Hypotension Pneumothorax
CRITERIA FOR FAILURE OF NPPV
MAJOR Respiratory arrest Loss of
consciousness Psychomotor
agitation Haemodynamic
instability Heart rate lt50 bm
MINOR Respiratory rate gt 35
mt pH lt730 Pao2 lt45mmHg
Intubate when one major two minor criteria
INVASIVE VENTILATION
Pressure RegulatedVolume Control [PVRC]
Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled
assistcontrol
Establishes a ldquolearning periodrdquo to determine
patientrsquos compliance which establishes regulation of pressurevolume
Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration
Pressure RegulatedVolume Control (PRVC)
1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume
The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume
Results in breath-to-breath variation of inspiratory pressure
Limitations Only an AC mode and requires a change to
Volume Support for weaning Only guarantees volume distally and not at
patient airway
TV AIRWAY PRESSURE
PROBLEMS
VCV preset fn of mechpropertyof lungs
lung injury
PCV acc to mecha property of lung
preset hypoventilation
volutrauma
PRVC preset lower paw necessary
Benefits of both
Comparison with established modes
Applications of PRVC
ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high
flow rates In whom VT has to be controlled ndashsurfactant
therapy
Benefits
Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to
mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort
BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]
Pressure controlled ventilation allowing spontaneous ventilation
Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest
airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to
ventilator in VCV
BIPAP -SUBDIVISIONS
CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at
lower level APRV ndash BIPAP - spontaneous breathing
at higher level Genuine BIPAP - spontaneous breathing
at both levels CPAP - spontaneous breathing at single
CPAP level
paw
t
Setting up BIPAP
Adjusted with ABG values High low PaCO2 Normal PaO2
VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2
mean airway pressure without altering VTRR
equidirectional alteration of P high P low
ADVANTAGES OF BIPAP
Less sedation Reduced atelectasis Ideal mode in pts with inadequate
spontaneous effort In face of deteriorating gas exchange
we can increase the invasiveness of ventilation without having to change mode
Airway Pressure Release Ventilation
(APRV) Outlined in 1987 Continuous positive airway pressure with
regular brief intermittent releases in airway pressure
The release phase results in alveolar ventilation and removal of carbon dioxide
APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance
It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation
Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance
APRV ndashCONTDhellip
Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation
APRV commences at an elevated baseline pressure and follows with a measured pressure release
During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels
Available on Draumlger and Puritan Bennett ventilators
APRV ndashCONTDhellip
Elevated baseline airway pressure during APRV may produce near complete recruitment
Minimizes low volume lung injury from cyclic recruitment
APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation
Needs a High flow CPAP circuit with release valve
Advantages of APRV Lower peak airway pressures Lower minute ventilation
Decreased adverse effects upon circulatory function
Spontaneous ventilation the entire ventilatory cycle
Decreased need for sedation
Near elimination of neuromuscular blockade Recruitment of alveoli
Indications for APRV ALI or low-compliance lung disease patients with airway disease
CONTRAINDICATIONS
Patients with Increased airway resistance
When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation
The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation
P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus
accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than
40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0
cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure
Settings of APRV
Pressure support ventilation
Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by
specific amount of positive pressure at airway
PS Terminated when insp Flow falls below a minimum trigger volume
Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau
` ADVANTAGES Less WOB low pressure high volume work similar to
spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is
achieved with PS of 5 cm H2O
Volume AssuredPressure Support (VAPS)
Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure
breath continues to guarantee volume - 1048707 PIP and inspiratory time increase
1048707 Guarantees volume on current breath (no previous breath averaging)
1048707 Combines the advantages of pressure and volume ventilation breath to breath
Characteristics of VAPS 1048707 The ventilator continuously measures the flow and
pressure and calculates delivered volume Depending on the actual settings breath may be flow
volume or time cycled 1048707 If the target tidal volume has been delivered
inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set
flow will persist until the desired volume has been reached (volume cycled breath)
1048707 Safety limits include high pressure and maximum inspiratory time1048707
Used in the Management of acute and recovering lung disease
Benefits of VAPS
1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort
Applications of VAPS 1048707 A patient who requires a substantial level of
ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony
1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change
Limitations 1048707 Will only increase pressure not lower pressure
with changing mechanics 1048707 Increases inspiratory time to assure volume
Volume support ventilation
Support mode Has PVRC as back up mode Allows spontaneous if preset MV is
achieved If fails deliver preset TV MV in lowest
possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure
limitlower amp upper MV alarm
Applications of VSV
Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations
in inspiratory pressure support
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
Complications and Side effects
AIR LEAK [80 -100]
MASK RELATED Discomfort Facial skin erythema Claustrophobia Skin necrosis- particularly
over bridge of nose Retention of secretions Failure to ventilate Upper airway obstruction
FLOW RELATED Nasal congestion Sinus ear pain Nasal dryness Eye irritation Gastric distension
MAJOR COMPLICATIONS Aspiration pneumonia - lt
5 Hypotension Pneumothorax
CRITERIA FOR FAILURE OF NPPV
MAJOR Respiratory arrest Loss of
consciousness Psychomotor
agitation Haemodynamic
instability Heart rate lt50 bm
MINOR Respiratory rate gt 35
mt pH lt730 Pao2 lt45mmHg
Intubate when one major two minor criteria
INVASIVE VENTILATION
Pressure RegulatedVolume Control [PVRC]
Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled
assistcontrol
Establishes a ldquolearning periodrdquo to determine
patientrsquos compliance which establishes regulation of pressurevolume
Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration
Pressure RegulatedVolume Control (PRVC)
1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume
The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume
Results in breath-to-breath variation of inspiratory pressure
Limitations Only an AC mode and requires a change to
Volume Support for weaning Only guarantees volume distally and not at
patient airway
TV AIRWAY PRESSURE
PROBLEMS
VCV preset fn of mechpropertyof lungs
lung injury
PCV acc to mecha property of lung
preset hypoventilation
volutrauma
PRVC preset lower paw necessary
Benefits of both
Comparison with established modes
Applications of PRVC
ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high
flow rates In whom VT has to be controlled ndashsurfactant
therapy
Benefits
Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to
mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort
BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]
Pressure controlled ventilation allowing spontaneous ventilation
Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest
airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to
ventilator in VCV
BIPAP -SUBDIVISIONS
CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at
lower level APRV ndash BIPAP - spontaneous breathing
at higher level Genuine BIPAP - spontaneous breathing
at both levels CPAP - spontaneous breathing at single
CPAP level
paw
t
Setting up BIPAP
Adjusted with ABG values High low PaCO2 Normal PaO2
VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2
mean airway pressure without altering VTRR
equidirectional alteration of P high P low
ADVANTAGES OF BIPAP
Less sedation Reduced atelectasis Ideal mode in pts with inadequate
spontaneous effort In face of deteriorating gas exchange
we can increase the invasiveness of ventilation without having to change mode
Airway Pressure Release Ventilation
(APRV) Outlined in 1987 Continuous positive airway pressure with
regular brief intermittent releases in airway pressure
The release phase results in alveolar ventilation and removal of carbon dioxide
APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance
It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation
Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance
APRV ndashCONTDhellip
Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation
APRV commences at an elevated baseline pressure and follows with a measured pressure release
During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels
Available on Draumlger and Puritan Bennett ventilators
APRV ndashCONTDhellip
Elevated baseline airway pressure during APRV may produce near complete recruitment
Minimizes low volume lung injury from cyclic recruitment
APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation
Needs a High flow CPAP circuit with release valve
Advantages of APRV Lower peak airway pressures Lower minute ventilation
Decreased adverse effects upon circulatory function
Spontaneous ventilation the entire ventilatory cycle
Decreased need for sedation
Near elimination of neuromuscular blockade Recruitment of alveoli
Indications for APRV ALI or low-compliance lung disease patients with airway disease
CONTRAINDICATIONS
Patients with Increased airway resistance
When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation
The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation
P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus
accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than
40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0
cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure
Settings of APRV
Pressure support ventilation
Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by
specific amount of positive pressure at airway
PS Terminated when insp Flow falls below a minimum trigger volume
Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau
` ADVANTAGES Less WOB low pressure high volume work similar to
spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is
achieved with PS of 5 cm H2O
Volume AssuredPressure Support (VAPS)
Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure
breath continues to guarantee volume - 1048707 PIP and inspiratory time increase
1048707 Guarantees volume on current breath (no previous breath averaging)
1048707 Combines the advantages of pressure and volume ventilation breath to breath
Characteristics of VAPS 1048707 The ventilator continuously measures the flow and
pressure and calculates delivered volume Depending on the actual settings breath may be flow
volume or time cycled 1048707 If the target tidal volume has been delivered
inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set
flow will persist until the desired volume has been reached (volume cycled breath)
1048707 Safety limits include high pressure and maximum inspiratory time1048707
Used in the Management of acute and recovering lung disease
Benefits of VAPS
1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort
Applications of VAPS 1048707 A patient who requires a substantial level of
ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony
1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change
Limitations 1048707 Will only increase pressure not lower pressure
with changing mechanics 1048707 Increases inspiratory time to assure volume
Volume support ventilation
Support mode Has PVRC as back up mode Allows spontaneous if preset MV is
achieved If fails deliver preset TV MV in lowest
possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure
limitlower amp upper MV alarm
Applications of VSV
Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations
in inspiratory pressure support
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
CRITERIA FOR FAILURE OF NPPV
MAJOR Respiratory arrest Loss of
consciousness Psychomotor
agitation Haemodynamic
instability Heart rate lt50 bm
MINOR Respiratory rate gt 35
mt pH lt730 Pao2 lt45mmHg
Intubate when one major two minor criteria
INVASIVE VENTILATION
Pressure RegulatedVolume Control [PVRC]
Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled
assistcontrol
Establishes a ldquolearning periodrdquo to determine
patientrsquos compliance which establishes regulation of pressurevolume
Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration
Pressure RegulatedVolume Control (PRVC)
1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume
The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume
Results in breath-to-breath variation of inspiratory pressure
Limitations Only an AC mode and requires a change to
Volume Support for weaning Only guarantees volume distally and not at
patient airway
TV AIRWAY PRESSURE
PROBLEMS
VCV preset fn of mechpropertyof lungs
lung injury
PCV acc to mecha property of lung
preset hypoventilation
volutrauma
PRVC preset lower paw necessary
Benefits of both
Comparison with established modes
Applications of PRVC
ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high
flow rates In whom VT has to be controlled ndashsurfactant
therapy
Benefits
Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to
mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort
BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]
Pressure controlled ventilation allowing spontaneous ventilation
Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest
airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to
ventilator in VCV
BIPAP -SUBDIVISIONS
CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at
lower level APRV ndash BIPAP - spontaneous breathing
at higher level Genuine BIPAP - spontaneous breathing
at both levels CPAP - spontaneous breathing at single
CPAP level
paw
t
Setting up BIPAP
Adjusted with ABG values High low PaCO2 Normal PaO2
VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2
mean airway pressure without altering VTRR
equidirectional alteration of P high P low
ADVANTAGES OF BIPAP
Less sedation Reduced atelectasis Ideal mode in pts with inadequate
spontaneous effort In face of deteriorating gas exchange
we can increase the invasiveness of ventilation without having to change mode
Airway Pressure Release Ventilation
(APRV) Outlined in 1987 Continuous positive airway pressure with
regular brief intermittent releases in airway pressure
The release phase results in alveolar ventilation and removal of carbon dioxide
APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance
It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation
Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance
APRV ndashCONTDhellip
Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation
APRV commences at an elevated baseline pressure and follows with a measured pressure release
During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels
Available on Draumlger and Puritan Bennett ventilators
APRV ndashCONTDhellip
Elevated baseline airway pressure during APRV may produce near complete recruitment
Minimizes low volume lung injury from cyclic recruitment
APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation
Needs a High flow CPAP circuit with release valve
Advantages of APRV Lower peak airway pressures Lower minute ventilation
Decreased adverse effects upon circulatory function
Spontaneous ventilation the entire ventilatory cycle
Decreased need for sedation
Near elimination of neuromuscular blockade Recruitment of alveoli
Indications for APRV ALI or low-compliance lung disease patients with airway disease
CONTRAINDICATIONS
Patients with Increased airway resistance
When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation
The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation
P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus
accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than
40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0
cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure
Settings of APRV
Pressure support ventilation
Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by
specific amount of positive pressure at airway
PS Terminated when insp Flow falls below a minimum trigger volume
Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau
` ADVANTAGES Less WOB low pressure high volume work similar to
spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is
achieved with PS of 5 cm H2O
Volume AssuredPressure Support (VAPS)
Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure
breath continues to guarantee volume - 1048707 PIP and inspiratory time increase
1048707 Guarantees volume on current breath (no previous breath averaging)
1048707 Combines the advantages of pressure and volume ventilation breath to breath
Characteristics of VAPS 1048707 The ventilator continuously measures the flow and
pressure and calculates delivered volume Depending on the actual settings breath may be flow
volume or time cycled 1048707 If the target tidal volume has been delivered
inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set
flow will persist until the desired volume has been reached (volume cycled breath)
1048707 Safety limits include high pressure and maximum inspiratory time1048707
Used in the Management of acute and recovering lung disease
Benefits of VAPS
1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort
Applications of VAPS 1048707 A patient who requires a substantial level of
ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony
1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change
Limitations 1048707 Will only increase pressure not lower pressure
with changing mechanics 1048707 Increases inspiratory time to assure volume
Volume support ventilation
Support mode Has PVRC as back up mode Allows spontaneous if preset MV is
achieved If fails deliver preset TV MV in lowest
possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure
limitlower amp upper MV alarm
Applications of VSV
Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations
in inspiratory pressure support
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
INVASIVE VENTILATION
Pressure RegulatedVolume Control [PVRC]
Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled
assistcontrol
Establishes a ldquolearning periodrdquo to determine
patientrsquos compliance which establishes regulation of pressurevolume
Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration
Pressure RegulatedVolume Control (PRVC)
1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume
The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume
Results in breath-to-breath variation of inspiratory pressure
Limitations Only an AC mode and requires a change to
Volume Support for weaning Only guarantees volume distally and not at
patient airway
TV AIRWAY PRESSURE
PROBLEMS
VCV preset fn of mechpropertyof lungs
lung injury
PCV acc to mecha property of lung
preset hypoventilation
volutrauma
PRVC preset lower paw necessary
Benefits of both
Comparison with established modes
Applications of PRVC
ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high
flow rates In whom VT has to be controlled ndashsurfactant
therapy
Benefits
Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to
mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort
BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]
Pressure controlled ventilation allowing spontaneous ventilation
Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest
airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to
ventilator in VCV
BIPAP -SUBDIVISIONS
CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at
lower level APRV ndash BIPAP - spontaneous breathing
at higher level Genuine BIPAP - spontaneous breathing
at both levels CPAP - spontaneous breathing at single
CPAP level
paw
t
Setting up BIPAP
Adjusted with ABG values High low PaCO2 Normal PaO2
VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2
mean airway pressure without altering VTRR
equidirectional alteration of P high P low
ADVANTAGES OF BIPAP
Less sedation Reduced atelectasis Ideal mode in pts with inadequate
spontaneous effort In face of deteriorating gas exchange
we can increase the invasiveness of ventilation without having to change mode
Airway Pressure Release Ventilation
(APRV) Outlined in 1987 Continuous positive airway pressure with
regular brief intermittent releases in airway pressure
The release phase results in alveolar ventilation and removal of carbon dioxide
APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance
It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation
Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance
APRV ndashCONTDhellip
Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation
APRV commences at an elevated baseline pressure and follows with a measured pressure release
During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels
Available on Draumlger and Puritan Bennett ventilators
APRV ndashCONTDhellip
Elevated baseline airway pressure during APRV may produce near complete recruitment
Minimizes low volume lung injury from cyclic recruitment
APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation
Needs a High flow CPAP circuit with release valve
Advantages of APRV Lower peak airway pressures Lower minute ventilation
Decreased adverse effects upon circulatory function
Spontaneous ventilation the entire ventilatory cycle
Decreased need for sedation
Near elimination of neuromuscular blockade Recruitment of alveoli
Indications for APRV ALI or low-compliance lung disease patients with airway disease
CONTRAINDICATIONS
Patients with Increased airway resistance
When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation
The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation
P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus
accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than
40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0
cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure
Settings of APRV
Pressure support ventilation
Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by
specific amount of positive pressure at airway
PS Terminated when insp Flow falls below a minimum trigger volume
Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau
` ADVANTAGES Less WOB low pressure high volume work similar to
spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is
achieved with PS of 5 cm H2O
Volume AssuredPressure Support (VAPS)
Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure
breath continues to guarantee volume - 1048707 PIP and inspiratory time increase
1048707 Guarantees volume on current breath (no previous breath averaging)
1048707 Combines the advantages of pressure and volume ventilation breath to breath
Characteristics of VAPS 1048707 The ventilator continuously measures the flow and
pressure and calculates delivered volume Depending on the actual settings breath may be flow
volume or time cycled 1048707 If the target tidal volume has been delivered
inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set
flow will persist until the desired volume has been reached (volume cycled breath)
1048707 Safety limits include high pressure and maximum inspiratory time1048707
Used in the Management of acute and recovering lung disease
Benefits of VAPS
1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort
Applications of VAPS 1048707 A patient who requires a substantial level of
ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony
1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change
Limitations 1048707 Will only increase pressure not lower pressure
with changing mechanics 1048707 Increases inspiratory time to assure volume
Volume support ventilation
Support mode Has PVRC as back up mode Allows spontaneous if preset MV is
achieved If fails deliver preset TV MV in lowest
possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure
limitlower amp upper MV alarm
Applications of VSV
Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations
in inspiratory pressure support
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
Pressure RegulatedVolume Control [PVRC]
Available on the Servo 300 Assist control mode Variable decelerating flow pattern Breaths are ndashpatient TRIGGER time cycled
assistcontrol
Establishes a ldquolearning periodrdquo to determine
patientrsquos compliance which establishes regulation of pressurevolume
Aim ndash is to deliver preset TV MV frequency with constant pressure [minimum] during the entire inspiration
Pressure RegulatedVolume Control (PRVC)
1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume
The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume
Results in breath-to-breath variation of inspiratory pressure
Limitations Only an AC mode and requires a change to
Volume Support for weaning Only guarantees volume distally and not at
patient airway
TV AIRWAY PRESSURE
PROBLEMS
VCV preset fn of mechpropertyof lungs
lung injury
PCV acc to mecha property of lung
preset hypoventilation
volutrauma
PRVC preset lower paw necessary
Benefits of both
Comparison with established modes
Applications of PRVC
ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high
flow rates In whom VT has to be controlled ndashsurfactant
therapy
Benefits
Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to
mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort
BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]
Pressure controlled ventilation allowing spontaneous ventilation
Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest
airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to
ventilator in VCV
BIPAP -SUBDIVISIONS
CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at
lower level APRV ndash BIPAP - spontaneous breathing
at higher level Genuine BIPAP - spontaneous breathing
at both levels CPAP - spontaneous breathing at single
CPAP level
paw
t
Setting up BIPAP
Adjusted with ABG values High low PaCO2 Normal PaO2
VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2
mean airway pressure without altering VTRR
equidirectional alteration of P high P low
ADVANTAGES OF BIPAP
Less sedation Reduced atelectasis Ideal mode in pts with inadequate
spontaneous effort In face of deteriorating gas exchange
we can increase the invasiveness of ventilation without having to change mode
Airway Pressure Release Ventilation
(APRV) Outlined in 1987 Continuous positive airway pressure with
regular brief intermittent releases in airway pressure
The release phase results in alveolar ventilation and removal of carbon dioxide
APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance
It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation
Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance
APRV ndashCONTDhellip
Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation
APRV commences at an elevated baseline pressure and follows with a measured pressure release
During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels
Available on Draumlger and Puritan Bennett ventilators
APRV ndashCONTDhellip
Elevated baseline airway pressure during APRV may produce near complete recruitment
Minimizes low volume lung injury from cyclic recruitment
APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation
Needs a High flow CPAP circuit with release valve
Advantages of APRV Lower peak airway pressures Lower minute ventilation
Decreased adverse effects upon circulatory function
Spontaneous ventilation the entire ventilatory cycle
Decreased need for sedation
Near elimination of neuromuscular blockade Recruitment of alveoli
Indications for APRV ALI or low-compliance lung disease patients with airway disease
CONTRAINDICATIONS
Patients with Increased airway resistance
When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation
The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation
P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus
accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than
40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0
cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure
Settings of APRV
Pressure support ventilation
Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by
specific amount of positive pressure at airway
PS Terminated when insp Flow falls below a minimum trigger volume
Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau
` ADVANTAGES Less WOB low pressure high volume work similar to
spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is
achieved with PS of 5 cm H2O
Volume AssuredPressure Support (VAPS)
Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure
breath continues to guarantee volume - 1048707 PIP and inspiratory time increase
1048707 Guarantees volume on current breath (no previous breath averaging)
1048707 Combines the advantages of pressure and volume ventilation breath to breath
Characteristics of VAPS 1048707 The ventilator continuously measures the flow and
pressure and calculates delivered volume Depending on the actual settings breath may be flow
volume or time cycled 1048707 If the target tidal volume has been delivered
inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set
flow will persist until the desired volume has been reached (volume cycled breath)
1048707 Safety limits include high pressure and maximum inspiratory time1048707
Used in the Management of acute and recovering lung disease
Benefits of VAPS
1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort
Applications of VAPS 1048707 A patient who requires a substantial level of
ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony
1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change
Limitations 1048707 Will only increase pressure not lower pressure
with changing mechanics 1048707 Increases inspiratory time to assure volume
Volume support ventilation
Support mode Has PVRC as back up mode Allows spontaneous if preset MV is
achieved If fails deliver preset TV MV in lowest
possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure
limitlower amp upper MV alarm
Applications of VSV
Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations
in inspiratory pressure support
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
Pressure RegulatedVolume Control (PRVC)
1048707 Inspiratory pressure is regulated based on the PressureVolume calculation of the previous breath compared to a target tidal volume
The ventilator continuously adapts the inspiratory pressure in responses to changing compliance and resistance to maintain the target tidal volume
Results in breath-to-breath variation of inspiratory pressure
Limitations Only an AC mode and requires a change to
Volume Support for weaning Only guarantees volume distally and not at
patient airway
TV AIRWAY PRESSURE
PROBLEMS
VCV preset fn of mechpropertyof lungs
lung injury
PCV acc to mecha property of lung
preset hypoventilation
volutrauma
PRVC preset lower paw necessary
Benefits of both
Comparison with established modes
Applications of PRVC
ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high
flow rates In whom VT has to be controlled ndashsurfactant
therapy
Benefits
Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to
mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort
BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]
Pressure controlled ventilation allowing spontaneous ventilation
Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest
airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to
ventilator in VCV
BIPAP -SUBDIVISIONS
CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at
lower level APRV ndash BIPAP - spontaneous breathing
at higher level Genuine BIPAP - spontaneous breathing
at both levels CPAP - spontaneous breathing at single
CPAP level
paw
t
Setting up BIPAP
Adjusted with ABG values High low PaCO2 Normal PaO2
VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2
mean airway pressure without altering VTRR
equidirectional alteration of P high P low
ADVANTAGES OF BIPAP
Less sedation Reduced atelectasis Ideal mode in pts with inadequate
spontaneous effort In face of deteriorating gas exchange
we can increase the invasiveness of ventilation without having to change mode
Airway Pressure Release Ventilation
(APRV) Outlined in 1987 Continuous positive airway pressure with
regular brief intermittent releases in airway pressure
The release phase results in alveolar ventilation and removal of carbon dioxide
APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance
It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation
Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance
APRV ndashCONTDhellip
Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation
APRV commences at an elevated baseline pressure and follows with a measured pressure release
During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels
Available on Draumlger and Puritan Bennett ventilators
APRV ndashCONTDhellip
Elevated baseline airway pressure during APRV may produce near complete recruitment
Minimizes low volume lung injury from cyclic recruitment
APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation
Needs a High flow CPAP circuit with release valve
Advantages of APRV Lower peak airway pressures Lower minute ventilation
Decreased adverse effects upon circulatory function
Spontaneous ventilation the entire ventilatory cycle
Decreased need for sedation
Near elimination of neuromuscular blockade Recruitment of alveoli
Indications for APRV ALI or low-compliance lung disease patients with airway disease
CONTRAINDICATIONS
Patients with Increased airway resistance
When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation
The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation
P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus
accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than
40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0
cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure
Settings of APRV
Pressure support ventilation
Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by
specific amount of positive pressure at airway
PS Terminated when insp Flow falls below a minimum trigger volume
Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau
` ADVANTAGES Less WOB low pressure high volume work similar to
spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is
achieved with PS of 5 cm H2O
Volume AssuredPressure Support (VAPS)
Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure
breath continues to guarantee volume - 1048707 PIP and inspiratory time increase
1048707 Guarantees volume on current breath (no previous breath averaging)
1048707 Combines the advantages of pressure and volume ventilation breath to breath
Characteristics of VAPS 1048707 The ventilator continuously measures the flow and
pressure and calculates delivered volume Depending on the actual settings breath may be flow
volume or time cycled 1048707 If the target tidal volume has been delivered
inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set
flow will persist until the desired volume has been reached (volume cycled breath)
1048707 Safety limits include high pressure and maximum inspiratory time1048707
Used in the Management of acute and recovering lung disease
Benefits of VAPS
1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort
Applications of VAPS 1048707 A patient who requires a substantial level of
ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony
1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change
Limitations 1048707 Will only increase pressure not lower pressure
with changing mechanics 1048707 Increases inspiratory time to assure volume
Volume support ventilation
Support mode Has PVRC as back up mode Allows spontaneous if preset MV is
achieved If fails deliver preset TV MV in lowest
possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure
limitlower amp upper MV alarm
Applications of VSV
Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations
in inspiratory pressure support
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
TV AIRWAY PRESSURE
PROBLEMS
VCV preset fn of mechpropertyof lungs
lung injury
PCV acc to mecha property of lung
preset hypoventilation
volutrauma
PRVC preset lower paw necessary
Benefits of both
Comparison with established modes
Applications of PRVC
ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high
flow rates In whom VT has to be controlled ndashsurfactant
therapy
Benefits
Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to
mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort
BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]
Pressure controlled ventilation allowing spontaneous ventilation
Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest
airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to
ventilator in VCV
BIPAP -SUBDIVISIONS
CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at
lower level APRV ndash BIPAP - spontaneous breathing
at higher level Genuine BIPAP - spontaneous breathing
at both levels CPAP - spontaneous breathing at single
CPAP level
paw
t
Setting up BIPAP
Adjusted with ABG values High low PaCO2 Normal PaO2
VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2
mean airway pressure without altering VTRR
equidirectional alteration of P high P low
ADVANTAGES OF BIPAP
Less sedation Reduced atelectasis Ideal mode in pts with inadequate
spontaneous effort In face of deteriorating gas exchange
we can increase the invasiveness of ventilation without having to change mode
Airway Pressure Release Ventilation
(APRV) Outlined in 1987 Continuous positive airway pressure with
regular brief intermittent releases in airway pressure
The release phase results in alveolar ventilation and removal of carbon dioxide
APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance
It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation
Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance
APRV ndashCONTDhellip
Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation
APRV commences at an elevated baseline pressure and follows with a measured pressure release
During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels
Available on Draumlger and Puritan Bennett ventilators
APRV ndashCONTDhellip
Elevated baseline airway pressure during APRV may produce near complete recruitment
Minimizes low volume lung injury from cyclic recruitment
APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation
Needs a High flow CPAP circuit with release valve
Advantages of APRV Lower peak airway pressures Lower minute ventilation
Decreased adverse effects upon circulatory function
Spontaneous ventilation the entire ventilatory cycle
Decreased need for sedation
Near elimination of neuromuscular blockade Recruitment of alveoli
Indications for APRV ALI or low-compliance lung disease patients with airway disease
CONTRAINDICATIONS
Patients with Increased airway resistance
When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation
The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation
P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus
accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than
40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0
cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure
Settings of APRV
Pressure support ventilation
Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by
specific amount of positive pressure at airway
PS Terminated when insp Flow falls below a minimum trigger volume
Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau
` ADVANTAGES Less WOB low pressure high volume work similar to
spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is
achieved with PS of 5 cm H2O
Volume AssuredPressure Support (VAPS)
Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure
breath continues to guarantee volume - 1048707 PIP and inspiratory time increase
1048707 Guarantees volume on current breath (no previous breath averaging)
1048707 Combines the advantages of pressure and volume ventilation breath to breath
Characteristics of VAPS 1048707 The ventilator continuously measures the flow and
pressure and calculates delivered volume Depending on the actual settings breath may be flow
volume or time cycled 1048707 If the target tidal volume has been delivered
inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set
flow will persist until the desired volume has been reached (volume cycled breath)
1048707 Safety limits include high pressure and maximum inspiratory time1048707
Used in the Management of acute and recovering lung disease
Benefits of VAPS
1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort
Applications of VAPS 1048707 A patient who requires a substantial level of
ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony
1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change
Limitations 1048707 Will only increase pressure not lower pressure
with changing mechanics 1048707 Increases inspiratory time to assure volume
Volume support ventilation
Support mode Has PVRC as back up mode Allows spontaneous if preset MV is
achieved If fails deliver preset TV MV in lowest
possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure
limitlower amp upper MV alarm
Applications of VSV
Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations
in inspiratory pressure support
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
Applications of PRVC
ALI Asthma COPD Postop patient Pediatric patient Pts with no breathing capacity- need initial high
flow rates In whom VT has to be controlled ndashsurfactant
therapy
Benefits
Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to
mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort
BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]
Pressure controlled ventilation allowing spontaneous ventilation
Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest
airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to
ventilator in VCV
BIPAP -SUBDIVISIONS
CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at
lower level APRV ndash BIPAP - spontaneous breathing
at higher level Genuine BIPAP - spontaneous breathing
at both levels CPAP - spontaneous breathing at single
CPAP level
paw
t
Setting up BIPAP
Adjusted with ABG values High low PaCO2 Normal PaO2
VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2
mean airway pressure without altering VTRR
equidirectional alteration of P high P low
ADVANTAGES OF BIPAP
Less sedation Reduced atelectasis Ideal mode in pts with inadequate
spontaneous effort In face of deteriorating gas exchange
we can increase the invasiveness of ventilation without having to change mode
Airway Pressure Release Ventilation
(APRV) Outlined in 1987 Continuous positive airway pressure with
regular brief intermittent releases in airway pressure
The release phase results in alveolar ventilation and removal of carbon dioxide
APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance
It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation
Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance
APRV ndashCONTDhellip
Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation
APRV commences at an elevated baseline pressure and follows with a measured pressure release
During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels
Available on Draumlger and Puritan Bennett ventilators
APRV ndashCONTDhellip
Elevated baseline airway pressure during APRV may produce near complete recruitment
Minimizes low volume lung injury from cyclic recruitment
APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation
Needs a High flow CPAP circuit with release valve
Advantages of APRV Lower peak airway pressures Lower minute ventilation
Decreased adverse effects upon circulatory function
Spontaneous ventilation the entire ventilatory cycle
Decreased need for sedation
Near elimination of neuromuscular blockade Recruitment of alveoli
Indications for APRV ALI or low-compliance lung disease patients with airway disease
CONTRAINDICATIONS
Patients with Increased airway resistance
When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation
The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation
P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus
accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than
40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0
cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure
Settings of APRV
Pressure support ventilation
Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by
specific amount of positive pressure at airway
PS Terminated when insp Flow falls below a minimum trigger volume
Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau
` ADVANTAGES Less WOB low pressure high volume work similar to
spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is
achieved with PS of 5 cm H2O
Volume AssuredPressure Support (VAPS)
Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure
breath continues to guarantee volume - 1048707 PIP and inspiratory time increase
1048707 Guarantees volume on current breath (no previous breath averaging)
1048707 Combines the advantages of pressure and volume ventilation breath to breath
Characteristics of VAPS 1048707 The ventilator continuously measures the flow and
pressure and calculates delivered volume Depending on the actual settings breath may be flow
volume or time cycled 1048707 If the target tidal volume has been delivered
inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set
flow will persist until the desired volume has been reached (volume cycled breath)
1048707 Safety limits include high pressure and maximum inspiratory time1048707
Used in the Management of acute and recovering lung disease
Benefits of VAPS
1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort
Applications of VAPS 1048707 A patient who requires a substantial level of
ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony
1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change
Limitations 1048707 Will only increase pressure not lower pressure
with changing mechanics 1048707 Increases inspiratory time to assure volume
Volume support ventilation
Support mode Has PVRC as back up mode Allows spontaneous if preset MV is
achieved If fails deliver preset TV MV in lowest
possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure
limitlower amp upper MV alarm
Applications of VSV
Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations
in inspiratory pressure support
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
Benefits
Can be used in all populations Low peak inspiratory pressure Inspiratory pressure adapts to
mechanical properties of lung CVS interference Improved gas distribution Less need for sedation Greater patient comfort
BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]
Pressure controlled ventilation allowing spontaneous ventilation
Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest
airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to
ventilator in VCV
BIPAP -SUBDIVISIONS
CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at
lower level APRV ndash BIPAP - spontaneous breathing
at higher level Genuine BIPAP - spontaneous breathing
at both levels CPAP - spontaneous breathing at single
CPAP level
paw
t
Setting up BIPAP
Adjusted with ABG values High low PaCO2 Normal PaO2
VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2
mean airway pressure without altering VTRR
equidirectional alteration of P high P low
ADVANTAGES OF BIPAP
Less sedation Reduced atelectasis Ideal mode in pts with inadequate
spontaneous effort In face of deteriorating gas exchange
we can increase the invasiveness of ventilation without having to change mode
Airway Pressure Release Ventilation
(APRV) Outlined in 1987 Continuous positive airway pressure with
regular brief intermittent releases in airway pressure
The release phase results in alveolar ventilation and removal of carbon dioxide
APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance
It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation
Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance
APRV ndashCONTDhellip
Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation
APRV commences at an elevated baseline pressure and follows with a measured pressure release
During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels
Available on Draumlger and Puritan Bennett ventilators
APRV ndashCONTDhellip
Elevated baseline airway pressure during APRV may produce near complete recruitment
Minimizes low volume lung injury from cyclic recruitment
APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation
Needs a High flow CPAP circuit with release valve
Advantages of APRV Lower peak airway pressures Lower minute ventilation
Decreased adverse effects upon circulatory function
Spontaneous ventilation the entire ventilatory cycle
Decreased need for sedation
Near elimination of neuromuscular blockade Recruitment of alveoli
Indications for APRV ALI or low-compliance lung disease patients with airway disease
CONTRAINDICATIONS
Patients with Increased airway resistance
When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation
The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation
P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus
accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than
40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0
cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure
Settings of APRV
Pressure support ventilation
Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by
specific amount of positive pressure at airway
PS Terminated when insp Flow falls below a minimum trigger volume
Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau
` ADVANTAGES Less WOB low pressure high volume work similar to
spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is
achieved with PS of 5 cm H2O
Volume AssuredPressure Support (VAPS)
Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure
breath continues to guarantee volume - 1048707 PIP and inspiratory time increase
1048707 Guarantees volume on current breath (no previous breath averaging)
1048707 Combines the advantages of pressure and volume ventilation breath to breath
Characteristics of VAPS 1048707 The ventilator continuously measures the flow and
pressure and calculates delivered volume Depending on the actual settings breath may be flow
volume or time cycled 1048707 If the target tidal volume has been delivered
inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set
flow will persist until the desired volume has been reached (volume cycled breath)
1048707 Safety limits include high pressure and maximum inspiratory time1048707
Used in the Management of acute and recovering lung disease
Benefits of VAPS
1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort
Applications of VAPS 1048707 A patient who requires a substantial level of
ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony
1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change
Limitations 1048707 Will only increase pressure not lower pressure
with changing mechanics 1048707 Increases inspiratory time to assure volume
Volume support ventilation
Support mode Has PVRC as back up mode Allows spontaneous if preset MV is
achieved If fails deliver preset TV MV in lowest
possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure
limitlower amp upper MV alarm
Applications of VSV
Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations
in inspiratory pressure support
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
BIPHASIC POSITIVE AIRWAY PRESSURE [BIPAP]
Pressure controlled ventilation allowing spontaneous ventilation
Shifts between two levels of PAP P low ndash pressure akin to PEEP In PCV [lowest
airway pressure] P high ndashpressure above PEEP [P plat] T high ampT low Subdivisions ndash CMV to CPAP Single mode covers entire spectrum Finer adjustment done after connecting the patient to
ventilator in VCV
BIPAP -SUBDIVISIONS
CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at
lower level APRV ndash BIPAP - spontaneous breathing
at higher level Genuine BIPAP - spontaneous breathing
at both levels CPAP - spontaneous breathing at single
CPAP level
paw
t
Setting up BIPAP
Adjusted with ABG values High low PaCO2 Normal PaO2
VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2
mean airway pressure without altering VTRR
equidirectional alteration of P high P low
ADVANTAGES OF BIPAP
Less sedation Reduced atelectasis Ideal mode in pts with inadequate
spontaneous effort In face of deteriorating gas exchange
we can increase the invasiveness of ventilation without having to change mode
Airway Pressure Release Ventilation
(APRV) Outlined in 1987 Continuous positive airway pressure with
regular brief intermittent releases in airway pressure
The release phase results in alveolar ventilation and removal of carbon dioxide
APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance
It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation
Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance
APRV ndashCONTDhellip
Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation
APRV commences at an elevated baseline pressure and follows with a measured pressure release
During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels
Available on Draumlger and Puritan Bennett ventilators
APRV ndashCONTDhellip
Elevated baseline airway pressure during APRV may produce near complete recruitment
Minimizes low volume lung injury from cyclic recruitment
APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation
Needs a High flow CPAP circuit with release valve
Advantages of APRV Lower peak airway pressures Lower minute ventilation
Decreased adverse effects upon circulatory function
Spontaneous ventilation the entire ventilatory cycle
Decreased need for sedation
Near elimination of neuromuscular blockade Recruitment of alveoli
Indications for APRV ALI or low-compliance lung disease patients with airway disease
CONTRAINDICATIONS
Patients with Increased airway resistance
When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation
The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation
P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus
accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than
40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0
cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure
Settings of APRV
Pressure support ventilation
Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by
specific amount of positive pressure at airway
PS Terminated when insp Flow falls below a minimum trigger volume
Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau
` ADVANTAGES Less WOB low pressure high volume work similar to
spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is
achieved with PS of 5 cm H2O
Volume AssuredPressure Support (VAPS)
Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure
breath continues to guarantee volume - 1048707 PIP and inspiratory time increase
1048707 Guarantees volume on current breath (no previous breath averaging)
1048707 Combines the advantages of pressure and volume ventilation breath to breath
Characteristics of VAPS 1048707 The ventilator continuously measures the flow and
pressure and calculates delivered volume Depending on the actual settings breath may be flow
volume or time cycled 1048707 If the target tidal volume has been delivered
inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set
flow will persist until the desired volume has been reached (volume cycled breath)
1048707 Safety limits include high pressure and maximum inspiratory time1048707
Used in the Management of acute and recovering lung disease
Benefits of VAPS
1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort
Applications of VAPS 1048707 A patient who requires a substantial level of
ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony
1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change
Limitations 1048707 Will only increase pressure not lower pressure
with changing mechanics 1048707 Increases inspiratory time to assure volume
Volume support ventilation
Support mode Has PVRC as back up mode Allows spontaneous if preset MV is
achieved If fails deliver preset TV MV in lowest
possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure
limitlower amp upper MV alarm
Applications of VSV
Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations
in inspiratory pressure support
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
BIPAP -SUBDIVISIONS
CMV BIPAP-no Spontaneous breathing IMV ndashBIPAP ndashspontaneous breathing at
lower level APRV ndash BIPAP - spontaneous breathing
at higher level Genuine BIPAP - spontaneous breathing
at both levels CPAP - spontaneous breathing at single
CPAP level
paw
t
Setting up BIPAP
Adjusted with ABG values High low PaCO2 Normal PaO2
VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2
mean airway pressure without altering VTRR
equidirectional alteration of P high P low
ADVANTAGES OF BIPAP
Less sedation Reduced atelectasis Ideal mode in pts with inadequate
spontaneous effort In face of deteriorating gas exchange
we can increase the invasiveness of ventilation without having to change mode
Airway Pressure Release Ventilation
(APRV) Outlined in 1987 Continuous positive airway pressure with
regular brief intermittent releases in airway pressure
The release phase results in alveolar ventilation and removal of carbon dioxide
APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance
It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation
Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance
APRV ndashCONTDhellip
Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation
APRV commences at an elevated baseline pressure and follows with a measured pressure release
During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels
Available on Draumlger and Puritan Bennett ventilators
APRV ndashCONTDhellip
Elevated baseline airway pressure during APRV may produce near complete recruitment
Minimizes low volume lung injury from cyclic recruitment
APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation
Needs a High flow CPAP circuit with release valve
Advantages of APRV Lower peak airway pressures Lower minute ventilation
Decreased adverse effects upon circulatory function
Spontaneous ventilation the entire ventilatory cycle
Decreased need for sedation
Near elimination of neuromuscular blockade Recruitment of alveoli
Indications for APRV ALI or low-compliance lung disease patients with airway disease
CONTRAINDICATIONS
Patients with Increased airway resistance
When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation
The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation
P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus
accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than
40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0
cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure
Settings of APRV
Pressure support ventilation
Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by
specific amount of positive pressure at airway
PS Terminated when insp Flow falls below a minimum trigger volume
Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau
` ADVANTAGES Less WOB low pressure high volume work similar to
spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is
achieved with PS of 5 cm H2O
Volume AssuredPressure Support (VAPS)
Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure
breath continues to guarantee volume - 1048707 PIP and inspiratory time increase
1048707 Guarantees volume on current breath (no previous breath averaging)
1048707 Combines the advantages of pressure and volume ventilation breath to breath
Characteristics of VAPS 1048707 The ventilator continuously measures the flow and
pressure and calculates delivered volume Depending on the actual settings breath may be flow
volume or time cycled 1048707 If the target tidal volume has been delivered
inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set
flow will persist until the desired volume has been reached (volume cycled breath)
1048707 Safety limits include high pressure and maximum inspiratory time1048707
Used in the Management of acute and recovering lung disease
Benefits of VAPS
1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort
Applications of VAPS 1048707 A patient who requires a substantial level of
ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony
1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change
Limitations 1048707 Will only increase pressure not lower pressure
with changing mechanics 1048707 Increases inspiratory time to assure volume
Volume support ventilation
Support mode Has PVRC as back up mode Allows spontaneous if preset MV is
achieved If fails deliver preset TV MV in lowest
possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure
limitlower amp upper MV alarm
Applications of VSV
Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations
in inspiratory pressure support
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
paw
t
Setting up BIPAP
Adjusted with ABG values High low PaCO2 Normal PaO2
VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2
mean airway pressure without altering VTRR
equidirectional alteration of P high P low
ADVANTAGES OF BIPAP
Less sedation Reduced atelectasis Ideal mode in pts with inadequate
spontaneous effort In face of deteriorating gas exchange
we can increase the invasiveness of ventilation without having to change mode
Airway Pressure Release Ventilation
(APRV) Outlined in 1987 Continuous positive airway pressure with
regular brief intermittent releases in airway pressure
The release phase results in alveolar ventilation and removal of carbon dioxide
APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance
It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation
Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance
APRV ndashCONTDhellip
Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation
APRV commences at an elevated baseline pressure and follows with a measured pressure release
During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels
Available on Draumlger and Puritan Bennett ventilators
APRV ndashCONTDhellip
Elevated baseline airway pressure during APRV may produce near complete recruitment
Minimizes low volume lung injury from cyclic recruitment
APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation
Needs a High flow CPAP circuit with release valve
Advantages of APRV Lower peak airway pressures Lower minute ventilation
Decreased adverse effects upon circulatory function
Spontaneous ventilation the entire ventilatory cycle
Decreased need for sedation
Near elimination of neuromuscular blockade Recruitment of alveoli
Indications for APRV ALI or low-compliance lung disease patients with airway disease
CONTRAINDICATIONS
Patients with Increased airway resistance
When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation
The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation
P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus
accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than
40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0
cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure
Settings of APRV
Pressure support ventilation
Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by
specific amount of positive pressure at airway
PS Terminated when insp Flow falls below a minimum trigger volume
Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau
` ADVANTAGES Less WOB low pressure high volume work similar to
spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is
achieved with PS of 5 cm H2O
Volume AssuredPressure Support (VAPS)
Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure
breath continues to guarantee volume - 1048707 PIP and inspiratory time increase
1048707 Guarantees volume on current breath (no previous breath averaging)
1048707 Combines the advantages of pressure and volume ventilation breath to breath
Characteristics of VAPS 1048707 The ventilator continuously measures the flow and
pressure and calculates delivered volume Depending on the actual settings breath may be flow
volume or time cycled 1048707 If the target tidal volume has been delivered
inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set
flow will persist until the desired volume has been reached (volume cycled breath)
1048707 Safety limits include high pressure and maximum inspiratory time1048707
Used in the Management of acute and recovering lung disease
Benefits of VAPS
1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort
Applications of VAPS 1048707 A patient who requires a substantial level of
ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony
1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change
Limitations 1048707 Will only increase pressure not lower pressure
with changing mechanics 1048707 Increases inspiratory time to assure volume
Volume support ventilation
Support mode Has PVRC as back up mode Allows spontaneous if preset MV is
achieved If fails deliver preset TV MV in lowest
possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure
limitlower amp upper MV alarm
Applications of VSV
Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations
in inspiratory pressure support
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
Setting up BIPAP
Adjusted with ABG values High low PaCO2 Normal PaO2
VT RR Alteration of P high P low ndash VT Alteration of T highT low - RR Decreased PaO2
mean airway pressure without altering VTRR
equidirectional alteration of P high P low
ADVANTAGES OF BIPAP
Less sedation Reduced atelectasis Ideal mode in pts with inadequate
spontaneous effort In face of deteriorating gas exchange
we can increase the invasiveness of ventilation without having to change mode
Airway Pressure Release Ventilation
(APRV) Outlined in 1987 Continuous positive airway pressure with
regular brief intermittent releases in airway pressure
The release phase results in alveolar ventilation and removal of carbon dioxide
APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance
It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation
Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance
APRV ndashCONTDhellip
Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation
APRV commences at an elevated baseline pressure and follows with a measured pressure release
During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels
Available on Draumlger and Puritan Bennett ventilators
APRV ndashCONTDhellip
Elevated baseline airway pressure during APRV may produce near complete recruitment
Minimizes low volume lung injury from cyclic recruitment
APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation
Needs a High flow CPAP circuit with release valve
Advantages of APRV Lower peak airway pressures Lower minute ventilation
Decreased adverse effects upon circulatory function
Spontaneous ventilation the entire ventilatory cycle
Decreased need for sedation
Near elimination of neuromuscular blockade Recruitment of alveoli
Indications for APRV ALI or low-compliance lung disease patients with airway disease
CONTRAINDICATIONS
Patients with Increased airway resistance
When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation
The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation
P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus
accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than
40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0
cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure
Settings of APRV
Pressure support ventilation
Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by
specific amount of positive pressure at airway
PS Terminated when insp Flow falls below a minimum trigger volume
Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau
` ADVANTAGES Less WOB low pressure high volume work similar to
spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is
achieved with PS of 5 cm H2O
Volume AssuredPressure Support (VAPS)
Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure
breath continues to guarantee volume - 1048707 PIP and inspiratory time increase
1048707 Guarantees volume on current breath (no previous breath averaging)
1048707 Combines the advantages of pressure and volume ventilation breath to breath
Characteristics of VAPS 1048707 The ventilator continuously measures the flow and
pressure and calculates delivered volume Depending on the actual settings breath may be flow
volume or time cycled 1048707 If the target tidal volume has been delivered
inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set
flow will persist until the desired volume has been reached (volume cycled breath)
1048707 Safety limits include high pressure and maximum inspiratory time1048707
Used in the Management of acute and recovering lung disease
Benefits of VAPS
1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort
Applications of VAPS 1048707 A patient who requires a substantial level of
ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony
1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change
Limitations 1048707 Will only increase pressure not lower pressure
with changing mechanics 1048707 Increases inspiratory time to assure volume
Volume support ventilation
Support mode Has PVRC as back up mode Allows spontaneous if preset MV is
achieved If fails deliver preset TV MV in lowest
possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure
limitlower amp upper MV alarm
Applications of VSV
Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations
in inspiratory pressure support
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
ADVANTAGES OF BIPAP
Less sedation Reduced atelectasis Ideal mode in pts with inadequate
spontaneous effort In face of deteriorating gas exchange
we can increase the invasiveness of ventilation without having to change mode
Airway Pressure Release Ventilation
(APRV) Outlined in 1987 Continuous positive airway pressure with
regular brief intermittent releases in airway pressure
The release phase results in alveolar ventilation and removal of carbon dioxide
APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance
It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation
Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance
APRV ndashCONTDhellip
Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation
APRV commences at an elevated baseline pressure and follows with a measured pressure release
During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels
Available on Draumlger and Puritan Bennett ventilators
APRV ndashCONTDhellip
Elevated baseline airway pressure during APRV may produce near complete recruitment
Minimizes low volume lung injury from cyclic recruitment
APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation
Needs a High flow CPAP circuit with release valve
Advantages of APRV Lower peak airway pressures Lower minute ventilation
Decreased adverse effects upon circulatory function
Spontaneous ventilation the entire ventilatory cycle
Decreased need for sedation
Near elimination of neuromuscular blockade Recruitment of alveoli
Indications for APRV ALI or low-compliance lung disease patients with airway disease
CONTRAINDICATIONS
Patients with Increased airway resistance
When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation
The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation
P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus
accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than
40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0
cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure
Settings of APRV
Pressure support ventilation
Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by
specific amount of positive pressure at airway
PS Terminated when insp Flow falls below a minimum trigger volume
Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau
` ADVANTAGES Less WOB low pressure high volume work similar to
spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is
achieved with PS of 5 cm H2O
Volume AssuredPressure Support (VAPS)
Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure
breath continues to guarantee volume - 1048707 PIP and inspiratory time increase
1048707 Guarantees volume on current breath (no previous breath averaging)
1048707 Combines the advantages of pressure and volume ventilation breath to breath
Characteristics of VAPS 1048707 The ventilator continuously measures the flow and
pressure and calculates delivered volume Depending on the actual settings breath may be flow
volume or time cycled 1048707 If the target tidal volume has been delivered
inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set
flow will persist until the desired volume has been reached (volume cycled breath)
1048707 Safety limits include high pressure and maximum inspiratory time1048707
Used in the Management of acute and recovering lung disease
Benefits of VAPS
1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort
Applications of VAPS 1048707 A patient who requires a substantial level of
ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony
1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change
Limitations 1048707 Will only increase pressure not lower pressure
with changing mechanics 1048707 Increases inspiratory time to assure volume
Volume support ventilation
Support mode Has PVRC as back up mode Allows spontaneous if preset MV is
achieved If fails deliver preset TV MV in lowest
possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure
limitlower amp upper MV alarm
Applications of VSV
Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations
in inspiratory pressure support
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
Airway Pressure Release Ventilation
(APRV) Outlined in 1987 Continuous positive airway pressure with
regular brief intermittent releases in airway pressure
The release phase results in alveolar ventilation and removal of carbon dioxide
APRV unlike conventional CPAP facilitates both oxygenation and CO2 clearance
It is the high CPAP level [referred to as PEEP high or P high] which enhances oxygenation
Timed releases to the low CPAP level [referred to as PEEP low or P low] aid in CO2 clearance
APRV ndashCONTDhellip
Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation
APRV commences at an elevated baseline pressure and follows with a measured pressure release
During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels
Available on Draumlger and Puritan Bennett ventilators
APRV ndashCONTDhellip
Elevated baseline airway pressure during APRV may produce near complete recruitment
Minimizes low volume lung injury from cyclic recruitment
APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation
Needs a High flow CPAP circuit with release valve
Advantages of APRV Lower peak airway pressures Lower minute ventilation
Decreased adverse effects upon circulatory function
Spontaneous ventilation the entire ventilatory cycle
Decreased need for sedation
Near elimination of neuromuscular blockade Recruitment of alveoli
Indications for APRV ALI or low-compliance lung disease patients with airway disease
CONTRAINDICATIONS
Patients with Increased airway resistance
When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation
The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation
P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus
accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than
40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0
cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure
Settings of APRV
Pressure support ventilation
Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by
specific amount of positive pressure at airway
PS Terminated when insp Flow falls below a minimum trigger volume
Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau
` ADVANTAGES Less WOB low pressure high volume work similar to
spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is
achieved with PS of 5 cm H2O
Volume AssuredPressure Support (VAPS)
Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure
breath continues to guarantee volume - 1048707 PIP and inspiratory time increase
1048707 Guarantees volume on current breath (no previous breath averaging)
1048707 Combines the advantages of pressure and volume ventilation breath to breath
Characteristics of VAPS 1048707 The ventilator continuously measures the flow and
pressure and calculates delivered volume Depending on the actual settings breath may be flow
volume or time cycled 1048707 If the target tidal volume has been delivered
inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set
flow will persist until the desired volume has been reached (volume cycled breath)
1048707 Safety limits include high pressure and maximum inspiratory time1048707
Used in the Management of acute and recovering lung disease
Benefits of VAPS
1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort
Applications of VAPS 1048707 A patient who requires a substantial level of
ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony
1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change
Limitations 1048707 Will only increase pressure not lower pressure
with changing mechanics 1048707 Increases inspiratory time to assure volume
Volume support ventilation
Support mode Has PVRC as back up mode Allows spontaneous if preset MV is
achieved If fails deliver preset TV MV in lowest
possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure
limitlower amp upper MV alarm
Applications of VSV
Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations
in inspiratory pressure support
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
APRV ndashCONTDhellip
Whereas more conventional modes of ventilation begin the ventilatory cycle at a baseline pressure and elevate airway pressure to accomplish tidal ventilation
APRV commences at an elevated baseline pressure and follows with a measured pressure release
During APRV spontaneous breathing may occur at either the plateau pressure or deflation pressure levels
Available on Draumlger and Puritan Bennett ventilators
APRV ndashCONTDhellip
Elevated baseline airway pressure during APRV may produce near complete recruitment
Minimizes low volume lung injury from cyclic recruitment
APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation
Needs a High flow CPAP circuit with release valve
Advantages of APRV Lower peak airway pressures Lower minute ventilation
Decreased adverse effects upon circulatory function
Spontaneous ventilation the entire ventilatory cycle
Decreased need for sedation
Near elimination of neuromuscular blockade Recruitment of alveoli
Indications for APRV ALI or low-compliance lung disease patients with airway disease
CONTRAINDICATIONS
Patients with Increased airway resistance
When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation
The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation
P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus
accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than
40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0
cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure
Settings of APRV
Pressure support ventilation
Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by
specific amount of positive pressure at airway
PS Terminated when insp Flow falls below a minimum trigger volume
Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau
` ADVANTAGES Less WOB low pressure high volume work similar to
spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is
achieved with PS of 5 cm H2O
Volume AssuredPressure Support (VAPS)
Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure
breath continues to guarantee volume - 1048707 PIP and inspiratory time increase
1048707 Guarantees volume on current breath (no previous breath averaging)
1048707 Combines the advantages of pressure and volume ventilation breath to breath
Characteristics of VAPS 1048707 The ventilator continuously measures the flow and
pressure and calculates delivered volume Depending on the actual settings breath may be flow
volume or time cycled 1048707 If the target tidal volume has been delivered
inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set
flow will persist until the desired volume has been reached (volume cycled breath)
1048707 Safety limits include high pressure and maximum inspiratory time1048707
Used in the Management of acute and recovering lung disease
Benefits of VAPS
1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort
Applications of VAPS 1048707 A patient who requires a substantial level of
ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony
1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change
Limitations 1048707 Will only increase pressure not lower pressure
with changing mechanics 1048707 Increases inspiratory time to assure volume
Volume support ventilation
Support mode Has PVRC as back up mode Allows spontaneous if preset MV is
achieved If fails deliver preset TV MV in lowest
possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure
limitlower amp upper MV alarm
Applications of VSV
Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations
in inspiratory pressure support
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
APRV ndashCONTDhellip
Elevated baseline airway pressure during APRV may produce near complete recruitment
Minimizes low volume lung injury from cyclic recruitment
APRV is less likely to produce over-inflation or high-volume lung injury as airway pressures are lowered (released) to accomplish ventilation
Needs a High flow CPAP circuit with release valve
Advantages of APRV Lower peak airway pressures Lower minute ventilation
Decreased adverse effects upon circulatory function
Spontaneous ventilation the entire ventilatory cycle
Decreased need for sedation
Near elimination of neuromuscular blockade Recruitment of alveoli
Indications for APRV ALI or low-compliance lung disease patients with airway disease
CONTRAINDICATIONS
Patients with Increased airway resistance
When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation
The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation
P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus
accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than
40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0
cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure
Settings of APRV
Pressure support ventilation
Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by
specific amount of positive pressure at airway
PS Terminated when insp Flow falls below a minimum trigger volume
Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau
` ADVANTAGES Less WOB low pressure high volume work similar to
spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is
achieved with PS of 5 cm H2O
Volume AssuredPressure Support (VAPS)
Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure
breath continues to guarantee volume - 1048707 PIP and inspiratory time increase
1048707 Guarantees volume on current breath (no previous breath averaging)
1048707 Combines the advantages of pressure and volume ventilation breath to breath
Characteristics of VAPS 1048707 The ventilator continuously measures the flow and
pressure and calculates delivered volume Depending on the actual settings breath may be flow
volume or time cycled 1048707 If the target tidal volume has been delivered
inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set
flow will persist until the desired volume has been reached (volume cycled breath)
1048707 Safety limits include high pressure and maximum inspiratory time1048707
Used in the Management of acute and recovering lung disease
Benefits of VAPS
1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort
Applications of VAPS 1048707 A patient who requires a substantial level of
ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony
1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change
Limitations 1048707 Will only increase pressure not lower pressure
with changing mechanics 1048707 Increases inspiratory time to assure volume
Volume support ventilation
Support mode Has PVRC as back up mode Allows spontaneous if preset MV is
achieved If fails deliver preset TV MV in lowest
possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure
limitlower amp upper MV alarm
Applications of VSV
Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations
in inspiratory pressure support
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
Advantages of APRV Lower peak airway pressures Lower minute ventilation
Decreased adverse effects upon circulatory function
Spontaneous ventilation the entire ventilatory cycle
Decreased need for sedation
Near elimination of neuromuscular blockade Recruitment of alveoli
Indications for APRV ALI or low-compliance lung disease patients with airway disease
CONTRAINDICATIONS
Patients with Increased airway resistance
When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation
The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation
P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus
accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than
40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0
cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure
Settings of APRV
Pressure support ventilation
Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by
specific amount of positive pressure at airway
PS Terminated when insp Flow falls below a minimum trigger volume
Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau
` ADVANTAGES Less WOB low pressure high volume work similar to
spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is
achieved with PS of 5 cm H2O
Volume AssuredPressure Support (VAPS)
Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure
breath continues to guarantee volume - 1048707 PIP and inspiratory time increase
1048707 Guarantees volume on current breath (no previous breath averaging)
1048707 Combines the advantages of pressure and volume ventilation breath to breath
Characteristics of VAPS 1048707 The ventilator continuously measures the flow and
pressure and calculates delivered volume Depending on the actual settings breath may be flow
volume or time cycled 1048707 If the target tidal volume has been delivered
inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set
flow will persist until the desired volume has been reached (volume cycled breath)
1048707 Safety limits include high pressure and maximum inspiratory time1048707
Used in the Management of acute and recovering lung disease
Benefits of VAPS
1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort
Applications of VAPS 1048707 A patient who requires a substantial level of
ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony
1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change
Limitations 1048707 Will only increase pressure not lower pressure
with changing mechanics 1048707 Increases inspiratory time to assure volume
Volume support ventilation
Support mode Has PVRC as back up mode Allows spontaneous if preset MV is
achieved If fails deliver preset TV MV in lowest
possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure
limitlower amp upper MV alarm
Applications of VSV
Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations
in inspiratory pressure support
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
Indications for APRV ALI or low-compliance lung disease patients with airway disease
CONTRAINDICATIONS
Patients with Increased airway resistance
When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation
The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation
P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus
accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than
40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0
cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure
Settings of APRV
Pressure support ventilation
Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by
specific amount of positive pressure at airway
PS Terminated when insp Flow falls below a minimum trigger volume
Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau
` ADVANTAGES Less WOB low pressure high volume work similar to
spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is
achieved with PS of 5 cm H2O
Volume AssuredPressure Support (VAPS)
Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure
breath continues to guarantee volume - 1048707 PIP and inspiratory time increase
1048707 Guarantees volume on current breath (no previous breath averaging)
1048707 Combines the advantages of pressure and volume ventilation breath to breath
Characteristics of VAPS 1048707 The ventilator continuously measures the flow and
pressure and calculates delivered volume Depending on the actual settings breath may be flow
volume or time cycled 1048707 If the target tidal volume has been delivered
inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set
flow will persist until the desired volume has been reached (volume cycled breath)
1048707 Safety limits include high pressure and maximum inspiratory time1048707
Used in the Management of acute and recovering lung disease
Benefits of VAPS
1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort
Applications of VAPS 1048707 A patient who requires a substantial level of
ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony
1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change
Limitations 1048707 Will only increase pressure not lower pressure
with changing mechanics 1048707 Increases inspiratory time to assure volume
Volume support ventilation
Support mode Has PVRC as back up mode Allows spontaneous if preset MV is
achieved If fails deliver preset TV MV in lowest
possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure
limitlower amp upper MV alarm
Applications of VSV
Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations
in inspiratory pressure support
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
When changing a patientrsquos mode of ventilation to APRV the initial settings are partly deduced from values of conventional ventilation
The clinician converts the plateau pressure of the conventional mode to P High and seeks an expired minute ventilation of 2 to 3 Lminute less than when on conventional ventilation
P Low is often initially set at 0 cm of water pressure A P Low of zero produces minimal expiratory resistance thus
accelerating expiratory flow rates facilitating rapid pressure drops T High is set at a minimum of 40 seconds A T High of less than
40 seconds begins to impact mean airway pressure negatively T Low is set between 05 and 10 seconds (often at 08 seconds) With these settings (P High = 35 cm of water pressure P Low = 0
cm of water pressure T High = 40 seconds T Low = 08 seconds) the mean airway pressure will equal 292 cm of water pressure
Settings of APRV
Pressure support ventilation
Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by
specific amount of positive pressure at airway
PS Terminated when insp Flow falls below a minimum trigger volume
Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau
` ADVANTAGES Less WOB low pressure high volume work similar to
spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is
achieved with PS of 5 cm H2O
Volume AssuredPressure Support (VAPS)
Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure
breath continues to guarantee volume - 1048707 PIP and inspiratory time increase
1048707 Guarantees volume on current breath (no previous breath averaging)
1048707 Combines the advantages of pressure and volume ventilation breath to breath
Characteristics of VAPS 1048707 The ventilator continuously measures the flow and
pressure and calculates delivered volume Depending on the actual settings breath may be flow
volume or time cycled 1048707 If the target tidal volume has been delivered
inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set
flow will persist until the desired volume has been reached (volume cycled breath)
1048707 Safety limits include high pressure and maximum inspiratory time1048707
Used in the Management of acute and recovering lung disease
Benefits of VAPS
1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort
Applications of VAPS 1048707 A patient who requires a substantial level of
ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony
1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change
Limitations 1048707 Will only increase pressure not lower pressure
with changing mechanics 1048707 Increases inspiratory time to assure volume
Volume support ventilation
Support mode Has PVRC as back up mode Allows spontaneous if preset MV is
achieved If fails deliver preset TV MV in lowest
possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure
limitlower amp upper MV alarm
Applications of VSV
Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations
in inspiratory pressure support
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
Pressure support ventilation
Weaning mode Patient trigger flow cycled Each inspiratory effort is augmented by
specific amount of positive pressure at airway
PS Terminated when insp Flow falls below a minimum trigger volume
Level of PS ndash Max insp pressure 3 Peak airway pressure - plateau
` ADVANTAGES Less WOB low pressure high volume work similar to
spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is
achieved with PS of 5 cm H2O
Volume AssuredPressure Support (VAPS)
Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure
breath continues to guarantee volume - 1048707 PIP and inspiratory time increase
1048707 Guarantees volume on current breath (no previous breath averaging)
1048707 Combines the advantages of pressure and volume ventilation breath to breath
Characteristics of VAPS 1048707 The ventilator continuously measures the flow and
pressure and calculates delivered volume Depending on the actual settings breath may be flow
volume or time cycled 1048707 If the target tidal volume has been delivered
inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set
flow will persist until the desired volume has been reached (volume cycled breath)
1048707 Safety limits include high pressure and maximum inspiratory time1048707
Used in the Management of acute and recovering lung disease
Benefits of VAPS
1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort
Applications of VAPS 1048707 A patient who requires a substantial level of
ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony
1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change
Limitations 1048707 Will only increase pressure not lower pressure
with changing mechanics 1048707 Increases inspiratory time to assure volume
Volume support ventilation
Support mode Has PVRC as back up mode Allows spontaneous if preset MV is
achieved If fails deliver preset TV MV in lowest
possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure
limitlower amp upper MV alarm
Applications of VSV
Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations
in inspiratory pressure support
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
` ADVANTAGES Less WOB low pressure high volume work similar to
spontaneous [SIMV ndashhigh prlow volume work] Easy acceptability Physiological conditioning of respiratory muscles WEANING Pressure level is decreased gradually Extubated when adequate gas exchange is
achieved with PS of 5 cm H2O
Volume AssuredPressure Support (VAPS)
Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure
breath continues to guarantee volume - 1048707 PIP and inspiratory time increase
1048707 Guarantees volume on current breath (no previous breath averaging)
1048707 Combines the advantages of pressure and volume ventilation breath to breath
Characteristics of VAPS 1048707 The ventilator continuously measures the flow and
pressure and calculates delivered volume Depending on the actual settings breath may be flow
volume or time cycled 1048707 If the target tidal volume has been delivered
inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set
flow will persist until the desired volume has been reached (volume cycled breath)
1048707 Safety limits include high pressure and maximum inspiratory time1048707
Used in the Management of acute and recovering lung disease
Benefits of VAPS
1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort
Applications of VAPS 1048707 A patient who requires a substantial level of
ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony
1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change
Limitations 1048707 Will only increase pressure not lower pressure
with changing mechanics 1048707 Increases inspiratory time to assure volume
Volume support ventilation
Support mode Has PVRC as back up mode Allows spontaneous if preset MV is
achieved If fails deliver preset TV MV in lowest
possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure
limitlower amp upper MV alarm
Applications of VSV
Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations
in inspiratory pressure support
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
Volume AssuredPressure Support (VAPS)
Patient triggering Allows spontaneous breathing without support Variable flow volume ventilation Decelerating non-limited variable flow rate Guaranteed tidal volume delivery 1048707 1048707 If targeted volume is not delivered at this pressure
breath continues to guarantee volume - 1048707 PIP and inspiratory time increase
1048707 Guarantees volume on current breath (no previous breath averaging)
1048707 Combines the advantages of pressure and volume ventilation breath to breath
Characteristics of VAPS 1048707 The ventilator continuously measures the flow and
pressure and calculates delivered volume Depending on the actual settings breath may be flow
volume or time cycled 1048707 If the target tidal volume has been delivered
inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set
flow will persist until the desired volume has been reached (volume cycled breath)
1048707 Safety limits include high pressure and maximum inspiratory time1048707
Used in the Management of acute and recovering lung disease
Benefits of VAPS
1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort
Applications of VAPS 1048707 A patient who requires a substantial level of
ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony
1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change
Limitations 1048707 Will only increase pressure not lower pressure
with changing mechanics 1048707 Increases inspiratory time to assure volume
Volume support ventilation
Support mode Has PVRC as back up mode Allows spontaneous if preset MV is
achieved If fails deliver preset TV MV in lowest
possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure
limitlower amp upper MV alarm
Applications of VSV
Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations
in inspiratory pressure support
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
Characteristics of VAPS 1048707 The ventilator continuously measures the flow and
pressure and calculates delivered volume Depending on the actual settings breath may be flow
volume or time cycled 1048707 If the target tidal volume has been delivered
inspiration is terminated (flow cycled breath) 1048707 If preset tidal volume has not been achieved the set
flow will persist until the desired volume has been reached (volume cycled breath)
1048707 Safety limits include high pressure and maximum inspiratory time1048707
Used in the Management of acute and recovering lung disease
Benefits of VAPS
1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort
Applications of VAPS 1048707 A patient who requires a substantial level of
ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony
1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change
Limitations 1048707 Will only increase pressure not lower pressure
with changing mechanics 1048707 Increases inspiratory time to assure volume
Volume support ventilation
Support mode Has PVRC as back up mode Allows spontaneous if preset MV is
achieved If fails deliver preset TV MV in lowest
possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure
limitlower amp upper MV alarm
Applications of VSV
Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations
in inspiratory pressure support
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
Benefits of VAPS
1048707 Lower peak airway pressure 1048707 Reduced patient work of breathing 1048707 Improved gas distribution 1048707 Less need for sedation 1048707 Improved patient comfort
Applications of VAPS 1048707 A patient who requires a substantial level of
ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony
1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change
Limitations 1048707 Will only increase pressure not lower pressure
with changing mechanics 1048707 Increases inspiratory time to assure volume
Volume support ventilation
Support mode Has PVRC as back up mode Allows spontaneous if preset MV is
achieved If fails deliver preset TV MV in lowest
possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure
limitlower amp upper MV alarm
Applications of VSV
Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations
in inspiratory pressure support
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
Applications of VAPS 1048707 A patient who requires a substantial level of
ventilatory support and has a vigorous ventilatory drive to improve gas distribution and synchrony
1048707 A patient being weaned from the ventilator and having an unstable ventilatory drive to supply a back-up tidal volume as a ldquosafety netrdquo in case the patientrsquos effort orand lung mechanics change
Limitations 1048707 Will only increase pressure not lower pressure
with changing mechanics 1048707 Increases inspiratory time to assure volume
Volume support ventilation
Support mode Has PVRC as back up mode Allows spontaneous if preset MV is
achieved If fails deliver preset TV MV in lowest
possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure
limitlower amp upper MV alarm
Applications of VSV
Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations
in inspiratory pressure support
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
Volume support ventilation
Support mode Has PVRC as back up mode Allows spontaneous if preset MV is
achieved If fails deliver preset TV MV in lowest
possible pressure Set TV RR close to spontaneous Set trigger insptime upper pressure
limitlower amp upper MV alarm
Applications of VSV
Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations
in inspiratory pressure support
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
Applications of VSV
Patients with limited breathing capacity Ready to be weaned Post op patient with intact resp drive Pts recovering from ALI Pts with ventilator dependence Pts requiring breath to breath variations
in inspiratory pressure support
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
BENEFITS OF VSV
Low PIP Inspiratory pressure adapts to
mechanical property of lung Backup with PRVC CVS interference Greater comfort Less sedation Improved gas distribution
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
Dual modes
Continously regulate applied pressure flow to achieve targeted MVTV based on feed back loop
Provide full partial ventilatory support Modify their operation within the confines of an individual
breath Dual control within breath dual control breath to breath Types Volume ndashassured pressure support Pressure augumentation Volume support Pressure regulated volume control Variable pressure volume control
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
Proportional assist ventilation [PAV]
PAV instructs machine to act as auxillary muscle ndash vigor controlled by patient
power adjusted by us to off set resistive amp elastic requirements
Pressure assistance - proportional to variable combination of inspired volume and inspiratory flow rate[ by patient]
Machine amplify patients efforts Dis advantage Requires a back up in case of apnoea
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
Independent lung ventilation
In protection of secretions of one lung Asymmetric disease ndash contusion aspiration Atlectasis
pulmonary embolism Thoracic procedures ILV ndash synchronously [rate linked ventilators single
ventilator with different circuits Asynchronously [ 2 ventilators] Differential PEEP with higher pressure to injured lung ndash
key strategy Equal tidal volume to both lungs Low respiratory rate to injured lung ndashprevent lung injury
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
Liquid ventilation -PAGE Partial [ both gas amp PFC ndashconventional ventilator can be
used] Total ndash only PFC [ needs special equipment] Ventilator used to perform the WOB because of high
viscous resistance PERFLUROOCTYL BROMIDE Inert surface tension lt water CO2 - Four times soluble O2 ndash twenty times soluble
Non absorbable amp poor solvent for surfactant Fill FRC with PFC amp bubble oxygenate with ventilator
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
Perflurocarbon associated gas exchange [PAGE]
IN RDS In infants Advantages Inert agent Increased oxygen delivery Liquid ndash recruit alveoli amp Prevents collapse of
alveoli during expiration Coat alveoli ndash stop release of free radicals Reduce surface tension at alveolar lining ndash
Improve dynamic compliance Used as surfactant amp vasodilatory agent
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
Inverse ratio ventilation [IRV] IE -21 -41 Normal ndash 12 Improves oxygenation by auto PEEP increase mean
airway pressure time for gas diffusion Intrapulmonary shunting Improves VQ matching ndashlung recruitment Dead space ventilation Adverse effects barotrauma high rate of trans vascular fluid flow ndash pulmonary edema Needs sedation PC ndashIRV ndash with PCV peak airway pressures are kept at
minimum Indicated in ARDS amp Diffuse lung injury
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
High frequency ventilation
Very low TV lt anatomical dead space at rates gtnormal rate
HFPPV[ 60-100mt] HFJV [100- 200mt] HFO [600- 3000 mt] HFFI-High frequency flow interruption High frequency percussive ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
HFFI-High frequency flow interruption
A device interrupts gas flow or high pressure at frequencies gt 15 Hz
emersions HFFI ndash a conduit with a ball in centre which moves to and fro at 200 cycles mt interrupting and along gas flow
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
High frequency percussive ventilation
Recently introduced High frequency breaths superimposed on
conventional breaths Pneumatically powered time cycled pressure
limited ventilator with inspiratory ampexpiratory oscillation
Unique is sliding venturi or phasitron mechanism Phasitron se at 200 - 900 bmt superimposed on
conventional 10 - 15 bmt
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
High frequency percussive ventilation
Phasitron mechanism At the heart of device is sliding venturi with jet orifice
at its mouth On inspiration a diaphragm connected to venturi fills
with gas amp pushes it forward blocking expiratory port amp jet comes in short percussive pulsations
Due to high pressure gradient between mouth amp alveolus ndashlarge amount of air entrained
As gradient drops further into inspiration air entrainment decreases but jet pulsations continue
Cycles to expiration
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
High frequency oscillation
Most widely used Inspirationamp Expiration active Sinusoidal flow TV gt DEADSPACE Electronically controlled proportioning valves ndash
provide positive pressure high frequency breaths in inspiratory limb
A jet venturimeter in expiratory limb creates ndashve pressure ndash expiration is active
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
High frequency ventilation
Gas exchange
1 bulk gas flow 2 coaxial flow
3 molecular diffusion 4 pendulft Advantage
Lower peak airway pressure
FRC
Efficient gas exchange
Lower transpulmonary pressure
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
High frequency ventilation
INDICATION Bronchopleural
fistula Neonatal RDS Air leak syndromes Diffuse lung injury Pneumothorax Bronchoscopy
CONTRAINDICATION COPD
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
Adaptive support ventilation
Excellent mode for initiating ventilation support amp weaning
Galileo ventilator Set patient weight PEEP pressure limit
ampvolume control [ 100 ml kg in adults 200mlkg in children ]
Breath to breath assessment is done PS is constantly adjusted
If inadequate mandatory breaths delivered Similar to PSV when spontaneous is present SIMV when inadequate
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
Neurologically adjusted ventilatory assist [NAVA]
Developed to overcome limitations of PAV
Electrical activity of inspiratory muscles ndash index of inspiratory neural drive
Processed signal ndashtransferred to ventilator to regulate ventilation
Research tool
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
Biologically variable ventilation (BVV)
Mimics spontaneous breath ndash breath variability
Ventilator modulate RRVT ndashfixed MV Based on concept that alveolar
recruitment achieved by high volumes exceeds decruitment caused by small volumes with net result being improvement in compliance amp oxygenation
Under research
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
Automatic tube compression
New component of ventilatory support under trial
Should be Combined with PSVPAVBIPAP Available on Drager Evita 4 amp Puritan Bennett
840 In intubated patient ndash pressure difference exists
between proximal ampdistal end of the ETT PETT = Paw ndash Ptrach
PETT - Reflects energy required for convective transport of gases
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
ATC ndashCONTDhellip
V ampPaw measured at proximal end of ETT and fed into ATC controller by staff
Based on this ATC controller selects the tube coefficients characterizing the corresponding pressure ndashflow relationship of the tube
Inspiratory PS in ATC mode equals actual pressure drop across the tube
By this closed loop system ventilator automatically compensate for ETT resistance in inspiration amp expiration
Reduces WOB amp increases patients comfort
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
Advances amp Adjuncts in Pediatric Mechanical Ventilation
VENTILATION STRATEGIES open lung concept by HFOV in RDS CDH Permissive hyper capnia ndashlow TV At high
rates Prone ventilation ndashALI Recruitment of dorsal lung copious
drainage of secretions extra vascular lung water is reduced
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
CONTDhellip
VENTILATORY MODES
Adaptive support ventilation
PAV PRVC NIV BIPAP HFV
ADJUNCTS Inhaled NO Tracheal gas
insufflations PAGE surfactant therapy
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation
FUTURE
Noninvasive ventilation is becoming popular New therapies for ARDS ndash HFO To improve gas exchange ndash prone
ventilation nitric oxide inhalation Lung recruitment maneuvers- CPAP 35-40 cm of
H2O with PEEP set at 2 cm of H2O above Pflex ampTV lt 6ml kg
Ventilatory adjuncts ndashautomatic tube compensation partial liquid ventilation