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Mechanical ventilation and RAD
Dr Satish Deopujari
Prof. K. Chellum Oration / CMC Vellore
26th June 2004
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Incidence of M.V. in RAD in India ?
Do we under ventilate these patients.
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Aggressive management ..
Proper oxygenation warmed and humidified
Continuous nebulization what dose ?Look for hypokalemia
Steroids / Ipatropium bromide / MgSO4Hydration / Ensure good Hemoglobin level.
Avoiding agitationKetamine
Newer modalities
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MgSO4 Mechanism of Action
Antagonizes translocation of Ca across cellmembrane, leads to SM relaxation and Inhibitsdegranulation of mast cells
Decreases release of ACH (decreases excitability ofmuscle fibre membranes)
Side Effects: Facial warmth/flushing, hypotension, nausea, emesis,
muscle weakness, sedation, loss of DTRs, respdepression
Dose: 20-40mg/kg IV over 30 min
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The decision to intubate pt in SA , is made on the basis clinical
deterioration,
Altered level of consciousness
Exhaustion / P. paradoxus
Inability to protect airway
Increasing arterial PCO2.
Quiet chest, absence of audible wheezing
PaO2 < 60 mmHg : not responding to adequate oxygenation
PaCO2 > 50 mmHg and rising more than 5 mmHg/ hour
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Zimmerman et al, reported that one or
more complications occurred in 46% ofintubated asthmatics.
More than one-third of all complications
occurred during intubation. 47 % of complications during the
intensive care unit stay
Difficult and esophageal intubationsoccurred in about 15% of all patients
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Standard preparation for rapid sequence
intubation .
cardio-respiratory and blood pressure
monitoring
Assistance monitoring of oxygen saturation
careful aspiration of oropharynx
bag and mask ventilation with 100% oxygen
emptying of the stomach by nasogastric tube
benzodiazepine should be considered (e.g.,
midazolam 0.1 - 0.2 mg/kg) permitting
relaxation during preoxygenation
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Ketamine hydrochloride (1 to 3 mg/kg)
Good choice for its sedative and
analgesic effects as well as its
bronchodilating characteristics.
Concomitant use of a benzodiazepine
can suppress the dysphoric effects ofKetamine.
Ketamine increases laryngeal secretionsbut does not block pharyngeal and
laryngeal reflexes, increasing the risk of
laryngospasm and aspiration in the
preintubation period
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Endotracheal tube.
largest endotracheal tube..
lower airflow resistance
Suctioning of thick mucosal secretionsFiber optic bronchoscopy : facilitated
A cuffed endotracheal tube
Sometimes useful even in small children
(
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Intubation.
oxygenation
H2 blockers , prokinetics . atropine
Lignocaine 4 % neb. 4mg / kg ( 1ml = 40 mg )
Sedation midazolam + ketamine / cricoidpressure
Paralysis ( Vecuronium .1 to .2 mg / kg )
Intubation
Suction
Confirmation of tube and proper fixation
Avoid positive pressure V. without cricoid P.
Proper monitoring
Oxygenation & Circulation status
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Fluid bolus for circulation
Lt heart pumps what
the
right heart gives it
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Ventilatory strategy
Permissive hypercapnia
low rate 50 % for the age
low pressureAvoiding barotrauma
low pressure
Minimal PEEP
Intrinsic PEEP
Dynamic hyperinflation (DHI)
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PEEP
Controversies remain about the role of PEEP in
status asthmaticus.Majority of cases, no PEEP should be applied
during mechanical ventilation (0 3 cm H2O
maximum)
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PEEP
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Intrinsic PEEP
Air leak syndrome
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A 'rapid sequence' for
extubation is justified
by the risk of further
bronchoconstriction
induced by the
presence of theendotracheal tube.
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Adding adjuvant therapy despite lack of
evidence is reasonable given the risks
associated with intubation and mechanicalventilation
More research is required in childhood status
asthmaticus!
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M. Ventilation is a BLEND of Art and science
TH
ANKS
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Adding adjuvant therapy despite lack ofevidence is reasonable given the risks
associated with intubation and
mechanical ventilation
More research is required in childhood
status asthmaticus!
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Mechanical ventilation
Less than 5% of patients with SArequired intubation and MV, braman et
al,jama1990
Indications: To decrease work of breathing.
To maintain adequate oxygenation .
Augment alveolar ventilation in face of airwayedema and diffuse mucus plugging of of the
small airways
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Indications of mechanical ventilation
Not governed by numbers but by the clinical conditions.
PaO2 < 60 mmHg or cyanosis not corrected by oxygen administration
PaCO2 > 50 mmHg and rising more than 5 mmHg/ hour
The decision to intubate and ventilate a child with status asthmaticusis primarily based on clinical criteria:
respiratory muscle fatigue, obvious exhaustion, disappearance of
pulsus paradoxus
diminution of thoracic amplitude during respiratory movements
diminution of air entry in the lungs : quiet chest, absence of audible
wheezing
pulsus paradoxus > 20 - 40 mmHg(inspiratory decline in systolic
blood pressure)
deterioration of mental status (lethargy, agitation, confusion, coma)
diaphoresis in recumbent position
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ideal ventilator settings reduce dynamic hyperinflation
(DHI): limited minute ventilation (MV) using an
appropriately low but adequate tidal volume (Vt) and
respiratory rate, with an extended expiratory time (TE)
