Bilevel Titrations:Who, What, Why, and When
Gary Hamilton, BS, RRTClinical Specialist
ResMed
Employed by ResMed Own stock options of ResMed
Disclosures
By the end of this session, you should be able to:
Identify when a CPAP may not be the device of choice
Recognize different uses of bilevel and the different disease states it is applicable to
Describe what tools are available to:◦ Increase tolerance and compliance◦ Treat the disease and/or disorder
Understand how to impact patientoutcomes by proper utilization of bilevel and its settings
Course Objectives
Why patients fail CPAP:
CPAP is uncomfortable
Patient may feel CPAP is uncomfortable at higher pressures despite pressure relief features
COPD patients have trapped air/pressure in their lungs, which may increase their work of breathing
Patient may need higher levels of ventilatory support CPAP cannot provide
CPAP Intolerance- next step Bilevel
Why make the switch from CPAP to Bilevel?
Patient Comfort: Cannot tolerate CPAP On a high CPAP pressure and cannot tolerate it
Ventilation: Obstructive disease Restrictive disease Neuromuscular disease
Comfort vs Ventilation
Bilevel- Can I get it paid for OSA?
Comfort/compliance features◦ Cpap
Lower pressure Ramp Pressure relief (Cflex or EPR) Waveform (sine vs square)
◦ Bilevel Ramp Pressure relief (Ipap and Epap) Waveform Rise time Trigger sensitivity Cycle sensitivity Ti control (controlling the time in inspiration or expiration) Pressure support ( muscle unloading)
Difference between Cpap and Bilevel
Bilevel Breath Cycle Values That Tools Can Impact
Patient Flow
Delivered Pressure IPAP
EPAP
Exhalation
TriggerCycle
Inhalation
Pressure support ( P)
OSA Airway problem
CompSA Airway and Ventilation problem
Cheyne-Stokes Ventilation problem
COPD Ventilation problem
Neuromuscular Ventilation problem
What If It Is Not Just an Airway Problem?
Can I get Bilevel paid for when it not OSA?
CompSA or Cheyne-StokesTools Available in Bilevel for
Specific Diseases
ST device◦ Is back-up rate machine (E0471)◦ Fixed rate – time controlled◦ Not very comfortable- little synchrony◦ Square wave- ventilates
Servo ventilator◦ Is back-up rate machine (E0471)◦ Should be more comfortable- tries to sync with pt◦ Sine wave- not trying to ventilate◦ Very automatic (servo)
Tools for CompSA and/or Cheynes Stokes
CompSA and the Apneic Threshold
Central apneas occur
CompSA patient not treated
CompSA patient on Servo
The ASV algorithm automatically adjusts the magnitude of pressure support breath by breath to:
◦ Provide minimal, comfortable support during the over-breathing phase (hyperpnea) or during normal breathing
◦ Increase support during the under-breathing phase (hypopnea or apnea)
Gives Support Only When Needed
VPAP Adapt SV
Patient Flow
COPDTools Available in Bilevel for
Specific Diseases
Lung tissue destroyed Elasticity of lungs
disappearing Poor functioning
diaphragm Reliance on accessory
muscles Air trapping
Tools For COPD- What are the problems?
Desaturations During REMin COPD Patient
Tools for COPD- Problems on Bilevel
• Auto-PEEP• Missed
triggers• Work of
breathing
• Expiratory time
• Lung emptying
Decreased expiratory time =Increase in
Delayed cycling = Decrease in
• May have difficulty exhaling on CPAP• Extends their inspiratory time• Asynchrony• Increases their work of breathing • Cycling problems (getting into exhalation)
Very High Quick to trigger 2.4 L/min
High More sensitive 4 L/min
Med Default 6 L/min
Low Less sensitive 10 L/min
Very Low Slow to trigger 15 L/min
Bilevel Tools- Sensitivity Adjustments
Very High Quick to cycle 50% of peak flow
High More sensitive 35%
Med Default 25%
Low Less sensitive 15%
Very Low Slow to cycle 8%
Adjustable Trigger Sensitivity
Patient Flow
EPAP
Adjustable Cycle Sensitivity
Patient Flow
EPAP
Bilevel Tools - Time cycle inspiration
Problem: Patient requires longer expiratory time (i.e. COPD)
Solution: Best option – Shorten Ti Max time
Additional options – Select higher cycle sensitivity,Select faster rise time
Rise Time◦ For comfort◦ Will affect how pressure “feels” to pt
Bilevel Tools – Ti Control
Bilevel Tools- Sine Wave
Square Wave Easy-Breathe
Neuromuscular and Obesity HypoventilationRestrictive Patients
Tools Available in Bilevel for Specific Diseases
Bilevel Tools- Asynchrony in Restrictive Patients
Premature cycling creates asynchrony• Lungs physically restricted
• Paralysis or muscles deterioratedOccurs in
restrictive patients
“However, premature cycling may also have detrimental
effects on patient-ventilator synchrony. Premature cycling is simply when the ventilator terminates the breath while the patient requires a long
inspiratory period.”
Gentile. Respir Care 2011
Bilevel Tools- Restrictive Diseases
An early fall in the absolute flow rates may trigger the
transition to EPAP prematurely. Certain devices provide a minimum IPAP time to ensure that IPAP lasts long enough to allow delivery of an adequate tidal volume.
) 4.8.4 Minimum IPAP duration (if available) may be increased if the device cycles from IPAP to EPAP
prematurely (eg, in restrictive chest wall
disorders). Level A – Consensus
Berry. J Clin Sleep Med 2010
Bilevel Tools- Increasing the Inspiratory Time
Bilevel Tools- When You Need to Ventilate
PS 5 PS 10 PS 15 PS 20
iVAPS – (ResMed) Intelligent Volume Assured Pressure Support
Bilevel Tools for Ventilation-VAPS
AVAPS (Philips) Average Volume Assured
Pressure Support
• Can assure Tidal Volume while the patient is sleeping• Is Servo Controlled
The iVAPS Algorithm: Example
Alveolar ventilation drops
◦ patient moves into REM sleep
◦ iVAPS rapidly increases PS until target Va is reached
Pt. Flow
PS
Ventilation [– AV –MV –TargetAV ]
SpO2
REM Onset
CPAP may not be the device of choice for specific patients Diagnoses will be a big determinant of what PAP machine will be
appropriate for the patient Goals of therapy will tell you what machine you should use
◦ Stabilize airway◦ Hypoventilate the patient◦ Ventilate the patient
Bilevel offers a greater amount of tools to:◦ Increase comfort of patient◦ Increase compliance of patient◦ Increase the chances of the therapy goals being met
Tools available◦ Wave forms◦ Time cycling◦ Sensitivity adjustments◦ Servo algorithms
Conclusion
