1. Bilevel Titrations: Who, What, Why, and When Gary Hamilton, BS, RRT
Clinical Specialist
ResMed
110162/

2. Disclosures
Employed by ResMed
Own stock options of ResMed

3. Course Objectives 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 patient outcomes by proper utilization of bilevel and its settings
So what exactly is Complex sleep apnea?
How prevalent is it? How big of a market/ opportunity is it for you?
How are these patients been treated?
How does the VPAP Adapt SV stack up against those methods?
Is Complex Sleep Apnea is new diagnosis? How does a patient with this condition qualify for treatment?
And lastly, once we know this, where are the opportunities? Who should I be talking to about Complex Sleep Apnea?

4. CPAP Intolerance- next step Bilevel
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
COPD- RCS, remember that this topic will be covered in detail in another program, so keep this very basic
CPAP does not provide ventilatory support, it just splints the airway

5. Comfort vs Ventilation
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
What is non tolerance of CPAP
What is a “High” CPAP pressure? Is it a number, like 14 or 15, or is it a patient who cannot tolerate any pressure they’re on?
Obstructive-COPD or Asthma (needs improved ventilation, lower CO2, Morbid Obesity)
Restrictive- (Scoliosis, Neuromuscular Disease, Paralysis, Pulmonary Fibrosis)

6. Bilevel- Can I get it paid for OSA?

7. Difference between Cpap and Bilevel
Comfort/compliance features
Cpap
Lower pressure
Ramp
Pressure relief (Cflex or EPR)
Waveform (sine vs square)
Bilevel
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)

8. Bilevel Breath Cycle Values That Tools Can Impact
Inhalation
Cycle
Trigger
Patient Flow
Exhalation
Delivered Pressure
IPAP
Pressure support ( P)
* Be sure to mention that ResMed VPAP is the only device in which Trigger and Cycle sensitivities can be changed (next slide).
What is the labs definition of high pressure?   ASM guidelines say chg to bilevel at 15 cm.  As well as saying to keep 4 cm difference between pressures.  Above 4 cm difference you begin to ventilate.
The patient’s inspiratory effort triggers the VPAP airflow
The air pressure increases to the set inspiratory pressure (IPAP)
IPAP ends and EPAP starts when the VPAP detects that the patient’s inspiratory flow has dropped to a specific value.
IPAP
Maintains or augments ventilation (stabilizes O2 and decreases PCO2 especially during sleep)
Decreases work of breathing and rests accessory muscles
EPAP
Splints the upper airway (same as CPAP)
Promotes alveolar recruitment, enhancing oxygen exchange (same as PEEP)
When properly set, EPAP overcomes PEEPi in COPD
EPAP

9. What If It Is Not Just an Airway Problem?
OSA Airway problem
CompSA Airway and Ventilation problem
Cheyne-Stokes Ventilation problem
COPD Ventilation problem
Neuromuscular Ventilation problem

10. Can I get Bilevel paid for when it not OSA?

12. CompSA or Cheyne-Stokes
Tools Available in Bilevel for Specific Diseases

13. Tools for CompSA and/or Cheynes Stokes
ST device
Is back-up rate machine (E0471)
Fixed rate – time controlled
Not very comfortable- little synchrony
Square wave- ventilates
Servo ventilator
Should be more comfortable- tries to sync with pt
Sine wave- not trying to ventilate
Very automatic (servo)

14. CompSA and the Apneic Threshold
CompSA patient on Servo
CompSA patient not treated
Central apneas occur
As discussed earlier, CompSA patients’ CO2 levels have downward swings into the apneic threshold and central apneas occur. This cycle continues when untreated.
However, when the CompSA patient is treated with VPAP Adapt SV, its algorithm will begin to resolve the CO2 swings until the CO2 level stabilizes and remain in normal range. Central events are then eliminated.
The goal of the ASV algorithm is to correct the CO2 swings and stabillize the breathing pattern. The CO2 levels will then remain in normal range and central apneas are eliminated.
The theory behind these methodologies, (using a non-vented FFM, bleed-in of supplemental CO2, or the addition of deadspace) is nothing more than having the patient re-breathe their CO2. When this is done, they then raise their CO2 level above their “Apneic threshold”.
To further explain this…..a person’s normal PCO2 is in the range of What causes the centrals to occur in the CompSA patient is that with the introduction of PAP therapy (PAP or bi-level), their CO2 level is driven downward. And at some point, they hit their apneic threshold……and when this happens…..central apneas begin to occur. So by re-breathing their CO2 in their own exhaled air or by entraining supplemental CO2, we are raising (or maintaining) their CO2 level to where the central apneas no longer occur.
CHF patients with CSA
ASV vs. additional Deadspace
Both improved CSA (reduced AHI)
Both stabilized ventilation
But Deadspace also:
Decreased total sleep time
Increased total arousal index
Increased sleep fragmentation
Increase in respiratory effort
Increased sympathetic activation?
Szollosi,D et al 2006 European Sleep Research Society

15. Gives Support Only When Needed
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)
VPAP Adapt SV
Once again, we are highlighting the ASVs ability to adjust PS up or down in order to maintain its target minute ventilation.
This therapy not appropriate for patients who:
1. have chronic and profound hypoventilation
2. moderate to severe COPD
3. restrictive thoracic or neuromuscular disease
Comfort through Synchronization:
It also looks at the instantaneous direction, magnitude and rate of change of the patient’s airflow
Delivered ventilation is matched to patient respiration via a series of set points identified in each breath
Patient Flow

16. Tools Available in Bilevel for Specific Diseases
COPD
Tools Available in Bilevel for Specific Diseases

17. Tools For COPD- What are the problems?
Lung tissue destroyed
Elasticity of lungs disappearing
Poor functioning diaphragm
Reliance on accessory muscles
Air trapping

18. Desaturations During REM in COPD Patient
This patient’s histogram reflects saturation levels for an Overlap patient on room air. Notice the O2 sat is <90% at the start of the study. The patient’s supine position undoubtedly causes the O2 sat to further decrease. The saturation decreases even more when the patient falls asleep and there is a slight relaxation of the respiratory muscles. In REM the saturation falls significantly due to loss of use of the accessory muscles and increased incidence of obstructive apneas.

19. Tools for COPD- Problems on Bilevel
May have difficulty exhaling on CPAP
Extends their inspiratory time
Asynchrony
Increases their work of breathing
Cycling problems (getting into exhalation)
Auto-PEEP
Missed triggers
Work of breathing
Delayed cycling = Decrease in
Decreased expiratory time =
Increase in
Expiratory time
Lung emptying
You might be wondering why COPD patients need the cycle sensitivity set so high? Well– remember we talked about how the COPD patient’s airways can be filled with mucus– which increases the resistance? We also talked about how the COPD patient’s airways can be inflamed– which also increases resistance.
That increased resistance causes the inspiratory flow to be slower than usual.
If the cycle sensitivity is set too low– it will be a LONG time before the ventilator cycles from inspiration to expiration.
You can see that delayed cycling results in a decreased expiratory time, and therefore decreased emptying of the lung. Not enough exhalation time leads to air-trapping or intrinsic peep– which leads to missed triggers and increased work of breathing.
Now– you might be curious– why does auto-peep cause missed triggers? If the patient’s lungs are trapping a lot of gas, the patient will require added effort to inspire through that auto PEEP to reach the triggering threshold.
Let’s try that together now. Take a big breath in and hold it, now- without exhaling– take another breath in. Do you see how it is harder to get that second breath? That is what happens to the COPD patinet.

20. Bilevel Tools- Sensitivity Adjustments
Adjustable Trigger Sensitivity
Adjustable Cycle Sensitivity
Patient
Flow
Patient
Flow
EPAP
EPAP
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
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%
*ResMed’s VPAP’s are the only bilevel with adjustable sensitivities for Trigger and Cycle.
Cycle- when flow disintegrates to % of peak flow then cycle occurs.
Trigger – how much volume is “pulled” before it triggers the breath. (2.4L of volume for Very setting)

21. Bilevel Tools - Time cycle inspiration
S Mode: IPAP 10 EPAP 6, rise time 150ms, TiMax 2.0, TiMin 0.3, trigger cycle med
S Mode: IPAP 10 EPAP 6, rise time 150ms, TiMax decreased to 1.0, TiMin 0.3, cycle sensitivity changed to higher
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

22. Bilevel Tools – Ti Control
Rise Time
For comfort
Will affect how pressure “feels” to pt

23. Bilevel Tools- Sine Wave
Easy-Breathe
Square Wave
*The reason for the mask pressure drop at the 1:00 to 1:10 minute section – while breathing on the VPAP device when you change modes in real time it takes the machine a few second to switch from Smode to Vauto.
What you are seeing is a pressure drop as a result of this.  Only occurs during real time pressure change while patient continues to breathe. 
Section 1 Spontaneous Mode (0:45 – 1:00) : IPAP 10, EPAP 6, (TiControl default settings) rise time 150ms, TiMax 2.0, TiMin 0.3, Trigger/Cycle sensitivities medium
VAuto Mode: Max IPAP 10, Min EPAP 6, PS 4, TiMax 2.0, TiMin 0.3, Trigger/Cycle sensitivities medium

24. Neuromuscular and Obesity Hypoventilation Restrictive Patients
Tools Available in Bilevel for Specific Diseases

25. Bilevel Tools- Asynchrony in Restrictive Patients
Premature cycling creates asynchrony
Occurs in restrictive patients
Lungs physically restricted
Paralysis or muscles deteriorated
“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.”
This slide shows another recent paper from Mike Gentile. (CLICK) Note that this paper is talking about how premature cycling can have a detrimental effect on patient-ventilator synchrony. He then goes on to explain that premature cycling is when the ventialtor stops the breath while the patient needs a longer inspiration.
Gentile. Respir Care 2011

26. 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.
) 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
In 2010 a group of some of the most respected key opinion leaders in sleep and ventilation wrote a consensus statement in the Journal of Clinical Sleep Medicine. They recognized that premature cycling is an issue in providing NIV to restrictive patients and recommended that IPAP Duration or TiMin be increased to ensure adequate breath time.
Berry. J Clin Sleep Med 2010

27. Bilevel Tools- Increasing the Inspiratory Time
Problem: Patient’s inspiratory effort is weak (i.e. restrictive disease)/can’t sustain
adequate inspiration
Solution: Best option – Increase/prolong Ti Min
Second option – Select lower cycle sensitivity

28. Bilevel Tools- When You Need to Ventilate
PS 5
PS 10
PS 15
PS 20

29. Bilevel Tools for Ventilation-VAPS
iVAPS – (ResMed)
Intelligent Volume Assured
Pressure Support
AVAPS (Philips)
Average Volume Assured Pressure Support
Can assure Tidal Volume while the patient is sleeping
Is Servo Controlled

30. The iVAPS Algorithm: Example
Alveolar ventilation drops
patient moves into REM sleep
iVAPS rapidly increases PS until target Va is reached
REM Onset
Ventilation [– AV –MV –TargetAV ]
Pt. Flow PS
If ventilation falls, pressure support is increased until the target is reached...this ensures the patient is not under-ventilated
SpO2

31. Conclusion 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