[Equipment] CPAP EPR vs. true bi-pap sensation/comfort

[jawsurgerycanidate453]

Hi everyone,

I'm aware of how CPAP + EPR imitates Bi-Pap support pressure up to 3 cm/h20. 

My question is for those who have experienced both CPAP + EPR then migrated to true bi-pap:

1.) if for the same effective inhale and exhale pressures, did it feel more comfortable on bi-pap?


I think the pressure curve is different between CPAP+EPR vs. bi-pap possibly. It seems like with EPR the unit maintains the CPAP pressure setting through inhalation, and starts to curve down the pressure during exhale, where the peak of the exhale is the (CPAP pressure - EPR).

With true bi-pap it seems like the curve is different, or maybe even more tunable. Like being able to drop to the lower pressure much faster, and earlier in the exhale. Again assuming same inhale/exhale pressure equivalents. I'm fully aware bi-pap allows for a larger gap of support pressure.

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I'm asking because on exhale, even with EPR it's still a bit uncomfortable. I was hoping that with true bi-pap, it would drop the resistance (go to a lower pressure) a bit faster than the EPR mechanism.

[SarcasticDave94]

Example of the difference, ResMed AirSense 10 AutoSet has no timing controls to shape the transition between EPAP and IPAP. However the ResMed AirCurve 10 VAuto does.

If that's what you feel you need, tell your doctor. Base it off of lack of comfort.

Want to show any representative OSCAR charts? Your issue might be setting based, it at least edits might help.

[jawsurgerycanidate453]

Added some oscar samples with varying pressure settings and EPR

           

[SarcasticDave94]

Have you tried this combo, pressure 7-10 EPR full time 3? You seem to get decent treatment with low pressure. Maybe adding in a small range while allowing EPR to work fully will help.

[jawsurgerycanidate453]

Have you tried this combo, pressure 7-10 EPR full time 3? You seem to get decent treatment with low pressure. Maybe adding in a small range while allowing EPR to work fully will help.

I can try to switch over to AutoPAP 7-10 with full time EPR. I had set it to manual because anything over 6 cm/h20 on exhale left me waking up in the middle of the night ripping the mask off. I think their original range was 8-16 cm/h20 on autopap when I first got it.


Do you know if my flow limits are typical for treatment that seems to be working? Is it not realistic to get the flow limits even lower or even to 0?  It seems like at high support pressures (higher EPR) the flow limits are lower but not 0. 

So I was wondering if going to bi-pap and having support pressure of 4-5 instead of the limit of 3 with EPR might help that even more.

[G. Szabo]

Do you know if my flow limits are typical for treatment that seems to be working? Is it not realistic to get the flow limits even lower or even to 0?  It seems like at high support pressures (higher EPR) the flow limits are lower but not 0. 

I have firsthand experience that it is feasible to achieve a 0.0 (95%) flow limit by tuning your PS with a Machine I have. 
I do not believe that you can find a "typical flow limit" definition for effective treatments. Nevertheless,  I learned on this forum (from Sleeprider, if I recall correctly) that the treatment target is to make your 95% flow limit less than 0.1.

[SarcasticDave94]

Flow limits don't look too bad to me. Zero isn't the goal, for FL or even events, but reasonably controlled and comfortable therapy that's what to expect.

My opinion, bilevel would be more clearly indicated if you needed higher pressures. Basically your current AutoSet with EPR 3 set would equal PS 3 in the VAuto given other things being identical.

Possibly try the AutoSet in Auto first. Exhaust all possibilities here then if it's not going well, certainly get a VAuto.

[jawsurgerycanidate453]

I wanted to thank everyone for their help! The level of knowledge on these boards is shocking! This is why i love online communities. I have some updates based on my learnings.


Found the detailed answer to my question:

As far as "feeling" between a Resmed Airsense Auto (CPAP) and a Resmed Airscurve VAUTO (Bi-pap) this post explains it best. First search result.

https://www.google.com/search?q=BiPAP-ri...stion.html

Long story short. Resmed CPAP with EPR feels similar to Resmed Bipap with EasyBreath on. With EasyBreath OFF not sure if that feels as comfortable, given the name of the feature I assume it doesn't

Running a Resmed Airsense in CPAP mode with EPR is closest to a Resmed AirCurve in bi-pap mode with equivalent pressures when used with EasyBreathe on. (Same effective inhale, exhale pressures, pressure support). With EasyBreath off on the Resmed Aircurve (bi-pap), the pressure curve is more rectangular. The above link to the forum post provides plenty of screenshots.

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Going from Fixed CPAP pressure to Auto on my Resmed Airsense 10 reduced my flow limitations!

I took SarcasticDave94 suggestion and switched to Auto and increased my pressure range. I also increased my EPR from 1 to 3. What I discovered was eye opening

• I can start the night at a low pressure of 6 cm/h20 which is very comfortable for me, and keeps my airway open. Since 4 cm/h20 is the lowest the Airsense 10 can go I get EPR of 2 at this level. (Even though its set at 3)
  
• As flow limitations start to rise, the algorithm bumps up my pressures. And the EPR has the side effect of fluctuating between 2 and 3 because of the lower cutoff of 4 cm/h20. Oddly, due to this edge case, it acts as a variable EPR.
  
• Highest inhale pressure gets to around 8.4 cm/h20 at which point I'm maxing out the full 3 cm/h20 of EPR.
  
• With this setup my 95% of flow limitations is 0.01 and 99.5% is 0.1 flow limitations!
  

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Wiki has good resource on flow limitation ranges

I was confused what were ideal flow limitation ranges. Here is what I learned

• Suggested ranges in wiki
  
• 95% and 99.5% refers to confidence interval in statistics. In OSCAR it seems to represent the value of flow limitation for 95% of the night vs 99.5% of the night