Can EPR use cause Central Apnea Events?

[Ron AKA]

I found the following post which suggests that the use of EPR (Expiratory Pressure Relief) can over ventilate the lungs, reduce CO2 in the bloodstream, and as a result cause clear air or Central Apnea events? Thoughts on the accuracy of the theory?

Not Understanding EPR Setting

[MyronH]

All I know, is that when I was using my Airsense 10, I noticed a decrease in CA's when I changed EPR from 3 to 1.

[DeepBreathing]

I think the person in your link has somewhat over-stated the position. Many people find that using EPR substantially improves their xPAP experience and allows them to adjust to using the machine far more readily.

Having said that, we have also seen a lot of people whose therapy-induced central apneas have reduced or cleared up by reducing EPR. The extent to which somebody is affected seems to vary substantially from person to person. The results will be there to see in #SleepyHead, and it's a very easy thing to experiment with, if you are so inclined.

Where I work, we only ever allow our patients to use EPR or C-Flex if they have had a sleep study with it and we can verify that it is not causing any harm.

It might just be careless phrasing, but if any medical professional told me I was not allowed to try something I would find a new medic quick smart!

[Hojo]

Short answer, yes.

[Apnea Infant]

I agree with DB in that EPR helped me get used to high pressures in the early months. It was my experience that reducing EPR from 3 to 2 then1 and finally turning it off reduced centrals for me but by then I had adjusted to CPAP and was braver in turning it off as I was lowering my pressures with the help of Sleepyhead.

I think there is a place for using it but to be watchful as we all are here.

[OpalRose]

I found the following post which suggests that the use of EPR (Expiratory Pressure Relief) can over ventilate the lungs, reduce CO2 in the bloodstream, and as a result cause clear air or Central Apnea events? Thoughts on the accuracy of the theory?

Not Understanding EPR Setting

Thanks for that link, that was interesting to read this sleep techs scare tatics about the use of EPR.  

He states he has only seen 5 people benefit from EPR.  I guess he doesn’t have many patients.  

If a person didn’t experience Clear Airway events during a sleep test, and there are no CA’s after,
then there is no reason not to use EPR for comfort if they wish.  This sometimes makes it more bearable to continue with Cpap therapy for those that have high pressure needs.

There are times that if you use EPR, then the minimum pressure may need adjusted to compensate.
No two people are alike, therefore you can’t just give “blanket” advice to everyone.

With that said, if you spend enough time on this forum, you would quickly notice that when we see a high CA count, the first thing we look at is if the person is using EPR.  At that point, we most always recommended that they lower it or turn it off completely to see if that helps.

The bottom line is that EPR use is for comfort.  To say it’s dangerous is a scare tactic.

My opinion only...I’m not in the Medical Field. Just going by experience.  

[Sleeprider]

I basically agree with what Sleeptech says in that post, and it mirrors much of my own suggestions here.  Where we disagree is this:

Where I work, we only ever allow our patients to use EPR or C-Flex if they have had a sleep study with it and we can verify that it is not causing any harm. Otherwise we do not use it at all. I can think of fewer than 5 people who have actually had some benefit from using EPR/C-Flex in all my years of being a sleep tech.

I have coached many users to utilize EPR is a way that reduces hypopnea and flow limitation, as well as increasing comfort. Provided they don't experience significant increases in central events, this has been an effective tool, and the same principles are used in bilevel therapy.  I have not achieved similar results using C-Flex or A-Flex and consider that a comfort-only implementation. I understand how a tech may believe they "don't ever allow" their patients to use features like Flex or EPR, but  I would never work with someone so deluded. This attitude stinks, and everyone would be better served if that was replaced with "I make sure they know how to use the feature".

The people who sell the machines and the reps for the companies who make them will extol the virtues of EPR/C-Flex and tell you that it is perfectly safe. IT IS NOT. One of the engineers who designed the system admitted as much to another tech I work with.

I have maintained the position that EPR is bilevel, and the principles of bilevel should be understood to properly implement EPR. Many people find it works great without that understanding, but there are therapeutic applications as well as potential drawbacks.  Flex also has a comfort benefit for some people, but I have not found it makes any beneficial effect on therapy. 
JMHO

[Ron AKA]

All I know, is that when I was using my Airsense 10, I noticed a decrease in CA's when I changed EPR from 3 to 1.

I tried that last night on my F&P machine (reduced EPR from 3 to 1). My AHI went up from 2.7 to 3.7. Since the F&P doesn't talk to SleepyHead I have no idea what the events were. I also increased the min pressure, and reduced the max pressure, so it was kind of a shot in the dark effort, and probably missed. Until I get my AirSense 10 and see the results I am getting, I suspect I cannot make much progress on the CA issue.

[kiwii]

Isn't he somewhat backing off of his initial stance in the comments section?

(emphasis added)

The idea is to drop the pressure slightly on expiration in order to make the pressure more tolerable. Sounds reasonable but it is, in fact, a huge problem and should be avoided in almost every instance.

For most people EPR is probably harmless, it's just that there are risks, and the number of people for whom it is a problem, albeit the minority, is still pretty significant.

[Ron AKA]

I have coached many users to utilize EPR is a way that reduces hypopnea and flow limitation, as well as increasing comfort. Provided they don't experience significant increases in central events, this has been an effective tool, and the same principles are used in bilevel therapy.  I have not achieved similar results using C-Flex or A-Flex and consider that a comfort-only implementation. 

You may find the article at the link below which compares the feature in different manufacturers interesting. The different manufacturers seem to differ most in how they initiate the EPR. I have also seen other articles which suggest manufacturers do not simply reduce the pressure for the whole exhale cycle, but only reduce it at the beginning. In other words the shape the exhale pressure response waveform. ResMed allows you to select EPR on ramp only, which seems like something worthwhile to try. The AirSense 10 also has an auto ramp feature which seems to start the ramp on detection of transition to sleep. I presume if you select EPR on ramp only, and also select auto ramp it will keep EPR on until you go to sleep and are ramped up to minimum pressure. Will try that when I get it. 

EPR Functions Compared