Seemingly little correlation between EPAP (or PS) and AHI or flow rate. [UARS]

[ldinks]

Hi all. 

Bad news. Those benefits above faded and I got worse over time. I fell asleep at work - which has never happened pre-BiPaP. Timed breaths haven't decreased. My smart watch says my light sleep and rem sleep are too high, my deep sleep extremely low. My sleep is roughly better than 2% of other users. I know they're not accurate, but to be that much of an outlier, consistently, is interesting.

I also talked to my partner about what I was like in my sleep before I used a BiPaP. I was a lot worse than I thought. A majority of what she noticed has barely changed since using the BiPaP either, although there are some notable improvements.

Now the good news. I have an appointment in about 7 hours to provide evidence for why I should have a sleep study despite not fitting "strict criteria". I very closely fit the NICE guidelines and I'm gathering OSCAR data, my home sleep study, and my smart watch, as well as making a list of weird sleep things my partner and parents say I do.

[Mandrake]

Your machine treats by maintaining a constant Tidal Volume, but it cannot because you have it handcuffed by restricting PS to 3.  This is something we need to keep in mind as the auto part is trying (but cannot) to maintain tidal volume vs managing Pressure, a different mode than we usually deal with.  We need to know what we are trying to treat.  
Can you provide a copy of your sleep studies, personal info redacted.  And why are you using this machine?  Your Title says UARS, I'm not saying that is not the case but PS is the main tool there.

OA - treated with EPAP pressure
H, FL, RERAs, and UARS - treated with PS
CA, is treated with maintaining volume, tidal or minute Vent, depending on brand.

Any correlations should be with the above.  

With UARS you need to manually check for flow limits because they are under-reported.

Hi Gideon

I am new to this, trying to educate myself as quickly as I can to be able to improve the results of my therapy.

Can you please explain what you mean with
"OA - treated with EPAP pressure
H, FL, RERAs, and UARS - treated with PS"

Does it mean the pressure under exhalation (not inhalation) is what matters for treating OA?
Can you please explain why/how? And why not IPAP (if that is the correct abbreviation for pressure during inhalation)?
And does that mean that in order to tolerate the highest possible EPAP, Flex (Philips) and EPR (Resmed) is ideally not used?

And what does PS mean? I assume Pressure Support? I.e. EPR, A-Flex, etc.
How/why does that treat H, FL, RERA etc?

Thanks in advance and looking forward to your reply.

[Crimson Nape]

Here are 2 links to help with definitions and acronyms.

Wiki - Definitions

Wiki - Acronyms

- Red

[Mandrake]

Here are 2 links to help with definitions and acronyms.

Wiki - Definitions

Wiki - Acronyms

- Red

Thanks. I obviously got it right then as to the meaning of the acronyms.
Still would love to understand the mechanisms of it though.
Why is it EPAP (and not IPAP) that is most important in treating OSA?
And how/why does PS (i.e. difference of IPAP/EPAP and not the pressure itself) matters the most in treating H, FL, etc?

[Dutchie]

OK, now it clicks a bit for me. DreamStation SV Auto. The OSCAR part looks OK to me, any negatives in the therapy from comfort and hour you feel?

So the coughing and such; but not a diagnosis of any lung or airway disease?

Hey Dave, I thought it was the Resmed ASV algorithm that focusses on minute ventilation. Read this article on the difference between the Resmed and the Philips Respironics ASV therapy.

 https://web.archive.org/web/202110060150...-with-ifl/

I have a Resmed Aircurve 10 ASV and can attest that it doesn't really pick up on flow limitation and the flow rate getting gradually smaller. Will give the Respironics System One ASV a try, to see if it actually tackled the reduced flow rate better.