adipasqu is correct. -SWS explained this with a bit more geekspeak back in JIMCHI's
thread too:
viewtopic.php?f=1&t=60687&p=573999#p574405
As for anything said by the person posting under the name StillAnotherGues
s (not to be confused with StillAnotherGues
t, aka Muffy, aka NotMuffy -- who is a smart sleep professional with a sassy demeanor), read my threads or Paper_Nanny's, and you'll see why this community gives little to no credence to anything he says. He randomly throws out one-liners like that without any evidence or support and usually without sufficient data to support his conclusion. He has also been often proven to be completely wrong, despite stating things with a matter-of-fact tone. I think my earlier post, -SWS's that I linked, and adipasqu's all do a pretty decent job of explaining when and under what conditions an increase in EPAP
could help you. But right now, without further data, the evidence doesn't support it, and because your
ASV is not increasing your EPAP when you sleep, there's a strong argument to be made for taking min EPAP even lower rather than higher.
Why? Your
ASV at least
thinks you are not having events and patterns that merit increasing your EPAP. Our ASVs are designed to auto-titrate for both the obstructive and central components. The min EPAP is precisely that -- a floor beneath which the
ASV won't try. Having that floor high makes sense for people who consistently need it to be high, as the
ASV makes changes to EPAP rather slowly (in contrast to IPAP, which it varies much more quickly). Might those hypopneas be obstructive and the
ASV is not reading the inputs well enough to increase your floor? Yup. Is it also possible the
ASV is doing its job and your current EPAP floor is either just right or even too high? Yup.
Back to your point: I would not put much stock at all in very brief periods of sleep. Going from an awake state to sleep is often subject to lots of disturbances for many people (central apneas come to mind especially). As for last night, it is a bit worse than previous nights, although your overall AHI isn't poor. The thing that's worse is your PTB, and higher pressure could have an exacerbating effect.
If you decide you want to try min EPAP=9 before going lower, I won't argue against it. Trial and error is the name of the game, and since we have very limited data with which to work, I wouldn't call it a wrong approach per se. (A blind man
will hit a bullseye if he throws enough darts.) However, I would urge you to log at least a day or two more at your current settings unless you're totally miserable. AHI across nights is often highly variable for many of us. Even putting aside the argument that it takes our bodies a little time to acclimate to new settings, it's really hard to figure out your "true" AHI at a given set of settings with only a couple nights of data.