Nope. Never figured out why I felt so good with the 10.2 AHI and it only happened once.
It was a fluke night. At that time my AHI was averaging 3 to 5 each night. I as about 4 months into therapy. I figured I just slept better and was never able to duplicate it at least with a high AHI.
I have other issues that mess with my sleep quality that the machine can't fix...so I know first hand that sometimes the numbers don't always mean we feel good or sleep good.
Your machine isn't increasing the pressure much because you don't need much to hold the airway open (count your blessings on that one) and you aren't having the usual stuff that precedes the airway collapsing that the machine will want to fight.
If I were going to use a fixed bilevel pressure under your circumstances I would pick something that is simply comfortable in terms of PS and a modest setting.
Try maybe 6 EPAP....PS of 4 and IPAP of 10 and see how you sleep and feel. The extra IPAP would help out somewhat with the collapsing of the airway. I don't really think your centrals are from the PS but if they are we can reduce PS. I think your centrals are probably SWJ not real centrals from poor sleep.
You really need to pick settings that let you sleep good and feel good and give them a chance with a fairly long term trial instead of worrying so much about the AHI. Let your body tell you if it is feeling good or not.
Give your body a chance to adjust to the settings and the AHI might just take care of itself once your body gets more used to things.
There is some truth to the "give it time" thing.
When I first started on bilevel pressures I found I like PS of 4 the best...really was comfortable for me and with the machine I had at the time it defaulted to 2 cm PS and I couldn't change it in auto mode. Not the same now but back then that was the way it had to be so I opted for fixed bilevel pressures because I liked 4 PS so much.
I picked some settings that worked at least part of the time...I think it was 8 EPAP and 12 IPAP with PS of 4 in fixed mode. I was getting AHI around 4 to 5...not great but acceptable and I felt decent enough. I made a promise to myself to leave it alone for 6 weeks as long as I was sleeping decently and feeling decent no matter what the AHI showed.
At first it varied quite a bit with sometimes the AHI being 6 to 7 and sometimes being 1 to 2...
But gradually the higher AHI numbers came less frequently and the lower numbers came more frequently. At the end of the 6 weeks experiment I was sleeping an average of 45 minutes longer and the AHI was averaging around 2 ish. More importantly...I was sleeping decent and feeling decent.
I still have times where the AHI flares up for whatever reason but I just chalk it up to a fluke night and don't worry about it.
My primary goal has always been....feel like I sleep decently and feel decent during the day and I don't really care what the AHI shows.
The best most perfect AHI in the world doesn't guarantee that you feel it....and I want to feel good during the day.
That's the most important thing to me.
Now some people say they can notice a big difference in how they sleep and feel with very slight differences in AHI...usually lower AHI means they feel better but not everyone says that. RobySue always said she felt better with an AHI of 3 ish than with 1 ish for some reason. Me...I have never really been able to tell the difference one way or another...obviously if 10.2 gives me an awesome superwoman day.
So I let my body dictate my settings and not the other way around. I ask myself what is my primary goal here....is it a good math score or sleep better and feel better?
This cpap stuff all comes with a huge YMMV sticker and part of the process is figuring out where YOU stand in things. Not what someone else needs but what you need to feel better.
I don't know why some people feel better with slightly higher numbers than others. About all I can surmise is they sleep better...get better more complete sleep cycles despite a few apnea events than others.
You will find that here people tend to recommend what works well for them because that's really all they know to offer.
It's human nature but you might be a little different than they are in some respects that we simply don't understand how or why it happens.
For me I learned that it wasn't so much the AHI that mattered in how I felt during the day....for me it was the hours of sleep that I was able to get and with bilevel I averaged 45 min to an hour more for some reason. Never could figure out why but I just slept better and longer when I used pressure support than when I didn't. Right now I am using PS of 3 on the ResMed AutoSet because that's all I can get with EPR.....I would really prefer PS of 4 but I wanted to try the new for Her AutoSet and I knew I was limited with PS of 3/EPR at 3.
It's good enough...not perfect but close enough that I am okay with it. One of these days I will get the bilevel model and go back to 4 PS because that's what feels perfect for me.
I have been at this cpap stuff for over 9 years now. I have tried LOTS of different things to see what helps me and what doesn't help me.
I have learned what my body needs or wants but it took lots of experiments to get to this point.
So ask yourself...what is your primary goal? If you are like me it will be sleeping good and feeling good and to hell with the numbers.
Other people need good "numbers" and that's okay too.
I did learn that with time that the numbers actually fell more into place when I gave things time. It takes a lot of time sometimes though and it's really hard to not fiddle with the settings when we have an off night and an off day the next day.
The most important lesson that I learned though was that experiment with the 6 weeks at fixed pressure...and I had some really ugly nights mixed in there. Took all my will power to stick with the original plan...which was pick something that I knew could let me sleep good and feel good and ride it out through the nights where it didn't. We can't do a damn thing about last night...it's gone and done with. If we continually change things based on last night we never give the body a chance to adjust to anything and there is a lot of truth to giving it time to adjust.
I may have to RISE but I refuse to SHINE.