Decreased pressure and OSAs

[Omne]

Still being a newbie I'm curious about something. How often does decreased pressure cause decreased OSAs?
The reason I ask is that last night I started at a fixed 11 and my OSAs went higher than normal for me. I got up for something and noticed the higher than normal AHI so I dropped the machine to a fixed 10 to see what would happen. Over the next couple of hours my OSAs and AHI dropped. CAs effectively didn't change, hypopneas stayed pretty much the same too. The only other change was that I had C-flex on set at 1 at the 11 and turned it off at 10.

I know it's only one night and might not mean anything but it still caught my attention because it seemed odd based on what I've been reading on here.

[Pugsy]

The lower AHI may not have been related to the pressure change at all.
It might have simply been related to the "we don't sleep the same each night".
I doubt that such a small change in Flex would account for it.
Perhaps related to sleeping position or perhaps REM stage sleep. Your first image shows some clustering that closely responds to when we would normally expect to see some REM stage sleep...and perhaps you simply didn't get any REM during that second image.
Sleeping position can do the same thing.

Given the pattern involved...my first suspect would be REM sleep and you just didn't get back into REM during that second image or the time was very brief for some reason.

It's common for OSA to be worse in REM (I have it 5 times worse in REM than in non REM). Same thing for supine sleeping though for me there never seemed to be much of a difference in pressure needs when supine vs side sleeping but there sure was for REM sleep.

[Omne]

Sounds good, thanks Pugsy.

Sometimes it takes a while to be able to recognize what's significant and what isn't.

[palerider]

Sounds good, thanks Pugsy.

Sometimes it takes a while to be able to recognize what's significant and what isn't.

I was going to say "never" in answer to your question, that it's not the pressure that made the difference, it was the gloopy meat bag on the end of the hose that's different, but I see Pugsy already said it, albeit in a much better way

as you get more experience, you'll realize that your sleep varies not only from night to night but during the night as well, of course, you can see this on an auto machine, as the pressure goes up and down during the night in response to how what's happening to you.

that's the main reason that when you're fine tuning your therapy, you leave things alone for a week, and see what the average is... it's also one of the worst problems with sleep studies and titration studies. they may wire you up, and then spend the night dinking with pressure, and in the end, say "you slept best at 9cm pressure".... (for a whole 32 minutes) read enough titration reports, and you'll be shaking your head.

[Omne]

it was the gloopy meat bag on the end of the hose

Aww that's so sweet....

that's the main reason that when you're fine tuning your therapy, you leave things alone for a week, and see what the average is... it's also one of the worst problems with sleep studies and titration studies. they may wire you up, and then spend the night dinking with pressure, and in the end, say "you slept best at 9cm pressure".... (for a whole 32 minutes) read enough titration reports, and you'll be shaking your head.

When they did my study they decided that a fixed 7 was best, the AHI was 9.5. When I got set up at home at 7 my AHI jumped to 20+ and hung around in double digits until I went to auto. I was shaking my head just reading mine.

For some reason my Dr. had them remotely switch it to a fixed 10 about a week ago. I let it run and it's been around 5-7 with not a lot of improvement in how I feel. I'm going try switching back to auto tonight with a 10 min and see how it goes.

[Pugsy]

You know they didn't get it right at my titration sleep study either. I came out of there with a RX for 8 and it works okay for everything but REM sleep and it's woefully inadequate for REM.
To be fair I suppose I have to mention that I only got 6 minutes of REM during my titration study....I had a horrible time falling asleep and staying asleep partly due to meds and partly due to the idiot tech.
So it didn't come as a big surprise once I got home and in my own routine and actually got some sleep where I went into REM that my pressure needs changed a lot.

Something similar may have happened to you at your titration study.

[70sSanO]

If you have an auto machine, you can set it with a tight range of 9-12 and just monitor the data over a period of time. Over the years I've done a lot of minor pressure tweaks on a straight CPAP machine, but with an APAP you really don't have to guess.

John