Changed my pressure to a flat 4 for a test

I almost wish I hadn't tried this, but it's worth knowing, I guess. I'm sure every night is probably different.

After a couple of months using my machine for 4-8 hours/night, and tweaking inching my low pressure eventually to 8 (to be closer to the 9-10 that I consistently see it raising me to) with 0-2 apneas/hour nightly, I decided to see how many apneas I'd have at the lowest pressure. I mostly wanted to know because my 1-night home sleep study prior to getting a prescription was a terribly fitful night mostly on my back (which was normal at that time), and now I'm trying to sleep on my side more, so I wanted to test the lowest pressure while sleeping only on my side. The sleep study logged me at 30-something apneas/hour but was not a good sample night at all.

I slept for 4 hours without changing position at a set pressure of 4 and I had 1.7 apneas/hour. Huh?

I often sleep without changing position now that I use this body pillow and have figured out the best arrangement for my head pillow, tube, atms, etc. Yet the pressure always adjusts up to between 9 and 11 during the night (latest minimum was set to 8 and has been for over a month). I never had it show lower than 9 when viewing my morning sleep report (from machine) and I'm still a bit too overwhelmed to make time read and decipher the Sleepyhead graphs. My quality of sleep seemed the same as always, which is fairly decent sleep.

I guess I will keep using the machine as I had been as I can't imagine that it'd raise my pressure for no good reason. I do not mind sleeping with it at all, except that I often take it off after 4 or so hours of sleep without realizing it. Maybe one day I can afford an overnight sleep study at the sleep lab.

Has another reader had a similar experience? It is confusing me.

It may be increasing the pressure because of Flow Limitations or snores which are early signs that the airway is trying to collapse.
There's more to cause the machine to increase the pressure than the OAs and hyponeas and the auto adjusting algorithm is fairly complex.

Look at your Flow Limitation graph at 4 cm pressure and compare it to when the machine goes to 8 or 9.

Oh, thank you, Pugsy. I will look at that when I get home.

Luv wrote: ↑

Sun Dec 09, 2018 12:24 pm

a set pressure of 4 and I had 1.7 apneas/hour. Huh?

There's more to sleep disordered breathing than just apneas and hypopneas...

https://www.youtube.com/watch?v=-gie2dhqP2c

All those things disturb your sleep, so all those things cause pressure to go up,

But only some of those things count in the AHI...

That was a very helpful video. Thank you, palerider.