Curiously, last night I tested the CPAP with the ramp still off, pressure at 9cm fixed and I lowered the EPR from 3 to 1. Breathing seemed more labored (I expected that and that probably would take a little while for the lungs to get used to pushing out air against more pressure) since it wasn't lowering as much upon exhale. However, I also wanted to see what it would do for how I felt the next day. I did feel more energetic today, but I also got a full 8 hours last night with the mask on, which is rare in itself and I'm still working on that. That's probably why. However, lots of events last night. 3 CA events and 6 obstructives. It felt like the EPR being set down was actually pushing the soft palate in my throat somehow and causing me to have more blockages, so that's kind of odd. Since I was a kid, I have always had this thing where I can blow air out of my nose and if I do it hard enough, it is like my soft palate blows up and causes a blockage of the air trying to escape from the throat to the sinuses. So that may just be something odd with my soft palate being a little larger or extended somehow. It puzzles me now why setting my EPR down lower actually causes more CA, obstructives and hypopneas.
I think the higher pressure must be causing CA events simply because more air is blowing to the point where the exhaled air with CO2 doesn't have as much of a chance to escape before being bumped out of the way with new air to inhale; so more CO2 is breathe in again than normal, potentially causing central apneas. At least, I speculate. Could be wrong.
I don't know why, but I actually have gotten so used to the pressure now that I feel good simply starting at full pressure and staying at it without using autoramp at all. My last "best" results so far on no ramp CPAP mode were at 9cm with EPR of 3. I had 1 obstructive, 2 centrals and one hypopnea for the whole night.
Every central event that I looked at, the breathing got slower and the chart measurement got lower until it virtually flatlined and then I started back breathing normally again and it went back up. In spite of the in-lab study (2.75 hours) and home sleep study (6 hours) saying that I didn't have central apnea, sometimes I think I might have just a touch of it on top of OSA. What I'm seeing on my nightly charts looks like legitimate CAs even down to the seconds where it just drops off and I stop breathing and start again. Yet there's only about 3 or 4 of them even on a bad night. I could lower the pressure from 9cm, but that's what is required to get my AHI down as long as it was between 0.5 and 1 on a typically decent night. Adjusting the pressure down to 8 would likely cause more OA events and maybe even centrals, so it is all a bit confusing and almost seems backwards in my case.
I'm attaching a quick grab of one of the CA events from last night. Definitely looks like a real central event to me. Also, before the one that was marked by the machine...I see one that wasn't marked by the machine and wasn't quite as pronounced, so it didn't label it CA.