After weight loss, I no longer have many obstructive apneas as I did some years ago, but I do have some centrals. In particular, I seem to go into periodic breathing during REM sleep. This doesn't cause significant O2 desaturations, but I wake up feeling pretty beat up and unrested, and that's the only abnormality I can see.
I have a tendency to hyperventilate as well during REM, with the breathing rate getting shallower and faster; I'll often wake up sweating in the middle of a dream, and the cpap data will show I had been hyperventilating for awhile. Actually, the better part of a decade ago I had to quit bilevel therapy because it would induce rapid-deep breathing and give me extreme hyperventilation, 30 deep breaths per minute.
Just lately I've acquired a bipap Auto/SV to see if it might enable me to smooth out the periodic breathing... which isn't dramatic but is very visible as a waxing/waning pattern...to see if that might allow me more IQ points in the daytime. And clearly it did smooth out the PB flow on the first few nights I used it. And it does not drive me into hyperventilation like a regular bipap will.
But after a few days it seems as though the algorithm is now just adding pressure support to every breath, whether there is PB or not. This makes for a very high pressure if a high max PS is set, and doesn't even out the PB.
So I am now trying PS set to Min:0 and Max:3, just to keep from getting discomfort and mask leaks from a lot of pressure support I don't need. But it isn't compensating for the PB. Any thoughts from you periodic breathing experts out there?
thanks