Stopped Being Able to Fall Asleep

[MisterClean]

Back in 2013 I was diagnosed with complex sleep apnea and given a PR DS960 ASV machine. I never could get used to it--especially it forcing breaths as I tried to fall asleep--but since I had stopped taking a medication that could have been causing my centrals a couple years ago this spring my doc ordered another sleep study. It was determined that I could go with a conventional BiPAP, and I wound up purchasing a gently used ResMed S9 VPAP Auto. Settings were 13/9, but with my doctor's blessing I have put it into Auto mode.

Here's the thing: For the first 2-3 weeks I was using the machine I was able to do something I could NEVER have done with the 960--fall asleep and, more or less, maintain sleep. I was getting 4-5-even 6 hours on the mask at night. And feeling 10X better during the day. Then, about a week ago, the bottom fell out. I'm hardly able to fall asleep with the machine at night and even when I do nod off, I wake up within like 30 minutes. It's awful.

Looking at the SH analysis, I've definitely been having more centrals. One reason may be that I had PS set to 2.4 and my doctor didn't like it. She said that PS should ideally be 4.0 and I should work up to that level. Also, I began to feel like I wasn't getting enough air at night so I increased the starting EPAP from like 4.4 to like 5.0. (I've tried it as high as 6.0.) I also reduced the ramp time from 30 minutes down to 5 or 10. Actually, recently I tried simply not using the ramp mostly because the S9 doesn't provide data on events while the ramp is active. Anyway, maybe I'm triggering more centrals by the higher pressure--and these are impacting my being able to fall asleep?

One other confounding feature is that when I first started on the machine I was on a trial of gabapentin, 300 mg morning and night. I got off of it due to side effects, the most pressing being daytime sleepiness. It will be quite ironic if the med that was making me miserably tired during the day was also allowing me to fall asleep on the machine at night! Before someone asks, and it's a logical question, it seems to be I was off of the gabapentin for the better part of a week BEFORE I started having trouble sleeping at night, but maybe it's still related?

One final thing: I realize that without the ramp I might also be feeling the FOT mechanism if I'm having even a short central while falling asleep. For that reason I suppose I should always be using the ramp. But even with the ramp I'm no longer falling asleep. I have literally tried for 3 hours before finally giving up and sleeping mask-less. This is so discouraging when, at least for the first two weeks, I was doing so well at night.

Any ideas or advice?

[Pugsy]

When did you work up to the PS of 4?
Have you seen a correlation between the number of centrals and the increasing of the PS from the 2.4 to the 4?

Some people will have centrals pop up with bilevel pressures and the greater the difference the more the centrals....even at relatively low PS.
I know one person who has a truck load of centrals with PS of 4 and essentially none with PS of 3 with all other settings being unchanged.

The centrals could be causing arousals and thus preventing you from progressing on into full sleep.

[MisterClean]

Thanks for responding, Pugsy. As I raised the PS beyond about 3.0 up to a high of 4.2, I began to have many more centrals. (When at 2.4 my AHI was often under 2.00, had two nights at 0.0!) When in the mid 3's I was seeing AHI's of 7, 11, 12. Mostly made of centrals, of course. It's not a perfect correlation: I had a couple of nights at higher PS when my AHI was lower, like under 5.0.

So maybe PS is the key? Unfortunately, I have discovered that the machine is more comfortable at higher levels of PS. Which is why they make machines with backup and machines like my old ASV, of course, but I really don't want to contemplate that.

Maybe I should try keeping the PS back at 2.4 or 2.6 with enough ramp that I don't feel any FOT waves and see how it goes? It's so frustrating to be sleeping well for the first time in years and then have it stop.

[Pugsy]

Maybe I should try keeping the PS back at 2.4 or 2.6 with enough ramp that I don't feel any FOT waves and see how it goes?

Worth trying. That's what I would be doing if it were me. Gotta get to sleep first and foremost.

[MisterClean]

Thank you, Pugsy. After making the changes we discussed things are much improved. I made it almost 5 hours last night. Much better night and feel much better during the day. Now I just need to get a better mask. What I use isn't awful but I'm aware that over the past 4-5 years there are new options.

Greg