AHI's way too high

[Grizz48]

Started on CPAP about 17 months ago. A very old sleep study data was used initially, and the setting was way too high (20) and was uncomfortable. My last sleep study was a couple of days before Thanksgiving, about 6 months ago, and they recommended a setting of 13. Then started with a ResMed S8 Elite II Autoset, Mirage Quattro FF mask. I use the FF mask because my mouth opens when sleeping. AHI numbers were good when in CPAP mode at 13 pressure. Switched to APAP mode at 11-16 pressure, good AHI numbers, so started bringing it down gradually every other week, getting down to 9-16. Left it there, AHI numbers were good at <5 with an occasional spike to 7-8. Sleeping was good. The pressure normally goes up to a nightly max of 11.8-12.8 in automode. Was there for a couple of months, and then AHI's began to go up drastically. Increased the APAP to 10-16 for a week, same result, then 11-16 for a week, same high result. Most nights AHI are now in the mid teens, but with a couple of nights at almost 30. !! Mostly hypops, maybe an AI once a night. However, sometimes I do see multiple AI's all in a row, usually an hour before I get up. Feeling lousy now, yawning and somewhat sleepy during the day.

What happened to get my AHI's way up there, and what can I do about it? I just reset my machine to 13-16, thinking maybe I need a little higher pressure all the time to prevent the hypops and occasional AI. Sound like the thing to do? What's with the occasional run of multiple AI's about once a week just before I get up? There will be 8-15 of them within a half hour, ranging from 11-16 seconds each.

Also, on the AHI graph (ResMed software) I always see a sawtooth effect, where the AHI will start at 0, then gradually increase for about an hour, then suddenly fall back to 0. It'll go as high as 25 sometimes, usually 15-20 though. What does that mean? When the sudden drop occurs, I see no corresponding event in any of the other data.

Thanks very much in advance for any wisdom anybody can offer. This is my first post, but I've been lurking, reading and learning, for a while.

[echo]

You might want to check back with your sleep lab, if you have eliminated all other causes, like for example leaks. Also...
Have you gained weight, changed/started/stopped any medication, or altered your sleep/life style in other ways?
Have you started sleeping on your back more?
Did they note any central apnea's during your PSG or at either titration?

The sawtooth effect is because it adds up the events per hour and then resets at the start of the hour (although I don't have that particular piece of software, that's what I've gathered from reading here).

Welcome to the Forum!

[wjp]

The fact that you are getting a big number in the last half hour before you get up may mean you are actually not sleeping. I have similar patterns of high HI's when I'm going to sleep, and again in the morning when I'm really awake, but still trying to get another couple of winks.

When you are awake your breathing is much less regular and uneven than when you are asleep. If you are lying in bed awake and breathing irregularly, the machine will not be able to do anything about it, but will still report it as an HI event.

[Grizz48]

Nothing changed as far as weight, meds, sleep habits, etc. Bumped the pressure up to 13 last night, this AM the AHI was 14.6, way too high. Leaks are usually between .08 and .24, is that too high? I'll give the increased pressure a few more nights and see if anything improves.