Struggling

Dear Forum,

DreamStation Auto BiPAP with full face mask (just switched yesterday to nasal pillow), pressures 22 and 14
I have 43 days of data now.
I live in the mountains at 7000 feet elevation (~2130m)
Average AHI over that 43-day period: 21
The figures from Sleepyhead attached here show a typical night, with a zoom in to a particular time interval for that same night just to show traces associated with typical events.
Conclusion: My sleep appears to be broken.
Questions: 1) Is there anything in these data images that suggests the many clear airway events may be artifacts of leaks or other equipment anomalies? I don't think so, because they appear in consistent intervals, and there do not appear to be any serious leaks. 2) What should I try to lower my AHI?

Thanks

Welcome to the forum.

How did you come by using these particular settings?

The huge ps is quite possibly exacerbating the centrals.

The settings were prescribed by the sleep lab that evaluated me. He told me he tried CPAP but that didn't work so shifted to Bi-level. Then he said he kept ramping up the pressure until he found a pressure setting that seemed to help. I wonder, should I be re-tested? Or try adjusting the pressures myself?

Your PS or pressure support (the difference between IPAP...inhale and EPAP exhale...is 8 cm.
That's almost guaranteed to induce/trigger central apneas because it causes too much carbon dioxide to be blown off and the blood levels for carbon dioxide don't get up the level for the brain to trigger the breathing reflex. It's actually carbon dioxide levels getting to a certain point that trigger the breathe reflex....has nothing to do with oxygen levels.

So it's very possible that it's the high PS causing the centrals. Not guaranteed but very suspicious and that would be the first thing I would alter if it were me. Cut it in half...to maybe 4 cm or maybe even lower if that doesn't help.

So if staying with fixed bilevel...14 EPAP and 18 IPAP.
Or go over to auto bilevel mode....14 EPAP PS minimum 4 and maximum of 4 with max IPAP 25 which will allow the pressure to go up should it need to go up to deal with the obstructive/hyponea stuff.

Now it's entirely possible that PS has nothing to do with the centrals but it is a logical experiment to try and won't hurt to try.
Some people get centrals triggered no matter what the pressure might be but sometimes people get lucky and it's simply a matter of reducing PS that fixes the problem.
I have a friend who has centrals like you are having with a PS of 4 but not with a PS of 3. Go figure that one but I have seen the reports to prove it. She needs PS to help with her high pressures but she's good with PS of 3 and her centrals stay below 1 per hour average with 3 PS.

Thanks very much for the suggestion! I will give it a try.