My story: I did a sleep test and was prescribed CPAP 6 years ago (my wife had been complaining about stopping breathing and gasping, and my BP had risen significantly). I used the Resmed S8 (pressure level 7) faithfully, BP dropped, and doctor said things were good after sleep test a year later, so I carried on for 5 years. No real problems (that I knew of) but realized recently that I was long overdue for a retest and a new machine. New doctor downloaded data from my S8 and found I had average AHI of 21, made appointment for a new sleep test (not until December!!) and arranged for an APAP loaner for a month (an S9 with pressure range 7-14). Based on the results from the loaner he prescribed an Airsense 10 Autoset (also set 7-14). I looked at the summary data from the S9 in ResScan (it didn't save detailed info) and the AHI results were all over the place (from 0.4 to 16) but he said it was because leaks were high due to my old mask (up to 72 L/min) and not to worry. So I got the Airsense 10 but decided I would monitor things myself -- did some research, installed Sleepyhead, etc.
I have been using the new machine and mask for 3 weeks. Leak is much lower but the results are still all over the place (AHI from 1.4 to 19.6, average 7.29) and almost all of my events are CAs. I tried to link a screenshot from Sleepyhead of a recent night with AHI=14.5 but haven't posted 8 times yet, can send it if anyone is interested.
My statistics for that night were
Obstructive Index 1.47
Hypopnea Index 0.49
Clear Airway Index 12.59
I note in the Sleephead "By Pressure" chart that events increase rapidly with increased pressure (AHI=8.8 at pressure 7, 13 at 8, 35 at 9, 51 at 10, 75 at 11). Does this mean that the pressure increases to stop OAs are causing CAs? I have seen discussions of EPR causing CAs and my level is currently set to 3, would reducing that help maybe? Should I be pushing the doctor to try an ASV machine?
One more issue: My best nights in the last 3 weeks were 7 in a row while on a cruise in the Caribbean (AHI from 2 to 6). I did a lot of things that are supposed to be bad for apnea (eating and drinking late in the evening, irregular sleep hours, etc.) but for some reason the sleep environment (I assume) more than made up for it. I have been working on replicating the conditions -- significant white noise (from ship's loud air conditioner), darker and cooler room than I am used to, softer pillow, etc. but no real success so far (AHI= 9.4 last night). The only other things I can think of are (1) Unlike at home, I spent no time at all using a computer or tablet so will try that on the weekend (no exposure to blue light before bed, etc.). (2) My wife is a light sleeper and changes position often during the night. The king bed on the ship was bigger and much more solid than the queen we use at home, so maybe her restlessness is affecting my sleep. Any thoughts?
Details I didn't mention: male age 60, 5'8" and 185 pounds, no other medical problems.