2 nights ago I was woken at 6:04am by an arousal, and felt the need to switch from my right side to my left side. I confirmed this for my records with 5 quick sniffs followed by 4 more (easily seen on a Flow Rate chart).
Just 70 seconds later I was awoken (not from real sleep, I suspect) by an oximeter vibration because my SpO2 had dropped to 89%. I was on my left side with my left wrist (the one with the oximeter on) hanging slightly off the bed and my right arm was across it. I lifted my right arm off it and then lifted my left wrist in the air, and the vibration stopped and SpO2 immediately jumped to 98%!
I thought this odd so, after about 3 minutes, I deliberately put my left wrist back hanging off the bed. That didn't seem to cause a vibration (though it looks like O2 did drop a lot). After mulling that over for another few minutes, I put my left wrist back hanging off the bed and laid my right arm across it. In less than a minute, the oximeter vibrated again!
I repeated this again and got the same result - and decided it was time to get up.
When I got all the data from the CPAP and the oximeter and SomnoPose into Oscar (see attached chart showing the most relevant clips), I realised the situation was even more complex than I thought. During this 20 minute episode, the ResMed 10 said I had NINE CA's (something I don't often get actually). I suspect none of these were real, especially as I was mostly awake during this time.
So is the oximeter really telling the truth about my body being short of oxygen, or is it just responding erroneously to a slightly cut-off blood supply to that hand?

Here is an expanded view of the first CA.
