Idiopathic CSA on ASV & sudden O₂ drops – ring glitch or body freak‑out?

[icipher]

Hey folks,

I’m hoping the hive mind can help make sense of a couple of odd nights. I’m a 42‑year‑old guy with idiopathic central sleep apnea. I’ve been on a ASV(resmed) for about a dozen years and generally run an AHI near zero with barely any leak. I also wear a Wellue O2Ring every night to check my oxygen levels; for the past year it’s been boringly perfect – almost no time under 90 % and fewer than 10 drops over 3 % on any given night.

Then, on December 10th, everything went sideways. I woke up feeling like a zombie, checked the O2Ring app, and saw:

125 drops over 3 %

21 minutes below 90 %

Lowest saturation 87 %

For context, my ASV data for that night showed AHI 0.13 with AI 0.00, HI 0.00, CAI 0.00 and UAI 0.13. Leak median was ~3.6 L/min and 95th percentile 6 L/min, pressure stayed in its usual range, and the machine didn’t score any apneas or hypopneas. My sleep tech reviewed the graphs and could only point to one modest leak blip around 2 AM; otherwise the night looked clean. I hadn’t been drinking, I wasn’t sick, and I even changed the filter and hoses last month.

Night 2 (Dec 11) was almost back to normal: average SpO₂ 96 %, only 37 seconds under 90 %, but still 77 drops over 3 %, when historically I ALWAYS have under 10. I typically don’t even hit 10. Again the ASV report was unremarkable (AHI 0.13, only hypopneas).

A few extra bits of context:

Diagnosed idiopathic central apnea ~12 years ago, stable since.

No obvious neuromuscular or cardiac disease, and I’m in decent shape.

I’d love to hear from other central apnea patients on ASV:

Have you seen occasional nights with weirdly high desat counts even though the ASV and AHI look normal?

Did anyone’s O₂ ring or pulse oximeter start overcounting drops after a while? Did sampling rate or finger perfusion play a role? I tried my ring while awake it it seems perfect. Shows 96% saturation. It's only 2 months old.

If you’ve had single “bad” nights like this, did they turn into a pattern or just stay one‑off blips?

I’m not looking for a diagnosis – just trying to figure out whether to chalk this up to sensor noise/leak, or whether I should be pushing my sleep doc for more testing. Any insights (or reassurance that I’m not the only one) would be awesome.

Thanks in advance.

[ChicagoGranny]

Night 2 (Dec 11) was almost back to normal: average SpO₂ 96 %, only 37 seconds under 90 %, but still 77 drops over 3 %, when historically I ALWAYS have under 10.

How do you grade your day of December 11? Energetic? Any excess sleepiness? At bedtime on the 11th - fatigued but not stressed?

Same questions for when today (12th) ends.

just trying to figure out whether to chalk this up to sensor noise/leak, or whether I should be pushing my sleep doc for more testing

Personally, I would want to see at least a week of bad days before involving the medical profession.

[icipher]

Night 2 (Dec 11) was almost back to normal: average SpO₂ 96 %, only 37 seconds under 90 %, but still 77 drops over 3 %, when historically I ALWAYS have under 10.

How do you grade your day of December 11? Energetic? Any excess sleepiness? At bedtime on the 11th - fatigued but not stressed?

Same questions for when today (12th) ends.

just trying to figure out whether to chalk this up to sensor noise/leak, or whether I should be pushing my sleep doc for more testing

Personally, I would want to see at least a week of bad days before involving the medical profession.

First day I definitely felt unrested when I woke up which is not typical. I typically feel well rested and ready to start the day. This morning which was day 2, I felt mostly normal. I am still just flabbergasted why my O2 ring shows over 1000% uptick in desaturations compared to historical data I have over the last year.

[ChicagoGranny]

I am still just flabbergasted why my O2 ring shows over 1000% uptick in desaturations compared to historical data I have over the last year.

I'm suspicious of the accuracy of your O2 data.

My sleep tech reviewed the graphs

If you use a free account at SleepHQ.com, our members can do just as well, or better, as your tech. You won't need to leave the house.

First day I definitely felt unrested when I woke up which is not typical. I typically feel well rested and ready to start the day. This morning which was day 2, I felt mostly normal.

It's best to judge your sleep at the end of the day. There are things that can make a person feel bad upon awakening that have little to do with the overall quantity and quality of sleep.

I hadn’t been drinking

Why not?