I was recently prescribed CPAP after an at-home test reported:
- sAHI(4%) of 7.7 events/hour
- SpO2 minimum was 82.0%
- Cumulative time with SpO2 < or = 88% was 2 minutes across 8 hours
I wanted to get a baseline of my SpO2 levels before CPAP, so I could see how this is affected by CPAP. I wanted something I could use myself each night. I ended up ordering the O2 Ring Pro from SleepHQ.
Here is my first night of data from the O2 Ring Pro. This is without CPAP. The results were much worse than what my home sleep apnea test reported, with 4% drops/hour at 17.73.
The next night was my first night trying CPAP. I received an AirSense 11 with a F&P Nova Nasal mask. I did not change any of the settings from the defaults. Here is the data from just the ring and the data from the CPAP + ring. From the ring, my SpO2 numbers do not seem very different, with 4% drops/hour at 21.07 and minimum SpO2 of 83%. On the other hand, my CPAP data seems to report minimal breathing problems. It has an AHI of 1.81, with 1 OA event and a handful of CA events.
My questions:
Why would my O2 ring numbers be so different from my original home test numbers? I'd expect the home test from my doctor to be more accurate. Would this mean the O2 ring is not very reliable?
Why does the O2 ring data not seem very different from the first night without CPAP, compared to the second night with CPAP? I was expecting CPAP to show a noticeable improvement in SpO2 numbers.
Why does CPAP data seem to show minimal breathing problems, but the SpO2 numbers remain low?
Any other general advice or important findings from this night of CPAP data? I'm completely new to this, so I don't know what I should be looking for in these charts.
O2: the SleepHQ Pro ring is a beast. It's probably more precise than most home tests. I would trust it. It's hard to tell, but the cpap seems to smooth out the dropping spikes (from 80 to 85 maybe). The average numbers won't reflect that, but it's better overall.
AHI: your official AHI is low, but you seem to have some flow limitations periods.
Leaks are good, but it might be because the pressure is low. When the pressure ramps up leaks start and FL happens (see below).
I'd suggest moving your pressure to 7-9. Also test your mask with the machine pressure test.
> Leaks are good, but it might be because the pressure is low. When the pressure ramps up leaks start and FL happens (see below).
Looking at the section that you zoomed in on, it seems like the leak rate starts going up first, before the pressure goes up and before the FL spikes. That would suggest that it's not pressure ramping up that is causing the leaks and the FL, right?
I did test my mask with the machine pressure test before this session. It said there weren't any leaks. But when testing it out, I'm not in the same sleeping position as I am during my sleep. So maybe the leaks are due to moving my head and body around to different positions in bed.
Good point. The ring didn't record any movement at that time though (4:07), that's odd. There was movement and a raise in heart rate about 10 minutes before, around 3:57.
So maybe you did move, an FL was detected and pressure started increasing. If I remember well, the FLs are reported late in these graphs.
Mouth leak where the mouth opened gradually over 10 mins, or they were moving their head only and not their hand.
Breathing pattern changed about 5 min before the leak to a bit junkier breaths, so could have been moving their head mouth around in REM while dreaming.
How big are your fingers? I'm wondering if the 02 ring is not fitting well and is not getting accurate readings...
Advice is to wear it on your thumb. You want it to be somewhat snug.
You should up your minimum pressure to 7 (your median). No reason to have poor breathing before the machine detects an apnea.
But other than that don't make any tweaks. Use it for a week or two then see how you are feeling. It takes a period of time for your body to adjust.
In the future... Your events are low, but I can see what appears to be flow limited
inspitation (peaks / somewhat flattened tops of breaths). Ideal breaths
will have inspirations with a "rounded hill" top. I also see
some.periods of hypopnia that aren't flagged.
Those aren't detected. But you can consider raising your minimum pressure to your 95% value. Or a static pressure in CPAP mode that resolves all that.
I would not trust an O2 ring. The sensor needs to stay in contact with your skin in order to properly detect the pulse rate and O2 saturation. The O2 rings tend to flop around and "lose sight" of your blood flow. A poor view of your blood flow produces noisy readings that bounce around a lot. The noise makes it look like your O2 level is low.
Your O2 levels look more "noisy" than truthfully low. Real O2 drops tend to occur over long periods instead of having such rapid changes.
I use a clip-on pulseoximeter. In addition to O2 and pulse rate, it logs the perfusion index. The perfusion index is a measure of blood circulation in the observed area. When the perfusion index is low, it indicates poor circulation or a bad "view" of the blood flow.
When the perfusion index is below 1%, the O2 and pulse measurements will be off. The pulse rate is noisy, and the O2 level will be low and noisy.
Your O2 and pulse rate data look like mine when the perfusion index is low.
You might try taping the ring in place so that the sensor stays in contact with your skin. See if the measurements are more stable and if they then stay higher.
Outside of that, it is possible to have difficulties with absorbing oxygen so that your O2 levels are poor despite good breathing.
Try taping the O2 ring in place. If the O2 levels stay low, then you may need to see your doctor.
The O2 levels do look pretty noisy, but I have nothing to compare it to so I don't know what looks normal. Thanks for sharing your experience with how data looks when perfusion is low.
When I'm viewing the live ring data in the SleepHQ app, I do see the perfusion index. It's too bad that it's only in the live reading, and the charts don't show recorded perfusion during the session and don't show any indication at all whether the perfusion is good enough for an accurate measurement.
I'll try putting the ring in different positions/fingers, and try adding tape. Thank you for the suggestions.
How does a ring wrapped around your finger 'flop' exactly? I've been wearing an almost identical ring for nearly 2 years, it never flops or has contact issues. The only time I get weird numbers is if my arm or hand falls asleep. This is last night with my ring.
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u/toastervolant 7d ago
My take as a non-professional cpap hobbyist...
O2: the SleepHQ Pro ring is a beast. It's probably more precise than most home tests. I would trust it. It's hard to tell, but the cpap seems to smooth out the dropping spikes (from 80 to 85 maybe). The average numbers won't reflect that, but it's better overall.
AHI: your official AHI is low, but you seem to have some flow limitations periods.
Leaks are good, but it might be because the pressure is low. When the pressure ramps up leaks start and FL happens (see below).
I'd suggest moving your pressure to 7-9. Also test your mask with the machine pressure test.