Desaturating with CPAP despite low AHI

Hello All,

New to CPAP. Got diagnosed two years ago with a 15.6AHI and was offered a mouthpiece or CPAP to which I took the mouthpiece. 2 years later got a notification from my apple watch that my heart rate was dipping below 40 for 10+ minutes on several occasions. Brought it up to my doctor and she seemed to think I should get a CPAP. Did a battery of tests on heart and its fine, thankfully.

One month in and I'm actually sleeping much better but still not great. I have been tracking my sleep with a BioStrap https://shop.biostrap.com for 4-5 years as I was concerned about Apnea. Prior to the CPAP I would desaturate many nights down to the low to mid 80's on a least one occasion. These desaturations would last for 30-60 minutes at that level. The CPAP seems to have helped dramatically to reduce these, but last night I got down to 87% which was for almost 30 minutes. I'm perplexed of what may be causing this. Can anyone make any sense out of the data from the machine? I have noticed most nights I have a few clear airway events which I know are not uncommon. I had one right at this time, but only for 12 seconds not the 30 minute desaturation.


Its an Airsense 11 with a heated hose and humidifier. I'm using a Fisher / Paykel Vitre full face mask. It does leak a little around the nose, but its the best fit out of the 10 that Kaiser gave me.

Timing on the data is an hour off compared to the wearable data.

robt_sf wrote: ↑

Thu May 19, 2022 2:02 pm

Hello All,

welcome to the zoo! unfortunately, i don't have the answer. i'm here to advise you oscar data for your screenshot should be organized thusly-

Dog Slobber wrote: ↑

Thu Jun 04, 2020 6:21 am

To format graph positions:

{Menu} / View / Reset Graphs / Standard



To reset graph sizes:

{Menu} / View / Reset Graph Heights



Turning on and off the Pie Chart and Calendar are also conveniently located on the View menu.

what you've posted is too much and too tiny.

good luck!

I searched for a while to try to find out on the technology behind the Biostrap oximetry as IMO it looks absolutely incapable of producing the level of accuracy you're looking for. The sampling rate looks to be absurd and it may be severely affected by motion and/or light artifact.

IIWY I'd get one of the entry-level stand alone oximeters (like Wellvue O2Ring, or inquire what everybody' is getting for the best bang for their buck) and monitor that separately.

The Biostrap info page says

Using the RMSSD method, we measure the distance between successive heartbeats and use that data to calculate your RR-interval which is then used in producing your HRV, Oxygen Saturation and Respiratory Rate.

https://help.biostrap.com/support/solut ... lse-report

but I'm like how can that be.

Rubicon wrote: ↑

Fri May 20, 2022 4:48 am

one of the entry-level stand alone oximeters

Looks to me that prices are down to around 50 bucks these days for overnight recorders.

This might work if secured with blue tape:

https://www.amazon.com/dp/B07RKVDHXH/

lazarus wrote: ↑

Fri May 20, 2022 6:59 am

https://www.amazon.com/dp/B07RKVDHXH/

$39 today.

I paid $50.

Used it last night. Worked great.