Oximeter feedback

[dataq1]

Are there no xPaP machines that use oximetry as the response to titrate against?
It would seem to me that blood desaturation is a much more effective method to detect apnea or hypopnea.
Is it possible to have apnea without desaturation?

[blarg]

My AHI for the sleep study was 37, yet my lowest O2 was 84%. Average was definitely > 90. My apneas and hypopneas are short in duration, yet they were obviously disturbing my sleep. I think by the time the oximeter picks it up you've already had your arousal in general.

[GoofyUT]

Besides, most oximeters, even the best with the most sophisticated signal processing, are LOADED with artifacts from patient movement, and other factors. Most allow some data smoothing before they alarm, but by the time the data smoothing algorithm takes effect, the flow degradations noted by auto-titrating PAPs will already invoke titrations, I believe. Or else, the APAP would be chasing its tail all night long following those artifacts, and would drive you NUTS!!! However, it WOULD be nice to note oximetry data in the detail data reported by data-capable PAPs. Many events scored as hypopneas may have NO desats associated and are, therefore, clincially insignificant. I know that resMed's RESLINK includes this capability. And, I know that DSM has been working on this problem. You might wish to correspond with him.

Cheers!

Chuck

[dataq1]

Hi blarg,
the average 02 is not as meaningful as the instantanous O2 level. Generally the sleep docs draw the line at 88%, anything below that point requires intervention. Actually the blood saturation reacts amazingly fast.
I've tried experiments and from a baseline of 96%, cessation of breathing for 20 seconds results in desaturation to 90% within the 30 seconds of the initial cessation. Resaturation takes a bit longer, so that another 20 second breathing cessation tends to drop the saturation level to 88%.

Of course this is just my body response when using an oximeter with a 4 second update rate.