pulse ox time to desat on apneas

[flylow]

For those of you with pulse ox equipment, I am wondering how long it takes on breath hold to see a drop in pulse ox. For example, does a ten second apnea (as recorded by my respironics) result in any drop in O2 pulse ox reading? And if so, what does it typically depress to?

[SingleMom]

This doesn't exactly answer your question, but my son has asthma. When we go to the Dr or hospital he has a habit of not taking deep breaths when doing pulse ox. Within a few seconds, it'll say he's down to 92 with his normal being 99. As soon as I tell him to breath it pops back up.

So it only takes a few seconds of not breathing to affect a reading.

[RipVW]

I think SingleMom is correct that it shouldn't take more than a few seconds, though I've never tried holding my breath while using my pusle oximeter. Perhaps some of our wise forum members can provide a definitive answer.

[mars]

Hi flylow

I just checked myself with my oximeter. The longest I can currently hold my breath is about 30 seconds, which produces very little movement on my oximeter. But I have discovered that the rate of desaturation varies depending on whether or not I hold my breath after breathing in, or breathing out, or halfway between in or out.

So when I have the machine on at night, I would think that any desaturation would depend on the initial amount of oxygen currently in the body, and the prescence or not of repeated events.

During the night, with the machine on and when I have the oximeter monitoring all night, I never desaturate. The machine does not prevent all apneas and hypopneas from starting, but it does prevent them from causing oxygen desaturation. So although I get an average AHi of 2.1 (including centrals), desaturation is not part of the equation, although a sleep disturbance may be.

Sometimes I can get clusters (which on my machine includes centrals), between 1 and 5 clusters over the night, but never desaturate.

When I nap sitting up, with my oximeter on, the alarm either goes off immediately (meaning I am getting clusters), or I can snooze for up to about an hour with no alarm going off, and get a refreshing sleep.

But I do not know what circumstances predispose me one way or the other.

I think it is time all machines were fitted with an oximeter.

Also, personal experience may not mean very much in the broader context. There are too many individual variables to make one persons experience a benchmark for someone else.

Except we have to keep above SpO2 88, in all circumstances.

cheers

Mars