Question on ODI + desats

I am away from home and my reference materials, but I think that the 3% drop is significant during sleep, as one of the defining factors of an apnea or hypopnea, with the other being a 10 second or more cessation of breathing. Which is why some docs have said cpap's aren't "accurate" since they only measure the breath and not the desaturations. And why some of us have purchased an oximeter.

I don't know whether a 3% drop that still stays above 90% is significant or not though. I wonder if it would depend on how many, and for how long. And if it affects your heart rate or blood pressure.

Hi,
It might also be dependant on what part of the country you are in as well.
To explain....when I worked in ICU in Southern California close to sea level we wanted our Heart surgery patients to keep their sats above 95% and when they were closer to 90% we started to worry. Here in Colorado where the altitude is higher and a 90% sat for a heart patient (or anyone else) is perfectly fine.
Just a thought.
Shar:)

gvz wrote:Sort of answered my own question ... sorry for bugging ya'll.

I also correlate my Contec oximeter reports with the ResScan data (via graphics program for now). I do see direct connections between my apneas (usually centrals in my case) and the desats. I'm glad that you posted, as I find this very interesting!

Same here. I've been comparing the printouts from EncoreView and the Contec just by eyeball (not nearly as cool as DreamOn's charts).

When the Contec shows a non-critical desast, for example from 97 to 93%, at the same time as EV shows an obstructive event, I'm assuming (I'm no expert here; someone please correct me if I'm wrong):

1. The obstructive event (apnea/hypopnea) shown by EncoreView is valid, and
2. The XPAP is terminated the obstruction, because the O2 sat goes back up quickly. On my diagnostic PSG I was below 90% saturation for 16% of the night, and that never happens to me on XPAP.

It seems like desats that don't go below 90% and don't last more than a minute wouldn't be harmful, but I don't actually know that.

BTW, I don't understand how the ResScan software computes the ODI, since it doesn't "know" your O2 sat.