10-second threshold

It's probably just a number pulled out of the hat, it has to be something lets make it 10 sec. Maybe in a study they found out most of the people studied breathed more that every 10 sec while sleeping. Ten sec of not breathing isn't very long. I don't think the body would go into panic mode in 10 sec. Most of my nights my apnea length avg 12 sec. Jim

Probably because a lot of scientifc data is measured in the decimal system, so it's natural to think about increments of ten.

gvz wrote:Hello,

Just wondering if anyone knows the reason behind the 10-second threshold that defines an apnea event?

Why 10 seconds, why not 8 seconds, or 5 seconds? Is it because in the people studied by CPAP manufacturers, that 10 seconds of non-breathing is the average or median threshold for causing an oxygen "desat" ?

Just curious..

You might send a PM to DeVilbiss Marketing and ask them to address the question. Their on-demand webinars did an excellent job of describing the 'standard' along with the ability to modify that standard to be more aggressive with the response to an event - but I do not recall it providing the background on why those figures were established originally.

gvz wrote:Hello,

Just wondering if anyone knows the reason behind the 10-second threshold that defines an apnea event?

Why 10 seconds, why not 8 seconds, or 5 seconds? Is it because in the people studied by CPAP manufacturers, that 10 seconds of non-breathing is the average or median threshold for causing an oxygen "desat" ?

Just curious..

I don't know the reply to the question formulated above, I would guess it would have to do with desats, as studied in breathing tests (nothing to do with cpap manufacturers). but I do have some thoughts about the following one:

gvz wrote:I guess maybe what I am getting at is.... you could have an entire night of 9-second obstructive or central apneas, and you'd get an AHI of 0.0, yes?

And maybe walk around feeling terrible the next day...

During a lab titration, they will watch breathing related arousals even if you're not having formal apneas.
During a lab titration, they will watch your oxygenation even if you're not having formal apneas.

They will take those two into account when searching for your optimal pressure.

When you use an APAP, the majority of machines analyse many thing about your breathing, in addition to apneas, and respond to them "pre-emptively"; or at least they attempt to do that. This includes snores, which all machines respond to, flow limitations, the shape you inahlataion exhalation, the pattern -- what have you. No APAP is limited to responding to apneas alone, and I doubt there will be many "9 second apneas and nothing else" in people's breathing with no other breathing problems.

However, if I were to have 0 AHI nights after which I felt miserable, I would try a gentle raise in pressure.