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Bama Rambler wrote:The masks have vents and also must have an Anti Asphyxia valve. However it's harder to breathe through than normal breathing so you struggle a bit with it and especially so if you're asleep.

If your OSA is severe enough it could certainly pose a potential life threatening situation. If it's that bad, you should really consider a battery pack or UPS (uninterruptable power supply) for your unit.

Usually, only full face (or oral) masks have anti-asphyxia valves. Nasal masks do not.

In theory, you'll open your mouth and breathe if you have a nasal mask and the machine quits. The idea seems to be that people don't suffocate in their sleep if their nose clogs up. I'm not completely convinced. If your nose clogs up, you'll open your mouth or stop breathing. If your machine stops, you'll still be breathing in and out, but the air goes back up the hose and then you inhale your exhaled air. Not a lot of the air goes in or out the exhale vent. Will you automatically open your mouth if you're inhaling and exhaling OK, but the O2 goes down and CO2 goes up?

archangle wrote: . . . Will you automatically open your mouth if you're inhaling and exhaling OK, but the O2 goes down and CO2 goes up?

If not (and you are a relatively healthy human who isn't drugged up), you wake up, as I understand it. (Although I'm no pro.)

At least, I think that's what these researchers concluded, even in the case of certain chronic hypercapnic patients on vents:

"Awakenings occurred in 19 of 19 trials within 5 min, with each subject waking and complaining of shortness of breath (mean time to arousal, 115 s; range, 26-264 s)."--http://www.ncbi.nlm.nih.gov/pubmed/10988121

But I could be wrong. Much of the wording is over my head in that study. Maybe someone who is more fluent in study-ese can translate better.