OSCAR Interpretation Test

[Geer1]

So last night I had an interesting episode. I am curious if anyone can come close to explaining what may have happened during this stretch.

[Sleeprider]

You are as good at interpreting Oscar data as anyone I know, including myself. My take is this cluster of events starts with an inhale and breath-hold followed by a 2-phase exhale. Next is a huge inhale sigh with equal volume exhale, however mask pressure does not follow the respiratory flow. A UA is flagged on the next inhale, and I can't guess what artifact of the algorithm would cause the flag unless the machine is unable to determine if respiratory volume falls into the apnea threshold due to large leak. After a long apnea which I suspect may involve some movement there is a series of flow spikes with minimal volume, and several pressure increases. The cluster of events moves into another large leak and mask pressure is lost.

I don't know that during the large leaks, the flow data is reliable, however the whole mess looks like choking or what I have fondly referred to as a positional apnea cluster. That's a lot of crap to stuff into 8-minutes of an otherwise good night. I'm curious about your interpretation.

[GuyScharf]

That is a bizarre sequence. My guess is that you were fighting your mask and that it was partially off. A leak rate of 120 lpm might be close to the maximum the machine can do and certainly well above the leak rate that the machine can be expected to compensate for. I am surprised, though, that the mask pressure didn't drop all the way to zero with a leak of that magnitude.

The mask pressure after you start that sequence is interesting. Difference between inhale and exhale is small, probably just FOT, and the machine keeps trying to increase the pressure after it flags an OA (which are probably incorrect flags).

And, then, finally at about 00:30:40 the session ends. Did you wake up then, or did smartstart start another session?

[pholynyk]

IIRC, 120 l/min is the physical maximum recorded in the edf file. (Actually 2 l/sec..) Anything more is off the scale.

[Geer1]

I wish I had it on video as it was a battle. GuyScharf figured it out, appears to be a spontaneous arousal at 00:21:45 followed by what must have been me ripping my mask off.

I remember being half asleep and fighting with my mask trying to stop it from blowing air. A lot of this time was me holding thumb over hose or hand over mask as I fumbled to try and put the mask back on. I figured this whole event took maybe a minute or two but when looking back I was surprised to see the battle lasted for over 8.5 minutes, I must have only been half awake. 

In my sleepy stupor I couldn't figure out how to get my mask to work so I gave up, turned off the machine and went back to sleep without it. I woke up 5.5 hrs later and wanted to put my mask back on and get a bit more sleep. I was finally able to figure out that when I had ripped the mask off not only had it come off the hose but one strap had come undone and pulled off the magnetic clip. I found the clip and reassembled the mask then I went back to sleep for a couple more hours with the machine.

Just a comical instance I figured was worth sharing.

[quiescence at last]

yeah, I was going to blame it on your home motherboard. Tell her to stop jumping on you.

QAL