bluetrout wrote:
Everything goes great until I wake up, usually with the machine at a high pressure forcing a lot of air which leaks. Can't get back to sleep with that going on so I stop the machine and get to sleep without it for another few hours. I'd like to get the full benefit from the CPAP but not sure how.
As pugsy points out, the highest your pressure went on this night is 10.5, and that was only during the PR Search algorithm's test pressure increases.
There is evidence that you woke up around 0:20 and hit the ramp button. The pressure had been running at around 10cm for about 20 minutes at that time. There was a small, but long leak around that time: The estimated excess leak rate was between 10 and 15 L/min, which is small enough to ignore--except for the fact that you say leaks wake you up.
There's a lot of ugliness going on between 1:20 and 2:00. The excess leak rate spikes to 30 L/min around 1:50. The PR machines base official Large Leaks on the total leak rate, which peaks at 60 L/min, and that's flirting with Large Leak territory. But this leak lasts only 15-20 minutes, and the leak is only flirting with Large Leak territory for 5-10 minutes. Again, that's not enough to worry about---except you say that leaks wake you up. There are several events between 1:20 and 2:00 as well. The pressure is increased from 9cm to 10cm
after the leak has spiked. The pressure increase seems to be in response to a small cluster of 2 or 3 Hs along with an OA scored right before the pressure increase. About 5 minutes after the pressure is increased to 10cm, your breathing settles down and the largish leak has disappeared.
It's possible that some of the ugliness between 1:20 and 2:00 is sleep-wake-junk that occurred when you were sort of awake, but still sort of asleep. You may have been barely awake enough to notice the leak and were fiddling to fix it. In any case, it looks like you settled back down into sleep by 2:00am.
You wake up and turn the machine OFF for good at around 3:15. At the time you turned the machine off the pressure was at 9cm and the excess leak rate was below 10 L/min. In other words, the data doesn't agree with your perceptions of what was going on when you woke up and turned the machine off.
So the question becomes:
Why are you perceiving the pressure is "high" and that are a lot of leaks when neither is the case?
It could be that you are just "waking up"---possibly from a perfectly normal post-REM wake. But instead of noticing that everything is "normal", your semi-awake brain notices that there's this
thing on your nose and that a lot of air is coming from the
thing. You're probably noticing the airflow from the exhaust vents in the mask and thinking that you've sprung a serious leak. And you probably are then attributing the "leak" that isn't really a leak to the machine's increased pressure, even though the pressure hasn't increased. And then for some reason you decide that you can't fix the leak quickly enough to get back to sleep. By this time, you've taken the mask off and you go back to sleep.
bluetrout wrote:Hmmm. You're right Pugsy. I was looking at the AHI going up at about 1:45 however the pressure wasn't high. The leak peaked around then too. Wonder if that's what woke me up.
My guess is that the leak around 1:45 did wake you up. But you fixed the leak and the flow rate then returns to what looks like a
normal sleep breathing pattern.
The feeling was that the air was pouring into the mask and that it was leaking everywhere. IT seemed loud and so the "roaring".
Was this right before you took the mask off?
If the exhaust vent is aimed in such a way that it hits the bedcovers and reflects back in your face, it
can feel like there is air blowing around everywhere and it can be
very noisy. If the hose is touching your pillow or your head, the conducted sound of both your breathing and the machine's fan can make it seem like everything is very loud and roaring.
Finally, I'll offer this: When you woke up around 0:20, your instincts were to press the ramp button and go back to sleep. That's not an unreasonable thing to do since it appears that your ramp only lasts for 10 minutes. Perhaps if you'd just pressed the ramp button to get the "excess pressure and air blowing everywhere" under control when you woke up and took the mask off, you would have quickly returned back to sleep.
