(02-23-2015, 11:53 AM)Jemstone Wrote: My Resmed S9's pressure goes really high every night about three hours in for no known reason...
I think we need just a bit more clarity. It does not seem like an APAP could just arbitrarily go "really high" and stay there for hours at a time, then arbitrarily go back to normal.
When pressure raises on an APAP, it does it in stages, meaning it will raise a cm or half a cm in response to flow limitations or after OA events. It may raise more or less, depending on the event and the severity. But once it raises, there is a time constant where it decreases at a slow rate for a percentage of the prior increase. If you have no other events for, lets say, a half hour or so, you can see this represented in SH on the pressure graph by a curved response as the pressure lowers but lowers more slowly minute by minute. Its like a scallop in the graph just after an event.
That would be normal. Unless you have a lot of events all at once, it should not just raise up "really high" and stay there.
So look let's get a look at your pressure graph to see if that is normal.
It could also be that 13 is where the APAP thinks your pressure should be, an intelligent decision made by it based on monitoring your respiration.
13 has never been a pressure that would wake me; it usually needs to get upwards of 16-17 or higher for that to happen. In fact, mine goes to 13 a few times a week. I have indeed seen my S9 autoset go rogue and runaway with pressure a couple of times, but I capped the high end at 14 to prevent that, and it hasn't done it now for months.