(12-26-2014, 09:54 AM)sgearhart Wrote: I just changed my S9 to a VPAP with a setting of 8-12 from a CPAP 10cmH2O. It turns on at 8 and ramps right up to 12 in about 30 seconds. It seems to ignore the minimum setting and go straight for the maximum. It has done this for the past 5 nights. I was going to post about this problem until I saw this thread. I'm going to do a Cold Boot and see if that helps.
There are two ways of looking at this.
First, it may be that this does not sound like it is working correctly. It seems that an APAP starts at the minimum pressure in the set range, and only goes up if it has a reason to, such as responding to breathing feedback and SA events. If the machine climbs up to the top of the range this quickly, it may be operating differently than what should be expected, as it does not seem that it even has time to respond to breathing feedback. And if little else has changed, why would the behavior of the machine change abruptly, unless it was not working properly?
On the other hand, it may be that your min pressure should be 12 or above, and there was indeed an abrupt change (in setting an APAP range over operating it as a brick). The straight 10 may be an educated guess based on a sleep study, and was too low in the first place.
8-12 is not a significantly large range, and not significantly different than straight 10. So maybe the machine really is seeing something immediately that is telling it to go to the top of its current set range. This is the advantage of APAP over CPAP in that it has the intelligence to titrate your pressure automatically based on feedback. IOW, it may be operating absolutely correctly.
Regardless, and speaking as an Engineer, my experience tells me that a cold boot seems like a reasonable thing to try, and it is non-invasive and can't really make anything worse. I am curious to see if it helps (odds are not that good, but it's worth a shot), so please post back your results.
I would also take this up with your sleep doc and your DME.