I think sometimes the S9 is just sent out with their factory default settings. That was true in my case. It starts at a minimum of 4 and a maximum of 20. The theory of course is the Resmed will figure out the best therapy for your situation. That's true, but then we add a full face mask that can have random leak issues, especially to begin with. So my decidedly uneducated opinion albeit backed up by my own experience is the Resmed can get a little confused over all of this, and in it's exhuberance to provide us with a nice time, decide to blow our socks off.
The cure is to determine what your appropriate range is, and adjust the machine accordingly. For openers, talk to your sleep docs and see if they determined a recommended pressure for you from your sleep test. Let's say that pressure was 12 (as an example). Then I would suggest setting the machine on a minimum of perhaps 10, and a maximum of perhaps 14. Install the Sleepyhead software to monitor your results for a few days and see if you are well served in the suggested range. Then small changes up or down can be made until you find your own sweet spot.
Anyhow, I do know the blast of pressure you are talking about and the above is how I solved it for myself.
WELCOME! to the forum.!
Hang in there for more responses to your post and best of luck to you with your CPAP therapy.
Forgive the question but I always wonder about posts referencing "high pressure".
What tells you that the pressure is high? What do you actually experience?
Pressure is nigh on impossible to experience directly -- it is only pressure DIFFERENTIAL that we feel.
Two main places this differential will show up:
Chipmunk cheeks if you have an FFM or Oral mask since the pressure outside your cheeks is lower and cheeks are fairly 'loose'.
Wind -- and wind is almost always LEAKS.
If the issue is WIND, then it might be partly due to a pressure increase (it only finds its way out to create the leak at higher pressures) but it is the wind of the leak we experience and not the pressure per se.
The reason for thinking of it this way is that if the issue is WIND then fixing the leak may be the best course.
Is there some other way you are sensing the "pressure"?
Sleep study AHI: 49 RDI: 60 -- APAP 10-11 w/AHI: 1.5 avg for 7-days (up due likely to hip replacement recovery)
"We can all breathe together or we will all suffocate alone."