sleepysteve,
First of all, I have a big disclaimer: I am a newbie and I don't even understand your question about factory upper pressure. I also have a Respironics System 1. I use nasal air pillows.
I have also run into the problem with what feels to me like "too much air" after 3-4 hrs sleep. This is what I think is going on in my case. I think I am changing the position of my head and neck (once sound asleep), in such a way that air cannot flow freely into my lungs and it has to go somewhere. In my case, "the excess air" which really needed to go to my lungs was going in my mouth or out through my mouth. The first time I made the connection was on a night that was unusually cool here in FL. Because it was so wonderfully cool, in my sleep I was tucking my chin down toward my chest which is my position of comfort in cool weather. When I straightened my head and neck, the air was going into my lungs...no "excess air" escaping into my mouth. I remembered (from many years of teaching CPR) that the way to open the airway is to tilt the head back. This is by no means a comfortable position for sleeping. I have since run into problems with air collecting in my mouth when I am on my side, and my shoulder is tilted forward, also if my head is tilted slightly forward as a result of repositioning my pillow. I think this problem might be worsened by being 20+ pounds overweight with a somewhat chunky neck.
I recently ordered a CPAP pillow which helps keep my head and neck in alignment. I sleep mostly side to side, so this is a good option for me. I have only had it for 2 nights, but it helps me keep my head and neck in alignment, and allows space for my headgear when I am sleeping on my side. It was a $50 investment on a non-returnable item, so I am happy that it seems to be helping.
The pressure on my machine is at a fixed pressure. This has been adjusted once at the Sleep Clinic. I have a follow up appointment in 2 weeks. It is possible that a slight adjustment in pressure will help get the air to my lungs with less fuss about my position. I will let the Nurse Practitioner decide on what changes, if any need to be made.
I am wondering if that factory set upper pressure is giving you a blast of air out of the mask. The air has to go somewhere. Also, do you know whether you tend to open your mouth while you are asleep? I think the open mouth/relaxed tongue (while asleep) can interfere with air getting to your lungs. I need to use a chin strap to keep my mouth closed. It seems like a lot a straps all over the place, but it seems to help.
I decided to respond to your question, because it had been unanswered from March 21. Good luck. I do think that the 2 1/2 - 3 hrs of CPAP is probably better than no CPAP. I hope that in this lengthy response, there is some little nugget that is useful to you.
