Pressure Setting

I have an Resmed S8 Escape on trial for the past couple of weeks. It's been set to 8 by my doctor and I personally have felt this setting is probably to low -- both because it seemed to be useless and because of previous experience with an APAP trial unit. I was on an auto pap -- the S8 Vantage for 2 months. My doctor said the 95% point from that trial was 8 and that's what he set the Escape based on.

What never made sense to me is that when I woke up in the morning the Autopap was often -- and I think typically said something like 9.8 and at the very end sometimes 12 when my allergies were worse. So I decided just to go in and reset the Escape to 10 for a night and see. Ironically I think it did seem to make me feel better even though I woke up several times because I opened my mouth -- either more or it just woke me up more at the higher pressure.

I guess this leads me to several questions:

1. Is there any disadvantage of running a higher pression? I'm thinking health downside, or is higher not always more effective, etc.
2. If there's no disadvantage why would one set a CPAP to 95% based on some trial -- one would think you'd want to just set it rather higher like 99% or 100% and/or with some added margin and go with that as it's likely to be more effective??
3. How do CPAC, CPAP with EPR, and Auto PAP typical pressures relate to each other? I guess I find it hard to believe that they would be the same -- one might think there would be some unknown fudge factor that needs to be applied to convert between the two.
4. Why would I see 9.8 on the auto quite often and sometimes 12 and my doctor choose 8? I've been mystified by this.
5. Finally -- I think my plan is to try 8, 10, 12 levels (or if 10 seems really good, 9 instead of 12) then go back to my doctor with specific feedback for discussion. Does that sound like a reasonable plan?

Anyway. Sorry for the long note. Anything anyone has to offer about the pressure level experiment I'm going to try, about the typical effect of pression, or about the differences between CPAP and APAP data would be a great help.

Thanks,
Rob

In the order asked;

1. Higher pressure can cause central apneas in some people. Some just can't tolerate high pressure.

2. I think they like to try the lowest possible setting first. Then they will move you up if no centrals were seen in a PSG. I think they should start a bit higher than the 95%.

3. a pressure of 9 should be the same on each machine. Or 10 or 12. Of course there is always a little wiggle room.

4. Your doctor may not know what he is doing. He may be playing it safe with a lower pressure. He may know that you had centrals on your PSG.

5. Sounds good to me, but then I have the software to see just what's happening. Remember to make just one change at a time. Then give that change a few nights(a week is better) to see how it's working for you.


Brenda

The 95% number means you spent only 5% of the night at higher pressure than 8, and 95% at 8 or lower.

My 95% pressure is 7. This how the distribution looks:

Pressure (cmH2O)
Time % - 6 cmH2O : 74
Time % - 7 cmH2O : 23
Time % - 8 cmH2O : 3

My machine (a PB 420E) is set up with a bias for 7 - but can take me lower when possible - which as you can see is quite frequent, and higher when necessary - which is rare.

I actually do far better like this, than I did when I tried a fixed pressure of 7.

O.