1. you have successfully shown that the pressure is increasing as a reaction to flow limitations, and that once you reach the maximum, you still have flow limitations that would have driven the pressure higher.
2. you have shown there is some effect of reducing the EPR to zero, and that the nasal pillows and especially nasal mask were not necessarily bad. I note that the ratio of OA to CA is better during the two nights where FFM and EPR reduction are both used. It is not clear whether the use of nasal mask or pillows made results better or whether they just didn't make it much worse. It is somewhat telling that the nasal mask has more trapped volume than the pillows and that the CA were worse in nasal pillows nights. Roughly, the higher the volume, the better your results (while in EPR reduction).
I also use the info provided earlier in the post for the 19 Jun. It shows CA clusters at both the lower (lowest) pressure, and at or above 10 cmH2O. ( http://www.apneaboard.com/forums/attachm...p?aid=1549 )
My view is that when you have used 'trapped air' for a longer period, your brain will stop reacting to the abundance of O2 and lack of CO2, as slight (but strange) as it is under CPAP. I think you will benefit from stabilizing with one mask type of your choice and EPR of zero, and staying at the same setup for more than a week (like others have suggested). 1
I also think that you should increase the upper limit by 0.5 to 1.0 cmH2O, but then wait more than a week.
Finally, there really isn't much time you stay under 8 cmH2O. It may not make a difference whether you start at 7 or change the minimum to 8.
1 trapped air increases the rebreathing of CO2 slightly, mimicking other therapies, including the one pointed out in the report you reviewed above - stating "experimentally successful treatment of CompSAS with PAP therapy plus controlling inhalation gases blended with 0.5–1% CO2 resulted in an immediate (1 min) decrease in AHI"
For sores from FFM, I suggest periodic use of a mask liner material.
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