Before expanding on my question, here is a brief history to date:
* Diagnosed with sleep apnea with AHI of 12 (AHI of 29/hr supine) and minimum sleep SaO2 of 87%. Given the AHIs reported on this board by others, I thought this is going to be a cinch to get from 12 to something under 5!
* After a few trials of nasal pillows and nasal masks, the best result for mask leaks and acceptable comfort was F&P Eson 2 nasal mask.
* Because of mouth leaks I tried chin restraints, trying to do the 'seal with tongue' trick, and finally Micropore tape across the mouth.
* The Eson 2 and Micropore tape gave what I think is a reasonable leak rate and reduced AHI to 2.23. All events were hypopnea. Pressure range was 7 to 12. Experience to date is that machine pressure runs up from the minimum set pressure to the maximum set pressure as soon as I'm asleep and mostly sticks close to the maximum until I wake up. With this combination there is potential for improvement with adjustments to leaks and pressure.
* I'm not too keen on a taped mouth on a permanent basis (friends would probably suggest full-time permanent would be a good idea). Sounds like it could end badly if something goes wrong, let alone the discomfort of greeting every day by ripping tape off my mouth. My next brilliant idea was to use a FFM and try to train myself to keep my big trap shut and if that worked to move back to a nasal mask. In the meantime the therapy would be working with the FFM.
* Several FFM trials later I have a PR Amara View mask which is comfortable and provides a good seal allowing me to sleep on the back and both sides with few leak problems as I move about. AHI increased when I started trialing FFMs. I have tried and am continuing to try different pressure ranges. To this novice the indicators were that the pressure range should be increased, but with a pressure range of 13.6 to 16, AHI was 12.29 (worse than my sleep study result). So far the best result has been AHI of 6.07 with a pressure range of 10 - 12. This is a work in progress.
Back to my question. I think it is well established that for general health reasons, breathing through the nose (particularly inhaling) is the preferred option. However, I don't know if this applies to sleep apnea and treatment with PAP to achieve a desirable AHI. During the day I breath mostly through my nose, but obviously from nasal mask experience I mouth breathe at times. I don't know for how long and when. I seem to spend periods of time where events are few and periods when events are high. I thought the pattern may be related to 'mouth open' and 'mouth closed' periods, but it could also be changes of sleeping position or other factors. The pattern can be seen in my charts from last night. There was no sleep during the second segment of the chart.
I am wondering if anyone has been able to ascertain whether keeping the mouth closed or open with a FFM gives the better result. Also, are there any distinguishing features of the SleepyHead charts that indicate mouth open or closed or at least when there has been a transition?
Thanks in advance for your wisdom.