I’m a bit confused on CPAP levels.  It seems to me that any level sufficient to hold the airway open would be good.  However, I observe on my titration test, and others, that this is not so.

At level 5 my RDI was 0.8 my AHI was 0.0
At level 7 my RDI was 1.3 my AHI was 0.0
At level 9 my RDI was 3.2 my AHI was 2.1
At level 11 my RDI was 22.7 my AHI was 19.7

After this test my Doctor raised my level from 5 to 9.
My next visit I complained that I didn’t seem to get as good a result on 9 so he increased it to 11.

Two questions:
1.  Why isn’t a level sufficient to hold the airway open all that is needed? and
2.  Can anyone explain my Doctor’s action in increasing the level from 9 to 11?

Thanks
Frank