The sleep clinic where I was at, I paid them a consultation to set the machine up right, and they were of the opinion, well, do it from 4-20 and then we will review after a month. I wasn't very happy as they just explained what the features on the machine do and didn't really do too much else.
It was nuts, had some awful nights, work up like I was being blown up. Chest hurt, panic (using the F30i at the time).
I watched "CPAP Pressure! Too Low, Too High, Just Right. How To Adjust Your CPAP Pressure Levels" and adjusted the pressure so the AHI was below 5 and comfortable, and the n95 ended up being about 6-7, so I adjusted it to 8 - slept great good AHI. The clinic wasn't happy when I told them (said they need more data, which I guess the do), and wanted me to set it higher (which I did, put it to 12).
The full face mask that came with the machine doesn't seal the pressure that great, when high pressure is being put in, it leaks a bit, and then the machine adds even more pressure and then I wake up (at least that is how it feels).
I like the ramp feature, as I just want to breathe like I am used to when I sleep. I have set up the machine so it is easier to breathe out (IPR3 - that feature is a 'lifesaver').
I bought an extra mask at the time (AirFit F30i Full Face) but I felt like I couldn't breathe, draw enough in due to that nose latex that is there, even with it removed (I cut it away), I just couldn't do that mask). I'm swapping it for the F20 Airfit, so hopefully that will hold pressure better (and also allow me to disconnect more easily!). Using the defaullt face mask that came with the machine which is a bit of a pain to strap on, but works much better and doesn't whistle like the F30i did. I also couldn't bear how that mask interfered with my trying to draw a breath.
My Doctor has no idea about cpap's really, apart from how to ventilate someone (at least he was honest enough to say so) and the sleep therapy place is run by two young lass's with Cert IV's, so not feeling confident.
P.S. I wish I didn't drool.
Questions
How are my settings?