Some nights I just can't use the cpap

yes if you weren't using the machine your AHI would have been higher.

benalexe wrote:So if I have an AHI of 2.0 on the machine does that mean that 2.0 is the result of the machine. If I did not have the machine it would be higher?

Yes it means the way the machine is set it prevented all but 2 of them per hour (This is an average). This is common - often when we drop into a deep REM sleep we will have more apneas. It could also mean that they are something called "centrals" which are triggered by your brain forgetting to tell you to breathe which is sometimes associated with sleep onset or REM or brain damage or high pressures. Generating central apneas are just about the only negative you can do with your machine by the way other then setting it too low to help. It is far less dangerous to play with your settings then it is for a diabetic to play with their insulin - which diabetics have total control over as well as total information - even if they are 8 or eighty!