It is my opinion that anyone with moderate-to-severe obstructive sleep apnea, or anyone with any form of central apnea or a tendency toward it, should probably check with his or her sleep doc before going on a trip that will require them to be under physically stressful circumstances above 8,000 feet during the day or that will require them to sleep above 6,000 feet while using the machine. On top of that consideration would be, for you, the risk of sleeping without PAP therapy at high altitudes, which, again, would depend on the severity of the condition and a person's medical history. None of that is something to take lightly.
Given the severity of my condition, for example, I would get a small, light, $300 lithium battery pack from CPAP.com in order to use my machine every night, and I would STILL do my best to keep base camp below 6,000 feet for sleeping, myself. I don't want to ruin my, or anyone else's, vacation.
But, hey, that is just one patient's opinion.
You would have to check with your DME/PCP on the specifics of your machine. Apnea can be affected by altitude, but how it affects the individual machines is beyond my knowledge.