troubleshooting pressure fluctuations in ResMed Air Sense 11

[fgrowcock]

During the course of an evening's use of the AirSense 11, the system suddenly starts putting out air at a higher pressure.  Of course, it awakens me, and I have to shut the system down and then start it back up again, at which point it seems to work ok...at least for awhile.  What can cause that and how can I stop it from doing that?

[jdougc]

Welcome to the forum,
Can you post a copy of your sleep report with your personal info redacted?
Are you on any medications that may affect your breathing or your sleep?
Do you have any health issues that may affect your breathing or your sleep?
Are you a side sleeper or do you sleep on your back?
Side sleeping is the best position for treating sleep apnea.

These cpap machines aggressively treat events during the night and raise the pressure. 
If you have tight clusters/groups of events,this is called positional apnea, the pressure can go quite high rapidly. The pressures can't open your airway, as this might be might be caused by you tucking your chin to your chest or laying on your back and gravity pulls your tongue or soft palate and blocks your airway. The high pressure can cause leaks and wakes you up. You shut the machine off and when you start it up again the starting or "ramp" pressure would be much lower. But this can happen several times during the night.
   
You may need to lower your maximum pressure to a reasonable level.
Many times the cpap user is given a machine with default pressure settings, 4-20 cm of pressure. 20 cm is very high for most users and would cause substantial mask leaks and wake you up.
Many use a soft cervical collar to help this issue, but without seeing your data, we can't know.
Even if your AHI is lower, under 5, your can have partial airflow restrictions, called "flow limitations". The cpap machine will try to treat these with raising the pressure. These flow limitations can cause daytime sleepiness even if your AHI is considered OK, under 5.

Please download Oscar software and put an SD card in your cpap machine.
Show these charts, press F12 for a screenshot or Fn F12 for a mac
Event Flags
Flow rate
Leak Rate
Pressure
Flow limits
Also we need to see the statistics and machine settings.