Resmed P10 nasal pillows: inhaling exhaled air.

Nubee here using the P10 pillow. Fits nicely and comfortable so far. I have the same concern about breathing stale exhaled air back into the tube. Yes the mesh ventilates, but it doesn't seem like enough relative to the volume and rate of exhalation. If the exhalation pressure coming out of your lungs is greater than the machine supplying fresh air, and the vent doesn't allow enough for to escape thru the mesh between breaths, how is there not a buildup of CO2 in the tube?

Has anyone actually monitored personal O2 levels to see whether these stale air complaints are "in our heads" or whether it's a real issue? My machine is the Airsense11 Auto set and I have been playing with the heated coil and humidity settings. My pressure setting are 4.0-16.0 as it auto detects and ramps up and down as required.

I have forced hot air in the house and it gets bone dry in the winter. First two nights it plugged up with water from rainout condensation which I drained in the middle of the night.
3rd night I tried the humidity auto setting but kept the tube temperature high around 84F. Temp at night is around 60F. No water plugging but I had to quit after 3.5 hours because I woke up feeling like I was breathing stale air out of a paper bag (like how others described).

How do I know if that sensation is from breathing warm moist air from the heated tube? Or if it's from my own exhalation? Why wouldn't there be a CO2 sensor placed in the machine just as a safety measure considering that it's (a) possible to block a vent and (b) the vent is not adequate enough?

Zombie thread alert folks. Be careful what/who you respond to.

The newbie that resurrected this thread needs to create a thread/topic of their own to get newer more correct advice.

To SleepyWes.....please start a new topic of your own.