AirFit™ N20 Nasal CPAP Mask [based Frankenmask]

[mesenteria]

If you stop up a number of the exhaust vents, the machine won't attempt to force more air through them.  It will adjust its amperage DOWN so that it maintains pressure against the newly restricted aperture.  This will have the effect of reducing volume at the same time, which may or may not be deleterious (based on your stated volumetrics earlier, I would say you're still going to get all the oxygen you can us in repose and REM sleep, with the one exception being someone with rather severe COPD, and that might be a whole nuther setup anyway).

[cronkster]

That's correct.  The machine will reduce its amperage and the vent flow rate will decrease but inside the mask the volume remains the same and pressure will remain at the selected settings. The only important flow rate inside the mask is that of your respiration, which is less than what the machine can instantaneously supply. As I wrote earlier, above a small minimum value, the vent flow rate is not an important factor for the purpose of CO2 scavenging. Do you see a contradiction with what I've written?