Cpap altitude adjustment

[tyrinryan]

I have never really understood the "compensates"; does this mean that there is some sort of altimeter in the machine. Otherwise how can it even know what the altitude is to "compensate" for it?
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[ChicagoGranny]

I have never really understood the "compensates"; does this mean that there is some sort of altimeter in the machine. Otherwise how can it even know what the altitude is to "compensate" for it?
'

No.

In thinner air, the machines increase fan speed so that a patient who lives at sea level using 10 cm H2O of CPAP, will continue to receive 10 cm H2O of CPAP when she sleeps at altitude, such as 8000 feet in the mountains.

The machines don't "know" they are at altitude. They just know what their pressure sensors are reading and adjust the fan speed to the readings.