CPAP = Continuous Positive Air Pressure
It is essentially made of an air compressor that intakes ambient air and compresses it to a set pressure.
It is measured in centimeter water pressure (cm H2O) and a typical CPAP machine can generate between 4- 20 cm H2O.
A typical therapeutic range of pressure is between 6-12 (cm H2O) and can become uncomfortable when at a higher pressure.
The function of CPAP is like a balloon pump putting air into the balloon to keep it from deflating.
CPAP pumps positive pressure to support your airway and prevents it from collapsing when airway muscles are relaxed during sleep.