Cpap machine is called continuous positive pressure machine. which uses compressed air to open and support the airway during sleep. It has one pressure setting that delivers between 4 to 20 cm H2O (a measure of air pressure that stands for centimeters of water pressure). that remains consistent throughout the night. However, many CPAP machines have a ramp feature that starts off with a lower pressure setting and gradually builds to the prescribed pressure.
BiPAP machines have two pressure settings — inhalation positive airway pressure (IPAP) and exhalation positive airway pressure (EPAP) — that allow for lower pressure levels during exhalation.