Used for treating forms of sleep disordered breathing , Continuous Positive Airway Pressure (CPAP) usually is administered while the patient is sleeping through a nasal or facial mask. The mask is connected by a tube to a small air compressor about the size of a small shoe box. The CPAP machine sends air under pressure through the tube into the mask, where it keeps the upper airway open and prevents it from collapsing. The advantages of CPAP are that it is very safe and provides immediate relief. The main disadvantage is that it must be put on each night for it to work.
Bi-Level Positive Airway Pressure therapy is a variation of the CPAP machine. Bi-Level machines eliminate some of the problems patients have with the CPAP because they sense when the patient is inhaling or exhaling and reduce the pressure for exhaling. This will allow the patient to exhale more easily. Bi-Level machines are used when the patient cannot tolerate the CPAP or when the patient has more than one respiratory disorder.