Positive pressure devices for treating sleep apnea have constantly evolved and improved since the origin of this form of treatment in 1982.

Devices include:

Continuous Positive Airway Pressure (CPAP): , in which a constant pressure is produced to keep the back of the throat (the airway) open during sleep

Bilevel PAP (BIPAP): A higher pressure is delivered during inspiration (breathing in) than during expiration (breathing out).  This may be more comfortable for some patients, and can help to improve breathing for problems other than sleep apnea as well.

Automated Positive Pressure (APAP or Autoset): The machine is able to measure your breathing and adjust the pressure as needed to treat sleep apnea.

Assisted Servoventilation (ASV):  A machine that is able to variably assist breathing for some specific breathing problems during sleep.