Continuous positive airway pressure (CPAP) is treatment provided by a machine worn at night or during times of sleep to treat sleep apnea, a sleep disorder in which a person regularly stops breathing during sleep for 10 seconds or longer. A CPAP machine increases air pressure in the throat, keeping tissues in the airway from collapsing when a person inhales.

The CPAP machine delivers air through a mask that covers the nose and mouth, through a mask that covers only the nose, or through a nasal pillow that covers only the openings of the nose.

CPAP is the most widely used treatment for sleep apnea caused by blocked airflow in the throat (obstructive sleep apnea).