Continuous positive airway pressure (CPAP) effectively reduces symptoms in about 80% of those with obstructive sleep apnea. During continuous positive airway pressure, a nasal mask forms a tight seal against the skin around the nose, and pressurized oxygen is delivered through the nasal mask. The air pressure helps prop open the upper airway, which reduces the chance of structures blocking the airway.

Bi-level positive airway pressure (BIPAP) may also be used to treat sleep apnea. Bi-level positive airway pressure is similar to continuous positive airway pressure, except that the pressure delivered through the mask varies according to the patient's breathing pattern.