CPAP stands for "continuous positive airway pressure." CPAP is a treatment that delivers slightly pressurized air during the breathing cycle. This makes breathing easier for persons with obstructive sleep apnea and other respiratory problems.

Nasal CPAP is given through a mask that is placed and secured over the person's nose or nose and mouth. Slight positive pressure is used to increase the amount of air breathed in without increasing the work of breathing.

A similar machine, called BiPAP (for bilevel positive airway pressure) is used as an alternative to CPAP.

These devices are useful for children with collapsible airways, small lung volumes, or muscle weakness that make it difficult to breathe.

CPAP or BiPAP may also be used for those who have acute respiratory failure, central sleep apnea, heart failure, or COPD.

It can take some time to become used to a CPAP device. However, most people who receive help from a respiratory therapist or doctor are able to use and benefit from the machine.

Basner RC. Continuous positive airway pressure for obstructive sleep apnea. N Engl J Med. 2007 Apr 26;356(17):1751-8.

Weaver TE, Maislin G, Dinges DF, Bloxham T, George CF, Greenberg H, et al. Relationship between hours of CPAP use and achieving normal levels of sleepiness and daily functioning. Sleep. 2007 Jun 1;30(6):711-9.