Continuous positive airway pressure

Continuous Positive Airway Pressure (CPAP) is a form of positive airway pressure ventilator, which applies mild air pressure on a continuous basis to keep the airways continuously open in individuals who are able to breathe spontaneously on their own. It is an alternative to positive end-expiratory pressure (PEEP). Both modalities stent the lungs' alveoli open and thus recruit more of the lung's surface area for ventilation. But while PEEP refers to devices that impose positive pressure only at the end of the exhalation, CPAP devices apply continuous positive airway pressure throughout the breathing cycle.

History

The first CPAP machine was developed in 1981 by Colin Sullivan. His invention was initially used in the treatment of sleep apnea, a condition characterized by pauses in breathing during sleep. Over the years, the use of CPAP has expanded to include treatment for other respiratory conditions such as chronic obstructive pulmonary disease (COPD) and congestive heart failure (CHF).

Mechanism of Action

CPAP works by creating a "pneumatic splint" for the upper airway, preventing the soft tissues of the upper airway from collapsing and thus maintaining an open airway. This is achieved by delivering a stream of compressed air via a hose to a nasal pillow, nasal mask, full-face mask, or hybrid, splinting the airway (keeping it open under air pressure) so that unobstructed breathing becomes possible, reducing and/or preventing apneas and hypopneas.

Uses

CPAP is most commonly used for the treatment of sleep apnea. It may also be used in preterm infants whose lungs have not fully developed. For example, physicians may use CPAP in infants with respiratory distress syndrome. It is associated with a decrease in the incidence of bronchopulmonary dysplasia. In some preterm infants whose lungs haven't fully developed, CPAP improves survival and decreases the need for steroid treatment for their lungs.

Side Effects

While CPAP therapy is effective in reducing apneas and less expensive than other treatments, some people find it uncomfortable. Common complaints include a feeling of chest discomfort, difficulty in inhaling, and nasal dryness. However, if the patient's pressure setting is too high, they can experience difficulty exhaling.

See Also

• Sleep apnea
• Positive airway pressure
• Ventilator

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