Continuous Positive Airway Pressure

Excerpt

Continuous positive airway pressure (CPAP) delivers a continuous flow of air to open the airways in individuals who are spontaneously breathing. Positive end-expiratory pressure (PEEP) refers to the pressure in the alveoli above atmospheric pressure at the end of expiration (see Image. Airway Pressure Release Ventilation Pressure Cycles with Superimposed Spontaneous Breathing). CPAP maintains PEEP by delivering constant pressure during both inspiration and expiration, measured in cm H2O. Unlike bilevel positive airway pressure, which varies pressure during inhalation (inspiratory positive airway pressure) and exhalation (expiratory positive airway pressure), CPAP requires patients to initiate all breaths without additional pressure above the set level.

By maintaining PEEP, CPAP reduces atelectasis, increases alveolar surface area, improves ventilation-perfusion (V/Q) matching, enhances oxygenation, and maintains upper airway patency. While CPAP aids oxygenation, it is often inadequate for full ventilation support, which requires additional inspiratory pressure, as provided by noninvasive ventilation. This activity reviews the mechanism of action, clinical indications, contraindications, preparation considerations, and potential complications of CPAP therapy in pediatric and adult populations.