Airway pressure release ventilation is a time-cycled alternant between two levels of positive airway pressure, with the main time on the high level and a brief expiratory release to facilitate ventilation.

Airway pressure release ventilation is usually utilized as a type of inverse ratio ventilation. The exhalation time is shortened to usually less than one second to maintain alveoli inflation. In the basic sense, this is a continuous pressure with a brief release. APRV currently the most efficient conventional mode for lung protective ventilation.

Different perceptions of this mode may exist around the globe. While 'APRV' is common to users in North America, a very similar mode, biphasic positive airway pressure (BIPAP), was introduced in Europe. The term APRV has also been used in American journals where, from the ventilation characteristics, BIPAP would have been perfectly good terminology. But BiPAP is a trademark for a noninvasive ventilation mode in a specific ventilator.

Other medical ventilator manufacturers have followed with their own brand names. Although similar in modality, these terms describe how a mode is intended to inflate the lung, rather than defining the characteristics of synchronization or the way spontaneous breathing efforts are supported.