Airway pressure release ventilation: theory and practice.

Airway pressure release ventilation (APRV) is a relatively new mode of ventilation, that only became commercially available in the United States in the mid-1990s. Airway pressure release ventilation produces tidal ventilation using a method that differs from any other mode. It uses a release of airway pressure from an elevated baseline to simulate expiration. The elevated baseline facilitates oxygenation, and the timed releases aid in carbon dioxide removal. Advantages of APRV include lower airway pressures, lower minute ventilation, minimal adverse effects on cardio-circulatory function, ability to spontaneously breathe throughout the entire ventilatory cycle, decreased sedation use, and near elimination of neuromuscular blockade. Airway pressure release ventilation is consistent with lung protection strategies that strive to limit lung injury associated with mechanical ventilation. Future research will probably support the use of APRV as the primary mode of choice for patients with acute lung injury.