UMEM Educational Pearls

Category: Critical Care

Title: APRV

Posted: 8/11/2009 by Mike Winters, MD (Updated: 3/3/2024)
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Airway Pressure Release Ventilation (APRV)

  • As emergency physicians manage mechanically ventilated patients for longer periods of time, it is important to be familiar with newer, alternative modes of ventilation
  • APRV is an open-lung ventilation strategy designed to provide oxygenation benefits while augmenting ventilation for patients with low compliance lung disease
  • APRV has been described as CPAP with brief, regular, intermittent releases in airway pressure - essentially cycling between two CPAP levels
  • The degree of ventilatory support is determined by the duration at each of the 2 CPAP levels and the distending pressure
  • The 5 major parameters of APRV, along with suggested initial settings include:
    • Phigh (high pressure): set at desired plateau pressure
    • Thigh (time spent at the high pressure): 4-6 seconds
    • Plow (low pressure): 0 cm H2O
    • Tlow (time spent at the low pressure): 0.6-0.8 seconds
    • FiO2: 100%
  • The pressure gradient between Phigh and Plow, Tlow, and the patient's spontaneous minute ventilation are the primary determinants of alveolar ventilation
  • When using APRV, be sure to optimize intravascular volume to offset the decrease in venous return that results from prolonged positive intrathoracic pressure


Stawicki SP, Goyal M, Sarani B. High-frequency oscillatory ventilation and airway pressure release ventilation: A practical guide. Journal of Intensive Care Medicine 2009;24(4):215-29.