Higher versus Lower Positive End-Expiratory Pressures in Patients with the Acute Respiratory Distress Syndrome

Mechanical ventilation is critical for the survival of most patients with acute lung injury and the acute respiratory distress syndrome (ARDS). However, some approaches to mechanical ventilation may cause additional lung injury,1,2 which could delay or prevent resolution of respiratory failure. Ventilator-induced lung injury may be caused by overdistention of aerated lung regions, especially when large tidal volumes are used.3?5 Ventilator-induced lung injury may also occur if a substantial portion of the lung is not aerated at end-expiration because of atelectasis, flooding, and consolidation. This may cause excessive mechanical forces in aerated lung regions,6 between aerated and nonaerated . . .