OSITIVE END-EXPIRATORY PRESsure (PEEP) is an essential component of the management of acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). 1 PEEP improves hypoxemia and decreases intrapulmonary shunting, and these effects have been the basis for titrating PEEP in clinical practice. 2 Numerous experimental studies showed that PEEP protected the lung in various models of ventilationinduced lung injury. 3-6 Although the mechanisms of this protective effect are not fully elucidated, they may be mediated by PEEP-induced alveolar recruitment, which avoids cyclic air-See also pp 637, 691, and 693.

The PRESERVE score might help ICU physicians select appropriate candidates for ECMO among severe ARDS patients. Future studies should also focus on physical and psychosocial rehabilitation that could lead to improved HRQL in this population.