Positive end-expiratory pressure (PEEP) has been viewed as an essential component of mechanical ventilation in acute respiratory distress syndrome (ARDS) and acute lung injury (ALI). However, clinical trials have not yet convincingly demonstrated that high PEEP levels improve survival. The object of this study was to test a priori hypotheses that a small but clinically important mortality benefit of high PEEP did exist, especially in patients with greater overall severity of illness and differences in PEEP protocols might have affected the study results.
University of Missouri-Columbia, Division of Pulmonary, Critical Care and Environmental Medicine, Five Hospital Drive, CE 412, Columbia, MO 65212, USA. obay@health.missouri.edu