Mechanical ventilation in acute lung injury and ARDS. Tidal volume reduction

Traditional mechanical ventilation practices used generous tidal volumes in patients with acute lung injury and acute respiratory distress syndrome (ALI/ARDS). This approach may have caused overdistention of aerated lung units, thus exacerbating lung injury in some patients. Several recent clinical trials of traditional versus lower tidal volume strategies in ALI/ARDS yielded disparate results. In the largest study, the lower tidal volume approach was associated with lower mortality and more ventilator-free days. This article reviews the rationale for tidal volume reduction in ALI/ARDS and the differences between the studies. Several different interpretations of the recent clinical trial results are addressed.