Abstract
Over the past three decades, experimental studies have contributed substantially to an increased understanding of the pathogenesis of acute lung injury (ALI) and its extreme manifestation, the acute respiratory distress syndrome (ARDS). However, many investigators have employed animal models that fail to accurately reproduce the heterogeneity of human ALI/ARDS, and which are difficult to sustain for the protracted periods needed to permit an assessment of the effects of mechanical ventilation and other supportive measures upon the evolution of the syndrome. Clinical studies are therefore critical to expanding our understanding of ALI/ARDS, and those that have contributed significantly to progress in this area are summarized herein. Trials of putative treatment strategies for ALI/ARDS are discussed elsewhere. For brevity, the abbreviation ALI is employed throughout, unless studies were performed specifically in patients with ARDS.