Acute Lung Injury

Acute respiratory distress syndrome (ARDS) is a clinical syndrome of acute respiratory failure due to acute lung inflammation and noncardiogenic pulmonary edema that often leads to multiorgan system failure and death. Although improvements in prevention and treatment have decreased both the incidence and the mortality of ARDS, it remains a substantial public health problem in the United States, Canada, and worldwide. In the current issue of Seminars in Respiratory and Critical Care Medicine, 11 articles highlight current clinical management strategies with an emphasis on emerging and future therapies as well as recent topics of major interest in clinical and basic research.

Thompson and Moss begin the issue with an article on ARDS definitions. They trace the history and evolution from the original description of ARDS in 1967 by Ashbaugh and coauthors to the recent Berlin modification of the American European Consensus Conference Guidelines. The limitations of current definitions and the persistent challenge of patient heterogeneity are discussed. The article by Meade and Lamontagne on clinical trial design further underscores the impact that patient heterogeneity may have on methodology, interpretation, and generalizability. Janz and Ware explore linkages between biomarkers and the extent of lung epithelial or endothelial injury and offer a potential strategy to improve patient homogeneity in clinical study design.

Although clinical risk factors for ARDS are well established, the role of genetic heterogeneity in determining risk and outcomes of ARDS is an area of active investigation. The article by Meyer and Christie highlights the progress and challenges in establishing the role and functional significance of genetic heterogeneity in ARDS. The H1N1 influenza outbreak helped emphasize the central role of viral pathogens in ARDS development. For this reason, Hendrickson and Mathay have provided an article that focuses on coronavirus-mediated severe acute respiratory syndrome (SARS) and pandemic H1N1 influenza. The emergence of a highly virulent H7N9 influenza epidemic in China at the time of this writing underscores the importance of both established and emerging viral pathogens as a major cause of severe lung injury.

Prevention, early identification, and treatment of ARDS have become important areas for clinical research in the past decade. In light of this, articles by Ortiz-Diaz and colleagues on novel therapies for ARDS prevention and by Mac Sweeney and colleagues on current and emerging pharmacological therapies for established ARDS are included here. State-of-the-art and new ventilator management strategies are explored in a separate article by al-Hegelan and McIntyre that covers both standard low tidal volume ventilator management and other ventilator modalities. The role for invasive hemodynamic monitoring in ARDS management is controversial, and the article by Martin provides a thorough overview of invasive and noninvasive hemodynamic monitoring strategies during the early, established, and resolution phases of ARDS.

Long-term outcomes after ARDS and a focus on morbidity, not solely survival, has become an important research niche over recent years. ARDS survivors have significant muscle weakness, mood disorders, and cognitive dysfunction. The article by Herridge and colleagues discusses the role that a rehabilitative medicine approach may play in targeting intensive care unit–acquired weakness. Long-term economic and health care utilization outcomes are addressed in a complementary article by Bice and colleagues. These authors highlight the contribution that prolonged mechanical ventilation, long-term acute care, and rehabilitative medicine programs make to overall health care costs for ARDS.

It is our hope that these authoritative articles will provide a current overview of issues at the forefront of ARDS management and current areas of active research.