Definitions for sepsis, septic shock, acute lung injury (ALI), and acute respiratory distress syndrome (ARDS) were developed by consensus conferences with the goal of achieving standardization of terminology and improved homogeneity of patient populations in clinical studies. Although such definitions have been useful in epidemiologic investigations, the criteria specified by the consensus conferences are broad and insufficiently specific to address the problem of heterogeneous mechanisms leading to clinical syndromes. An important challenge is to progress from clinical syndromes, as presently defined, to more specific entities that are delineated by alterations in specific immunologic or biochemical pathways. Such mechanistic definitions will provide more homogeneous groups of patients who can be identified at early stages of their clinical course. This approach encourages focused investigation of pathways leading to organ system dysfunction and death and, also, provides an efficient framework for the development of new therapies useful in critically ill patients.
From the Divisions of Pulmonary Sciences and Critical Care Medicine (Drs. Abraham, Parsons, and Repine) and Infectious Diseases (Dr. Dinarello), University of Colorado Health Sciences Center, Denver, CO; the Cardiovascular Research Institute, University of California at San Francisco, San Francisco, CA (Dr. Matthay); the Department of Intensive Care, Erasme University Hospital, Free University of Brussels, Brussels, Belgium (Dr. Vincent); the Department of Infectious Diseases, Hammersmith Hospital, London, UK (Dr. Cohen); the Division of Infectious Diseases, Brown University Medical School, Providence, RI (Dr. Opal); the Division des Maladies Infectieuses, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland (Dr. Glauser); and the Departments of Pulmonary and Critical Care Medicine, The Cleveland Clinic Foundation, Cleveland, OH (Dr. Fisher).