Definition of ALI/ARDS.

Although acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are caused by different injuries and conditions, their similar clinical picture makes a compelling case for them to be studied as a single entity. An array of potential specific targets for pharmacologic intervention can be applied to ALI/ARDS as one disease. Although a working definition of ALI/ARDS that includes pulmonary and extrapulmonary causes can have benefit in standardizing supportive care, it can also complicate assessments of the efficacy of therapeutic interventions. In this article, definitions that have been recently used for ALI/ARDS in various clinical studies are discussed individually.