Epidemiology of acute lung injury.

To review the epidemiology of acute lung injury (ALI) with particular emphasis on its effect on public health. Published studies on the definitions, incidence, and outcomes of ALI. ALI is a syndrome of acute hypoxemic respiratory failure that is not primarily cardiac in origin. The diagnostic criteria for the syndrome have not been well studied for their reliability or validity. The lack of a gold standard for the diagnosis of ALI is a challenge to clinical investigation. Recent data on the incidence of ALI (20-50 cases/105 person-years) indicate that it is more common than previous estimates for the incidence of acute respiratory distress syndrome (3-8 cases/105 person-years). There is conflicting evidence as to whether the mortality rate in the broader patient population with ALI is different from the mortality rate in acute respiratory distress syndrome. Mortality attributable to and associated with ALI in the United States is comparable to HIV infection, breast cancer, and asthma. Morbidity from impaired cognitive function, functional status, and psychiatric complications has been reported in survivors of ALI. Recent studies of the epidemiology of ALI have reported higher incidence rates for this syndrome than previously described. The mortality and morbidity rates associated with ALI are considerable, with significant impact on public health.