Epidemiology of acute lung injury.

MacCallum, Niall S; Evans, Timothy W

PURPOSE OF REVIEW Acute lung injury and its extreme manifestation, acute respiratory distress syndrome, complicate a wide variety of serious medical and surgical conditions, only some of which affect the lung directly. Despite recent evidence-based advances in clinical management, acute lung injury and acute respiratory distress syndrome are associated with significant mortality. Detailed epidemiology is essential in guiding the recruitment of patients into trials of new therapeutic interventions, thereby improving outcome and allowing directed allocation of scarce resources. RECENT FINDINGS The incidence of acute lung injury in the United States overall (17-64 per 100,000 person-years) seems to be higher than in Europe, Australia, and other developed countries (17-34 per 100, 000 person-years). The mortality rates for patients with acute respiratory distress syndrome range from 34 to 58%. The hypothesis that pulmonary and extrapulmonary acute respiratory distress syndromes are different disease entities continues to gain momentum. A genetic predisposition to acute respiratory distress syndrome may contribute to its pathogenesis and outcome. SUMMARY Recent epidemiologic studies of the incidence of acute lung injury and acute respiratory distress syndrome have indicated a similar incidence in developed societies, and they confirm that mortality is falling in comparison with a decade ago. The awaited publication of new consensus guidelines for the definition of acute lung injury and acute respiratory distress syndrome may render new studies necessary.