Contributions to the epidemiology of acute respiratory failure.

Recently, incidence ranges for acute respiratory failure (ARF), acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) in adults were reported and found to be 77.6–88.6, 17.9–34.0, and 12.6–28.0 cases/100 000 population per year, respectively. Mortality rates of approximately 40% were reported for patients with acute respiratory failure, and similar or slightly lower rates for those with ALI and ARDS. Some experts believe that there is a trend toward lower mortality rates in ALI and ARDS, but this suggestion has not been scientifically validated. Additional organ failures, but not oxygenation indices, appear to be crucial with regard to predicting outcome. Finally, it has remained uncertain whether there exists seasonal variability with respect to the frequency of various forms of respiratory failure.