Incidence, clinical course, and outcome in 217 patients with acute respiratory distress syndrome

Objective. To assess prospectively acute respiratory distress syndrome incidence, etiologies, physiologic and clinical features, and mortality and its predictors in four intensive care units in Argentina. Design. Prospective inception cohort. Setting. Four general intensive care units in teaching hospitals. Patients: All consecutive adult patients admitted between January 3, 1999, and January 6, 2000, that met the criteria of the American- European Consensus Conference for acute respiratory distress syndrome. Interventions: None. Measurements and Main Results: A total of 235 patients developed acute respiratory distress syndrome, and 217 survived for >24 hrs; these were further analyzed. Main risk factors were: sepsis (44%, including 65 pneumonia cases), shock (15%), trauma (11%), gastric aspiration (10%), and other (34%). At admission, nonsurvivors had significantly higher Acute Physiology and Chronic Health Evaluation 11, Sequential Organ Failure Assessment and McCabe scores, and lower oxygenation and pH. During the first week, Pao(2)/Fio(2), Sequential Organ Failure Assessment, pH, base excess, and driving pressure consistently discriminated between survivors and nonsurvivors. Hospital mortality was 58%. One third of patients died early. Main causes of death were multiple organ dysfunction syndrome, sepsis, and septic shock; refractory hypoxemia was uncommon. Factors independently associated with mortality were organ dysfunctions on day 3, Pao(2)/Fio(2) on day 3, and McCabe score. Conclusions. Acute respiratory distress syndrome was a frequent syndrome in this cohort. Sepsis was its leading cause, and pneumonia was the most common single diagnosis. Mortality was high but similar to most recent series that included serious comorbidities. Independent predictors of death 72 hrs after admission emphasize the importance of both extrapulmonary and pulmonary factors together with preexisting severe illnesses.