ObjectiveTo perform a descriptive study of patients with acute respiratory failure secondary to acquired immunodeficiency syndrome-related Pneumocystis carinii pneumonia and to identify variables that are predictive of death within 3 months.DesignCase series study.SettingInfectious disease intensive care unit (ICU) in a university hospital.PatientsDetailed clinical, laboratory, and ventilatory data were collected prospectively within 48 hrs of admission and during the ICU stay in 110 consecutive human immunodeficiency virus-infected patients requiring ICU management with or without mechanical ventilation for P. carinii pneumonia-related acute respiratory failure.Measurements and Main Resultsor=to5 days (OR, 2.8; 95% CI, 1.1-6.9), nosocomial infection (OR, 5.2; 95% CI, 2.1-12.9), and pneumothorax (OR, 5; 95% CI, 1.7-14.7) were predictive of death within 3 months of ICU admission. Among patients with delayed mechanical ventilation on day 3 or later and with a pneumothorax associated or not associated with a nosocomial infection, the predicted probability of 3-month death was close to 100%.ConclusionsOur data suggest that the most significant predictive factors of death were identifiable during the course of P. carinii pneumonia-related acute respiratory failure rather than at admission and can help in bedside decisions to withdraw intensive care support in such patients. (Crit Care Med 1999; 27: 1109-1115)