Aetiology and prognostic factors of patients with AIDS presenting life-threatening acute respiratory failure.

Respiratory failure is a significant contributor to morbidity and mortality in patients with the acquired immune deficiency syndrome (AIDS). We performed a study to investigate the aetiology, prognostic factors, and short- and long-term outcome of AIDS patients with life-threatening respiratory failure and pulmonary infiltrates. Forty-two AIDS patients (29 of whom required mechanical ventilation), admitted to a Respiratory Intensive Care Unit (ICU) from 1985 to 1992 because of severe respiratory failure (arterial oxygen tension/fractional inspiratory oxygen (Pa,O2/FI,O2) ratio at hospital admission 19 +/- 14 kPa (mean +/- SD)) and diffuse pulmonary infiltrates, were studied for evaluation of the aetiology and outcome. Necropsy studies were performed in 14 out of 23 (61%) patients who died. Pneumocystis carinii was the most common aetiology of pulmonary infiltrates (28 patients (67%)). Overall, 19 patients survived (45%) and 23 (55%) died. A multivariate analysis of prognostic factors influencing the outcome of the whole population showed that the presence of P. carinii pneumonia and the requirement for mechanical ventilation (MV) were the major determinants of outcome for this type of patient. The median survival time after ICU discharge for P. carinii pneumonia patients was lower (49 days) when compared to that of the remaining patients (154 days). Median survival time after ICU discharge for patients needing MV (112 days) did not differ from that observed in patients not requiring artificial ventilatory support (154 days). Although the ICU survival rate in this study was reasonable, 55% for the whole population, and 36% for P. carinii pneumonia patients, the poor outcome after ICU discharge, in particular for P. carinii pneumonia patients, deserves the reassessment of ICU admission criteria for this type of AIDS population.