Aids and the lung. 6-- Management of respiratory failure in patients with the acquired immune deficiency syndrome and Pneumocystis carinii pneumonia.

Pneumocystis carinii pneumonia is the most common life threatening infection in patients with AIDS and is responsible for up to 85% of all respiratory episodes.'The disease ranges in severity from a mild infection with a normal chest radiograph and an indolent course2 to respiratory failure requiring assisted ventila- tion, where the mortality may exceed 90O%.' Pneumocystis pneumonia is now likely to be diagnosed at an earlier stage than it was in the past because of increased awareness by both physicians and patients and also because of the increased sensitivity of the bronchoscopic and laboratory methods now available.Despite these diagnostic advances and increased aware- ness, the mortality ofpneumocystis pneumonia has not fallen.3Several recent studies have attempted to identify which patients with pneumocystis pneumonia are likely to have a poor outcome.45These studies have looked at several aspects, including patterns of symptoms and clinical findings, the degree of abnor- mality on the chest radiograph, measures of oxygenation and results of laboratory tests such as serum lactate dehydrogenase activity.The prognostic markers associated with a poor outcome are summarised in table 1.In essence, these studies show that patients with severe pneumocystis pneumonia do badly and that there is no reliable index of prediction that will permit clinicians to identify prospectively those patients who are likely to have a poor disease course.This article will discuss the management of HIV positive patients with pneumocystis pneumonia who deteriorate while having treatment and develop respiratory failure.