Nasal continuous positive airway pressure in Pneumocystis carinii pneumonia

10 cm H2O of nasal continuous positive airway pressure (CPAP) was applied in nine subjects with Pneumocystis carinii pneumonia and the acquired immunodeficiency syndrome, all of whom had presented with bilateral pulmonary infiltrates and hypoxaemia. The procedure was tolerated well by eight patients and none of the nine had complications. 20 minutes of nasal CPAP without supplemental oxygen increased mean PaO2 from 55.9 to 68.4 mm Hg and decreased the calculated alveolar-arterial oxygen gradient from 48.3 to 34.3 mm Hg. In one patient who was breathing oxygen at 4 litres per minute, PaO2 increased by 35 mm Hg. Nasal CPAP could be a useful method for augmenting oxygenation in P carinii pneumonia.