SK Sanyal, FS Chebib, JR Gilbert and WT Hughes
Department of Pediatrics, King Faisal University, Dammam, Saudi Arabia.

Early reliable identification of patients with Pneumocystis carinii pneumonia (PCP) who will require ventilatory support would be desirable. To develop a predictive system to meet this need, we studied, prospectively, the sequential alterations in vital signs and acid-base and blood-gas profiles associated with this disease in 55 children with cancer, 29 of whom did not require ventilatory support (Group I) and 26 who did (Group II). None of the patients had acquired immunodeficiency syndrome (AIDS). On admission to the hospital the only feature that distinguished patients in Group I from those in Group II was the mean (+/- SD) respiratory rate (38.7 +/- 2.1 versus 49.1 +/- 3.5 breaths/min, p < 0.02). By 12 h after admission there was a significant difference in the partial pressure of oxygen (PaO2) between Groups I and II (75.1 +/- 3.2 mg Hg versus 65.4 +/- 3.1 mm Hg, p < 0.05), and also in the two groups' inspired fraction of oxygen (FIO2; 24.9 +/- 0.54% versus 29.6 +/- 1.6%, p < 0.01). Both alterations, as well as tachypnea, persisted for the remainder of the study period. The maximum FIO2 did not exceed 45% in Group I, and by 60 h after admission to the hospital, all patients in this group had persistent increases in PaO2 that exceeded 80 mm Hg, permitting decreases in FIO2 to that of room air. In Group II, hypoxemia was refractory despite an increase in FIO2 to 50%, at which point ventilatory support was begun (at a mean of 81.1 +/- 32.3 h after admission).(ABSTRACT TRUNCATED AT 250 WORDS)