A prospective, randomized, controlled study of children (age: 1 month - 17 years) with acute hypoxemic respiratory failure was performed to determine whether 24 hrs of inhaled nitric oxide (INO) improves oxygenation index (OI) more than conventional therapy alone. Twelve patients were treated with 10 ppm INO from the onset of randomization and 12 control patients were initially managed by conventional therapy alone. After 24 hours, control patients were also treated with 10 ppm INO. Blood gases were measured at baseline, at 1 hour after randomization, and at 24-hour intervals for 2 days. INO improved OI during the initial hour of therapy. However, 24 hours after randomization, the OI of surviving treated patients were not improved in comparison to baseline or the OI of 10 surviving controls. A similar number of patients in each group developed >20% decrease, or >20% increase, in OI during the initial 24 hours after randomization. OI acutely improved in control patients when INO was started after 24 hours of conventional therapy. The OI of these patients remained improved on INO 48 hours after randomization. In conclusion, OI is initially improved by 10 ppm INO in children with acute hypoxemic respiratory failure. However, a sustained improvement in oxygenation may not occur during prolonged therapy in some patients.

* p < 0.05, before vs. after the onset of INO, analysis of variance for repeated measures