A randomized, controlled study of the 1-hour and 24-hour effects of inhaled nitric oxide therapy in children with acute hypoxemic respiratory failure.

STUDY OBJECTIVE: To determine whether 24 h of inhaled nitric oxide improves oxygenation greater than conventional therapy alone in children with acute hypoxemic respiratory failure.

DESIGN: Prospective, randomized, controlled study.

SETTING: Twenty-six-bed pediatric ICU in a tertiary children's hospital.

PATIENTS: Twenty-four patients with acute bilateral lung disease requiring a positive-end expiratory pressure >6 cm H2O and a fraction of inspired oxygen >0.5 for >12 h.

INTERVENTIONS: Twelve patients were treated with 10 ppm inhaled nitric oxide from the onset of randomization and 12 control patients were initially maintained on a regimen of conventional therapy alone. After a period of 24 h, control patients were also treated with 10 ppm inhaled nitric oxide. Hemodynamic and blood gas measurements were performed at baseline, at 1 h after randomization, and at 24-h intervals for 2 days.

MEASUREMENTS AND RESULTS: Inhaled nitric oxide decreased the ratio of pulmonary to systemic vascular resistance and improved oxygenation indexes during the initial hour following randomization. However, 24 h after randomization, the oxygenation indexes of 11 surviving treated patients were not improved in comparison to baseline or the oxygenation indexes of 10 surviving control patients. Oxygenation indexes acutely improved in control patients when inhaled nitric oxide was started after 24 h of conventional therapy. Oxygenation indexes remained improved in the initial control patients after 24 h of inhaled nitric oxide.

CONCLUSIONS: Pulmonary vascular resistance and systemic oxygenation are acutely improved by 10 ppm inhaled nitric oxide in some children with severe lung disease. However, a sustained improvement in oxygenation may not occur during prolonged therapy. Thus, inhaled nitric oxide may have a limited therapeutic role in children with acute hypoxemic respiratory failure.