Background: Persistent pulmonary hypertension (PPHN) is a significant cause of neonatal morbidity and mortality frequently associated with diseases of term and near-term infants. In recent years, it has also been recognized in preterm infants with respiratory distress syndrome (RDS). We report our experience of inhaled nitric oxide (INO) use in critically ill premature infants with PPHN.

Results: Six infants ranging between 25 to 34 weeks gestation with acute respiratory failure not consistent with severe RDS radiographically but with echocardiographic evidence of PPHN were treated with INO. Three infants were inborn and three were transferred in for respiratory failure. Four infants received surfactant (1 to 4 doses) prior to INO without improvement. The initial dose of INO used was 20 to 25 ppm. All 6 infants had a good response with improvement in the alveolar-arterial gradient (AaD02) with a mean decrease of 289.7 ±111.7 (p<0.001) and oxygenation index(OI) with a mean decrease of 50.6 ±20.7 (p<0.002). These changes were observed during a mean time period of 14.1 ±8.9 hours after initiation of INO. The mean duration of INO administration was 68.6±66.9 hours. All six infants survived and had normal head ultrasounds prior to discharge. The maximum methemoglobin levels were 0.4% to 2.4% and no obvious side effects from INO were recognized. Table

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Conclusion: Inhaled nitric oxide therapy can be used effectively and safely in premature infants with PPHN.