Inhaled nitric oxide in persistent pulmonary hypertension of the newborn refractory to high-frequency ventilation

Background:
This study was designed to evaluate the effect of nitric oxide
(NO) on the management of neonates with severe persistent pulmonary
hypertension refractory to high-frequency oscillatory ventilation.

      Methods:
      The birth weight and the gestational age of infants
            were 3125.5 ± 794 g (mean ± SD) and 39 ± 2.4 weeks, respectively. All
            neonates were ventilated for an average of 137.5 min (range 90-180 min) prior to
            NO therapy. The mean oxygenation index (OI) of all neonates prior to NO was
            46.3 ± 5 (mean ± SEM). NO was initially administered at 20 parts per
            million (ppm) for at least 2 h and increased gradually by 2 ppm to a maximum of
            80 ppm.


      Results:
      Eighteen infants (75%) responded and six (25%) did not respond to
            the treatment. Three neonates died in the responding group, while all the
            non-responders died (P = 0.0001). The survival rate was 62.5% among all
            neonates. NO significantly decreased OI (P < 0.0001) and improved
            the arterial/alveolar (a/A) oxygen ratio (P < 0.0001) within the
            first 2 h of NO therapy in 61.1% of the responders. However, the OI and the a/A
            oxygen ratio remained almost the same throughout the treatment in the
            non-responders and the non-survivors.


      Conclusion:
      Inhaled NO at 20 ppm, following adequate ventilation for 2 h without
            significant response, could be used to identify the majority of the
            non-responders in order to seek other alternatives.