RESPONSE OF PREMATURE-INFANTS WITH SEVERE RESPIRATORY-FAILURE TO INHALED NITRIC-OXIDE

Elevated pulmonary vascular resistance is seen in premature infants wi th severe respiratory distress syndrome (RDS). inhaled nitric oxide (N O) has been shown to decrease pulmonary Vascular resistance and to imp rove oxygenation in some patients with respiratory failure. The purpos e of this study was to determine whether premature infants with severe RDS would respond to inhaled NO with an improvement in oxygenation. E leven premature infants (mean gestational age 29.8 weeks) with severe respiratory failure caused by RDS were treated with NO in four concent rations [1, 5, 10, 20 parts per million (ppm) NO] and with placebo (0 ppm NO). Arterial blood gas measurements were drawn immediately before and at the end of each of the 15-minute treatments and were used to d etermine the arterial/alveolar oxygen ratio (Pao(2)/PAo(2)). Ten of th e 11 infants had a greater than 25% increase in Pao(2)/PAo(2). Five of the 11 had a greater than 50% increase in Pao(2)/PAo(2). Despite norm al cranial ultrasound imaging prior to NO, 3 infants had intracranial hemorrhage (ICH) noted on their first ultrasound scan after this brief period of NO treatment, and 4 additional infants developed ICH later during their hospitalization. No infant had significant elevations of methemoglobin concentrations after the total 60-minute exposure to NO. NO may be an effective method of improving oxygenation in infants wit h severe RDS. The disturbing incidence of [CH in this small group of i nfants needs to be carefully evaluated before considering routine use of NO for preterm infants. (C) 1997 Wiley-Liss, inc.