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Objective: To report the neurodevelopmental outcome of infants enrolled in a randomized multicenter trial of early inhaled nitric oxide (iNO) in term and near-term neonates with hypoxic respiratory failure and pulmonary hypertension., Study Design: Neonates born at > or = 34 weeks gestation who required assisted ventilation and had an oxygenation index > or = 15 and < 25 were randomized to an early iNO group or a control group. A comprehensive neurodevelopmental assessment of survivors was performed at age 18 to 24 months., Results: The trial enrolled 299 infants, of which 266 (89%) survived to age 18 to 24 months (136 in the early iNO group and 130 in the control group). Follow-up evaluations were done on 234 (88%) of surviving infants. There were no differences between the 2 groups in the incidence of neurodevelopmental impairment (early iNO, 27%; control, 25%) and hearing impairment (early iNO, 23%; control, 24%). Mental development index scores were similar in the 2 groups; however, psychomotor developmental index scores were significantly higher in the control group (early iNO, 89 +/- 17.7; control, 93.5 +/- 18.4)., Conclusions: Early iNO therapy for hypoxic respiratory failure in term and near-term infants is not associated with an increase in neurodevelopmental impairment or hearing loss at 18 to 24 months postnatal age.

The systemic and pulmonary vascular effects of adenosine 5'-triphosphate (ATP) were investigated in 12 newborn lambs during normoxia and during alveolar hypoxia (10% oxygen, 5% carbon dioxide, and 85% nitrogen). Lambs had catheters in the descending aorta, main pulmonary artery, and were studied after a 3-day recovery. We infused ATP or an equal volume of saline solution (control) into the right atrial line in doses ranging from 0.01 to 2.5 mumol/kg per minute. In normoxic lambs, ATP caused a significant decrease in pulmonary vascular resistance in doses of 0.08 to 2.5 mumol/kg per minute, and in systemic vascular resistance in doses of 0.3 to 2.5 mumol/kg per minute. Infusion of ATP in hypoxic lambs caused decreases in pulmonary artery pressure and pulmonary vascular resistance in all the doses tested. Systemic vascular resistance decreased, and cardiac output and heart rate increased in doses greater than 0.3 mumol/kg per minute in hypoxic lambs during ATP infusion. The effects of ATP in hypoxic lambs were not blocked by propranolol, indomethacin, or theophylline. Plasma ATP levels in left atrial blood samples did not change significantly during the infusion of ATP. We conclude that ATP is a vasodilator in lambs, and its effects are specific for pulmonary circulation at doses of less than or equal to 0.15 mumol/kg per minute. The vasodilator effects of ATP appear to be independent of P1 purinergic and beta-adrenergic mechanisms, and of prostacyclin synthesis.