Echocardiographic assessment of inhaled nitric oxide in newborn infants with severe hypoxemia

ABSTRACT

Nitric oxide inhalation can benefit newborn babies with persistent pulmonary hypertension with right to left extrapulmonary shunt [EPS]. We compared the effects of inhaled nitric oxide [NO] on systemic oxygenation and mean pulmonary blood flow velocity [MPBFV] using doppler ultrasound in severely hypoxic newborn infants with or without extrapulmonary shunt. With a median dose of 20 parts per million [ppm], oxygenation index decreased significantly in both groups [EPS, [p < 0.001] and non-EPS [p <0.05]]. The percentage decrease was significantly greater in the EPS group [p<0.001]. MPBFV increased significantly in the EPS group [p<0.001] only. There was significant correlation between the percentage decrease in oxygenation index and the percentage increase in MPBFV after 1 h of inhaled NO in the EPS group only. We conclude that inhaled NO may improve some newborn infants with severe hypoxemia without significant EPS by improving ventilation perfusion matching. Careful Doppler ultrasound could help to predict the likelihood of beneficial effects of inhaled NO. Nitric oxide being more effective in newborn infants with extrapulmonary shunting than those without by increasing pulmonary blood flow