Patients:We studied retrospectively the echocardiographic features of newborns with persistent pulmonary hypertension who had been randomised to receive inhaled nitric oxide or conventional therapy. We sought to identify the predictors of extracorporeal membrane oxygenation therapy, death, and response to inhaled nitric oxide.Results:Among 85 neonates studied, an extrapulmonary right-to-left shunt through either an oval foramen and/or an arterial duct was present in 80 (94%) cases. In the 64 patients (75%) with adequate images for measurements, left ventricular ejection fraction was normal or mildly depressed in 87%, but there was a decreased index of left ventricular output, inferior to 2 l/min/m2, in 61% of the cases. Using multivariate analysis, an exclusive right-to-left ductal shunt was found to be an independent predictor of death, with odds ratio of 7.8, and 95% confidence intervals from 1.2 to 52.8, with a p value of 0.04. There was also a non-significant trend toward greater use of extracorporeal membrane oxygenation in patients with a predominant left-to-right ductal shunt, the odds ratio being 0.13, with 95% confidence intervals from 0.01 to 1.22, and a p value of 0.07. In the 40 patients randomised to receive inhaled nitric oxide, 28 had a positive response as defined by a 20% reduction in the index of oxygenation as measured from the post-ductal arterial blood gas sample. A left-to-right atrial shunt increased the risk of failing to respond to inhaled nitric oxide, with an odds ratio of 7.46, 95% confidence intervals from 1.23 to 45.1, and a p value of 0.028.Conclusion:Detailed Doppler echocardiographic screening of patients with suspected persistent pulmonary hypertension of the newborn may refine the selection of groups for specific treatment, and identify risk factors.
Inhaled Nitric Oxide at Birth Reduces Pulmonary Vascular Resistance and Improves Oxygenation in Preterm Lambs
