Right and Left Ventricular Planimetry in Newborns Treated with Inhaled Nitric Oxide † 1639

Abstract

Planimetry was performed by two-dimensional echocardiography in 33 newborns with lung disease and pulmonary hypertension who were treated with inhaled nitric oxide to determine the influence of therapy on right and left ventricular size and function. The area of each ventricle was measured during diastole and systole from apical 4-chamber images before and after (30-60 minutes) the onset of 20 parts per million inhaled nitric oxide. Areas were indexed according to patient weight. Ventricular function was determined by(diastolic area-systolic area)/diastolic area. The severity of pulmonary hypertension was evaluated by Doppler echocardiography. Values are expressed as mean ± standard error, * p <0.05. Results: There were no changes in heart rate, systemic blood pressure, and right or left ventricular function. However, nitric oxide acutely decreased the oxygenation index (53± 5 vs. 30 ± 3*), the proportion of right to left ductal shunt(nonrestrictive ductus arteriosus, n=22; 0.60 ± 0.06 vs. 0.31 ± 0.06*), the systolic pulmonary arterial pressure (closed or restrictive ductus arteriosus, n=11; 71 ± 8 vs. 50 ± 7, mmHg*), and the indexed right ventricular diastolic (0.84 ± 0.04 vs 0.75 ± 0.03, cm2/kg*) and systolic (0.62 ± 0.04 vs 0.55 ± 0.03, cm2/kg*) areas. Baseline heart rate, blood pressure, blood gases, and Doppl. Baseline left ventricular function (0.28 ± 0.03, n=8 vs. 0.39± 0.02, n=25*) was less in patients who developed an increase in left ventricular diastolic area following nitric oxide inhalation. Conclusions and speculation: Oxygenation and pulmonary hemodynamics improve after nitric oxide inhalation in newborns with lung disease and pulmonary hypertension. This results in a decrease in right ventricular size; however, patients may develop an increase in left ventricular size if left ventricular function is decreased.