ABSTRACT
The pressure and volume demands of the right and left ventricles may dramatically
change following selective pulmonary vasodilation in newborns with pulmonary hypertension.
Thus, ventricular planimetry was performed by two-dimensional echo-cardiography in
35 newborns with lung disease and increased pulmonary vascular resistance who were
treated with inhaled nitric oxide to determine the influence of therapy on right and
left ventricular size and function. The end-diastolic and end-systolic areas of each
ventricle were measured from apical 4-chamber images before, and 30 to 60 minutes
after, the onset of 20 parts per million inhaled nitric oxide. Estimates of ventricular
function were determined by the systolic decrease in ventricular area, (diastolic
area - systolic area) • 100/diastolic area. Heart rate, systemic blood pressure, and
left ventricular areas did not change. However, the oxygenation index, the proportion
of right-to-left ductal shunt (nonrestrictiveductus arteriosus, n = 22), the systolic pulmonary arterial pressure (closed or restrictive ductus arteriosus,
n = 13), and the right ventricular diastolic and systolic areas were decreased after
nitric oxide inhalation. The baseline systolic decrease in left ventricular area was
lower in a subgroup of patients who developed an increase in left ventricular diastolic
area following nitric oxide inhalation. Thus, nitric oxide improves pulmonary hemodynamics
and decreases right ventricular size in newborns with lung disease and pulmonary hypertension.
However, newborns may develop an increase in left ventricular size if left ventricular
function is decreased prior to therapy.
Keywords
Lung disease - persistent pulmonary hypertension in the newborn - nitric oxide - echocardiography
