Pulmonary hypertension and right ventricular dysfunction in growth-restricted, extremely low birth weight neonates.

This case series reports an acute episode of hypoxemia and systemic hypotension in seven infants under 1 kg, taking place several hours or days after birth, after a period of stability and in the absence of significant lung disease. These patients were growth-restricted at birth and had a history of chronic fetal hypoxia and oligohydramnios. Pulmonary hypertension and right ventricular dysfunction were found by echocadiography. Right ventricular ejection fraction was significantly depressed during the acute episode, compared to baseline values measured after recovery. The timing of symptoms seemed related to ductus arteriosus closure or constriction. Oxygenation and right ventricular function improvement occurred within a few days under ventilatory and inotropic support, while milrinone was administered in five cases. In conclusion, pulmonary hypertension is a rare but significant cause of hypoxemia in preterm infants, and pulmonary vasodilator therapy should be considered in the presence of right ventricular dysfunction.