Shunts in Patients With Respiratory Distress Syndrome

In Reply.— We agree with Dr Evans that bidirectional ductal shunting is more common than net right-to-left ductal shunting in premature neonates with severe RDS and persistent pulmonary hypertension. Our conclusion that large right-to-left shunts via the ductus are common findings in these cases was not intended to exclude the presence of concomitant left-to-right shunting. In our study population the incidence of right-to-left ductal shunting at 12 and 24 hours of age was 86% and 94% in premature neonates with fatal RDS, 39% and 34% in the severe RDS group, 4% and 0% in the no/mild RDS group, and 6% and 0% in the full-term neonates without RDS.