PLASMA ENDOTHELIN-1 IN THE NEONATAL RESPIRATORY-DISTRESS SYNDROME

In order to study the contribution of the vasoconstrictory peptide end othelin-1 (ET-1) to the elevation of the pulmonary vascular resistance in the neonatal respiratory distress syndrome (RDS) seven preterm inf ants were studied at 2, 24 and 48 hours of age for plasma ET-1 concent rations and systolic pulmonary artery pressure (PAP), measured by Dopp ler sonography. Plasma ET-1 levels were high during the first day afte r birth, but declined soon to normal levels thereafter. During the stu dy period, the systolic PAP also decreased, whereas the systemic press ure remained unchanged. There were no correlations between plasma ET-1 and vascular pressures, but there was a significant association betwe en ET-1 and the requirement of supplemental oxygen and the arterial-al veolar oxygen tension ratio. Our results thus suggest that high plasma ET-1 levels in the acute phase of RDS reflect the severity of the pul monary disease, but may not significantly contribute to the elevation of the pulmonary vascular resistance in the RDS.