Persistent Pulmonary Hypertension of the Newborn

Persistent pulmonary hypertension of the newborn or persistent fetal circulation is a clinical syndrome that is usually apparent within the first 2 days after birth because of the presence of hypoxemia (2;12;19). The syndrome was first described in an abstract by Gersony, Due, and Sinclair (6) in 1969. Two infants were reported who had “RV decompensation, cyanosis and clear lung fields… in the absence of recognizable cardiac, pulmonary, hematologic or CNS disease.” The syndrome has been associated with aspiration of meconium, diaphragmatic hernia, asphyxia, hemorrhage, shock, and maternal infection (4;18). In other cases, there is no clear antecedent event. Despite considerable interest in the problem and a wealth of research related to pulmonary vasoregulation and vascular development in the fetus and newborn, the etiology of the syndrome remains obscure 20 years since its recognition.