The effects of indomethacin on the pulmonary vascular response to hypoxia in the premature and mature newborn goat.

The effects of indomethacin on the pulmonary circulation and the response of the circulation to hypoxia were investigated in premature and mature newborns using an isolated perfusion technique on otherwise intact left lungs in situ. There was an increase in pulmonary vascular resistance and augmentation of the increase in pulmonary vascular resistance during hypoxia following indomethacin. These effects were greater in the premature than in the mature newborn. Indomethacin effectively removes a dilator influence on the pulmonary circulation. The results are consistent with the concept that prostaglandins are important in regulating pulmonary vascular resistance.