Ductus closure in preterm infants. Effects on cerebral hemodynamics.

Intracranial arterial blood flow velocities were studied before and after ductus closure by surgery (n = 8) and indomethacin (n = 10) in very low birth weight infants. Blood flow velocities were measured non-invasively through the fontanel with a pulsed Doppler velocimeter. Ligation of the ductus was associated with a 62% increase in mean flow velocity 24 hours after surgery, mainly secondary to increased diastolic flow velocity. Indomethacin (0.2 mg/kg i.v.) induction of ductus constriction was associated with a 36% decrease of mean flow velocity one hour after administration. At 24 hours, the intracranial blood flow velocity had returned to the pretreatment level but was still significantly lower than after ligation. Ductus closure is associated with marked changes in cerebral hemodynamics. Ligation causes increased arterial blood flow velocities and indomethacin administration seems to reduce blood flow velocities to the brain.