The effect of indomethacin on cerebral blood-flow velocity in premature infants

The prostaglandin synthetase inhibitor indomethacin is known to cause significant reduction in cerebral blood-flow (CBF) in certain newborn animals. The authors studied the effect of indomethacin on the CBF velocity of small premature infants, using duplex Doppler real-time ultrasound, and made a record of blood pressure (BP) and heart rate. Indomethacin was infused intravenously in five infants. Repeated measurements were made from the anterior cerebral artery for one hour after injection. There was a significant reduction in mean blood-flow velocity of 40 per cent two minutes after the injection, and it remained 35 per cent below pre-dose levels for at least one hour. There was a simultaneous rise of 15 per cent in systemic BP by one minute after injection. It is argued that these these changes represent a significant reduction in CBF, and this may increase the likelihood of border-zone ischaemic infarction in ill premature infants with pre-existing critical cerebral perfusion.