Autoregulation of Cerebral Blood Flow

Abstract

The effect of phenobarbital and pancuronium on cerebral blood flow (CBF) and CBF autoregulation are studied in newborn piglets after chemically induced seizures with bicuculline. Given 3 or 15 min after the onset of seizures, phenobarbital significantly reduces CBF (59 ±11 and 56 ± 17 vs. 84 ± 24 ml/min/100 g - p < 0.01). Moreover, during graded hypotension induced by graded haemorrhage, phenobarbital provides reestablishment of CBF autoregulation altered by seizures. In the same experimental model, pancuronium induces in control animals a rise of CBF (61 ± 15 vs. 38 ± 11 ml/min/100 g - p < 0.001). During graded hypotension pancuronium is associated to a loss of CBF autoregulation (r = 0.76, p < 0.001). Given as an adjunct treatment, in case of seizures, pancuronium has no significant effect on changes in cerebral haemodynamics. From these data, we conclude that pancuronium jeopardizes the haemodynamic adaptation to the induced hypovolemia and that phenobarbital may present a protective effect on cerebral haemodynamics and the subsequent risk for ischaemia or haemorrhage.