The effect of methoxyflurane on cerebral blood flow in the dog.

Abstract

IN NEUROSURGICAL ANAESTHESIA, there is a place for a volatile agent which will cause neither a significant rise in cerebral blood flow (CBF) nor an increase in intracranial pressure. Most inhalational agents in concentrations greater than 1 MAC increase both cerebral blood flow and intracranial pressure.l-7 Of the agents whose effects have been reported, methoxyflurane in low concentration appears to cause the least rise in cerebro-spinal fluid (CSF) pressure in patients undergoing neurosurgical procedures, whether or not a space-occupying lesion exists. Fitch s showed that methoxyflurane (0.5 per cent inhaled concentration) caused an insignificant change in CSF pressure in patients with normal csF pathways and only a small rise in those with a space occupying lesion. Wollman et al2 found that with cyclopropane and diethyl ether cerebral blood flow in man was decreased during light anaesthesia and that cerebral perfusion increased as anaesthesia was deepened. The explosive risk limits the usefulness of these agents in neurosurgery. Since a non-explosive agent which produces little change in CSF pressure and CBF might have considerable clinical advantages, the effects of light methoxyflurane anaesthesia on CBF were studied in dogs.