THE EFFECTS OF CLINICAL CONCENTRATIONS OF HALOTHANE ON THE BLOOD FLOW AND OXYGEN UPTAKE OF THE CEREBRAL CORTEX

Abstract

Clinical concentrations of halothane vaporized in nitrous oxide-oxygen caused vasodilatation in the cerebral cortex of anaesthetized dogs at constant arterial carbon dioxide tension. The vasodilatory action on the cerebral circulation was greater the higher the concentration of halothane. Consequently 2 per cent halothane increased blood flow through the cerebral cortex more than did 0.5 per cent halothane. However, the administration of 4 per cent halothane reduced mean blood pressure so markedly that blood flow was not elevated above the control value. The oxygen uptake of the cerebral cortex was depressed by halothane and this depression was greater with 2 per cent halothane than with 0.5 per cent. These results are discussed with reference to the effects of halothane on intracranial pressure and on the oxygenation of the brain.