Cerebrovascular and Metabolic Effects of Isoflurane and Halothane: A Preliminary Report
Cerebrovascular and metabolic effects of volatile anaesthetics, barbiturates and narcotics have been extensively studied in animals and humans (Smith 1975). Although most of these agents cause a dose-dependent decrease in cerebral oxygen consumption, the cerebrovascular properties vary considerably. In contrast to barbiturates, most volatile anaesthetics increase CBF, usually in a dose-dependent manner. Since cerebral vasodilatation caused by these agents leads to an increase in cerebral blood volume, administration of volatile anaesthetics to patients with intracranial space occupying lesions are considered dangerous, although the risk of increased intracranial pressure can usually be controlled by means of adequate hyperventilation. The introduction of isoflurane has caused a great deal of interest, since it has been suggested that the cerebral vasodilatory properties in humans are less pronounced than those of halothane (Murphy et al. 1974; Eintrei et al. 1985). Reports suggesting that cerebral metabolic effects of isoflurane differ from halothane are based on observations in animals (Cucchiara et al. 1974; Newberg et al. 1983; Todd et al. 1984). Mean hemispheric blood flow and cerebral oxygen consumption were therefore studied in humans during isoflurane and halothane anaesthesia.
KeywordsCerebral Blood Volume Volatile Anaesthetic Halothane Anaesthesia Brain Blood Flow Intracranial Space
- Murphy FL, Kennwell EM, Johnstone RE et al. (1974) The effects of enflurane, isoflurane, and halothane on cerebral blood flow and metabolism in man. Abstracts of scientific papers, American society of anesthesiologists, annual meeting, pp 61–62Google Scholar