Effect on Cerebral Oxygenation by Sevoflurane or Propofol Using Near-infrared Spectroscopy in Carotid Endarterectomy

The aim of this study is comparing the effect on cerebral oxygenation by sevoflurane-remifentanil or propofol-remifentanil anesthesia in patient undergoing carotid endarterectomy. Cerebral oxygenation is measured by near-infrared spectroscopy. Sevoflurane and propofol reduce the cerebral metabolic rate for oxygen in similar degree. Propofol decrease the cerebral blood flow by dose-dependent manner, however, sevoflurane increase the cerebral blood flow in the concentration of avobe 1 MAC. Both drugs are widely used in general anesthesia for neurosurgical procedure, and their effect on cerebral oxygenation are acceptable. There is little data about the effect of general anethetics on cerebral oxygenation in patients undergoing carotid endarterectomy, who have imparied cerebral circulation. Our hypothesis is sevoflurane will show better cerebral oxygenation than propofol in patient have impaired cerebral circulation.