Neurophysiological parameters during halothane anaesthesia in experimental models of cerebral ischemia

Types of anaesthesia in different experimental models of ischemia vary, with consequent difficulties in analysis of results obtained by the authors. The aim of this work was to evaluate EEG and SEPs parameters in a group of rabbits submitted to anaesthesia with halothane. We used White New Zealand rabbits prepared for EEG recording according to the Monnier and Gangloff's stereotaxic method. SEPs were obtained by medial nerve stimulation according to a method standardized in our laboratory. Each animal was anaesthetized with halothane plus nitrous oxide and oxygen or halothane plus oxygen for surgical MAC, which was maintained for a time corresponding to the duration of surgical intervention. We evaluated all parameters in basal conditions and after the administration of anaesthesia until EEG and SEPs returned to basal values. Evoked potentials remained altered for a longer period of time and returned to basal levels only two hours after anaestethic suspension.