Cerebral oxygen saturation is improved by xenon anaesthesia during carotid clamping

INTRODUCTION: The cerebral protective effect of xenon anesthesia could be of interest during carotid surgery. The purpose of this study was to compare the effects of xenon on cerebral oxygen saturation with those of propofol during carotid clamping. METHODS: After approval of Research Ethics Board and patient informed consent, 74 patients scheduled for carotid endarterectomy were enrolled. Patients were not randomized but were well matched by preoperative characteristics. Patients in the Xenon group were the ones scheduled for surgery in the operative theater equipped with the xenon anesthesia system. Anesthesia was started with a target control infusion of propofol and remifentanil. Patients were then divided into the control group (37 patients) with anesthesia maintained with target control infusion propofol and remifentanil and the Xenon group with anesthesia maintained with xenon (target inspired concentration of 60%) and target control infusion remifentanil. Remifentanil and xenon or propofol were stopped at the end of skin closure. RESULTS: A cerebral oxygen saturation decrease below 55% was less frequently observed in the Xenon group during carotid cross-clamping (7/37 patients vs 15/37; p=0.01). Compared with values observed before clamping, the decrease in cerebral oxygen saturation during clamping was significantly less important in the Xenon group (12±11% vs 17±14%, p=0.04). Blood pressure and heart rate were not different between groups during carotid clamping. CONCLUSIONS: This pilot study suggests that xenon anesthesia may be associated to higher cerebral oxygen saturation values when compared to propofol anesthesia during cross-clamping for carotid endarterectomy.