By now, a series risk factors of cardiovascular diseases, which are also related to the development of postoperative cognitive dysfunction (POCD), are becoming more common.The investigators don't know whether propofol based anesthesia has a more severe impact on early postoperative cognitive function than sevoflurane in elderly patients with metabolic syndrome. In this study, the investigators want to investigate propofol versus sevoflurane anesthesia on the effects of early postoperative cognitive function in elderly patients with metabolic syndrome.
The purpose of this study is to investigate propofol versus sevoflurane anesthesia on the effects of early postoperative cognitive function in elderly patients with metabolic syndrome.