General Anesthesia
Electrocardiogram (ECG), heart rate (HR), mean arterial pressure (MAP), pulse oxygen saturation (SpO2), end-tidal partial pressure of carbon dioxide (ETCO2), body temperature, and bispectral index (BIS) were monitored before anesthesia, and peripheral venous access of the upper limbs was opened. All subjects received standard general anesthesia. Sevoflurane was mixed with oxygen/air to maintain anesthesia, and the circulatory system was ventilated with positive pressure. Propofol 4-6 mg/kg/h and remifentanil 0.1-0.3 μg/kg/min were given intraoperatively to maintain anesthesia. According to the operation needs, cisatracurium 0.05 mg/kg was injected intravenously. All procedures are performed by the same team of surgeons and do not require any additional local anesthesia by the surgeon. At the end of the surgery, before extubation and full consciousness, patients were randomly examined and treated by independent staff.