Standard anesthesia procedures
Anaesthesia, head and neck surgeons, Mercadone, hypothermia
MUSCLE RELAXATION
All procedures were performed by the same team of head and neck surgeons, and anaesthesia was administered by two experienced anaesthesiologists and recorded by a trained recorder.All patients fasted for 6–8 h before surgery. Non-invasive blood pressure, electrocardiography, oxygen saturation, and anaesthesia depth (Narcotrend) were monitored after the patient entered the operating room.TOFr value was obtained by closed-loop muscle relaxation monitoring system (Guangxi Weilark Technology Co., LTD.), and obtained by stimulating the ulnar nerve of the wrist with an electric current that causes the adductor pollicis response. Before induction, electrodes, muscle tension sensors and temperature sensors should be properly installed as follows: Firstly, 75% alcohol was used to clean the skin. The distal electrode was placed 1 cm from the radial side of the flexor carpi ulnar muscle to the transverse line of the proximal wrist, and the proximal electrode was placed 2.5 cm from the proximal side of the distal electrode. Tape was used to fix the electrode to prevent the electrode from falling off. In addition, the muscle tension sensor is placed in the thumb web space on the same side, and properly fixed with tape to prevent displacement. Finally, place the temperature sensor in the inner pollicis muscle of the palm and secure it with tape to prevent it from falling off. Parameter setting: Stimulation current 50mA, pulse width 200us, the interval of electrical stimulation was 15 s. The TOFr value can be continuously monitored when the start button is pressed, and the muscle relaxation monitoring can be stopped by pressing the pause button.To reduce measurement bias, the measuring arm will be covered with two layers of cloth to prevent hypothermia of the arm, and the arm will be properly fixed to prevent squeezing or touching.Before induction of anaesthesia, peripheral venous access was established, and shoulder and head pillows were padded. Anaesthesia induction was initiated with midazolam (Jiangsu Enhua Pharmaceutical Co. Ltd.) 0.05 mg/kg, propofol (Aslikan Pharmaceutical Co. Ltd.) TCI 4 µg/ml, sufentanil (YICHANG humanwell Pharmaceutical Co. Ltd.) 0.2–0.4 µg/kg, remifentanil (YICHANG Humanwell Pharmaceutical Co. Ltd.) TCI 2 ng/ml, rocuronium (Mercadone Co. Ltd.) 0.6 mg/kg. At the same time, mechanically controlled ventilation was started, adjusting respiratory parameters (tidal volume = body weight × [All patients were intubated with a NIM™ standard enhanced electromyography (EMG) endotracheal tube (Medtronic, Jacksonville, FL) assisted by visual laryngoscopy (7.0 mm internal diameter (ID) for males, 6.0 mm ID for females). The EMG tube electrodes were placed at the level of the vocal cords, and the endotracheal tube was secured. The initial mode was the standby state. The initial respiratory parameters were set as tidal Volume 8 ml/kg (standard body weight), respiratory rate 12 times/min, and respiratory ratio 1:2. The anaesthetic state was maintained with propofol and remifentanil, the Narcotrend was kept between 45 and 64, and the end-tidal carbon dioxide partial pressure (PETCO