Anesthesia methods
When the patients entered the operating room, midazolam 0.04mg/kg, propofol 1.8mg/kg, rocuronium 0.9mg/kg and sufentanil were used to induce anesthesia.(the sufentanil dose of experimental group A, B, and C were prepared by other researchers according to the numbers in the random number table, and the dose of control group D were 0.4μg/kg, uniformly diluted into 5ml). After induction, positive pressure ventilation with mask was performed, and at the same time, bilateral superior laryngeal nerve block and bilateral transverse abdominal fascia block were performed by a trained anesthesiologist. After the block is completed, endotracheal intubation can be performed by visual laryngoscope. Sevoflurane 1.5%, propofol 0.05mg/(kg.min), rocuronium 5ug/(kg.min) and remifentanil 0.06μg/(kg.min) were used for anesthesia maintenance.