Intervention
Anaesthesiologist A treated the surface of the tip of the endotracheal tube according to the random number table. In Group C, normal saline (2 ml) was evenly sprayed onto the front end of the tracheal tube up to the two black marked lines near the cuff. In Group L two grams of compound lidocaine/prilocaine cream (compound lidocaine/prilocaine cream, 10 g, containing 25 mg each of lidocaine and prilocaine, Tongfang Pharmaceutical Group Co., Ltd. Beijing China) was evenly applied onto the front end of the tracheal tube up to the two black marked lines near the cuff. In Group T, 2 ml of 10% tetracaine (tetracaine hydrochloride for injection, 50 mg, Chengdu Zhengkang Pharmaceutical Co., Ltd. Chengdu, China) was evenly sprayed onto the front end of the tracheal tube up to the two black marked lines near the cuff. In Group F, two grams of compound lidocaine/prilocaine cream were first applied onto the front end of the tracheal tube up to the two black marked lines near the cuff then a small container with a spray function was used to evenly spray 2 ml of 10% tetracaine injection onto the front end of the tracheal tube where compound lidocaine adhered. The method of applying compound lidocaine/prilocaine cream onto the front end of the tracheal tube up to the two black marked lines near the cuff was performed according to a previous study [