Effects of atomized Esketamine combined with dexmedetomidine on postoperative pharyngalgia and perioperative stress response in patients with colorectal cancer

Interventions: Blank control group:Preoperative atomization of 5ml normal saline;Esketamine group:Preoperative atomization inhalation of 0.5mg/kg Esketamine plus normal saline to prepare 5ml;Dexmedetomidine group:Atomized inhalation of 1 ug/kg dexmedetomidine plus physiological saline is 5 ml;Dexmedetomidine combined with esketamine group:Atomized inhalation of 0.25mg/kg esketamine +0.5ug/kg dexmedetomidine plus normal saline was configured as 5ml 30min before surgery Primary outcome(s): Incidence of postoperative sore throat Study Design: Parallel