Effect of dexmedetomidine epidural infusion on the quality of early postoperative recovery in elderly patients undergoing laparoscopic radical colorectal cancer surgery

Interventions: Dexmedetomidine + ropivacaine group:The L1~L2 intervertebral space was selected for epidural puncture catheterization, and dexmedetomidine (0.5µg/ml) + ropivacaine (0.125%) was given epidurally in a loading volume of 10ml followed by continuous pumping at 5ml/h until the end of the operation.;ropivacaine group:Epidural puncture catheterization was the same as in the DR group, and epidural ropivacaine (0.125%) was given in a loading volume of 10 ml followed by continuous pumping at 5 ml/h until the end of the operation.
Primary outcome(s): The Quality of Recovery-15 score;Delirium assessment
Study Design: Parallel