Effect of intraoperative intravenous esketamine on postoperative delirium in older patients undergoing hip fracture surgery: protocol for a randomised, double-blind, placebo-controlled trial.

Introduction: Postoperative delirium (POD) is a common complication after hip fracture surgery in older patients. Esketamine may be beneficial in alleviating the occurrence of POD. Our trial aim is to investigate whether the intravenous administration of esketamine can improve POD in older patients undergoing surgery for hip fracture.