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

introductionPostoperative 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. METHODS AND ANALYSIS: This randomised controlled trial will be conducted at the Chengdu Integrated TCM & Western Medicine Hospital in Chengdu, China. A total of 260 older patients scheduled for hip fracture surgery under general anaesthesia will be randomly allocated to either an esketamine group (group E) or a control group (group C) at a 1:1 ratio (n=130 in each group). After tracheal intubation, group E will receive continuous infusion of esketamine at a rate of 0.3 mg/kg/h intraoperatively until the beginning of skin incision closure. Group C will receive equivalent volumes and rates of 0.9% normal saline; the injection methods are in accordance with those in group E. The primary outcome is the incidence of POD within 3 days after surgery, which will be evaluated using the confusion assessment method two times per day. Secondary outcomes are subtypes, duration of delirium, length of hospital stay, pain severity score within 3 days after surgery and 30-day all-cause mortality. Pain severity scores at rest will be evaluated using a numeric rating scale. Safety outcomes will include hallucination, dizziness, nightmares, nausea and vomiting. All analyses will be performed in line with the intention-to-treat principle. ETHICS AND DISSEMINATION: Ethics approval was obtained from the Medical Ethics Committee of Chengdu integrated TCM & Western Medicine Hospital (2024KT022). All patients will provide written informed consent before enrolment. The results of the trial will be published in an appropriate journal or an oral presentation at academic meetings. TRIAL REGISTRATION NUMBER: Chinese Clinical Trial Registry (ChiCTR2400081681).