Effect of Subanesthetic Dose of Esketamine Infusion on Postoperative Sleep Disturbance in Elderly Undergoing Laparoscopic Gastrointestinal Surgery：protocol for a randomized controlled trial（RCT）

Objective Postoperative sleep disturbance (PSD) is a common problem in elderly patients, affecting postoperative recovery and potentially increasing the risk of complications. Esketamine is an N-methyl-D-aspartate (NMDA) receptor antagonist that has the potential to improve postoperative sleep. The aim of this randomized controlled trial is to evaluate the impact of intraoperative infusion of sub-anesthetic doses of esketamine on PSD in elderly patients undergoing laparoscopic gastrointestinal tumor resection. Methods This study is a randomized, single-center, double-blind, placebo-controlled trial. We plan to recruit 90 elderly patients (aged 65-80 years) who are scheduled for elective laparoscopic gastrointestinal tumor resection. The patients will be randomly assigned to two groups in a 1:1 ratio using a random number table. Patients in the esketamine group (group K) will receive a continuous intraoperative infusion of esketamine (0.1mg/kg·h), while patients in the control group (group C) will receive an equal volume of normal saline. The primary outcome is the incidence of PSD assessed by the Numerical Rating Scale (NRS) and the Athens Insomnia Scale (AIS). The secondary outcomes are the emotional status evaluated by the Hospital Anxiety and Depression Scale (HADS), postoperative pain intensity evaluated by the Visual Analogue Scale (VAS), the incidence of postoperative adverse reactions, and the plasma concentration of relevant inflammatory markers. Ethics and Dissemination The study has been approved by the Ethics Committee of the Second Affiliated Hospital of the Naval Medical University (Approvall Number: 2024SL073, 15 December 2024). Patients need to provide written consent before taking part in the study. The findings will be published with open access. This study was conducted in accordance with the Declaration of Helsinki. Trial registration： The study protocol has been registered in the Chinese Clinical Trial Registry (ChiCTR2400087222) on July 23, 2024.