This prospective, randomized controlled clinical trial aims to evaluate whether remimazolam can reduce the incidence of postoperative delirium (POD) in elderly patients undergoing laparoscopic radical gastrectomy for gastric cancer. A total of 170 patients aged 65 years or older will be enrolled and randomized in a 1:1 ratio to receive either remimazolam or a propofol-midazolam regimen for anesthesia induction and maintenance. Standard perioperative monitoring, BIS-guided anesthesia depth control, and postoperative pain management will be applied in both groups. The primary outcome is the incidence of postoperative delirium within 5 days after surgery, assessed twice daily using the 3D-CAM. Secondary outcomes include emergence agitation, extubation time, postoperative pain scores, cognitive function at discharge, intraoperative hemodynamic stability, unplanned ICU admission, postoperative complications, and length of ICU stay. This study aims to determine whether remimazolam provides a safer and more effective anesthetic option for improving postoperative neurological outcomes and recovery in elderly patients undergoing laparoscopic radical gastrectomy.

This prospective, randomized, controlled clinical trial is designed to investigate the efficacy and safety of remimazolam in reducing postoperative delirium (POD) among elderly patients undergoing laparoscopic radical gastrectomy. Postoperative delirium is a common and serious complication in older surgical patients and is associated with prolonged recovery, cognitive decline, increased morbidity, higher healthcare costs, and long-term mortality. Despite advances in perioperative care, effective strategies for reducing POD in elderly patients undergoing major abdominal surgery remain limited. Remimazolam, a novel ultra-short-acting benzodiazepine, offers rapid metabolism, hemodynamic stability, and reliable reversibility, making it a potentially advantageous anesthetic agent for this high-risk patient population.

A total of 170 eligible patients aged 65 years or older will be enrolled at The First Affiliated Hospital of Nanjing Medical University. Participants will be randomized in a 1:1 ratio to receive either remimazolam (R group) or a propofol-midazolam regimen (P group) during anesthesia induction and maintenance. Randomization will be performed using a computer-generated sequence and sealed opaque envelopes. Anesthesia depth will be monitored by BIS, and drug dosages will be dynamically adjusted to maintain BIS between 40 and 60 while keeping hemodynamic parameters within 20% of baseline values. Standardized perioperative management will be applied to all participants, including opioid analgesia, muscle relaxation, controlled ventilation, vasoactive medication titration, and postoperative PCIA.

Postoperative delirium will be assessed twice daily from postoperative day 1 to day 5 using the 3D-CAM diagnostic criteria by trained evaluators blinded to group allocation. Delirium assessments will also be conducted on the day of surgery at least two hours after emergence. Additional postoperative evaluations will include pain scores (NRS), emergence agitation, MMSE cognitive assessments, extubation time, PACU duration, length of hospitalization, and adverse events such as intraoperative awareness, hypotension, postoperative nausea and vomiting, or unplanned ICU admission.

Intraoperative data-including anesthesia duration, surgical duration, anesthetic drug dosages, opioid consumption, vasoactive medication use (converted to norepinephrine-equivalent doses), fluid balance, and estimated blood loss-will be recorded. Preoperative data collection includes demographics, comorbidities, Charlson Comorbidity Index, medication history, laboratory findings, and sleep quality. Data collection will continue until postoperative day 5 or hospital discharge, whichever occurs first.

The primary outcome of this trial is the incidence of postoperative delirium within five days after surgery. Secondary outcomes include the severity and subtype of delirium, emergence agitation, cognitive function at discharge, postoperative pain scores, extubation time, postoperative complications, PACU stay, ICU stay, and length of hospitalization. Statistical analyses will be conducted by investigators blinded to group allocation using standard tests for normality, t-tests or Mann-Whitney U tests for continuous variables, and Chi-square or Fisher exact tests for categorical variables. A two-sided P value <0.05 will be considered statistically significant.

This study is expected to provide evidence regarding whether remimazolam offers superior neurocognitive outcomes, improved hemodynamic stability, and fewer postoperative complications compared with propofol-based anesthesia in elderly patients undergoing laparoscopic radical gastrectomy. The findings may support the development of safer anesthesia strategies and enhanced recovery protocols for elderly surgical patients.

Inclusion Criteria:

• Age ≥ 65 years.
• Body mass index (BMI) between 18 and 28 kg/m².
• ASA physical status I-III.
• Scheduled for elective laparoscopic radical gastrectomy under general anesthesia at Jiangsu Province Hospital.
• Able and willing to sign informed consent.

Exclusion Criteria:

• Severe respiratory, cardiovascular, renal, or hepatic dysfunction.
• Stroke within the past 6 months or other central nervous system diseases.
• History of schizophrenia, epilepsy, Parkinson's disease, myasthenia gravis, or other psychiatric disorders.
• History of alcohol abuse or psychoactive substance dependence.
• Severe visual, hearing, or language impairment preventing communication.
• Allergy or contraindication to propofol or benzodiazepines.
• Preoperative cognitive impairment assessed by MMSE (≤24 for ≥middle-school education; ≤20 for primary school; ≤17 for no formal education).
• Participation in another drug clinical trial within 1 month before surgery.