Overview

This study aims to compare the efficacy and safety of remimazolam tosylate and propofol for postoperative sedation in patients aged 65 years or older undergoing cardiac surgery with cardiopulmonary bypass. Postoperative delirium (POD) is a common complication in older patients after cardiac surgery and may adversely affect postoperative recovery and clinical outcomes. Whether remimazolam tosylate reduces the incidence of POD compared with propofol under standardized sedation and analgesia protocols remains uncertain.

This is a single-center, prospective, randomized, double-blind, double-dummy, active-controlled superiority trial. A total of 600 eligible patients will be randomized in a 1:1 ratio to receive remimazolam tosylate or propofol for continuous sedation in the cardiac surgery intensive care unit (ICU). In both groups, the infusion rate will be titrated to maintain a target Richmond Agitation-Sedation Scale (RASS) score of -2 to 0, with standardized analgesia and postoperative care.

The primary outcome is the incidence of POD within 7 days after surgery. Delirium will be assessed using the Confusion Assessment Method for the ICU (CAM-ICU) in patients who are intubated or unable to communicate verbally, and the Chinese version of the 3-Minute Diagnostic Interview for Confusion Assessment Method (3D-CAM-CN) in patients who are able to communicate.

Secondary clinical outcomes include time to first delirium, delirium duration and severity, achievement of the target sedation level, pain scores, rescue sedative use, time to extubation, ICU length of stay, hospital length of stay, and safety outcomes, including hypotension, bradycardia, and vasopressor use.

This study aims to determine whether remimazolam tosylate reduces the incidence of POD compared with propofol in older patients after cardiac surgery. The findings may provide clinical evidence to guide postoperative sedative selection and help improve delirium prevention and postoperative recovery in this population.

Eligibility

Inclusion Criteria

1\. Age ≥65 years. 2. Undergoing elective cardiac surgery with cardiopulmonary bypass, including coronary artery bypass grafting (CABG), valve surgery, or combined CABG and valve surgery.

3\. Admission to the cardiac surgery intensive care unit (ICU) after surgery, with an anticipated need for invasive mechanical ventilation and continuous sedation for at least 2 hours.

4\. Written informed consent obtained from the participant or their legally authorized representative.

5\. No delirium identified during the preoperative assessment. Exclusion Criteria

1. Emergency or salvage cardiac surgery.
2. Heart transplantation, ventricular assist device implantation, surgery for aortic dissection requiring deep hypothermic circulatory arrest, or other cardiac procedures outside the scope of this study.
3. Severe psychiatric disorders, diagnosed Alzheimer's disease or dementia, or preoperative delirium.
4. Severe alcohol use disorder or a history of severe alcohol misuse.
5. Previous cerebrovascular events or other conditions causing severe visual, hearing, or communication impairment that would prevent reliable delirium assessment despite appropriate assistance.
6. Known hypersensitivity or contraindications to either study drug or its excipients, or severe hepatic or renal failure.
7. Decompensated acute circulatory failure or hemodynamic instability at the time of randomization.
8. Concurrent participation in another interventional clinical trial that could affect the primary outcome.