Can a new anesthetic give older surgery patients a better Night's sleep?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Aged between 65 and 80 years. * Scheduled for elective laparoscopic radical resection of colorectal cancer. * American Society of Anesthesiologists (ASA) physical status class II-III. * Able to understand the study protocol and provide written informed consent. Exclusion Criteria: * Known allergy to any study medications. * Preoperative sleep disorder (Pittsburgh Sleep Quality Index \[PSQI\] score \> 10). * Regular use of sedatives, antipsychotics or hormonal drugs within the past month. * Preoperative cognitive impairment, screened using the education-adjusted Mini-Mental State Examination (MMSE). * Preoperative history of neurological or psychiatric disorders, including Alzheimer's disease, Parkinson's disease, depression and anxiety disorders. * Severe preoperative comorbidities involving the cardiovascular, cerebrovascular, respiratory, hepatic or renal systems, as follows:New York Heart Association (NYHA) functional class IV; current or recent (within 2 months) congestive heart failure; myocardial infarction or coronary stent implantation within the preceding 3 months; Uncontrolled frequent ventricular premature beats (\>5 beats per minute), couplets, triplets, paired ventricular arrhythmias, multifocal ventricular premature beats, or R-on-T phenomenon; Second-degree atrioventricular block (Mobitz II type), third-degree atrioventricular block or sick sinus syndrome without pacemaker implantation; Stroke or transient ischemic attack within the preceding 3 months; Severe hypertension (blood pressure ≥ 180/110 mmHg); Severe respiratory tract infection (including common cold), or maximal voluntary ventilation (MMV) \< 30% of the predicted value; Severe hepatic dysfunction (Child-Pugh score \> 9); Acute or chronic renal failure without renal replacement therapy: Acute kidney injury was defined as an absolute increase in serum creatinine ≥ 0.3 mg/dL (≥26.5 μmol/L) or a relative increase ≥ 50% from baseline, or urine output \< 0.5 mL/(kg·h) for more than 6 consecutive hours. Chronic renal failure or uremia was defined as serum creatinine \> 451 μmol/L and estimated glomerular filtration rate (eGFR) \< 30 mL/min/1.73 m². * Severe coagulation disorders. * Refusal to participate in the trial. * Anticipated postoperative admission to the intensive care unit (ICU).