Background: Endoscopic retrograde cholangiopancreatography (ERCP) is a key technique for treating pancreatobiliary diseases in the elderly. However, traditional sedative and analgesic regimens (e.g., sufentanil combined with propofol) are associated with a high incidence of respiratory depression, postoperative nausea and vomiting (PONV), and delayed recovery in elderly patients. Anricofen is a novel peripherally selective κ-opioid receptor agonist that provides analgesia with minimal central respiratory depression. Ciprofol is a new sedative agent characterized by rapid onset and quick recovery. The combination of these two drugs may offer a safer sedation and analgesia regimen for elderly patients undergoing ERCP.

Objective: To evaluate the efficacy and safety of anricofen combined with ciprofol for deep sedation in elderly patients undergoing ERCP, compared with the traditional regimen (sufentanil combined with ciprofol).

Methods: This is a single-center, randomized, double-blind, controlled trial. A total of 141 elderly patients aged 60-90 years with ASA physical status II-III scheduled for elective ERCP will be enrolled and randomly assigned in a 1:1:1 ratio to three groups: Anricofen 0.3 μg/kg + Ciprofol 1.0 mg/kg, Anricofen 0.5 μg/kg + Ciprofol 1.0 mg/kg, or Sufentanil 0.1 μg/kg + Ciprofol 1.0 mg/kg. The primary efficacy endpoint is the intraoperative pain control success rate (proportion of time with Behavioral Pain Scale [BPS] score ≤3 ≥90%). The primary safety endpoint is the incidence of respiratory depression (respiratory rate <10 breaths/min or SpO₂ <90% requiring intervention). Secondary outcomes include sedation depth, body movement episodes, recovery time, PONV incidence, and others.

Significance: This study aims to provide a sedation and analgesia regimen with lower risk of respiratory depression and faster recovery for elderly patients undergoing ERCP.

Inclusion Criteria:

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Inclusion Criteria:

1. Age 60-90 years.
2. American Society of Anesthesiologists (ASA) physical status II or III.
3. Scheduled for elective endoscopic retrograde cholangiopancreatography (ERCP).
4. Body mass index (BMI) between 18 and 30 kg/m².
5. Willing and able to provide written informed consent.

Exclusion Criteria:

1. Severe neurological disorders (acute stroke, uncontrolled seizures, epilepsy).
2. Psychiatric disorders or cognitive impairment (Mini-Mental State Examination score <24).
3. Uncontrolled hypertension (preoperative blood pressure ≥180/110 mmHg) or hypotension (<90/60 mmHg).
4. Severe cardiac disease: sinus bradycardia, sick sinus syndrome, unstable angina, or myocardial infarction within the past 3 months.
5. Severe hepatic or renal dysfunction.
6. Difficult airway or severe respiratory disease.
7. Achalasia.
8. Known allergy to anricofen, sufentanil, ciprofol, or other study medications.
9. Use of opioid analgesics or sedatives within 7 days prior to surgery.
10. Preoperative pulse oxygen saturation (SpO₂) <90% on room air.
11. Pregnancy or lactation.
12. Participation in any other drug clinical trial within the past 3 months.
13. Refusal to participate in the study.

Exclusion Criteria:

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