needs major change in study protocol

This randomized, double-blind, controlled clinical trial evaluates whether adding dexmedetomidine to an oliceridine-based patient-controlled intravenous analgesia (PCIA) regimen can improve postoperative pain control and tolerability after video-assisted thoracoscopic lobectomy in adults with high nicotine dependence (Fagerström score ≥6). A total of 102 participants are allocated 1:1:1 into three groups: (1) oliceridine PCIA alone; (2) oliceridine PCIA plus low-dose dexmedetomidine (0.05 μg/kg/h); or (3) oliceridine PCIA plus standard-dose dexmedetomidine (0.1 μg/kg/h). PCIA solutions are prepared to 100 mL, delivered with a basal rate of 2 mL/h, a 0.5-mL bolus, and a 15-minute lockout; a small loading dose is given near the end of surgery. Tramadol is permitted as rescue analgesia per protocol.

The primary objectives are to compare postoperative pain intensity at rest and with movement and overall patient satisfaction within 48-72 hours after surgery. Secondary objectives include sedation level, negative affect (anxiety/depression) scores, comfort and functional recovery scales, effective PCIA presses, rescue analgesic use, and safety outcomes (nausea/vomiting, shivering, bradycardia, hypotension, hypoxemia, and respiratory depression). Outcomes are assessed at approximately 4, 8, 12, 24, and 48 hours after surgery, with a satisfaction survey at 72 hours.

The investigators hypothesize that oliceridine PCIA combined with dexmedetomidine-particularly at 0.1 μg/kg/h-will reduce movement-related pain, decrease rescue opioid needs and PCIA presses, improve mood and comfort scores, and maintain acceptable hemodynamic and respiratory safety compared with oliceridine alone.

Adults scheduled for first-time thoracoscopic lobectomy at two centers are screened preoperatively; key exclusions include significant conduction abnormalities, severe organ dysfunction, inability to use PCIA, or recent exposure to α2-agonists/opioids that could confound results. After surgery, participants are randomized to one of three masked PCIA regimens. Study personnel, patients, and outcome assessors remain blinded. Standardized anesthetic and postoperative care pathways are followed. Pain (rest/movement visual analog scales), sedation (Ramsay), mood (self-rating anxiety/depression), comfort/function scales, and adverse events are recorded at prespecified time points through 48 hours; patient satisfaction is collected at 72 hours. Data are analyzed with appropriate parametric/non-parametric tests for continuous variables and χ²/Fisher's exact tests for categorical outcomes, with two-sided α=0.05.

Inclusion Criteria

• American Society of Anesthesiologists (ASA) physical status II-III
• Male patients aged 65 years or younger
• Undergoing lobectomy for the first time
• High nicotine dependence, confirmed by the Fagerström Test for Nicotine Dependence (FTND) with an FTND score of 6 or higher
• No history of substance abuse and no recent use of analgesic medications (e.g., opioids or non-steroidal anti-inflammatory drugs) prior to surgery
• Able to understand the procedure for patient-controlled intravenous analgesia (PCIA) and able to complete the study assessment scales

Exclusion Criteria

• History of mental illness or cognitive disorder; or currently receiving antidepressant treatment and unable to cooperate with examinations and assessments
• Bradycardia (heart rate 50 beats/min or lower) or second- or third-degree atrioventricular block
• Body mass index (BMI) greater than 30 kg/m²
• Use of analgesics, sedatives, beta-blockers, or alpha-2 agonists prior to surgery
• Required reoperation due to serious postoperative complications (e.g., bleeding)
• Severe cardiovascular, cerebrovascular, hepatic, or renal disease, resulting in inability to remove the endotracheal tube after surgery or inability to use the analgesia pump correctly
• Failure to abstain from smoking for at least 2 weeks prior to surgery