Opioid-Free Versus Opioid-Based Anesthesia in Bariatric

This study is designed as a prospective, randomized, controlled clinical trial. It will be conducted in the operating rooms of the University of Health Sciences, Diyarbakır Gazi Yaşargil Training and Research Hospital. Patients aged 18 to 65 years who are scheduled for elective bariatric surgery and meet the inclusion criteria (ASA physical status I-III) will be enrolled in the study.

Eligible patients will be informed both verbally and in writing during their preoperative anesthetic evaluation, and written informed consent will be obtained at least 24 hours prior to surgery.

Patients will be randomly assigned to one of two groups using computer-generated randomization:

Group O (Opioid group)

Group NO (Opioid-free group)

All patients will receive 40 mg IV pantoprazole and 4 mg IV ondansetron 30 minutes before surgery as preoperative medication. Standard ASA monitoring will be applied, and fasting guidelines will be followed. Depth of anesthesia will be monitored in all patients using BIS, and maintained within a target range of BIS 40-60 to ensure adequate depth with no response to surgical stimuli.

Anesthesia Protocol:

Group O (Opioid Group):

General anesthesia will be induced with 2 mg/kg propofol, 2 µg/kg fentanyl, and 0.6 mg/kg rocuronium based on ideal body weight (IBW). Maintenance will be achieved using remifentanil (Ultiva®) infusion at 0.1-0.3 µg/kg/min and 1 MAC sevoflurane. Following induction, all patients will receive a bilateral transversus abdominis plane (TAP) block under ultrasound guidance using 40 mL of 0.25% bupivacaine.

Group NO (Opioid-Free Group):

General anesthesia will be induced with 2 mg/kg propofol, 0.5 mg/kg ketamine, and 0.6 mg/kg rocuronium (IBW). Anesthesia will be maintained with dexmedetomidine infusion at 0.2-1.4 µg/kg/h and 1 MAC sevoflurane. Following induction, a bilateral TAP block will also be performed using 40 mL of 0.25% bupivacaine under ultrasound guidance.

Postoperative Analgesia Protocol:

During skin closure, all patients will receive 1 g IV paracetamol and 50 mg IV ketoprofen. At the end of surgery, neuromuscular blockade will be reversed using sugammadex, and patients will be safely extubated.

In the postoperative period, patients will be followed in the surgical ward for 48 hours with a standardized analgesic protocol:

1 g IV paracetamol every 6 hours

4 mg IV ondansetron every 8 hours

50 mg IV ketoprofen every 12 hours

Pain will be assessed using the Visual Analog Scale (VAS). If VAS ≥ 4, 100 mg IV tramadol will be administered as rescue analgesia, and all interventions will be documented in the patient records.

Inclusion criteria

Age 18-65 years

BMI >35

ASA class III-IV

Elective bariatric surgery (e.g., sleeve gastrectomy)

Written informed consent

Exclusion criteria

Refusal to participate

Severe cardiac/pulmonary/psychiatric illness

Allergy to study drugs

Conversion to emergency surgery

Withdrawal at any point by patient or investigator

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