This prospective randomized controlled trial aims to compare the clinical effectiveness and safety of opioid-free anesthesia (OFA) versus traditional opioid-based anesthesia (OBA) in adult patients undergoing laparoscopic bariatric surgery. The study evaluates postoperative pain, need for rescue analgesia, incidence of postoperative nausea and vomiting (PONV), intraoperative nociception monitoring (NOL index), and patient satisfaction. A total of 60 patients were randomized into two parallel groups receiving either OFA or OBA according to standardized anesthetic protocols.
Bariatric surgery is the most effective treatment for severe and morbid obesity, but perioperative pain management and PONV remain significant challenges. Traditional opioid-based anesthesia is associated with adverse effects such as respiratory depression, postoperative hyperalgesia, ileus, and delayed recovery. Opioid-free anesthesia is an emerging strategy based on the use of multimodal, non-opioid agents-including dexmedetomidine, lidocaine, and ketamine-aimed at providing adequate analgesia while reducing opioid-related complications. This randomized controlled trial evaluates whether OFA improves postoperative pain control, reduces the requirement for rescue analgesia, and promotes better perioperative outcomes compared to OBA in laparoscopic bariatric surgery. Outcomes include NRS pain scores at multiple time points, NOL monitoring during surgery, PONV occurrence, and patient satisfaction at discharge.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
60
Participants receive standard opioid-based general anesthesia consisting of: * Continuous remifentanil infusion (2 mg diluted in 40 mL saline), * Propofol for induction, * Rocuronium for neuromuscular blockade, * Desflurane for maintenance, * Dexamethasone 4-8 mg for PONV prophylaxis, * Cefazolin for antibiotic prophylaxis, * Esomeprazole for stress-ulcer prevention. Postoperative analgesia includes paracetamol + ketorolac/parecoxib + metamizole, with tramadol and/or morphine provided as rescue. NOL, BIS, TOF, and standard monitoring are used.
Participants receive opioid-free anesthesia consisting of: * Dexmedetomidine bolus (15-20 μg), * Continuous infusion of dexmedetomidine 50 μg + ketamine 50 mg + lidocaine 500 mg in 50 mL saline (rate: 1 mL/10 kg), * Propofol for induction, * Rocuronium for neuromuscular blockade, * Desflurane for maintenance, * Dexamethasone for PONV prophylaxis, * Cefazolin and esomeprazole for prophylaxis. * The analgesic infusion is reduced by half 30 min before end of surgery and continued for 1 hour in PACU. Postoperative analgesia includes paracetamol + ketorolac/parecoxib + metamizole, with tramadol 100 mg as rescue. Monitoring includes NOL, BIS, TOF.
Hospital Lusíadas Amadora - Lusíadas Saúde, S.A.
Amadora, Portugal
Postoperative pain intensity measured by the Numerical Rating Scale for Pain (NRS)
Postoperative pain will be assessed using the Numerical Rating Scale for Pain (NRS), a validated 11-point scale ranging from 0 (no pain) to 10 (worst pain imaginable). Higher scores indicate a worse outcome, reflecting greater pain intensity. Pain intensity will be compared between the opioid-free anesthesia group and the opioid-based anesthesia group at predefined postoperative time points.
Time frame: Time Frame: - Within 30 minutes of arrival at the Post-Anesthesia Care Unit (PACU); - At PACU discharge (assessed up to 2 hours after PACU admission) - Within the first 24 postoperative hours; - 48 hours postoperatively (at hospital discharge).
Intraoperative nociception (NOL Index)
Nociception will be assessed using the NOL (Nociception Level) Index, a multiparametric autonomic signal-based monitor. Lower values reflect better nociceptive control. Comparisons will be made between OFA and OBA groups at all recorded time points.
Time frame: Multiple standardized time points during surgery (15 to 180 minutes)
Need for rescue analgesia
The proportion of patients requiring rescue analgesia (tramadol and/or morphine) will be compared between the opioid-free anesthesia group and the opioid-based anesthesia group.
Time frame: - During PACU stay (assessed up to 2 hours after PACU admission); - Within the first 24 postoperative hours.
Opioid consumption
Total opioid dose administered as rescue analgesia will be recorded and compared between groups.
Time frame: - During PACU stay (assessed up to 2 hours after PACU admission); - Within the first 24 postoperative hours.
Incidence of postoperative nausea and vomiting (PONV)
PONV will be assessed using the Postoperative Nausea and Vomiting Impact Scale, comparing frequency and severity between groups. The total score ranges from 0 (no nausea or vomiting) to 6 (maximum impact). Higher scores indicate a worse outcome, reflecting greater severity and clinical impact of postoperative nausea and vomiting.
Time frame: At 6 hours and 24 hours after surgery
Need for PONV treatment
Proportion of patients requiring antiemetic treatment will be evaluated and compared.
Time frame: First 24 postoperative hours
Patient satisfaction
Patient satisfaction will be assessed using a Numerical Satisfaction Rating Scale and compared between groups. Total score ranges from 1 (minimum satisfaction) to 10 (maximum satisfaction). Higher scores indicate a better outcome, reflecting greater patient satisfaction.
Time frame: 48 hours postoperatively (at hospital discharge).
Postoperative complications
Occurrence of perioperative complications (respiratory, cardiovascular, surgical, or anesthesia-related) will be recorded.
Time frame: Periprocedurally.
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