Bilateral Ultrasound-guided Intermediate Cervical Plexus Block for Opioid-free Anaesthesia in Total Thyroidectomy: A Prospective Observational Study

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Introduction: Opioid-free Anaesthesia (OFA) avoids opioidrelated adverse effects and suits thyroid surgery, which carries a high risk of Postoperative Nausea and Vomiting (PONV). Evidence for cervical plexus techniques as the basis of a fully opioid-free anaesthesia for total thyroidectomy is limited. Aim: To evaluate the efficacy of bilateral ultrasound-guided Intermediate Cervical Plexus Block (ICPB) in providing opioidfree anaesthesia for total thyroidectomy. Materials and Methods: This prospective, observational study included 82 adults (American Society of Anesthesiology (ASA) physical status I-II, aged 18-65 years) undergoing elective total thyroidectomy. Patients were divided into two groups with 41 in each group on the basis of clinical feasibility. Group A received bilateral ultrasound-guided ICPB (7 mL of 0.2% ropivacaine with 0.25 µg/kg dexmedetomidine per side) with a non-opioid general anaesthetic; Group B received a standard opioidinclusive general anaesthetic with intravenous fentanyl 2 µg/ kg. The primary outcome was intraoperative haemodynamic stability and total anaesthetic-agent consumption; secondary outcomes were postoperative pain (Visual Analogue Scale, VAS), 24-hour rescue-analgesic requirement and opioid-related adverse effects. Data was analysed using Statistical Package for Social Sciences (SPSS) v. 20. Results: The mean age of the study participants in group A was 47.15±8.19 years and 47.73±8.26 years in group B. Two groups were comparable for age, body mass index, sex and ASA status (p>0.05). Intraoperative and post-extubation heart rate was significantly higher in group B from 15 minutes after induction up to 2 hours and up to 1 hour after extubation (p<0.05), whereas systolic and diastolic pressures did not differ (p>0.05). Median consumption of sevoflurane, propofol and vecuronium was lower in group A (p=0.001). VAS scores and rescue-analgesic requirements were similar over 24 hours (p>0.05). PONV (0 vs 7; p=0.01) and pruritus (0 vs 6; p=0.03) occurred only in group B; transient voice change occurred in 2 patients in group A (p=0.15). No block-related complications occurred. Conclusion: Bilateral ultrasound-guided ICPB allowed an opioid-free intraoperative technique for total thyroidectomy while providing postoperative analgesia comparable to an opioid-based technique. It reduced intraoperative anaestheticagent requirements and was associated with fewer opioidrelated adverse effects, without delaying recovery