Efficacy of Dexamethasone versus Dexmedetomidine as an Adjuvant to Bupivacaine for Bilateral Superficial Cervical Plexus Block in Thyroid Surgeries: A Randomised Clinical Trial

Introduction: Thyroid surgeries are among the most frequently performed endocrine surgeries globally. Pain control is one of the many challenges faced by perioperative physicians in post thyroid surgery patients; if, left untreated, it can progress to chronic pain. Regional anaesthesia, such as Bilateral Superficial Cervical Plexus Block (BSCPB), can provide excellent analgesia in the initial postoperative period without the side effects of systemic analgesics. Aim: To assess postoperative pain using Visual Analogue Scale (VAS) scores at various intervals upto 24 hours postoperatively and to evaluate the duration of the superficial cervical plexus block. Secondary objectives include assessing intraoperative haemodynamic stability, analgesic consumption, and block related complications. Materials and Methods: This randomised double-blinded clinical trial was conducted in the Department of Anaesthesiology at a teritary care centre, BLDE (Deemed to be University) Shri BM Patil Medical College, Hospital and Research Centre in Vijayapur, Karanataka, India, from April 2023 to March 2024 on 74 American Society of Anaesthesiologists (ASA) grades I-II patients undergoing elective thyroid procedures were randomly assigned to two groups: Group Dexmedetomidine (DexD) (n=37), which received US-guided BSCPB with 10 mL of 0.5% bupivacaine and 25 mcg of dexmedetomidine on both sides; and Group Dexamethasone (DexA) (n=37), which received US guided BSCPB with 10 mL of 0.5% bupivacaine and 4 mg of dexamethasone on both sides. Intraoperative blood pressure, Heart Rate (HR), and Mean Arterial Pressure (MAP) were measured at predefined time periods. Postoperative VAS scores were assessed at predefined intervals, along with the time taken for the first analgesic request and the cumulative postoperative analgesic dose consumed. Student's t-test and Chi-square test were used for data comparison. Results: The mean age in Group DexD was 42.59 +/- 8.64 years, and in Group DexA it was 45.40 +/- 8.96 years. Group DexD had significantly lower postoperative VAS scores for upto eight hours (2.108 vs. 2.72; p-value=0.0002), and the time before the first rescue analgesia request was significantly longer than that of Group DexA (688.37 +/- 55.75 min vs. 593.64 +/- 72.56 min; p-value=0.001). The total postoperative analgesic utilisation in the first 24 hours was significantly lower in Group DexD compared to Group DexA (81.08 +/- 20.754 mg vs. 104.17 +/- 44.921 mg; p-value=0.006). Group DexA experienced a lower incidence of nausea (p-value=0.002) and vomiting (p-value=0.001) in the postoperative period. Conclusion: Dexmedetomidine performed better than dexamethasone when added to bupivacaine for BSCPB for pain management during the postoperative period in patients undergoing thyroid surgical procedures. However, when added, dexamethasone has the advantage of reducing nausea and vomiting in the postoperative period.