Does dexmedetomidine improve analgesia of superficial cervical plexus block for thyroid surgery?

Background and Aims: Bilateral superficial cervical plexus block (BSCPB) is effective in reducing pain following thyroid surgeries. We studied the effect of dexmedetomidine on duration and quality of analgesia produced by BSCPB with 0.5% ropivacaine in patients undergoing thyroid surgeries. Methods: In this prospective double-blinded study, 60 adults undergoing thyroid surgeries were randomised into two equal groups to receive BSCPB, either with 20 ml 0.5% ropivacaine (Group A) or 20 ml 0.5% ropivacaine with 0.5 mu g/kg dexmedetomidine (Group B) after induction of anaesthesia. Visual analogue scale (VAS) was used to assess analgesia postoperatively at 0, 2, 4, 6, 12 and 24 h and patient satisfaction at 24 h. Haemodynamics were recorded peri-operatively. Wilcoxon signed rank test and Mann-Whitney U-test were applied for VAS and sedation scores. Unpaired t-test was applied for age, weight, duration of surgery and duration of post-operative analgesia. Results: There was significantly longer duration of analgesia in Group B (1696.2 +/- 100.2 vs. 967.8 +/- 81.6 min; P < 0.001) and higher patient satisfaction at 24 h (7 [7-9] vs. 5 [4-6]; P < 0.001). While VAS score for pain were similar up to 6 h, they were lower in Group B at 12 h (0 [0-1] vs. 2 [1-2]; P < 0.001) and 24 h (2 [2-2] vs. 5 [5-6]; P < 0.001). Haemodynamic stability and sedation scores were similar across the groups. There were no adverse events. However, pain during swallowing persisted in both the groups. Conclusion: Combination of 0.5% ropivacaine and dexmedetomidine for BSCPB provided significantly prolonged and better quality of postoperative analgesia and patient satisfaction than with 0.5% ropivacaine alone in patients undergoing thyroidectomy.