Comparison of analgesic efficacy of dexamethasone and dexmedetomidine as an adjuvant to local anaesthetic in transversus thoracic muscle plane block in adult patients undergoing median sternotomy: A randomised controlled trial.

BACKGROUND: Post-sternotomy pain contributes significantly to delayed recovery following cardiac surgery. The transversus thoracic muscle plane block (TTPB) is a recently described regional anaesthetic technique that provides analgesia to the anterior chest wall. The addition of adjuvants such as dexamethasone and dexmedetomidine may enhance the analgesic efficacy of TTPB. OBJECTIVES: This study compared the analgesic efficacy of dexamethasone and dexmedetomidine as adjuvants to bupivacaine for TTPB in patients undergoing median sternotomy. METHODS: 66 adult patients (ASA I-III) scheduled for cardiac surgery via median sternotomy were recruited for this randomised trial. Following induction of anaesthesia, all patients received bilateral TTPB and were allocated to three groups: dexamethasone (0.25 % bupivacaine + 8 mg dexamethasone), dexmedetomidine (0.25 % bupivacaine + 1 µg/kg dexmedetomidine), and a control group (0.25 % bupivacaine alone). The primary outcome was the time to first rescue analgesia following extubation. Secondary outcomes included 24-hour postoperative fentanyl consumption, intraoperative fentanyl requirement, pain scores, extubation time, patient satisfaction, and adverse events. RESULTS: Time to first rescue analgesia was significantly longer in the dexmedetomidine group than in the dexamethasone and control groups (P 0.001). Twenty-four-hour postoperative fentanyl consumption was significantly lower in both adjuvant groups than in the control group (P < 0.001). Pain scores were consistently lower with dexmedetomidine and dexamethasone groups. Extubation time and intraoperative fentanyl consumption were comparable among the three groups (P > 0.05). CONCLUSION: Both dexamethasone and dexmedetomidine improved TTPB analgesia. Dexmedetomidine significantly prolonged the duration of analgesia, whereas 24-hour postoperative opioid consumption was comparable between the adjuvant groups.