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 0.05).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.