The Analgesic Effect of Dexamethasone and Magnesium Sulphate (MgSO4) as an adjuvant to 0.25% Bupivacaine in ultrasound guided Pectoral Nerve Block (PEC Block) for unilateral Modified Radical Mastectomy: A Comparative Study

Background: Postoperative pain following unilateral modified radical mastectomy (MRM) has been managed with Pectoral nerve block (PEC block). Several initiatives are ongoing to get the effective and safe way of prolongation analgesic effect postoperatively. Therefore, many types of adjuvants are adding to the local anaesthetic agents to prolong their analgesic effect. In this study either dexamethasone or magnesium sulphate (MgSO4) has added as an adjuvant to 0.25% bupivacaine in pectoral plane block (PEC block) for unilateral modified radical mastectomy. Here we observed which of the adjuvant would prolong the analgesic effect of 0.25% bupivacaine. Methods: This randomized controlled trial was conducted at the Department of Anaesthesia, Analgesia, Palliative and Intensive Care Medicine, Dhaka Medical College following approval of the ethical committee. These patients were selected from the department of General Surgery, Dhaka Medical College during preanaesthetic checkup periods. Total 50 patients were scheduled for modified radical mastectomy and divided into Group A and Group B (each group contain 25 patients). The patients of the both groups were given pectoral plane block under ultrasound guide with 0.25% bupivacaine. The patients of Group A received magnasium sulphate 150 mg and Group B received dexamethasone 10 mg as an adjuvant to 0.25% bupivacaine. Pectoral nerve block was performed before induction of general anaesthesia and onset of sensory block was assessed among the both groups. All patients were observed peri-operatively and data were recorded into the data collection form. Finally, data was analyzed by SPSS version 22. Observation and Results: Socio-demographic profile were similar among the both groups (p>0.05). No significant difference was noted in terms of ASA score and BMI (p>0.05). Mean duration of the analgesia (min) and time requirement of rescue analgesic therapy were significantly higher in dexamethasone group (p<0.05) than MgSO4 group. Post-operative requirement of pethidine (72.5±8.5vs 55.2±5.4 mg; p<.045) was also higher in MgSO4 group. Side effects profile like nausea and vomiting also significantly small in dexamethasone (4%) group than people received MgSO4 group (20%) (p<0.05). Conclusion: Use of dexamethasone in comparison to MgSO4 as an adjuvant to bupivacaine could prolong analgesia in postoperative period for pectoral plane block in unilateral modified radical mastectomy. CBMJ 2022 January: vol. 11 no. 01 P: 4-13