Dexamethasone Versus Magnesium Sulphate as Adjuvant to Bupivacaine in Ultrasound Guided Transverse Abdominis Plane (TAP) Block for Postoperative Analgesia in Abdominoplasty

Abstract Background Dexamethasone and Magnesium sulphate (MgSO4) have been used as an adjunct to local anesthesia. This study aims to compare Dexamethasone 8mg and MgSO4 200mg as an adjunct to bupivacaine 0.25% in Transversus Abdominis Plane (TAP) block for postoperative analgesia in patients undergoing abdominoplasty under general anesthesia. Objective Comparing the postoperative analgesia of Dexamethasone versus Magnesium sulphate added to Bupivacaine in Ultrasound Guided Transversus Abdominis Plane (TAP) block after abdominoplasty regarding the pain relief and amount of rescue analgesia needed postoperative. Methods Sixty patients undergoing abdominoplasty under general anesthesia with ASA physical status I or II, of both sexes aged 21 – 50 years were recruited and randomized in three equal groups. Group B-D received 18ml 0.25% bupivacaine with 8 mg dexamethasone, Group B-Mg received 18ml 0.25% bupivacaine with 200 mg MgSO4 and Group B (control group) received 18ml 0.25% bupivacaine with 2ml normal saline. Time to first analgesic request, VAS score at rest and movement, hemodynamic parameters and side effects were recorded in each group post-TAP block upon arrival to the (PACU) and after 30 min, every hour during the first 12 hours and every 4 hours thereafter for 24 hours in the surgical ward. Results The mean differences in VAS score at rest and movement from 0-8 h was significantly lower in dexamethasone and MgSO4 compared to control group (p < 0.001). Time to first analgesic request was significantly longer in group B-D (12.8±1.3 h) compared to group B-M (7.8±1.0 h) and group B (0.7±0.2 h) (p < 0.001). The mean value of pethidine requirement was statistically higher in Group B compared to Group B-D and Group B-Mg (p < 0.001). Conclusion Compared to magnesium sulphate, the addition of dexamethasone to bupivacaine in TAP block as postoperative analgesia after abdominoplasty provides better analgesia, longer duration of analgesia and reduced need for rescue analgesics, with fewer adverse effects.