Transversus Abdominis Plane Block Following Cesarean Section: A Prospective Randomized Controlled Study Comparing the Effects on Pain Levels of Bupivacaine, Bupivacaine plus Dexmedetomidine, and Bupivacaine plus Dexamethasone

Background: The transversus abdominis plane (TAP) block is providing effective postoperative analgesia in patients undergoing cesarean section (CS). This study aims to evaluate and compare the effects on pain levels of bupivacaine alone versus bupivacaine combined with dexmedetomidine and bupivacaine combined with dexamethasone in ultrasound-guided TAP block for postoperative pain after CS. Material and Method: In this randomized controlled trial, 120 patients with American Society of Anesthesiologists (ASA) physical status I and II scheduled for elective cesarean section under spinal anesthesia were randomly divided into three groups. At the end of the surgery, an ultrasound-guided TAP block was performed on all patients: bupivacaine 0.5% (Group B), bupivacaine 0.5% + dexmedetomidine (1 mu g/kg) (Group BD), and bupivacaine 0.5% + dexamethasone (4 mg) (Group BDx). Postoperatively, all patients were evaluated at 0, 1, 4, 8, 16, and 24 h for visual analog scores VASs, tramadol consumption, complications, and patient satisfaction. A p value of < 0.05 is statistically significant. Results: At 0 h, VASs in the sitting and supine positions were significantly higher in the BDx group (0.85 +/- 1.61 and 0.85 +/- 1.36, respectively) compared to the B group (0.05 +/- 0.32 in both positions) and the BD group (0.15 +/- 0.48 in both positions) (p = 0.005 and p = 0.001, respectively). At the 24th hour, VASs in the sitting and supine positions were significantly lower in the BDx group (1.7 +/- 1.2 and 1.43 +/- 1.05) compared to the B group (2.3 +/- 0.68 and 2.2 +/- 0.72) and the BD group (2.57 +/- 1.01 and 2.28 +/- 0.78) (p = 0.005 and p = 0.001, respectively). At 0 h, the tramadol requirement was highest in the BDx group at 12.5%, while it was not required in the B and BD groups (p = 0.005). At 0 h, the rate of nausea and vomiting was highest in the BDx group at 17.5%, compared to 2.5% in the BD group and 0% in the B group (p = 0.003). Patient satisfaction scores were higher in the dexamethasone group compared to the other groups. This was significant between Group B and Group BDx (p = 0.009 < 0.05). Conclusions: Adding dexmedetomidine or dexamethasone to bupivacaine in ultrasound-guided TAP blocks reduces postoperative pain and increases patient satisfaction after cesarean sections. Dexamethasone, due to its delayed onset but extended duration, achieves lower pain scores and higher satisfaction. Further research is necessary to confirm these findings.