Effect of dexmedetomidine as an adjuvant to ropivacaine in ultrasound-guided transversus abdominis plane block for post-operative pain relief in cesarean section

Introduction: Peripheral nerve blocks after cesarean section (C-section) reduce post-operative use of analgesic agents. Transversus abdominis plane (TAP) block is an effective way to provide postoperative analgesia. TAP block with ropivacaine alone has not consistently been proven to be useful after C-section, and dexmedetomidine has not been studied as an adjuvant to ropivacaine for TAP blocks after C-section. Objective: To compare the combination of dexmedetomidine and ropivacaine to ropivacaine alone for TAP block after C-section for time to onset of pain and time to rescue analgesia. Materials and Methods: Forty American Society of Anesthesiology grade I or II patients undergoing C-section were enrolled in this randomized, controlled, double-blind study. Twenty patients each were allocated to two groups receiving bilateral TAP block. Test group received TAP block with 3 mg/kg of ropivacaine with 50 μg of dexmedetomidine. Control group received TAP block with 3 mg/kg of ropivacaine. Patient demographics, time to initial reporting of pain, time to first rescue analgesia, quality of block, and side effects were recorded. Results: Time to initial onset of pain (6.6 vs. 5.03 h; P = 0.01) and time to first rescue analgesia (7.8 vs. 6.47 h; P = 0.03) were significantly longer in the test group compared with control group. The two groups were similar in demographics and quality of block. No significant difference in side effects was noted between the two groups. Conclusion: Addition of dexmedetomidine to ropivacaine for TAP block in patients undergoing C-section prolonged the time to initial onset of pain and time to first rescue analgesia.