The Analgesic Efficacy of Ultrasound-guided Transversus Abdominis Plane (TAP) Block Combined With Oral Multimodal Analgesia In Comparison With Oral Multimodal Analgesia After Caesarean Delivery: A Randomized Controlled Trial

Background: The transversus abdominis plane (TAP) block is used increasingly in parturients after caesarean delivery. This is a randomized controlled trial to evaluate the effectiveness of bilateral single-shot of TAP blocks in patients who received multimodal oral analgesia for postoperative pain relief.Methods: Parturients who were scheduled for elective caesarean delivery under spinal anaesthesia were recruited and randomized to receive bilateral single-shot of TAP blocks or placebo in addition to multimodal oral analgesia which consisted of regular tramadol, celecoxib and paracetamol, with oral oxycodone used as a rescue for breakthrough pain. Only parturients in the TAP group would receive the TAP blocks with an injection of 15ml (0.25%) ropivacaine on each side under aseptic techniques. All the parturients were evaluated for pain or related complications in the first 24 hours after surgery. The primary outcome is the percentage of parturients who required oxycodone as a rescue analgesia. Results: 80 and 79 parturients were allocated to the TAP and placebo group respectively. 9 out of 79 (11.4%) parturients in the TAP group and 15 out of 73 (20.5%) parturients in the placebo group required oxycodone for breakthrough pain, P = 0.122. Conclusions: Bilateral single-shot of TAP blocks confer little additional benefit when a multimodal oral analgesic regimen is used for pain control after caesarean section under spinal anaesthesia.Trial registration: Clinical Trial Registry of China (http://www.chictr.org.cn) identifier:ChiCTR-INR-16010130, retrospectively registered on Dec 12, 2016.