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 15 ml (0.25%) ropivacaine on each side under aseptic techniques. All the parturients were evaluated for pain or related complications in the first 24 h after surgery. The primary outcome is the percentage of parturients who required oxycodone as a rescue analgesia. Results: Eighty and 79 parturients were allocated to the TAP and placebo group respectively. Nine 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.