The analgesic efficacy of TAP blocks after cesarean section: a systematic review
Abstract Number: F-10
Abstract Type: Original Research
Introduction: Pain relief after cesarean section (CS) remains challenging. In addition to visceral pain, there is incisional pain. Recently, there has been interest in transversus abdominis plane (TAP) blocks in decreasing somatic pain. This systematic review evaluates the efficacy of TAP blocks in parturients for post CS pain relief.
Methods: Multiple electronic databases were searched using free text combinations of the following terms “ transversus abdominis plane block “and “ cesarean” and “ caesarean”. The search results were then limited to English language and randomized controlled trials (RCTs) in humans. The reference lists of the articles were reviewed to identify other relevant studies. This review included all RCTs that used a placebo or any comparator and evaluated TAP blocks in parturients having CS. Primary outcomes were opioid requirement and pain control. Data were extracted independently by 2 reviewers. The methodological quality of the studies was evaluated independently by 2 reviewers.
Results: A total of 7 studies involving 460 patients met eligibility. 204 patients received TAP blocks. Quality scores were high (median Jadad score=5, range 3-5). In 5 studies, ultrasound guidance was used to place TAP blocks. Levobupivacaine, bupivacaine or ropivacaine were used for TAP blocks in the studies. In one study, all patients received general anesthesia. Patients received spinal anesthesia in the remaining studies. Follow up of patients ranged from 24h to 6 weeks. There were 3 studies that used spinal morphine and 2 of these compared the efficacy of spinal morphine to TAP blocks. These studies did not show any analgesic benefit of TAP blocks. The remaining 4 studies showed decreased analgesic requirements when TAP blocks were used. No study evaluated TAP block failure rate. One patient experienced an anaphylactoid reaction to the ropivacaine injected in the TAP block. No other complications were reported.
Meta-analysis is ongoing and results will be presented at the meeting.
Discussion: When spinal morphine was used, ultrasound guided or landmark based TAP blocks did not improve analgesia. However, when spinal morphine was not used, both ultrasound guided and landmark TAP blocks improved analgesia after CS. TAP blocks should be considered in patients not receiving spinal morphine.