Ultrasound-guided Transversus Abdominis Plane Block After Cesarean Section Using Two Different Bupivacaine Volumes With a Fixed Drug Mass. A Randomized Comparative Trial.

Cesarean section is commonly associated with moderate to severe postoperative pain, which may delay mobilisation, impair breastfeeding, and affect mother-infant bonding. Although opioids, NSAIDs, and neuraxial techniques are commonly used for post-cesarean analgesia, their side effects have encouraged the use of peripheral nerve blocks such as the transversus abdominis plane block.

The TAP block is a fascial plane block that provides analgesia by depositing local anaesthetic between the internal oblique and transversus abdominis muscles. Its efficacy after cesarean section has been demonstrated, particularly when long-acting intrathecal opioids are not used. However, the optimal local anaesthetic volume and dose remain unclear. Since the TAP block depends on adequate spread of local anaesthetic, larger volumes may improve analgesic coverage, but increasing the dose may raise the risk of systemic toxicity.

Therefore, this study investigates whether using the same fixed mass of bupivacaine in two different volumes affects the analgesic efficacy of TAP block after cesarean section, hypothesising that the larger volume may provide better postoperative analgesia.