[Contribution to post-caesarean analgesia of ultrasound-guided transversus abdominis plane block]

Objective: The aim of this study was to evaluate the contribution made by ultrasound-guided transversus abdominis plane block (TAP) to the quality of the analgesia with intrathecal opioids obtained in patients undergoing elective caesarean delivery.

Material and methods: A prospective, randomized study in patients submitted to elective caesarean section with spinal anaesthesia with 0.5% hyperbaric bupivacaine. The patients were randomized into 3 groups according to the added complementary drug for analgesia: group A morphine 0.1mg; group B fentanyl 10 μg; group C 10 μg fentanyl+bilateral TAP block. The TAP block with 20 ml of 0.5% levobupivacaine on each side, after surgery. Groups A and B, were injected with 20 ml of saline. Postoperative analgesia was performed with morphine bolus through a system of patient-controlled analgesia (PCA). We studied the pain on a visual analogue scale at 12 and 24h at rest and movement, the time elapsed to require the first bolus, and morphine bolus in 24h. Secondary effects such as nausea, vomiting, pruritus, and drowsiness, were also evaluated. The level of patient satisfaction was also recorded.

Results: A total of 90 patients were included. At rest the 12/24h VAS score was: group A, at 12h 2.1 ± 1.2, at 24h 4.7 ± 1.6; group B at 12h 4.3 ± 2.9, at 24h 4.8 ± 2; group C at 12h 1.9 ± 1.09, at 24h 2.3 ± 1.2 (P<.05). Walking improved analgesia more in group C (P ≤.02). The time of asking for the first bolus was lower in group B: group A 9.3 ± 4.9h (P=.02 compared to group C), in group B 2 ± 1.8h (P<.001 compared to group C) and group C 13.2 ± 2.1h. The number of bolus in 24h in group B was 38 ± 5, in group A 10 ± 2 (P<.05), group C 5 ± 2 (P<.001). Delayed nausea was increased in group B (36.6%) and pruritus was greater in group A (36.6%).

Conclusions: Ultrasound (US)-guided TAP block improves spinal opioid analgesia, with a decrease in VAS scores in the first 24h, and reduces opioid requirement and secondary effects after caesarean delivery.