Efficacy of ultrasound-guided transversus abdominis plane blocks for post-cesarean delivery analgesia: a double-blind, dose-comparison, placebo-controlled randomized trial.

BACKGROUND

The analgesic benefit of TAP (transversus abdominis plane) blocks for cesarean delivery pain remains controversial. We compared the analgesic efficacy of two doses of local anesthetic for TAP blocks after cesarean delivery.

METHODS

Sixty women having cesarean delivery under spinal anesthesia were randomized to receive ultrasound-guided TAP blocks using either high-dose ropivacaine (3mg/kg), low-dose ropivacaine (1.5mg/kg) or placebo. Patients received intrathecal 0.75% bupivacaine 10-12mg, fentanyl 10μg and morphine 150μg and standard multimodal analgesia. The primary outcome was the difference in pain with movement using a numeric rating scale at 24h. Other outcomes included time to first request for analgesia, pain scores at 6, 12, 36, 48h and at 6 and 12weeks, opioid consumption, adverse effects, quality of recovery, and satisfaction.

RESULTS

There were no differences between groups in the primary outcome. Mean ± SD pain scores (0-10) with movement at 24h were: high-dose ropivacaine 3.6±1.5, low-dose ropivacaine 4.6±2.1 and placebo 4.1±1.7. With respect to secondary outcomes, the mean ± SD pain scores at 6h were lower in the high-dose group 2.0±1.8 compared to the low-dose 3.4±2.7 and placebo groups 4.2±2.0 (P=0.009). Pain scores at 12h were also lower in the high-dose group 2.2±2.0 compared to the low-dose group 4.1±2.7 and placebo group 4.0±1.3 (P=0.011). There was no difference in other outcomes between groups.

CONCLUSIONS

Neither high- or low-dose TAP blocks as part of a multimodal analgesia regimen including intrathecal morphine improved pain scores with movement at 24h after cesarean delivery when compared to placebo TAP blocks. High-dose TAP blocks may improve pain scores up to 12h after cesarean delivery.