Efficacy of continuous in-wound infusion of levobupivacaine and ketorolac for post-caesarean section analgesia: a prospective, randomised, double-blind, placebo-controlled trial

BACKGROUND: In-wound catheters for infusion of local anaesthetic for post-caesarean section analgesia are well tolerated in parturients. Few studies have examined continuous in-wound infusion of a combination of local anaesthetic and non-steroidal anti-inflammatory drug for post-caesarean section analgesia. This single centre study evaluated post-operative analgesic efficacy and piritramide-sparing effects of continuous in-wound infusion of either local anaesthetic or non-steroidal anti-inflammatory agent, or the combination of both, versus saline placebo, when added to systemic analgesia with paracetamol. METHODS: After National Ethical Board approval, 59 pregnant women scheduled for non-emergency caesarean section were included in this prospective, randomised, double-blind, placebo-controlled study. The parturients received spinal anaesthesia with levobupivacaine and fentanyl. Post-operative analgesia to 48 h included paracetamol 1000 mg intravenously every 6 h, with the studied agents as in-wound infusions. Rescue analgesia with piritramide was available as needed, titrated to 2 mg intravenously. Four groups were compared, using a subcutaneous multi-holed catheter connected to an elastomeric pump running at 5 mL/h over 48 h. The different in-wound infusions were: levobupivacaine 0.25% alone; ketorolac tromethamine 0.08% alone; levobupivacaine 0.25% plus ketorolac tromethamine 0.08%; or saline placebo. The primary outcome was total rescue piritramide used at 24 h and 48 h post-operatively, under maintained optimal post-caesarean section analgesia. RESULTS: Compared to placebo in-wound infusions, ketorolac alone and levobupivacaine plus ketorolac in-wound infusions both significantly reduced post-operative piritramide consumption at 24 h (p = 0.003; p < 0.001, respectively) and 48 h (p = 0.001; p < 0.001). Compared to levobupivacaine, levobupivacaine plus ketorolac significantly reduced post-operative piritramide consumption at 24 h (p = 0.015) and 48 h (p = 0.021). For levobupivacaine versus ketorolac, no significant differences were seen for post-operative piritramide consumption at 24 h and 48 h (p = 0.141; p = 0.054). CONCLUSION: Continuous in-wound infusion with levobupivacaine plus ketorolac provides greater opioid-sparing effects than continuous in-wound infusion with levobupivacaine alone. TRIAL REGISTRATION: German Clinical Trials Register: retrospectively registered on 30 July, 2014, DRKS 00006559.