Continuous ropivacaine wound infiltration versus epidural morphine after unplanned caesarean delivery: A noninferiority randomised controlled study.

Abstract

Background: Treatment programs designed to enhance recovery after caesarean delivery include multimodal analgesia to ensure optimal analgesia while reducing exposure to systemic opioids. Evidence for the effectiveness of continuous wound infiltration with local anaesthetic after unplanned caesarean delivery is needed.

Objective: To determine whether continuous ropivacaine wound infiltration has noninferior analgesic properties compared to epidural morphine, while reducing side effects related to opioids.

Design: Triple-blinded, noninferiority, randomised controlled trial.

Setting: One university hospital, between February 2015 and August 2021.

Patients: Eighty-one women undergoing unplanned lower segment caesarean section under epidural anaesthesia.

Intervention: At the end of the procedure, randomly assigned patients received either an epidural bolus of 0.9% saline with 48 h continuous ropivacaine wound infusion (ropivacaine group) or an epidural bolus of morphine with 48 h 0.9% saline wound infusion (morphine group).

Main outcome measures: Pain during mobilisation at 24 h postsurgery was assessed using the visual analogue pain scale (VAS 0 to 10) with no indication of the allocated group.

Results: Pain scores were 4.4 (95% CI, 3.6 to 5.1) in the ropivacaine group versus 3.1 (95% CI, 2.4 to 3.9) in the morphine group. The mean VAS pain difference between the two groups was 1.2 (95% CI, 0.2 to 2.3), which exceeded the prespecified noninferiority margin of 1. The differences between the two groups at rest and during mobilisation at 6 and 24 h were statistically significant. The ropivacaine group received rescue morphine more frequently, and were less satisfied despite fewer morphine-related side effects. Continuous wound infiltration was not technically feasible in 18% of the patients.

Conclusions: We failed to show that continuous ropivacaine wound infiltration was noninferior to epidural morphine in providing analgesia after unplanned caesarean delivery. Because of a significant rate of technical failures, continuous wound infiltration should only be considered when neuraxial morphine is contraindicated.