Background: Sternal pain after cardiac surgery results in considerable discomfort. Single-injection parasternal fascial plane blocks have been shown to reduce pain scores and opioid consumption during the first 24 h after surgery, but the efficacy of continuous infusion has not been evaluated. This retrospective cohort study examined the effect of a continuous infusion of local anaesthetic through parasternal catheters on the integrated Pain Intensity and Opioid Consumption (PIOC) score up to 72 h.

Methods: We performed a retrospective analysis of patients undergoing cardiac surgery with median sternotomy at a single academic centre before and after the addition of parasternal nerve catheters to a standard multimodal analgesic protocol. Outcomes included PIOC score, total opioid consumption in oral morphine equivalents, and time-weighted area under the curve pain scores up to 72 h after surgery.

Results: Continuous infusion of ropivacaine 0.1% through parasternal catheters resulted in a significant reduction in PIOC scores at 24 h (−62, 95% confidence interval −108 to −16; P<0.01) and 48 h (−50, 95% CI −97 to −2.2; P=0.04) compared with no block. A significant reduction in opioid consumption up to 72 h was the primary factor in reduction of PIOC.

Conclusions: This study suggests that continuous infusion of local anaesthetic through parasternal catheters may be a useful addition to a multimodal analgesic protocol in patients undergoing cardiac surgery with sternotomy. Further prospective study is warranted to determine the full benefits of continuous infusion compared with single injection or no block.