Efficacy of opioid-sparing analgesia after median sternotomy with continuous bilateral parasternal subpectoral plane blocks

Objectives: Regional anesthetic techniques, traditionally underutilized in cardiac surgery, may play a role in multimodal analgesia, effectively improving pain control and reducing opioid consumption. We investigated the efficacy of continuous bilateral ultrasound-guided parasternal subpectoral plane blocks following sternotomy. Methods: We reviewed all opioid-naïve patients who underwent cardiac surgery via median sternotomy under our enhanced recovery after surgery protocol between May 2018 and March 2020. Patients were grouped based on postoperative pain management strategy–those who received standard Enhanced Recovery After Surgery (ERAS) multimodal analgesia alone (no nerve block group) versus those receiving ERAS multimodal analgesia plus continuous bilateral parasternal subpectoral plane blocks (block group). In the block group, parasternal subpectoral plane catheters were placed under ultrasound-guidance on each side of the sternum with initial 0.25% ropivacaine bolus, followed by continuous 0.125% bupivacaine infusions. Postoperative patient-reported numerical rating scale pain scores and opioid consumption in morphine milligram equivalents were compared through postoperative day 4. Results: Of 281 patients included in the study, the block group comprised 125 (44%) patients. Although baseline characteristics, type of surgery, and length of stay were similar between groups, average numerical rating scale pain scores and opioid consumption were significantly lower in the block group through postoperative day 4 (all P values < .05). We also observed a 44% reduction in total opioid consumption after surgery in the block group (75.1 vs 133.1 MME; P = .001) and 1 less hospital day requiring opioids (4.2 vs 3 days; P = .001). Conclusions: Continuous bilateral parasternal subpectoral plane blocks may further reduce poststernotomy pain and opioid consumption within the context ERAS multimodal analgesia.