Superficial parasternal intercostal plane blocks in cardiac surgery: a systematic review and meta-analysis

Purpose Traditional multimodal analgesic strategies have several contraindications in cardiac surgery patients, forcing clinicians to use alternative options. Superficial parasternal intercostal plane blocks, anesthetizing the anterior cutaneous branches of the thoracic intercostal nerves, are being explored as a straightforward method to treat pain after sternotomy. We sought to evaluate the literature on the effects of superficial parasternal blocks on pain control after cardiac surgery. Methods We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs). We searched MEDLINE, Embase, CENTRAL, and Web of Science databases for RCTs evaluating superficial parasternal intercostal plane blocks in adult patients undergoing cardiac surgery via midline sternotomy published from inception to 11 March 2022. The prespecified primary outcome was opioid consumption at 12 hr. The risk of bias was assessed with the Cochrane Collaboration Risk of Bias Tool, and the quality of evidence was evaluated using the grading of recommendations, assessments, development, and evaluations. Outcomes were analyzed with a random-effects model. All subgroups were prespecified. Results We reviewed 1,275 citations. Eleven RCTs, comprising 756 patients, fulfilled the inclusion criteria. Only one study reported the prespecified primary outcome, precluding the possibility of meta-analysis. This study reported a reduction in opioid consumption (−11.2 mg iv morphine equivalents; 95% confidence interval [CI], −8.2 to −14.1) There was a reduction in opioid consumption at 24 hr (−7.2 mg iv morphine equivalents; 95% CI, −5.6 to −8.7; five trials; 436 participants; moderate certainty evidence). All five studies measuring complications reported that none were detected, which included a sample of 196 blocks. Conclusion The literature suggests a potential benefit of using superficial parasternal blocks to improve acute postoperative pain control after cardiac surgery via midline sternotomy. Future studies specifying dosing regimens and adjuncts are required. Study registration PROSPERO (CRD42022306914); first submitted 22 March 2022.