Efficacy of Ultrasound-Guided Pectointercostal Fascial Block Versus Control and Alternative Regional Techniques in Cardiac Surgery: A Systematic Review and Meta-Analysis with Dose–Response Analysis

Background and Objectives: Ultrasound-guided pectointercostal fascial block (USG-PIFB) is increasingly used for post-sternotomy analgesia, but its efficacy remains uncertain. Prior meta-analyses pooled ultrasound-guided blocks with surgeon-performed infiltration, introducing heterogeneity. We aimed to determine the analgesic efficacy of USG-PIFB in adult cardiac surgery by restricting inclusion to ultrasound-guided techniques. Materials and Methods: Six databases were searched through December 2025, with an update search of open sources and trial registries in September 2026, for randomized controlled trials comparing USG-PIFB with control (Comparison 1) or with an alternative regional technique (Comparison 2) in adults undergoing sternotomy. The primary outcome was 24-h opioid consumption in intravenous morphine milligram equivalents. Random-effects meta-analysis (REML, Knapp–Hartung), subgroup, sensitivity and meta-regression analyses, an exploratory trial sequential analysis and GRADE assessment were performed. Results: Twenty-nine trials (2664 participants) were included: 24 in Comparison 1 and eight in Comparison 2. In 13 trials (902 participants), USG-PIFB reduced 24-h opioid consumption (mean difference −6.60 mg; 95% CI, −10.92 to −2.27; I2 = 97.7%), but the 95% prediction interval (−22.24 to 9.04 mg) included no effect and small-study effects could not be excluded. Pain scores were lower by 0.8 to 1.4 points at rest (extubation, 12 and 24 h) and during movement (12 h). Extubation was earlier and intensive care stay shorter, with extreme heterogeneity. No dose–response relationship was detected, and the difference from deep parasternal techniques was near zero. No local anesthetic systemic toxicity or block-attributable pneumothorax was reported; one block-site hematoma occurred in a USG-PIFB recipient. Certainty of evidence was low for rescue analgesic use and block-related complications and very low for all other outcomes. Conclusions: USG-PIFB may modestly reduce 24-h opioid consumption, but the magnitude and reproducibility of this effect across clinical settings remain uncertain. It is best regarded as one component of multimodal analgesia, and adequately powered multicentre trials are needed.