Effect of Continuous Bilateral Erector Spinae Plane Block on Neutrophil-Lymphocyte Ratio in On-Pump CABG: A Prospective Randomized Study

Background: Cardiac surgery using cardiopulmonary bypass causes a pronounced systemic inflammatory response. The neutrophil-lymphocyte ratio (NLR) is a readily accessible inflammatory biomarker associated with adverse outcomes after cardiac surgery. Regional anesthesia has been shown to modulate the inflammatory process by various mechanisms. Erector spinae plane (ESP) block reduces nociception and opioid use, but its effect on perioperative inflammatory markers is not well described. This study evaluated whether bilateral ESP block attenuates the perioperative rise in NLR in patients undergoing on-pump coronary artery bypass graft (CABG) surgery. Methods: This prospective randomized study included 120 adults undergoing elective on-pump CABG randomized to bilateral ultrasound-guided ESP block (ESP, n = 60) or conventional opioid-based analgesia (Opioid, n = 60). ESP was performed pre-induction. NLR and platelet-lymphocyte ratio (PLR) were measured until the second postoperative day (POD). Secondary endpoints included ICU length of stay, mechanical ventilation duration, and total opioid consumption. Results: Baseline characteristics were comparable between groups. NLR increased in both groups after surgery and peaked at POD1. However, POD1 NLR was significantly lower in the ESP group compared with the opioid group (13.99 vs 18.58, P = 0.007). The ESP group showed shorter ICU stay ( P = 0.02) and lower total perioperative opioid consumption ( P = 0.01). Conclusions: Bilateral ESP block attenuated the early postoperative rise in NLR and reduced opioid requirements in on-pump CABG patients, suggesting modulation of the inflammatory response in addition to analgesic benefits.