Impact of Variable Heparin Doses on Blood Transfusion Requirement in On-Pump Coronary Artery Bypass Grafting (CABG) Patients

Objectives: This study aimed to investigate the correlation between different intraoperative heparin doses and postoperative blood transfusion requirements in patients undergoing on-pump coronary artery bypass grafting (CABG). Methodology: A prospective observational comparative study was conducted at the Department of Anaesthesiology, Aga Khan University Hospital, between October 2022 and May 2023. A total of 74 patients scheduled for primary CABG were included and categorized into two groups: Group A (300– 350 units/kg) and Group B (≥351 units/kg). Baseline demographic and clinical characteristics were documented. Protamine was administered at 1 mg per 100 units of heparin for reversal. Postoperative outcomes, including transfusion requirement, chest drain output, and CICU stay, were recorded. Data were analyzed using SPSS 26.0, with t-tests, Mann–Whitney U tests, and chi-square tests applied; p < 0.05 was considered significant. Results: Among 74 patients, 40.54% (n=15) in Group A required blood transfusions compared with 64.86% (n=24) in Group B (p=0.032), indicating a significant association between higher heparin dose and transfusion requirement. Mean 24-hour chest drain output was greater in Group B (733 ± 246 ml) than Group A (584 ± 184 ml), though not statistically significant (p > 0.05). Stratified analysis revealed above-average body surface area (BSA) as a significant predictor of transfusion in Group B (p=0.010), while clopidogrel history and platelet count showed non-significant trends. Conclusion: Higher intraoperative heparin doses were associated with increased postoperative transfusion needs in CABG patients, emphasizing the importance of optimized anticoagulation protocols to balance thrombotic prevention and bleeding risks.