Tehran University of Medical Sciences The Research in Heart Yield and Translational Medicine (RHYTHM) 3115-7270 19 3 2024 07 31 162 169 Alireza Hosseini Department of Surgery, Chamran Hospital, Isfahan University of Medical Sciences, Isfahan, Iran. Mehran Shahzamani Department of Surgery, Chamran Hospital, Isfahan University of Medical Sciences, Isfahan, Iran. Atefe Hashemabadi Department of Blood Circulation Technology, Isfahan University of Medical Sciences, Isfahan, Iran. Alireza Andalib Department of Immunology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran. 2023 04 23 2024 09 12 Background: Cardiopulmonary bypass (CPB) can adversely affect coagulation and systemic inflammatory response. Given that the optimal strategy for priming CPB in cardiac surgery remains a matter of debate, this study aimed to investigate the effects of albumin 20% and hydroxyethyl starch 6% as priming solutions on bleeding and interleukin-6 (IL-6) levels during CPB. Methods: This randomized clinical trial involved 40 patients undergoing coronary artery bypass surgery at Shahid Chamran Hospital between July 2021 and July 2022. Participants were assigned to 2 groups: the first group received 50 mL of albumin 20% as the priming solution for the CPB circuit, while the second group received 500 mL of hydroxyethyl starch 6%. Bleeding and IL-6 levels were assessed before and after the intervention. Results: The albumin group comprised 80.0% men and 20.0% women, with a mean age of 66.45±5.84 years. The hydroxyethyl starch 6% group consisted of 85.0% men and 15.0% women, with a mean age of 63.05±5.92 years (P>0.05). The findings revealed that 12 hours after CPB, the IL-6 level in the hydroxyethyl starch 6% group (mean: 171.6±77.71 pg/mL) was significantly higher than that in the albumin group (mean: 105.8±36.45 pg/mL; P=0.002). At 48 hours after CPB, the mean bleeding was not significantly different between the groups (P=0.950). Conclusion: Albumin 20% was more effective than hydroxyethyl starch 6% concerning IL-6 levels. However, no significant differences in bleeding were observed between the groups at 48 hours post-CPB. https://rhythm.tums.ac.ir/index.php/jthc/article/view/1850