A Comparison of the Clinical Outcomes of Minimum and Maximum Hematocrit Levels During Cardiopulmonary Bypass (CPB) in Low-risk Patients Undergoing Coronary Artery Bypass Graft Surgery (CABG): A Cross-sectional Study

Background: This study investigated the clinical outcomes at the minimum and maximum levels of hematocrit (HCT) during cardiopulmonary bypass (CPB) in low-risk patients undergoing coronary artery bypass graft (CABG) surgery. Materials and Methods: In this cross-sectional study, 85 patients who underwent CABG with an ejection fraction of greater than 35% were selected. Based on the HCT range during CPB, patients were divided into two groups: minimum HCT: HCT = 16–18% and maximum HCT: HCT = 25–27%. Then the operation outcomes, amount of drainage, and transfusion were recorded and compared between these groups. Results: In the middle tube 8 h after surgery and left tube 24 h after surgery, the amount of drainage in the minimum HCT group with mean of 71.00 ± 130.9 and 60.65 ± 71.23, respectively, was significantly lower than the maximum HCT group with mean of 101.5 ± 246.50 and 123.76 ± 93.17, respectively (P value < 0.05). The incidence of cognitive disorders in the maximum HCT group was significantly higher than in the minimum HCT group (11.1% vs. 0%, P value = 0.041). Also, the mean transfusion of packed red blood cell (PRBC) and fresh frozen plasm (FFP) during CPB in the maximum HCT group, with mean of 346.7 ± 86.22 and 396.1 ± 21.05, respectively, were significantly higher than the minimum HCT group with mean of 178.8 ± 80.91 and 136.8 ± 46.77, respectively (P value < 0.05). After CPB, there was no significant difference in transfusion products (P value > 0.05). Conclusion: According to the results of this study, patients undergoing CABG surgery with maximum HCT level versus minimum HCT level during CPB, need more packed cells and fresh frozen plasma products transfusion, which will be associated with the complication of cognitive impairment.