Introduction: During cardiopulmonary bypass (CPB), adequate prime solution allows pre-treatment of the tubing line, oxygenator and blood pump, evacuation of air from the arterial conduit, and appropriate blood dilution. However, the volume of prime solution may also affect the blood transfusion rate.

Objective: This study evaluated the effect of different volumes of CPB prime solution used in two different cardiac surgery centres on blood transfusion rate, as well as the relationship between the volume of CPB prime solution and early clinical outcomes.

Methods: A total of 323 patients who underwent CPB-guided cardiac surgery were included in this retrospective study. Patients with different prime solution volumes in two different cardiac surgery centres were included in the study. Each centre was considered as a separate study group. The data of the groups were compared statistically.

Results: There were 195 patients in group 1 and 128 patients in group 2. The preoperative characteristics and laboratory variables of the two groups were similar (p > 0.05). The amount of additional fluid given during CPB, the amount of urine and haemofiltrate removed by the patients, intraoperative bleeding drainage rate, postoperative platelet and erythrocyte values, need for intracardiac defibrillation, need for inotropic support and intra-aortic balloon pump (IABP) requirement during CPB weaning, duration of postoperative mechanical ventilation support, and duration of intensive care unit (ICU) stay were similar in both groups (p > 0.05). However, intraoperative erythrocyte transfusion rates, postoperative bleeding drainage rates, postoperative erythrocyte transfusion rates, postoperative leukocyte value and length of hospital stay were significantly higher in group 2 (p = 0.000; p=0.006; p = 0.000; p= 0.009; p = 0.037, respectively). Additionally, postoperative haemoglobin and haematocrit values were significantly lower in group 2 (p = 0.034; p = 0.047, respectively).

Conclusion: As a result of this study, we observed that low prime solution volume vs. high prime solution volume impacts the negative variables of CPB patients. We believe that perfusionists avoiding high prime solution volumes in fluid management during CPB will positively reduce the blood transfusion rate/amount, and also reduce other negative variables.