Effects of Cardiopulmonary Bypass Circuit Shortening on Transfusion Reduction: A Retrospective Cohort Study in the Cardiac Surgery Patients

Hemodilution anemia, due to the use of crystalloid liquids during the preparation of cardiopulmonary bypass (CPB) circuits, results in the increased number of RBC, which may lead to hemolysis, acute pulmonary injury, allergic reactions, metabolic and coagulative abnormalities, volume overload, alloimmunization, immunosuppression, graft versus host reaction, and a remarkable increase in hospitalization costs. The present study aimed to evaluate the effects of shortened cardiopulmonary bypass circuits on the blood salvage process in patients undergoing cardiac surgery with cardiopulmonary bypass and determine the cutoff BSA value for effectiveness. A retrospective cohort study was performed in a private hospital, Ankara, Turkey, between January 2011 and November 2015 to assess 235 patients having a CPB with shortened circuits. The control group comprised 240 patients who underwent cardiac surgery utilizing a standard extracorporeal circulation circuit at our institution. In the case group, to achieve a low-priming volume, the CPB circuit was shortened and CPB console was positioned as close as possible to the operative field. The arterial line (3/8”) and the venous line (1/2) were 80 cm and 90 cm, respectively, shorter in the case group than in the control group. Patient data were collected by retrospective medical chart review. Intraoperative red blood cell (RBC) transfusion amount was 465 ± 141.5 mL in the case group and 722.5 ± 285.4 mL in the control group (P < 0.001). Postoperative RBC transfusion was 418.7 ± 198.1 mL in the case group and 628.7 ± 452.3 mL in the control group (P < 0.001). The total amount of RBC transfusion was 742.4 ± 228.7 mL in the case group and 1012.3 ± 625.5 mL in the control group (P < 0.001). ROC analysis showed that shortening the CPB circuits was effective in patients with a BSA of < 1.67 (AUC = 0.84; P < 0.001) Shortening of the CPB circuit could be helpful to avoid severe hemodilution and to reduce RBC use in small adult patients (with BSA < 1.67) undergoing cardiac surgery with cardiopulmonary bypass.