The Comparison of the Concentration of Free Hemoglobin in Packed RBC, Intraoperative Salvaged Blood and CPB Residual Blood during Cardiac Surgery

Background: Intraoperative autotransfusion or residual blood in a cardiopulmonary bypass (CPB) circuit has been used to reduce the need for an homologous blood transfusion during cardiac surgery.However, it may contain some free hemoglobin released from damaged cells.The load of blood containing free hemoglobin may cause renal dysfunction.We measured the amount of free hemoglobin in banked blood, cell saver blood and CPB blood to evaluate what is the least hemolytic blood transfused in cardiac surgery.Methods: This study was performed in 20 patients undergoing cardiac surgery.In each patient, the banked blood, intraoperative salvaged blood with a cell saver and CPB residual blood were sampled at the end of the operation.The concentration of free hemoglobin, hemoglobin and platelet counts were measured in these blood samples and percent of hemolysis was calculated (%hemolysis = [free hemoglobin] / [free hemoglobin + hemoglobin])Results: In salvaged blood with a cell saver, CPB residual blood and banked blood, hemoglobin concentrations were 20.1 ± 2.7 g/dl, 8.0 ± 1.1 g/dl, and 22.2 ± 2.7 g/dl, respectively.Free hemoglobin concentrations were 336.6 ± 239.5 mg/dl, 49.2 ± 26.8 mg/dl, and 279.5 ± 167.5 mg/dl respectively.Platelet counts were 26.1 ± 22.2 × 10 3 /mm 3 , 116.8 ± 56.5 × 10 3 /mm 3 , and 94.9 ± 43.6 × 10 3 /mm 3 respectively.% Hemolysis were 1.6 ± 1.1%, 0.6 ± 0.4%, and 1.2 ± 0.7% respectively.In the comparison between the salvaged blood with a cell saver and CPB residual blood, free hemoglobin concentration, % hemolysis, and platelet counts had positive correlations (r = 0.8, 0.7, and 0.6). Conclusions:In twenty cardiac surgeries, CPB residual blood had a lower free hemoglobin level than the other two blood groups.The platelet counts in CPB residual blood were higher than those in cell saver blood but did not differ from those in banked blood.Therefore, CPB residual blood was the least hemolytic blood among the three blood groups when a transfusion was performed in cardiac surgery.(Korean J Anesthesiol 2002; 43: 588∼593)