Kinetic study of whole blood filtration during extracorporeal circulation (E.C.C)

Abstract

The authors realized from twelve patients with cardiac diseases, a kinetic study of the erythrocyte filtration flow (E.F.F) during and after extracorporeal circulation (E.C.C) surgery. In most of the cardiac patients, E.F.F was lower than in the control group; since the beginning of anesthesia, E.F.F increased and remained significantly higher throughout E.C.C with a maximal value at the 30^th mn (2 p < 0.001). At the end of E.C.C and in the post-operative period, E.F.F decreased below the reference values (2 p < 0.001). In order to explain this E.F.F kinetic the authors discussed the influence of the following factors: a) factors acting on the whole blood viscosity: hematocrit decrease and fibrinogen decrease enhanced the E.F.F; b) factors acting on the erythrocyte deformability: hypothermia and Pv¯O₂ increase are positively correlated with E.F.F (2 p < 0.001); alcalosis is closely related to E.F.F decrease and there is a significant relationship (2 p < 0.05) between 2,3-DPG decrease and E.F.F decrease in the post-operative period (3^th hour); the decrease of internal red cell viscosity, related to the mean corpuscular hemoglobin concentration (MCBC) enhanced erythrocyte deformability (2 p < 0.01). Total hemodilution seems to be important in explaining the E.F.F increase during E.C.C. It could also intervene in the post-operative period by limiting the 2,3-DPG decrease and so the E.F.F decrease.