[Hemorheological changes during mammary coronary bypass grafting]

Hemorheological studies were performed in 44 patients subjected to mammary coronary bypass surgery during induction of anesthesia, at initiation of cardiopulmonary bypass, at the end of operation, on the 1(st) and 2(nd) or 3(rd) postoperative day. Methods included determination of whole blood and plasma viscosity with estimation of suspension stability and calculation of Caisson viscosity and fluidity limit. Rigidometry was used for assessment times of linear (T(1)) and three dimensional (T(2)) aggregates formation, final aggregates dimensions, total hydrodynamic strength of aggregates (beta), index of strength of especially large aggregates. Indexes of aggregation and deformation of erythrocytes were also calculated. Cardiopulmonary bypass was associated with lengthening of T(1) and shortening of T(2), increase of aggregates dimension and their hydrodynamic strength beta and lowering deformability of erythrocytes. By the end of operation increase of difference between Caisson and asymptotic viscosity was noted. Postoperative period was characterized by improvement of deformability of erythrocytes, prolongation of T(2), increases of aggregates dimension, their hydrodynamic strength beta, and fluidity limit. Thus measures of intensive therapy should be directed at correction of disturbances of rheological properties of blood with consideration of their changes specific for cardiosurgical patients.