Thixotropy of Blood and Proneness to Thrombus Formation

• "While the viscosity of blood lias been studied extensively (Copley, Stainsby, and Bayliss-), only a few studies have involved the use of a rotational viscometer. These included Brundage, Wells and Merril, and Wells et al.,-~ the latter applying a Brookfield cone plate viscometer. Neither study was carried out at rates of shear below 10 seer. The present author considered that the region below the 10 sec." is of the greatest importance in the determination of the colloidal structures of blood. The project began with the aim of studying viscosity, thixotropy and clotting of human blood in the absence of anticoagulants . by means of a rotational viscometer. The results obtained suggested a further line of investigation, namely, a correlation of the aggregation of red cells and the thrombus formation. The thixotropic slope and the position of a thixotropic curve were previously found to be intimately related to the degree of aggregation (flocculation) of dispersed particles and to the sedimentation volume; these parameters indicated the size of flocculae and the strength of the interparticle adhesion. It was presumed that a similar use might be made of a thixotropic flow curve in the case of blood. Methods