Rheo-simulation: A new method for the assay of clotting process and factor XIII 1

Abstract

Rheo-Simulation is a method to simulate extracorporeally in vivo blood flow. It is done by “shaking” the cup of the thrombelastograph with a very small precessional movement. The radian of this movement is about 0,030 mm with a frequency of about 45 Hz. So the surface speed of the Rheo-Simulation cup is 9.5 mm/sec, resembling the velocity of blood flow in a vein. Native blood or citrated and recalcified plasma in the thrombelastograph, subjected to Rheo-Simulation during the clotting process, will clot as a very sudden event. Presumably this occurrence will be due to some extent to a new form of clotting, according to Copley’s theory, viz. the aggregation of fibrinogen in polymolecular layers both on the cup and on the rod of the measuring device which finally and suddenly grow together. The structure of this clot is relatively independent on the presence of platelets, but strongly dependent on the presence of plasma clotting factor XIII. Its total lack will, even in the presence of platelets, not allow any clot formation in the plasma subjected to Rheo-Simulation. Plasma factor XIII in an amount of 1 per cent is sufficient to allow for a normal clot structure in the Rheo-Thrombelastogram (Rheo-TEG).