THE QUICK MACHINE - A MATHEMATICAL-MODEL FOR THE EXTRINSIC ACTIVATIONOF COAGULATION

The present paper describes a mathematical model of the kinetics of th e extrinsic coagulation cascade in vitro. The coagulation factors FI, FII, FV, FVII, FX, heparin and antithrombin III (ATIII) as well as sol uble fibrin polymers are considered. The effect of single-factor defic iencies of the factors II, V, VII and X, diseases like hypo- and dysfi brinogenaemia, hepatic insufficiency, inhibited polymerisation by degr adation products, heparin therapy with and without ATIII deficiency an d coumarin therapy on prothrombin time can be portrayed. Physiology of coagulation is represented in a dynamic mathematical model as a diffe rential equation system. The model is based on three reaction types: e nzymatic cleavage, complex formation and polymerisation. The model was implemented in a continuous simulation program on a personal computer using the Pascal programming language. Unknown rate constants were es timated by chi(2) fit. Prothrombin time calculated by the model was co mpared to the training set of 20 plasma samples. In most but not all c ases the model harmonized quite well with the coagulometric data.