[Influence of temperature on spatial fibrin clot formation process in thrombodynamics]

In this study we have investigated the process of spatial fibrin clot formation in non-steered platelet-free plasma at the temperatures from 20°C to 43°C using thrombodynamics - the novel in vitro hemostasis assay, which imitates the process of hemostatic clot growth in vivo. During data processing the following parameters were calculated: initial (V i ) and stationary (V st ) rates of clot growth which characterize initiation and propagation phases of clotting process, and clot size on the 30 th minute. The temperature dependence of extrinsic and intrinsic tenase activities, which determine values of the initial and stationary clot growth rates, respectively, have been also measured. It was established that the temperature lowering from 37°C to 24°C extends mainly on the initiation phase of clot growth, while the stationary rate of clot growth changes insignificantly. Meanwhile none of the thrombodynamics parameters shows the dramatic change of plasma coagulation system condition at the temperature of 24°C (acute hypothermia). Using the thrombodynamics assay an assumption, that the temperature lowering does not change the state of plasma hemostasis system significantly has been confirmed.