[Effect of temperature on rheologic properties of blood and internal viscosity of erythrocytes]. / Vliv teploty na reologické vlastnosti krve a vnitrní viskozitu erytrocytu.

ABSTRACT

BACKGROUND: The blood viscosity is one of the factors affecting tissue blood flow. Aim of the study was to establish how the blood viscosity and internal viscosity of the red cell (Tk) may be influenced by change of the temperature. METHODS AND RESULTS: We have measured plasma and blood viscosity in 20 samples of human plasma and 17 samples of human blood. Viscosity was established with rotational viscometer under the temperature ranging from 25 degrees C to 45 degrees C. Concomitantly the internal viscosity of the red cell (Tk) was estimated. Plasma and blood viscosities are decreasing with the temperature elevation but the change is not linear through temperature range used for testing. The most pronounced change was found in relatively lower temperatures. Relative viscosity of the blood did not change significantly with the temperature except of measurements under low shear conditions performed in low temperature. Relative blood viscosity increased with temperature fall in such a situation. The internal viscosity of the red cell (Tk) increased significantly with temperature elevation. CONCLUSIONS: The average values of the blood and plasma viscosity fell with temperature elevation but the change was not linear. The plasma viscosity change was the highest in the low temperature range. These findings together with significant differences between relative and dynamic blood viscosity in low shear conditions and in 25 degrees C showed that blood viscosity was influenced by qualitative changes of the plasma followed by higher aggregation of the red cells.