Effects of Daflon 500 mg* on haemoconcentration and alterations of white blood cell count elicited by the upright position in anaesthetized dogs.

In the passive upright position, arterial and venous pressures in the human feet increase capillary pressure which leads to the filtration of fluid from the circulating plasma into the tissues of the feet. Loss of fluid concentrates both red cells and plasma so that the haematrocrit and plasma protein concentration of venous blood leaving the feet greatly exceed their mean values in the circulation. To study this phenomenon in animals, we used Beagle dogs in upright position. In blood of saphenous vein, red cells, haematocrit and plasma protein concentration have been studied. As in human (Moyses et al. Haemoconcentration and accumulation of white cells in the feet during venous stasis. Int J Microcirc Clin Exp 1987;5:311-20) red cells, haematocrit and plasma protein concentration increase in upright position. The increases in red cells, haematocrit and plasma protein concentration were higher and levels were greater after 2 hours when compared to the corresponding values after 1 hour. Daflon 500 mg, a micronized purified flavonoidic fraction, (200 mg/kg-1 per os) administered 20 minutes before upright position, significantly reduced these increases. This model might be a suitable model to test drugs interfering with venous stasis.