Viscidation of Blood during Short Term Bed Rest – Its Possible Importance in the Etiology of Deep Vein Thrombosis

Abstract

Twelve male volunteers were submitted to strict bed rest. Before, 36 hours, and 84 hours after the start of immobilisation venous blood was drawn. Blood viscosity, haematocrit, plasma viscosity, red cell aggregation, red cell deformability, blood pressure, heart rate and body weight were determined. Results show marked haemoconcentration with significant elevations of blood viscosity, haematocrit, plasma viscosity and red cell aggregation during bed rest. Body weight declines by more than 1 kg. It is suggested that haemoconcentration reduces the fluidity of blood, which in turn decreases flow, thereby predisposing to venous thrombosis in clinical situations with bed rest