Since several authors have found abnormal blood viscosity in patients suffering from Raynaud’s disease but did not study them at the moment when the phenomenon appeared, we want to find out whether haemorheological changes might be provoked in the patients during a cold-induced phenomenon. The study was conducted on ten selected patients suffering from Raynaud’s phenomenon only in one hand when exposed to cold. A relevant and statistically very significant increase of the viscosity was noted in the blood coming from the hand during the cold-induced ischemia. When the ischemia had disappeared, blood viscosity levels returned to those recorded before the experience. No variations were evident in either plasma and serum viscosity, or in packed red cell volume and in plasma fibrinogen concentration. In the other arm of the same patients, a much smaller increase in blood viscosity was noted. No variations were found in any of the parameters observed in six control subjects. These results seems to suggest that blood viscosity changes specifically in relation to the disease, that this change may be related to the behaviour of the red cells (increased aggregability or decreased deformability) as the consequence of the ischemia, and that this hyperviscosity may potentiate the hindrance to the flow at the microcirculatory level.
Influence of Deformability of Human Red Cells upon Blood Viscosity
