Effect of the acute phase reaction on blood viscosity after infrainguinal arterial bypass

A new method of determining apparent blood viscosity at low shear rates using a porous bed viscometer has been validated in an experimental study of canine blood altered by isovolemic hemodilution. The data confirm the ability of the technique to detect the non-Newtonian behavior of blood at higher hematocrit and fibrinogen values. The technique was then employed in a limited clinical study of nine patients undergoing infrainguinal vascular reconstruction to evaluate the effect of operation and the associated increase in serum fibrinogen levels, resulting from the acute phase reaction, on blood viscosity. Although there was a substantial change in serum glycoprotein levels, the concurrent relative decrease in red cell mass after operation resulted in a decrease in whole blood viscosity. These findings support the beneficial effect of moderate hemodilution as a means of compensating for the potentially detrimental effects of the acute phase reaction on blood rheology.