Effect of normal human erythrocytes on blood rheology in microcirculation.

Background: Effects of RBCs on blood rheology were studied using a microchannel array flow analyzer (MC-FAN).

Methods: Fluidity of four types of samples prepared from the venous blood of healthy volunteers was examined in terms of passage time through the microchannel array of MC-FAN (model KH-3): (1) physiological saline-RBC suspensions and plasma-RBC suspensions, each adjusted to a predetermined hematocrit value; (2) suspensions of glutaraldehyde-treated hardened RBCs; (3) fibrinogen-RBC and albumin-RBC suspensions; and (4) dextran-RBC suspensions.

Results: Hematocrit positively correlated with passage time. Both plasma and fibrinogen prolonged passage time significantly. Hardened RBCs completely obstructed the microchannel. The passage time of dextran-RBC suspensions was prolonged in a dextran molecular weight- and concentration-dependent manner and was dependent on the passage time of the solution alone.

Conclusions: Blood rheology, as determined by MC-FAN, is affected not by RBC aggregation but hematocrit, RBC deformability, and the passage time of the solution.