[Transient rheological study of blood stored in a liquid state]

The rheological properties of blood stored in different conditions (in liquid state or as globular concentrates in the presence of the classical anticoagulant ACD or CPD solutions, or according to the SAG procedure) have beenn studied with a Couette viscosimeter. Apparent viscosity was measured at very low shear stress (0.05 s-1) as a function of the storage time. Furthemore the dynamic rheological parameters (thixotropy, viscoelasticity and rheofluidification) were determined. Blood viscosity increases strongly as a function of storage time, particularly on whole blood. Its variation is weaker on globular concentrates, particularly with SAG. Thixotropy, viscoelasticity and rheofluidification, on the contrary, are not strongly perturbated. These rheological modifications are closely related with the changaes occuring in the morphology and in the aggregation state of the stored red blood cells.