Viscosity of animal erythrocyte suspensions mixed with a perflurocarbon emulsion

Artificial blood substitutes (ABS) offer an alternative to donated blood. Increasing the oxygen carrying capacity of blood plasma through the addition of a Perfluorocarbon emulsion (PFE) is one approach in creating a blood substitute. The peripheral resistance of the circulatory system may be altered depending on the rheological properties of the ABS. Measurements of the rheological behavior of mixtures of a PFE, Oxygent, and erythrocyte suspensions were conducted at room temperature at different hematocrits using sheep (nonaggregating) and swine (aggregating) erythrocytes. The pure PFE was found to be shear thinning. Adding 6 and 12 g per 100 mL of sheep blood at the various hematocrits increased the viscosity of the suspension from as low as 4% (6 g PFE/40% Hct) to as high as 26.5% (12 g PFE/plasma). The nonaggregating sheep erythrocyte and PFE mixtures exhibited Newtonian behavior. Shear thinning behavior continued upon addition of 6 and 12 g per 100 mL of swine blood at the various hematocrits, with a slight increase in viscosity in most cases. It was observed that adding 12 g of PFE (approximately 3 x intended clinical dose) to 40% Hct swine blood at room temperature led to a significant decrease in viscosity.