Viscosity of human blood hemodiluted with crystalline hemoglobin solution

Hemoglobin solution has been proposed as a blood substitute and, when administered intravenously, causes hemodilution that affects the viscosity of the circulation fluid. To quantitate the changes in viscosity, hemodilutions were made by mixing freshly drawn human blood with a 7-g/dl hemoglobin solution in different proportions. Viscosity measurements were made with a micro-cone plate viscosimeter at various shear rates. The results demonstrate that even at low or moderate hemodilutions with hemoglobin solution, the viscosity of blood decrease considerably at each shear rate investigated. The decrease of viscosity is greater with increasing hemodilution. A shear thinning effect is observed with whole blood and with each hemodiluted sample. The viscosity-hematocrit relationship, which could be demonstrated not only by cone-plate but also by the Ostwald viscosimeters at a fixed shear rate, shows that the concentration of red blood cells significantly affects the viscosity of blood. Hemodilution of blood with hemoglobin solution not only reduces the viscosity but also may improve the blood flow.