An Effective Blood Replacement Fluid That Targets Oxygen Delivery, Increases Plasma Viscosity, and Has High Oxygen Affinity

Summary To the present the development of blood substitutes has had as a goal to reproduce the properties of blood. New information on how oxygen is transported in microcirculation allows the design of fluids that may be more efficacious than blood during transfusion/resuscitation. These fluids induce vasodilation and increase peripheral vascular resistance through increased blood viscosity, achieving the dual goal of lowering arteriolar oxygen consumption and delivering more oxygen to the tissues. Restoration of tissue function is ensured by reducing the possibility that tissue micro-regions fall below the threshold of anaerobic metabolism. This goal is attained by using high-affinity modified hemoglobins that act as a reservoir of oxygen only deployed when the circulating blood arrives at tissue regions where pO2 is very low, even though tissue pO2 may be appear to be below normal. A special feature of an oxygen carrying plasma expander designed according to this premise is that it requires comparatively small amounts of hemoglobin to be effective, a factor that is important since presently human hemoglobin appears to be the oxygen carrier of choice.