Low oxygen affinity hemoglobin solution increases oxygenation of partially ischemic tissues during acute anemia

Abstract

Maintenance of post‐surgical tissue oxygenation depends on the ability of the specific tissue to recruit perfusion and oxygen (O2) supply. However, when native O2 carrying capacity is lacking, fluids to improve O2 carrying capacity based in hemoglobin (Hb) could prevent partially ischemic tissue hypoxia by increasing O2 release from the remaining red blood cells. Responses to facilitated O2 transport after exchange transfusion with polymerized bovine Hb (PBH) were studied in a chronic partially ischemic tissue model, induced by large feeding arterioles ligation during hamster window chamber model implantation. PBH affects in microvascular perfusion and tissue oxygenation were studied after exchange transfusion of 40% of animal's blood volume. Experimental groups were defined by the concentration of PBH used, namely: PBH at 13g/dl [PBH13], PBH at 4 g/dl in albumin solution to matching colloidal osmotic pressure (COP) [PBH4], and no PBH only albumin solution at matching COP [PBH0]. Restitution of O2 carrying capacity with PBH13 increased blood pressure and produced vasoconstriction compared to PBH4 and PBH0. On the other hand, PBH4 maintained blood pressure without significant vasoconstriction, increased tissue pO2, arteriolar O2 supply and extraction to the partially ischemic tissue compared to PBH0 and PBH13. Results suggest the existence of an optimal concentration of low O2 affinity acellular Hb to increase oxygenation of partially ischemic tissue during anemic conditions. This work was supported by BRP R24‐HL64395 and P01 HL071064.