Low Oxygen-Affinity Hemoglobin Solution Increases Oxygenation of Partially Ischemic Tissue During Acute Anemia

BackgroundMaintenance of postsurgical tissue oxygenation depends on the ability of the specific tissue to recruit perfusion and oxygen (O2) supply. 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.Study DesignResponses 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 arteriole ligation during hamster window chamber model implantation. PBH effects 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, ie, PBH at 13 g/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).ResultsRestitution of O2-carrying capacity with PBH13 increased blood pressure and produced vasoconstriction compared with PBH4 and PBH0. On the other hand, PBH4 maintained blood pressure without substantial vasoconstriction, increased tissue partial pressure of O2, arteriolar O2 supply, and extraction to the partially ischemic tissue compared with PBH0 and PBH13.ConclusionsResults suggest the existence of an optimal concentration of low O2-affinity acellular Hb to increase oxygenation of partially ischemic tissue during anemic conditions.