title: Low oxygen-affinity hemoglobin solution increases oxygenation of partially ischemic tissue during acute anemia.
abstract: BACKGROUND
  Maintenance of postsurgical tissue oxygenation depends on the ability of the specific tissue to recruit perfusion and oxygen (O(2)) supply. When native O(2)-carrying capacity is lacking, fluids to improve O(2)-carrying capacity based in hemoglobin (Hb) could prevent partially ischemic tissue hypoxia by increasing O(2) release from the remaining red blood cells.
  
  
  METHODS
  Responses to facilitated O(2) 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).
  
  
  RESULTS
  Restitution of O(2)-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 O(2), arteriolar O(2) supply, and extraction to the partially ischemic tissue compared with PBH0 and PBH13.
  
  
  CONCLUSIONS
  Results suggest the existence of an optimal concentration of low O(2)-affinity acellular Hb to increase oxygenation of partially ischemic tissue during anemic conditions.
authors.affiliation: Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA. pcabrales@ucsd.edu
authors.forename: Pedro
authors.initials: P
authors.lastname: Cabrales
mesh_terms: D000208:Acute Disease; D000740:Anemia / Q000097:blood* / Q000503:physiopathology; D000818:Animals; D001794:Blood Pressure / Q000502:physiology; D001802:Blood Substitutes / Q000494:pharmacology*; D002417:Cattle; D006224:Cricetinae; D004195:Disease Models, Animal; D006439:Hemodynamics; D006454:Hemoglobins / Q000494:pharmacology*; D007511:Ischemia / Q000097:blood* / Q000503:physiopathology / Q000517:prevention & control*; D008026:Ligation; D008297:Male; D008833:Microcirculation; D010100:Oxygen / Q000097:blood* / Q000494:pharmacology; D011108:Polymers / Q000494:pharmacology*; D011897:Random Allocation; D018709:Statistics, Nonparametric; D014661:Vasoconstriction / Q000502:physiology
chemical_list: D001802:Blood Substitutes; D006454:Hemoglobins; D011108:Polymers; C080663:polymerized bovine hemoglobin; D010100:Oxygen