title: Anemia tolerance during normo-, hypo-, and hypervolemia.
abstract: Restrictive intraoperative fluid management has been demonstrated to improve outcome of visceral and lung surgery in several studies. However, subsequent hypovolemia (HOV) may be accompanied by a decrease of anemia tolerance, resulting in increased transfusion needs. We therefore investigated the effect of volume status on anemia tolerance.
  
  
  
  Eighteen domestic pigs of either sex (mean weight, 23.5 ± 4.8 kg) were anesthetized, ventilated, and randomized into three experimental groups: normovolemia (no intervention), HOV (blood loss of 40% of blood volume), and hypervolemia (HEV; volume infusion of 40% of blood volume). The animals were then hemodiluted until their individual critical hemoglobin concentrations (Hbcrit) were reached by the exchange of whole blood for hydroxyethyl starch (HES; 130:0.4). Subsequently, organ-specific hypoxia was assessed using pimonidazole tissue staining in relevant organs. Hemodynamic and metabolic variables were also investigated.
  
  
  
  Despite significant differences in exchangeable blood volume, Hbcritwas the same in all groups (2.3 g/dL, NS). During HOV, tissue hypoxia was aggravated in the myocardium, brain, and kidneys, whereas tissue oxygenation of the liver and intestine was not influenced by volume status. HEV increased tissue hypoxia in the lungs, but did not impact tissue oxygenation of other organs.
  
  
  
  The combination of hemorrhagic HOV with subsequent anemia leads to accentuated tissue hypoxia, revealed by a significant increase in pimonidazole binding at Hbcrit, in heart, lungs, brain, and kidney. The lungs were the only organ that showed increased tissue hypoxia after pretreatment of HES infusion and subsequent anemia by normovolemic hemodilution.
authors.affiliation: Clinic of Anesthesiology, Intensive Care Medicine and Pain Therapy, Sana Klinikum Offenbach, Offenbach, Germany.
authors.forename: Malte
authors.initials: M
authors.lastname: Krömker
authors.affiliation: Clinic of Anesthesiology, Intensive Care Medicine and Pain Therapy, Sana Klinikum Offenbach, Offenbach, Germany.
authors.forename: Patrick
authors.initials: P
authors.lastname: Lauscher
authors.affiliation: Department of Anesthesiology and Critical Care Medicine, University Hospital Mannheim, Faculty of Medicine, University of Heidelberg, Heidelberg, Germany.
authors.forename: Harry
authors.initials: H
authors.lastname: Kertscho
authors.affiliation: Department of Anesthesiology, Intensive Care Medicine and Pain Therapy, University Hospital Frankfurt, Frankfurt am Main, Germany.
authors.forename: Kai
authors.initials: K
authors.lastname: Zacharowski
authors.affiliation: Clinic for Anesthesiology and Intensive Care Medicine, Eberhard Karls University, Tübingen, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Rosenberger
authors.affiliation: Department of Anesthesiology and Critical Care Medicine, Faculty of Medicine of the Kepler University, Linz, Austria.
authors.forename: Jens
authors.initials: J
authors.lastname: Meier
mesh_terms: D000740:Anemia / Q000209:etiology / Q000503:physiopathology / Q000628:therapy; D000818:Animals; D005260:Female; D006438:Hemodilution; D006439:Hemodynamics; D020896:Hypovolemia / Q000209:etiology / Q000503:physiopathology / Q000628:therapy; D000860:Hypoxia / Q000209:etiology / Q000503:physiopathology / Q000628:therapy; D007430:Intraoperative Care; D008297:Male; D009928:Organ Specificity; D013552:Swine