title: Normovolemic hemodilution improves oxygen extraction capabilities in endotoxic shock.
abstract: We studied the effects of normovolemic hemodilution on tissue oxygen extraction capabilities in a canine model of endotoxic shock. Eighteen anesthetized and mechanically ventilated dogs underwent normovolemic hemodilution with 6% hydroxyethyl starch solution to reach hematocrit (Hct) levels around 40, 30, or 20% before the administration of 2 mg/kg of Escherichia coli endotoxin. Cardiac tamponade was then induced by repeated injections of normal saline into the pericardial sac to reduce cardiac output and study whole body oxygen extraction capabilities. Whole body critical oxygen delivery was lower in the Hct 20% and 30% groups (8.4 +/- 0.4 and 10.4 +/- 0.7 ml. kg(-1). min(-1), respectively) than in the Hct 40% group (12.8 +/- 0.8 ml. kg(-1). min(-1)) (both P < 0.005). The whole body critical oxygen extraction ratio was higher in the Hct 30% and 20% groups (49.1 +/- 8.2 and 55.2 +/- 4.6%, respectively) than in the Hct 40% group (37.1 +/- 4.4 %) (both P < 0.05). Liver critical oxygen extraction ratio was also higher in the Hct 30% and 20% groups than in the Hct 40% group. The arterial lactate concentrations and the gradient between ileum mucosal PCO(2) and arterial PCO(2) were lower in the Hct 20% and 30% groups than in the Hct 40% group. We conclude that, during an acute reduction in blood flow during endotoxic shock in dogs, normovolemic hemodilution is associated with improved tissue perfusion and increased oxygen extraction capabilities.
authors.affiliation: Department of Intensive Care, Erasme University Hospital, Free University of Brussels, Route de Lennik 808, B-1070 Brussels, Belgium.
authors.forename: J
authors.initials: J
authors.lastname: Creteur
authors.forename: Q
authors.initials: Q
authors.lastname: Sun
authors.forename: O
authors.initials: O
authors.lastname: Abid
authors.forename: D
authors.initials: D
authors.lastname: De Backer
authors.forename: P
authors.initials: P
authors.lastname: Van Der Linden
authors.forename: J L
authors.initials: JL
authors.lastname: Vincent
mesh_terms: D000818:Animals; D001784:Blood Gas Analysis; D001810:Blood Volume / Q000502:physiology*; D001831:Body Temperature / Q000502:physiology; D002245:Carbon Dioxide / Q000378:metabolism; D002305:Cardiac Tamponade / Q000503:physiopathology; D017666:Deuterium Oxide / Q000378:metabolism; D004285:Dogs; D004731:Endotoxins / Q000633:toxicity; D006400:Hematocrit; D006438:Hemodilution; D006454:Hemoglobins / Q000378:metabolism; D008070:Lipopolysaccharides / Q000633:toxicity; D010101:Oxygen Consumption / Q000502:physiology*; D012772:Shock, Septic / Q000378:metabolism*
chemical_list: D004731:Endotoxins; D006454:Hemoglobins; D008070:Lipopolysaccharides; D002245:Carbon Dioxide; C044101:endotoxin, Escherichia coli; D017666:Deuterium Oxide