title: Hypoproteinemia does not alter plasma volume expansion in response to a 0.9% saline bolus in awake sheep.
abstract: OBJECTIVE
  To test the hypothesis that hypoproteinemia reduces plasma volume expansion produced by a bolus of crystalloid solution given to awake sheep.
  
  
  METHODS
  Prospective and observational.
  
  
  METHODS
  Laboratory.
  
  
  METHODS
  Five female merino sheep (n = 5) weighing 37 ± 3 kg were anesthetized.
  
  
  METHODS
  Each animal was subjected to a 5-day test period: day 1: 50 mL/min 0.9% saline infusion over 20 mins. Days 2-4: daily plasmapheresis and replacement of the shed plasma with 6 L of 0.9% saline were performed in increments.
  
  
  RESULTS
  Fractional plasma volume expansion after rapid infusion of saline on days 1 and 5 was calculated from changes in hemoglobin concentration. There was a significant reduction in total plasma protein concentration after plasmapheresis (p < .05). Colloid osmotic pressures were also significantly lowered (p < .05). A crystalloid infusion of 0.9% saline did not alter any of these values compared with baseline. The hemodynamic measurements did not show significant differences between the experiments. The plasma volume expansion reached approximately 20% at the end of infusion and stayed at 10-15% during the experiments. No difference was found in plasma volume expansion produced by a bolus of 50 mL/min of 0.9% in the hypoproteinemic state when compared with the euproteinemic state (p = .61). No difference in cumulative urinary output was found between the two states.
  
  
  CONCLUSIONS
  In contrast to our hypothesis, severe acute hypoproteinemia does not reduce plasma volume expansion in response to 50 mL/min 0.9% saline infusion in nonspleenectomized sheep when compared with the resultant plasma volume expansion after a 50 mL/min of 0.9% infusion in the euproteinemic state.
authors.affiliation: Department of Anesthesiology, University of Texas Medical Branch, Galveston, TX, USA.
authors.forename: Kirk I
authors.initials: KI
authors.lastname: Brauer
authors.forename: Lance P
authors.initials: LP
authors.lastname: Brauer
authors.forename: Donald S
authors.initials: DS
authors.lastname: Prough
authors.forename: Peter
authors.initials: P
authors.lastname: Rodhe
authors.forename: Robert G
authors.initials: RG
authors.lastname: Hahn
authors.forename: Daniel L
authors.initials: DL
authors.lastname: Traber
authors.forename: Lilian D
authors.initials: LD
authors.lastname: Traber
authors.forename: Christer H
authors.initials: CH
authors.lastname: Svensen
mesh_terms: D000818:Animals; D001798:Blood Proteins / Q000032:analysis; D002302:Cardiac Output / Q000187:drug effects / Q000502:physiology; D005260:Female; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology; D006454:Hemoglobins / Q000032:analysis; D007019:Hypoproteinemia / Q000097:blood / Q000503:physiopathology*; D009997:Osmotic Pressure / Q000187:drug effects / Q000502:physiology; D010952:Plasma Substitutes / Q000494:pharmacology*; D010953:Plasma Volume / Q000187:drug effects / Q000502:physiology*; D010956:Plasmapheresis; D012756:Sheep / Q000502:physiology; D012965:Sodium Chloride / Q000494:pharmacology*
chemical_list: D001798:Blood Proteins; D006454:Hemoglobins; D010952:Plasma Substitutes; D012965:Sodium Chloride