title: Isovolemic hemodilution alters the ratio of whole-body to large-vessel hematocrit (F-cell ratio). A prospective, randomized study comparing the volume effects of hydroxyethyl starch 200,000/0.62 and albumin.
abstract: OBJECTIVE
  To evaluate potential changes in the ratio of whole-body/large-vessel hematocrit (f-cell ratio) during isovolemic hemodilution and to compare the volume effects of 2 different plasma exchange solutions (hydroxyethyl starch 200,000/0.62 6% and human albumin 5%).
  
  
  METHODS
  Prospective, randomized, controlled trial.
  
  
  METHODS
  Operating theater in a university hospital.
  
  
  METHODS
  24 gynecological patients scheduled for elective surgery.
  
  
  METHODS
  Isovolemic hemodilution was performed using 2 different plasma exchange solutions. Plasma volume was determined using dye dilution technique before and after hemodilution. The volume of withdrawn blood was measured from the change in weight of the blood bags taking into account the specific gravity of blood.
  
  
  RESULTS
  The volume of administered plasma exchange solutions exceeded the amount of withdrawn blood by 80 +/- 47 ml (p < 0.001). Plasma volume was 3,067 +/- 327 ml before and 3,517 +/- 458 ml after hemodilution. Using red cell volumes calculated from measured plasma volumes and peripheral hematocrit, a deficit of 249 +/- 133 ml (p < 0.0001) in red cells after hemodilution appeared with the measured withdrawn red cell volumes taken into account. This finding can be explained by a change in the f-cell ratio during isovolemic hemodilution. The volume effect of the exchange solutions was 1.05 for hydroxyethyl starch and 0.95 for albumin.
  
  
  CONCLUSIONS
  The results demonstrate that a change in the f-cell ratio occurs during isovolemic hemodilution. The estimation of red cell volume or plasma volume changes by using either the hematocrit or plasma or red cell volume determinations together with the hematocrit may lead to erroneous results.
authors.affiliation: Institut für Anaesthesiologie, Ludwig-Maximilians-Universität München, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Haller
authors.forename: H
authors.initials: H
authors.lastname: Brechtelsbauer
authors.forename: C
authors.initials: C
authors.lastname: Akbulut
authors.forename: W
authors.initials: W
authors.lastname: Fett
authors.forename: J
authors.initials: J
authors.lastname: Briegel
authors.forename: U
authors.initials: U
authors.lastname: Finsterer
mesh_terms: D000328:Adult; D001810:Blood Volume / Q000187:drug effects* / Q000502:physiology; D004911:Erythrocyte Volume / Q000187:drug effects; D005260:Female; D005831:Genital Diseases, Female / Q000097:blood / Q000601:surgery*; D005833:Genital Neoplasms, Female / Q000097:blood / Q000601:surgery*; D006400:Hematocrit / Q000145:classification*; D006438:Hemodilution / Q000379:methods*; D006801:Humans; D006895:Hydroxyethyl Starch Derivatives / Q000008:administration & dosage*; D008875:Middle Aged; D010951:Plasma Exchange; D010952:Plasma Substitutes / Q000008:administration & dosage; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012016:Reference Values; D012709:Serum Albumin / Q000008:administration & dosage*; D014680:Veins
chemical_list: D006895:Hydroxyethyl Starch Derivatives; D010952:Plasma Substitutes; D012709:Serum Albumin