title: Effect of intravenous hydroxyethyl starch on the accuracy of measuring hemoglobin concentration.
abstract: OBJECTIVE
  To determine if intravenous hydroxyethylstarch (HES) affects the accuracy of hemoglobin (Hb) measurements, as artificial colloids are known to increase red blood cell sedimentation rates.
  
  
  METHODS
  Prospective, randomized study.
  
  
  METHODS
  Tertiary-care academic medical institution.
  
  
  METHODS
  We randomized 40 surgical American Society of Anesthesiologists (ASA) physical status I and II patients undergoing preoperative autologous blood donation before elective orthopedic surgery. Patients were randomized to receive volume replacement with 500 mL of 6% HES 200,000/0.5 or 500 mL of electrolyte solution. Measurements of Hb concentration and leukocyte count were performed using an analyzer with a suction needle sampling from the bottom of the test tube. Measurements were performed after mixing and repeated after a 10-minute period of upright positioning of the tube (at rest).
  
  
  RESULTS
  In the study group that received HES, Hb levels were increased above baseline after resting (mean increase to 151% of baseline values, P < .01), whereas the leukocyte count was decreased (mean decrease to 39% of baseline values, P < .01). No difference between baseline and resting measurements were observed in patients who received intravenous crystalloids. In addition, we repeatedly measured the Hb concentration in an unstirred tube with and without the addition of HES. In blood samples containing HES, the Hb concentration was increased above baseline after 2.5 minutes of resting, compared with 30 minutes without HES addition (P < .05).
  
  
  CONCLUSIONS
  Mixing of test tube contents before sampling is critical for accurate measurement of the Hb concentration in the blood of patients who received intravenous HES.
authors.affiliation: Department of Anesthesiology and Intensive Care Medicine, Tübingen University Hospital, Tübingen D-72076 Tübingen, Germany.
authors.forename: Hans-Jürgen
authors.initials: HJ
authors.lastname: Dieterich
authors.forename: Birgid
authors.initials: B
authors.lastname: Neumeister
authors.forename: Arzu
authors.initials: A
authors.lastname: Agildere
authors.forename: Holger K
authors.initials: HK
authors.lastname: Eltzschig
mesh_terms: D001799:Blood Sedimentation; D006454:Hemoglobins / Q000032:analysis*; D006801:Humans; D006895:Hydroxyethyl Starch Derivatives / Q000494:pharmacology*; D007262:Infusions, Intravenous; D007958:Leukocyte Count; D011446:Prospective Studies
chemical_list: D006454:Hemoglobins; D006895:Hydroxyethyl Starch Derivatives