title: Preanalytics: The (in-)stability of volatile POCT parameters and the homogeneity of blood in syringes at the market.
abstract: BACKGROUND
  In between calibrations, quality controls and so on reduce the availability of blood gas analyzers. Despite the intended urgency of the measurements, these inhibitory circumstances cause delays of measurements. The comparison of changes (primarily PO2 and PCO2, secondarily ctHb) in syringes from different suppliers and the embedding into guideline ranges are the objectives of this study.
  
  
  METHODS
  Five matrices were tonometered at two levels within the German guideline (RiLi-BAEK) controlled range. Matrices were aspired into each syringe and blood gas analysis accomplished after 0 to 30min. The procedure was repeated 5 to 8-fold for the gas concentrations and every condition which consisted of syringe type (7), matrices (5) and time delay (7).
  
  
  RESULTS
  Syringes produce almost identical effects on partial pressures during the 30min observation period. Initial fast changes arise when partial pressure (PP) differs widely from the atmospheric pressure and are followed by diffusion, gas production or consumption and ctHb depending effects.
  
  
  CONCLUSIONS
  Only normal arterial blood gases without "atmospheric pollution" are not affected by the syringe materials within 30min. The homogeneity of a de-aerated and capped ICU-patients' sample is hardly to be provided after more than 10min of resting without mechanical assistance.
authors.affiliation: Department of Anesthesiology, University of Regensburg, Regensburg, Germany. Electronic address: michael.gruber@UKR.de.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Gruber
authors.affiliation: Department of Anesthesiology, University of Regensburg, Regensburg, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Felbermeir
authors.affiliation: Department of Anesthesiology, University of Regensburg, Regensburg, Germany.
authors.forename: Regina
authors.initials: R
authors.lastname: Lindner
authors.affiliation: Department of Anesthesiology, University of Regensburg, Regensburg, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Kieninger
mesh_terms: D001769:Blood; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D000067716:Point-of-Care Testing; D013048:Specimen Handling; D013594:Syringes
chemical_list: D006454:Hemoglobins
keywords: Hemoglobin; Partial pressures; Point-of-care testing; Syringes; Tonometry