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Relating Measuring Signals From PO2 Electrodes to Tissue PO2: A Theoretical Study

  • K. Groebe
Part of the Advances in Experimental Medicine and Biology book series (AEMB, volume 316)

Abstract

Organ surface P O 2 measurement by oxygen sensitive electrodes has proved to be an efficient tool for monitoring changes in tissue oxygenation status in a number of experimental and clinical situations. A parameter giving more direct information is the P O 2 distribution within tissue cells which, however, can only be assessed by more invasive methods. To date, a quantitative relation between P O 2 electrode measurements and P O 2 in tissue cells has not been established. Part of this problem lies in the fact that any surface electrode P O 2 measurement is not confined to tissue cells but rather represents some average over P O 2 values in a certain volume containing not only tissue cells but also blood vessels and connective tissue. Such a catchment volume of a typical P O 2 surface electrode of 15 µm diameter is thought to be a half sphere of about 25 µm diameter [7], the mean P O 2 in which corresponds to the measuring signal. The present study addresses the problem of relating surface P O 2 measurements to intracellular P O 2. To that end, the notion of electrode catchment volume is critically evaluated. Its magnitude and errors in electrode P O 2 measurement are quantified for a frequently used electrode type. The results are then used to calculate the P O 2 which will be measured by the surface electrode in a tissue exhibiting the heterogeneous P O 2 distributions typical of working muscle.

Keywords

Surface Electrode Capillary Density Tissue Surface Electrode Voltage Electrode Measurement 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer Science+Business Media New York 1992

Authors and Affiliations

  • K. Groebe
    • 1
  1. 1.Institut für Physiologie und PathophysiologieJohannes Gutenberg Universität MainzMainzWest Germany

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