A Simple Apparatus for Frequent Measurement of Gastrointestinal Intraluminal PCO2

Authors

  • Piper L. Wall DVM, PhD,

    Corresponding author
    1. *Department of Zoology/Genetics, Iowa State University Ames, Iowa
    2. †Department of Surgical Education, Iowa Methodist Medical Center Des Moines, Iowa
      Department of Surgical Education 1221 Pleasant Street, Suite 550 Des Moines, Iowa 50309
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  • Akella Chendrasekhar MD,

    1. †Department of Surgical Education, Iowa Methodist Medical Center Des Moines, Iowa
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  • Gregory A. Timberlake MD

    1. †Department of Surgical Education, Iowa Methodist Medical Center Des Moines, Iowa
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Department of Surgical Education 1221 Pleasant Street, Suite 550 Des Moines, Iowa 50309

Summary

The accuracy and precision of an end-tidal infrared CO2 monitor and customized capnography tubing system designed to measure gastrointestinal intraluminal CO2 partial pressure (PiCO2) were tested in vitro. Samples were taken from the customized capnography tubing placed in either 5% or 10% CO2 gas at discrete intervals ranging from one minute to twelve minutes. For a given time interval, the tubing PCO2 measurement was a constant fraction of the actual PCO2 (all standard errors < 0.02). For increasing time intervals, the ratio of the tubing PCO2 to actual PCO2 increased logarithmically. In the 5% and 10% CO2, the regression coefficients were 0.89 and 0.85 for 8 French tubing and 0.99 and 0.91 for 6 French tubing. Beacuase of its accuracy and precision, this system may provide automated gastrointestinal CO2 partial pressure monitoring at short intervals (e.g. 5 minutes), facilitating testing of the role of gastrointestinal PiCO2 information in treatment algorithms. (Vet Emerg & Crit Care, 1998; 8: 109–116)

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