Determinants of distortions in CO 2 catheter sampling systems: A mathematical model

A mathematical model was developed to predict the distortions in the measured expiratory CO 2 concentration time profile caused by catheter sampling systems. Parameters considered included the expiratory flow and concentration profiles, the sample flow rate, the sample tube dimensions and the sample...

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Bibliographic Details
Published inRespiration physiology Vol. 41; no. 1; pp. 127 - 136
Main Authors Epstein, R.A., Reznik, A.M., Epstein, M.A.F.
Format Journal Article
LanguageEnglish
Published Elsevier B.V 1980
Subjects
Carbon dioxide
Expired gas
Technique for gas sampling
Expired gas
Carbon dioxide
Technique for gas sampling
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Summary:A mathematical model was developed to predict the distortions in the measured expiratory CO 2 concentration time profile caused by catheter sampling systems. Parameters considered included the expiratory flow and concentration profiles, the sample flow rate, the sample tube dimensions and the sample cell volume. Unless care is taken in choosing the parameters of a catheter sampling system, particularly in the presence of low expiratory flow rates and short expiratory times, the CO 2 concentration profile may be severely distorted. In worst case situations end tidal CO 2 plateaux may not be recognized or alternately artifactual plateaux may be produced. Sample flow rate and sample cell volume are the most important parameters while distortion within the sample tube itself is relatively less important.
ISSN:0034-5687
DOI:10.1016/0034-5687(80)90028-6