Abstract: Stroke volumes measured by impedance were compared with values obtained by dye dilution and an electromagnetic flowmeter (EMF) on 14 dogs during drug‐induced changes in cardiac contraction strength and peripheral resistance changes. Grouping all data for a total of 305 points showed correlations between dye and EMF, dye and impedance, and EMF and impedance of 0.89, 0.68, and 0.72, respectively. Correlations for individual dogs between dye and EMF, dye and impedance, and EMF and impedance ranged from 0.60 to 0.99, −0.39 to 0.96, and −0.26 to 0.89, respectively. These data suggest that the use of impedance cardiac output measurements to make treatment decisions about individual patients could result in serious error.

The purpose of this study was to determine the sensitivity of the thoracic electrical impedance change to blood-volume changes in various regions of the thorax. Using recently euthanatised dogs blood was infused in both a stepwise and a continuously varying manner into the ventricles, atria, lungs and isolated segments of the aorta. The results show that the impedance sensitivities to volume changes in the atria and aorta are similar, whereas the volume changes of the ventricles showed a significantly smaller effect. Equal blood-volume pulses into the lungs or aorta cause an impedance change of a similar magnitude, but estimates based on control-pressure changes indicate the effect of aorta volume change on the impedance to be less than 30%. The data, therefore, indicate that changes in volume of several of the intrathoracic cardiovascular structures are likely to be involved in the generation of a composite cardiogenic electrical impedance change.

Annals of the New York Academy of SciencesVolume 170, Issue 2 p. 724-732 IMPEDANCE CARDIOGRAPHY AS A NONINVASIVE METHOD OF MONITORING CARDIAC FUNCTION AND OTHER PARAMETERS OF THE CARDIOVASCULAR SYSTEM* W. G. Kubicek Ph.D., W. G. Kubicek Ph.D. Department of Physical Medicine and Rehabilitation, College of Medical Sciences, University of Minnesota, Minneapolis, Minn.Search for more papers by this authorR. P. Patterson M.E.E., R. P. Patterson M.E.E. Department of Physical Medicine and Rehabilitation, College of Medical Sciences, University of Minnesota, Minneapolis, Minn.Search for more papers by this authorD. A. Witsoe M.E.E., D. A. Witsoe M.E.E. Department of Physical Medicine and Rehabilitation, College of Medical Sciences, University of Minnesota, Minneapolis, Minn.Search for more papers by this author W. G. Kubicek Ph.D., W. G. Kubicek Ph.D. Department of Physical Medicine and Rehabilitation, College of Medical Sciences, University of Minnesota, Minneapolis, Minn.Search for more papers by this authorR. P. Patterson M.E.E., R. P. Patterson M.E.E. Department of Physical Medicine and Rehabilitation, College of Medical Sciences, University of Minnesota, Minneapolis, Minn.Search for more papers by this authorD. A. Witsoe M.E.E., D. A. Witsoe M.E.E. Department of Physical Medicine and Rehabilitation, College of Medical Sciences, University of Minnesota, Minneapolis, Minn.Search for more papers by this author First published: July 1970 https://doi.org/10.1111/j.1749-6632.1970.tb17735.xCitations: 291 * Supported by National Aeronautics and Space Administration contract NAS 9-4500 and Social and Rehabilitation Service grant RT-2. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat References 1 Harvey, W. 1628. Exercitatio Anatomica de motu cordis et sanguinis in animalibus. Frankfurt , Germany . 2 Atzler, E. & G. Lehmann. 1932. Über ein neues verfahren zur darstellung der hentltig-keit (dielektrographie). Arbeitsphysiologie 6: 636–680. 3 Nyboer, J., S. Bagno, A. Barnett & R. H. Halsey. 1949. Radiocardiograms-the electrical impedance changes of the heart in relation to electrocardiograms and heart sounds. Amer. Soc. Clin. Inv. 19: 773. 4 Nyboer, J. 1959. Electrical Impedance Plethysmography. Charles C Thomas. Springfield , Ill. 243 pp. 5 Whitehorn, W. V. & E. R. Perl. 1949. The use of change in capacity to record cardiac volume in human subjects. Science 109: 262–263. 6 Geddes, L. A. & L. E. Baker. 1968. Principles of Applied Biomedical Instrumentation.: 150–205. John Wiley & Sons. New York , N. Y. 7 Kubicek, W. G., J. M. Karnegis, R. P. Patterson, D. A. Witsoe & R. H. Mattson. 1966. Development and evaluation of an impedance cardiac output system. Aerospace Med. 37: 1208–1212. 8 Smith, J. J., V. T. Wiedmeier, F. E. Trlstani & K. E. Cooper. 1968. Measurement of cardiac output during body tilt using the impedance cardiograph. Fed. Proc. 28: 643. 9 Harley, A. & J. C. Greenfield, Jr. 1968. Determination of cardiac output in man by means of impedance plethysmography. Aerospace Med. 39: 248–252. 10 Judy, W. V., F. M. Langley, K. D. McCowen, D. M. Stinnett, L. E. Baker & P. C. Johnson. 1969. Comparative evaluation of the thoracic impedance and isotope dilution methods for measuring cardiac output. Aerospace Med. 40: 532–536. 11 Siegel, J. H. & M. Fabian. 1968. The quantification of myocardial contractility by impedance plethysmography. Fed. Proc. 27: 445. 12 Kubicek, W. G., A. H. L. From, R. P. Patterson, A. Castaneda, R. C. Lillehei & R. Ersek. 1969. Impedance cardiography as a non-invasive means to monitor cardiac function. American Association for Advancement of Medical Instrumentation. In press. 13 Pomerantz, M., R. Baumgartner, J. Launioson & B. Eiseman. 1969. Transthoracic electrical impedance for early detection of pulmonary edema. Surgery 66: 260–268. Citing Literature Volume170, Issue2International Conference on Bioelectric ImpedanceJuly 1970Pages 724-732 ReferencesRelatedInformation

Impedance cardiograph for monitoring heart functions, and program for computing stroke volume and cardiac output from thoracic impedance changes during cardiac cycle

Four-electrode impedance plethysmograph measures ventricular stroke volume of cardiac output of humans. The instrument is automatic, operates with only one recording channel, and minimizes patient discomfort.