Annals of Biomedical Engineering

, Volume 17, Issue 1, pp 61–73 | Cite as

A continuous cardiac output computer based on thermodilution principles

  • R. A. Normann
  • R. W. Johnson
  • J. E. Messinger
  • B. Sohrab


A totally self-contained instrument for the measurement of cardiac output is described. The microcomputer controlled instrument is based upon the principles of thermodilution and is capable of making cardiac output determinations on a minute by minute basis. A bolus of heat is delivered to the blood via a resistive heating element wound on the surface of a conventional thermodilution catheter, and the resulting transient pulmonary artery blood temperature increase is monitored with the thermistor located near the tip of the catheter. The performance of the instrument was tested in a mock circulatory loop and in dogs for periods of up to 13 hours. The accuracy and reproducibility of flow determinations made with the system compare favorably with those made with a conventional cardiac output monitor. This study demonstrates the feasibility of a stand-alone cardiac output computer that can provide virtually continuous measurements of blood flow without the intervention of a technician.


Thermodilution Indicator dilution Continuous cardiac output computer Cardiac output Canine cardiac output Blood temperature noise 


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  1. 1.
    Afonso, S.; Herrick, J.F.; Rowe, G.G.; Crumpton, C.W. Temperature variations in the venous system of dogs. Am. J. Physiol. 202:278–282; 1962.Google Scholar
  2. 2.
    Forrester, J.S.; Ganz, W.; Diamond, G.; McHugh, T.; Chonette, D.W.; Swan, H.J.C. Thermodilution cardiac output determination with a single flow-directed catheter. Am. Heart J. 83:306–311; 1972.CrossRefPubMedGoogle Scholar
  3. 3.
    Ganz, W.; Swan, H.J.C. Measurement of blood flow by thermodilution. Am. J. Cardiol. 29:241–246; 1972.PubMedGoogle Scholar
  4. 4.
    Ganz, W.; Donoso, R.; Marcus, H.S.; Forrester, J.S.; Swan, H.J.C. A new technique for measurement of cardiac output by thermodilution in man. Am. J. Cardiol. 27:392; 1971.CrossRefPubMedGoogle Scholar
  5. 5.
    Hamilton, W.F.; Riley, R.L.; Attyah, A.M.; Cournand, al. Comparison of the Fick and dye injection methods of measuring the cardiac output in Man. Am. J. Physiol. 153:309–321; 1948.Google Scholar
  6. 6.
    Johnson, R.W. Heat Transport Through the Heart with Applications to Thermodilution Signal Processing. Ph. D. Dissertation, University of Utah; 1987.Google Scholar
  7. 7.
    Johnson, R.W.; Normann, R.A. Mathematical and mechanical modeling of heat transport through the heart. Ann. Biomed. Eng.; in press.Google Scholar
  8. 8.
    Johnson, R.W.; Normann, R.A. Signal processing strategies for the enhancement of the signal to noise ratio of thermodilution measurements. Ann. Biomed. Eng.; 16:265–278; 1988.CrossRefPubMedGoogle Scholar
  9. 9.
    Philip, J.H.; Long, M.C.; Quinn, M.D.; Newbower, R.S. Continuous thermal measurement of cardiac output. IEEE Trans. on Biomed. Eng. 31:393–399; 1984.Google Scholar
  10. 10.
    Riedinger, M.S.; Shellock, F.G. Technical aspects of the thermodilution method for measuring cardiac output. Heart and Lung 13:215–221; 1984.PubMedGoogle Scholar
  11. 11.
    Thompson, R.B.Disorders of the Blood. Edinburgh: Churchil Livingstone; 1978.Google Scholar
  12. 12.
    Wessel, H.U.; James, G.W.; Paul, M.H. Effects of respiration and circulation on central blood temperature of the dog. Am. J. Physiol. 211:1403–1412; 1966.PubMedGoogle Scholar

Copyright information

© Pergamon Press plc 1989

Authors and Affiliations

  • R. A. Normann
    • 1
  • R. W. Johnson
    • 2
  • J. E. Messinger
    • 1
  • B. Sohrab
    • 3
  1. 1.Department of BioengineeringUniversity of UtahSalt Lake City
  2. 2.Edwards DivisionBaxter Health Care CorpSanta Anna
  3. 3.Lifescan, IncMountain View

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