Whole-body gas exchange in human predicted by a cardiopulmonary model

K. Lu, J. W. Clark, F. H. Ghorbel, D. L. Ware, J. B. Zwischenberger, A. Bidani

Research output: Contribution to journalArticlepeer-review

30 Scopus citations


We have developed a closed-loop model of whole-body human gas exchange to simulate apnea and apneic oxygenation and have included it in our previously developed model of the human cardiopulmonary (CP) system. In our previous CP model, gas exchange occurred only in the lungs, where the inlet blood O2 and CO2 concentrations were fixed at constant values. We now add a description of gas exchange in the peripheral tissues, and couple the lung and tissue (i.e., central and peripheral) gas exchangers via a circulatory loop with variable transport delays. Thus, gas transport in the lungs and peripheral tissues of the body now interact as part of a closed-loop system, wherein the output of one gas exchanger provides the input to the other. A peripheral chemosensitive loop has also been added to mimic the influence of blood gas composition on the heart and vasculature. Parameters of this new CP model were adjusted manually to yield good approximation to hemodynamic and blood gas waveforms. Using the same set of parameters, the CP model redicted the integrated cardiovascular and blood-tissue gas composition responses to pronounced changes in lung gas composition, and thus simulated changes encountered in apnea with and without passive oxygenation. In summary, this study represents a bold effort in large-scale modeling of physiological systems. The presented model is a significant extension of our previous CP model in that it more accurately represents whole-body gas exchange and can explain how the cardiovascular, pulmonary, and autonomic nervous systems interact in response to purely pulmonary challenges such as apnea and apneic oxygenation. With further refinement, this model may help investigators better understand the complex biophysics of cardiopulmonary disease such as cor pulmonale and sleep-related disorders of breathing (obstructive and central sleep apnea).

Original languageEnglish
Pages (from-to)1-19
Number of pages19
JournalCardiovascular Engineering
Issue number1
StatePublished - Mar 2003


  • Apnea
  • Apneic oxygenation
  • Fluid filtration
  • Gas exchange
  • Lymphatic flow
  • Physiological modeling

ASJC Scopus subject areas

  • Surgery
  • Cardiology and Cardiovascular Medicine
  • Transplantation


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