A discussion of some single-compartment systems using intravascular tracers for the estimation of respiratory parameters

Herbert B. Hechtman, Michael H Reid

Research output: Contribution to journalArticle


A compartmental theory for pulmonary tracer gas dynamics has been developed. Analytic results which estimate lung volume during breathing and breath holding, and alveolar ventilation are shown to agree closely with independent experimental methods. The techniques presented are based entirely on the use of intravascular tracers (indocyanine green, iodoantipyrine and xenon), and do not require measurements at, or control of, the airway. Tracer concentration is sampled as a 'dye-dilution curve' in a systemic artery following a bolus injection into the right heart. Transient analyses of tracer distribution in the proposed lung models give estimates of functional residual capacity, lung volume distal and including respiratory bronchioles and alveolar ventilation. Lung tissue and blood volumes are similarly estimated. Under steady-state conditions with a constant-tracer infusion, the analytic model reduces to a simple form requiring only two tracer sample measurements, rather than a dilution curve, to determine alveolar ventilation. Incomplete recovery of tracers, the effects of vessel transit delays and nonlinear blood-gas partition coefficients, that occur with oxygen and carbon dioxide, are discussed.

Original languageEnglish (US)
Pages (from-to)415-424
Number of pages10
JournalMedical & Biological Engineering
Issue number4
Publication statusPublished - Jul 1974



  • intravascular tracers
  • Respiratory parameters
  • single-compartment systems

ASJC Scopus subject areas

  • Engineering(all)

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