A modified rebreathing technique using an infrared gas analyzer

Khalid W. Barazanji, Murugappan Ramanathan, Robert L. Johnson, Connie C W Hsia

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


To lower the cost and improve accessibility of the rebreathing technique for measuring cardiopulmonary function during exercise, we implemented a fast-response infrared (IR) gas-analyzer system to simultaneously measure lung diffusing capacity, cardiac output, lung tissue volume, and lung volume by a rebreathing technique in five healthy subjects at rest and during steady-state exercise. Interferences by water vapor and CO2 on the analyzer were determined and corrected for. During rebreathing, a gas mixture of 0.4% C2H2-0.3% CH4-9%. He-30% O2, and either 0.3% C18O or 0.3% C16O in a balance of N2 was simultaneously sampled by both a mass spectrometer and the IR analyzer, permitting paired comparisons. Measurements obtained by the two devices were not significantly different. We conclude that this modified rebreathing technique using the IR analyzer is accurate for the measurement of cardiopulmonary function at rest and during exercise.

Original languageEnglish (US)
Pages (from-to)1258-1262
Number of pages5
JournalJournal of applied physiology
Issue number4
StatePublished - Apr 1996


  • cardiac output
  • exercise
  • lung diffusing capacity
  • lung tissue volume
  • lung volume
  • mass spectrometer

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)


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