Accuracy and precision of CPET equipment: A comparison of breath-by-breath and mixing chamber systems

Casper Beijst*, Goof Schep, Eric Van Breda, Pieter F.F. Wijn, Carola Van Pul

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

13 Citations (Scopus)


Cardiopulmonary exercise testing (CPET) has become an important diagnostic tool for patients with cardiorespiratory disease and can monitor athletic performance measuring maximal oxygen uptake Vo2;max. The aim of this study is to compare the accuracy and precision of a breath-by-breath and a mixing chamber CPET system, using two methods. First, this study developed a (theoretical) error analysis based on general error propagation theory. Second, calibration measurements using a metabolic simulator were performed. Error analysis shows that the error in oxygen uptake (Vo2) and carbon dioxide production (Vco2) is smaller for mixing chamber than for breath-by-breath systems. In general, the error of the flow sensor δV, the error in temperature of expired air δTB and the delay time error δtdelay are significant sources of error. Measurements using a metabolic simulator show that breath-by-breath systems are less stabile for different values of minute ventilation than mixing chamber systems.

Original languageEnglish
Pages (from-to)35-42
Number of pages8
JournalJournal of Medical Engineering and Technology
Issue number1
Publication statusPublished - Jan 2013


  • Breath-by-breath
  • Cardiopulmonary exercise testing
  • Error analysis
  • Metabolic simulator
  • Mixing chamber


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