Simulation system for a rebreathing technique to measure multiple cardiopulmonary function parameters

Cuneyt Yilmaz, William W. Chance, Robert L. Johnson, Connie C W Hsia

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


Background: We developed a simple method for simulating a rebreathing maneuver to test the accuracy of the apparatus for simultaneous measurement of lung volume, diffusing capacity of the lung for carbon monoxide (DLCO), diffusing capacity of the lung for nitric oxide (DLNO), and pulmonary blood flow (Qc). Methods: A test gas mixture containing 0.3% methane, 0.3% CO, 0.8% acetylene, 30% O2, and 40 ppm nitric oxide in balance of nitrogen was sequentially diluted with a rebreathing gas mixture containing 0.3% acetylene, 0.3% methane, and 21% O2 in balance of nitrogen in order to simulate the in vivo end-tidal disappearance of the test gas mixture. Simulation of one rebreathing maneuver consisted of at least four serial dilution steps with a performance time of < 5 min. Using this technique, we estimated functional residual capacity, Qc, DLCO, and DLNO at various flow rates and dilution ratios (0.95 to 4.04 L, 3.54 to 6.83 L/min, 7.27 to 15.12 mL/min/mm Hg, and 6.51 to 12.00 mL/min/mm Hg, respectively) and verified simulation results against nominal values. The same apparatus also could simulate a single-breath procedure. Results: Compared to nominal values, errors in measured values by rebreathing and singlebreath DLCO simulation remained < 5% and 7%, respectively. Slopes of the correlations were close to 1.0 (within ± 5% and ± 6.4% in rebreathing and single-breath DLCO simulation studies, respectively). Conclusion: The results demonstrate the feasibility of this simulation method for standardizing the experimental measurements obtained by rebreathing and single-breath techniques. Incorporation of these simulation steps enhances the noninvasive assessment of cardiopulmonary function.

Original languageEnglish (US)
Pages (from-to)1309-1314
Number of pages6
Issue number5
StatePublished - May 1 2009


  • Cardiac output
  • Diffusing capacity of the lung for carbon monoxide
  • Diffusing capacity of the lung for nitric oxide
  • Dilution
  • Lung volume
  • Pulmonary blood flow
  • Rebreathing technique
  • Simulator
  • Single breath
  • System volume

ASJC Scopus subject areas

  • Pulmonary and Respiratory Medicine
  • Critical Care and Intensive Care Medicine
  • Cardiology and Cardiovascular Medicine


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