Optimizing the calculation of DM,CO and VC via the single breath single oxygen tension DLCO/NO method

Kirsten E. Coffman, Bryan J. Taylor, Alex R. Carlson, Robert J. Wentz, Bruce D. Johnson

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


Alveolar-capillary membrane conductance (DM,CO) and pulmonary-capillary blood volume (VC) are calculated via lung diffusing capacity for carbon monoxide (DLCO) and nitric oxide (DLNO) using the single breath, single oxygen tension (single-FiO2) method. However, two calculation parameters, the reaction rate of carbon monoxide with blood (θCO) and the DM,NO/DM,CO ratio (α-ratio), are controversial. This study systematically determined optimal θCO and α-ratio values to be used in the single-FiO2 method that yielded the most similar DM,CO and VC values compared to the 'gold-standard' multiple-FiO2 method. Eleven healthy subjects performed single breath DLCO/DLNO maneuvers at rest and during exercise. DM,CO and VC were calculated via the single-FiO2 and multiple-FiO2 methods by implementing seven θCO equations and a range of previously reported α-ratios. The RP θCO equation (Reeves, R.B., Park, H.K., 1992. Respiration Physiology 88 1-21) and an α-ratio of 4.0-4.4 yielded DM,CO and VC values that were most similar between methods. The RP θCO equation and an experimental α-ratio should be used in future studies.

Original languageEnglish (US)
Pages (from-to)19-29
Number of pages11
JournalRespiratory Physiology and Neurobiology
StatePublished - Jan 15 2016


  • Alveolar-capillary membrane conductance
  • Lung diffusing capacity
  • Pulmonary-capillary blood volume
  • Submaximal exercise

ASJC Scopus subject areas

  • General Neuroscience
  • Physiology
  • Pulmonary and Respiratory Medicine


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