title: Optimizing the calculation of DM,CO and VC via the single breath single oxygen tension DLCO/NO method.
abstract: Alveolar-capillary membrane conductance (D(M,CO)) and pulmonary-capillary blood volume (V(C)) are calculated via lung diffusing capacity for carbon monoxide (DL(CO)) and nitric oxide (DL(NO)) using the single breath, single oxygen tension (single-FiO2) method. However, two calculation parameters, the reaction rate of carbon monoxide with blood (θ(CO)) and the D(M,NO)/D(M,CO) ratio (α-ratio), are controversial. This study systematically determined optimal θ(CO) and α-ratio values to be used in the single-FiO2 method that yielded the most similar D(M,CO) and V(C) values compared to the 'gold-standard' multiple-FiO2 method. Eleven healthy subjects performed single breath DL(CO)/DL(NO) maneuvers at rest and during exercise. D(M,CO) and V(C) were calculated via the single-FiO2 and multiple-FiO2 methods by implementing seven θ(CO) equations and a range of previously reported α-ratios. The RP θ(CO) 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 θ(CO) equation and an experimental α-ratio should be used in future studies.
authors.affiliation: Mayo Graduate School, Mayo Clinic, 200 1st Street SW, Rochester, MN, USA. Electronic address: Coffman.Kirsten@mayo.edu.
authors.forename: Kirsten E
authors.initials: KE
authors.lastname: Coffman
authors.affiliation: Sport & Health Sciences, University of Exeter, Heavitree Road, Exeter, UK; Division of Cardiovascular Diseases, Mayo Clinic, 200 1st Street SW, Rochester, MN, USA. Electronic address: B.Taylor@exeter.ac.uk.
authors.forename: Bryan J
authors.initials: BJ
authors.lastname: Taylor
authors.affiliation: Division of Cardiovascular Diseases, Mayo Clinic, 200 1st Street SW, Rochester, MN, USA. Electronic address: Carlson.Alex@mayo.edu.
authors.forename: Alex R
authors.initials: AR
authors.lastname: Carlson
authors.affiliation: Division of Cardiovascular Diseases, Mayo Clinic, 200 1st Street SW, Rochester, MN, USA. Electronic address: Wentz.Robert@mayo.edu.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Wentz
authors.affiliation: Division of Cardiovascular Diseases, Mayo Clinic, 200 1st Street SW, Rochester, MN, USA. Electronic address: Johnson.Bruce@mayo.edu.
authors.forename: Bruce D
authors.initials: BD
authors.lastname: Johnson
mesh_terms: D000328:Adult; D001784:Blood Gas Analysis; D001810:Blood Volume; D002248:Carbon Monoxide / Q000097:blood; D015444:Exercise / Q000502:physiology*; D064368:Healthy Volunteers; D006801:Humans; D016014:Linear Models; D010100:Oxygen / Q000097:blood*; D011650:Pulmonary Alveoli / Q000098:blood supply*; D011653:Pulmonary Diffusing Capacity; D012143:Respiratory Physiological Phenomena; D013997:Time Factors; D055815:Young Adult
chemical_list: D002248:Carbon Monoxide; D010100:Oxygen
keywords: Alveolar-capillary membrane conductance; Lung diffusing capacity; Pulmonary-capillary blood volume; Submaximal exercise