title: Nitrogen monoxide and carbon monoxide transfer interpretation: state of the art.
abstract: Just a few clinicians routinely measure the subcomponents of the lung diffusing capacity for Carbone monoxide (DLCO). This is because the measurement of membrane and blood conductances for CO (DmCOand DbCO= θCO× Vc, respectively) by the classic Roughton and Forster method is complicated and time consuming. In addition, it mistakenly assumes a close relationship between alveolar oxygen partial pressure (PAO2) and mean intracapillary oxygen partial pressure (PcapO2) which is the true determinant of specific conductance of haemoglobin for CO (θCO). Besides that, the critical multistep oxygenation method along with different linear equations relating 1/θCOto PcapO2gave highly scattered DmCOand Vcvalues. The Dm and Vccan also be derived from a simultaneous measurement of DLNOand DLCOwith the blood resistance for NO assumed to be negligible. However, recent in vitro and in vivo experiments point towards a finite value of θNO(about 4·5 mlNO× mlblood-1× min-1× mmHg-1). Putting together the arguments and our clinical data allows us to report here the state of the art in partitioning the CO diffusing capacity into its constitutive components, with the goal to encourage further studies examining the sensitivity of DmCOand Vcto alterations observed in parenchymal diseases.
authors.affiliation: Department of Pneumology, St. Elisabeth Hospital, Namur, Belgium.
authors.forename: Jean Benoit
authors.initials: JB
authors.lastname: Martinot
authors.affiliation: Laboratoire de Physiologie et CHU de Bordeaux, Bordeaux, France.
authors.forename: Hervé
authors.initials: H
authors.lastname: Guénard
authors.affiliation: Service de Physiologie, Hôpital Cochin, Paris, France.
authors.forename: Anh-Tuan
authors.initials: AT
authors.lastname: Dinh-Xuan
authors.affiliation: Service de Nutrition et Diabète, CHU de Bordeaux, Bordeaux, France.
authors.forename: Henri
authors.initials: H
authors.lastname: Gin
authors.affiliation: Service de Pneumologie, CHU de Bordeaux, Bordeaux, France.
authors.forename: Claire
authors.initials: C
authors.lastname: Dromer
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000097:blood; D002248:Carbon Monoxide / Q000097:blood*; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D008168:Lung / Q000378:metabolism* / Q000503:physiopathology; D008171:Lung Diseases / Q000097:blood* / Q000175:diagnosis / Q000503:physiopathology; D008954:Models, Biological; D009569:Nitric Oxide / Q000097:blood*; D010100:Oxygen / Q000097:blood; D010313:Partial Pressure; D011653:Pulmonary Diffusing Capacity
chemical_list: D015415:Biomarkers; D006454:Hemoglobins; D009569:Nitric Oxide; D002248:Carbon Monoxide; D010100:Oxygen
keywords: interstitial lung disease; nitric oxide; pulmonary fibrosis; respiratory function tests