title: In vivo estimates of NO and CO conductance for haemoglobin and for lung transfer in humans.
abstract: Membrane conductance (Dm) and capillary lung volume (Vc) derived from NO and CO lung transfer measurements in humans depend on the blood conductance (θ) values of both gases. Many θ values have been proposed in the literature. In the present study, measurements of CO and NO transfer while breathing 15% or 21% O2 allowed the estimation of θNO and the calculation of the optimal equation relating 1/θCO to pulmonary capillary oxygen pressure (PcapO2). In 10 healthy subjects, the mean calculated θNO value was similar to the θNO value previously reported in the literature (4.5mmHgmin(-1)) provided that one among three θCO equations from the literature was chosen. Setting 1/θCO=a·PcapO2+b, optimal values of a and b could be chosen using two methods: 1) by minimizing the difference between Dm/Vc ratios for any PcapO2, 2) by establishing a linear equation relating a and b. Using these methods, we are proposing the equation 1/θCO=0.0062·PcapO2+1.16, which is similar to two equations previously reported in the literature. With this set of θ values, DmCO reached the morphometric range.
authors.affiliation: Laboratory of Physiology, Bordeaux University, France. Electronic address: guenardherve@hotmail.com.
authors.forename: Hervé Jean-Pierre
authors.initials: HJ
authors.lastname: Guénard
authors.affiliation: Department of Pneumology, St. Elisabeth Hospital, Namur, Belgium. Electronic address: martinot.j@scarlet.be.
authors.forename: Jean-Benoit
authors.initials: JB
authors.lastname: Martinot
authors.affiliation: Department of Mathematics, UMR CNRS 8628, Paris South University, France. Electronic address: sebastien.Martin@math.u-psud.fr.
authors.forename: Sebastien
authors.initials: S
authors.lastname: Martin
authors.affiliation: Department of Mathematics, UMR CNRS 8628, Paris South University, France. Electronic address: bertrand.Maury@math.u-psud.fr.
authors.forename: Bertrand
authors.initials: B
authors.lastname: Maury
authors.affiliation: Department of Kinesiology, University of Toledo, OH, USA. Electronic address: sophielalande6@gmail.com.
authors.forename: Sophie
authors.initials: S
authors.lastname: Lalande
authors.affiliation: Laboratory of Physiology, Bordeaux University, France.
authors.forename: Christian
authors.initials: C
authors.lastname: Kays
mesh_terms: D000328:Adult; D000368:Aged; D002196:Capillaries / Q000378:metabolism; D002248:Carbon Monoxide / Q000097:blood / Q000378:metabolism*; D005260:Female; D006454:Hemoglobins / Q000378:metabolism*; D006801:Humans; D016014:Linear Models; D008168:Lung / Q000098:blood supply / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D008955:Models, Cardiovascular; D009569:Nitric Oxide / Q000097:blood / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism; D011312:Pressure; D011653:Pulmonary Diffusing Capacity; D011659:Pulmonary Gas Exchange; D055815:Young Adult
chemical_list: D006454:Hemoglobins; D009569:Nitric Oxide; D002248:Carbon Monoxide; D010100:Oxygen
keywords: Carbon monoxide; Diffusion; Gas exchange; Lung; Nitrogen monoxide