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Vitalie Faoro, Gael Deboeck, Marco Vicenzi, Anne-Fleur Gaston, Bamodi Simaga, Grégory Doucende, Ilona Hapkova, Emma Roca, Enric Subirats, Fabienne Durand, Robert Naeije
PURPOSE: There has been suggestion that a greater "pulmonary vascular reserve" defined by a low pulmonary vascular resistance (PVR) and a high lung diffusing capacity (DL) allows for a superior aerobic exercise capacity. How pulmonary vascular reserve might affect exercise capacity at moderate altitude is not known. METHODS: Thirty-eight healthy subjects underwent an exercise stress echocardiography of the pulmonary circulation, combined with measurements of DL for nitric oxide (NO) and carbon monoxide (CO) and a cardio-pulmonary exercise test at sea level and at the altitude of 2250m...
May 17, 2017: Medicine and Science in Sports and Exercise
Colin Borland, J Michael B Hughes, Hervé Guénard
Nitric oxide was introduced over 30 years ago as a test gas for alveolar capillary diffusion. As for CO its transfer has been interpreted according to the Roughton Forster relationship: 1/DL=1/DM+1/θVc. There has been disagreement, since the first measurements of DLNO, over whether θNO is infinite and thus DLNO=DMNO. There is overwhelming in vitro evidence that θNO is finite yet several groups (Coffman et al., 2017; Tamhane et al., 2001) use an infinite value in vivo. They also assume that DMNO is greater than twice DMCO, making DMCO less than that predicted by the physical laws of diffusion...
March 1, 2017: Respiratory Physiology & Neurobiology
Colin Borland, Suhani Patel, Qingyu Zhu, Alain Vuylsteke
There is controversy as to whether the lung Diffusing Capacity for Nitric Oxide (DLNO) is a direct measure of DM in the Roughton-Forster equation or whether θNO is finite and DM is greater than DLNO. Despite in vitro evidence that θNO is finite, some groups believe that it is infinite in vivo and that DMNO/DMCO (α) is greater than predicted by the combined Fick/Graham law of Gas Diffusion through a membrane. We here present a hypothesis applying the fundamental rules of combined diffusion and chemical reaction to a red cell to explain (i) why θNO could be finite in vitro but effectively infinite in vivo and (ii) why ∝ could appear greater than predicted...
February 27, 2017: Respiratory Physiology & Neurobiology
X Giraud, N N Le-Dong, K Hogben, J B Martinot
The simultaneous measurement of the lung transfer factor for carbon monoxide (DLCO) and nitric oxide (DLNO) is now available as a powerful method for studying the alveolar-capillary gas exchange. However, application of the DLNO-CO technique in daily settings is still limited by some technical drawbacks. This paper provides a manufacturer's overview of the measuring principles, technical challenges and current available solutions for implementing the DLNO-CO measurement in to a marketed device. This includes the recent developments in technology for NO sensors, latest findings on NO uptake and new statistical methods...
February 16, 2017: Respiratory Physiology & Neurobiology
Gerald S Zavorsky, Connie C W Hsia, J Michael B Hughes, Colin D R Borland, Hervé Guénard, Ivo van der Lee, Irene Steenbruggen, Robert Naeije, Jiguo Cao, Anh Tuan Dinh-Xuan
Diffusing capacity of the lung for nitric oxide (DLNO), otherwise known as the transfer factor, was first measured in 1983. This document standardises the technique and application of single-breath DLNO This panel agrees that 1) pulmonary function systems should allow for mixing and measurement of both nitric oxide (NO) and carbon monoxide (CO) gases directly from an inspiratory reservoir just before use, with expired concentrations measured from an alveolar "collection" or continuously sampled via rapid gas analysers; 2) breath-hold time should be 10 s with chemiluminescence NO analysers, or 4-6 s to accommodate the smaller detection range of the NO electrochemical cell; 3) inspired NO and oxygen concentrations should be 40-60 ppm and close to 21%, respectively; 4) the alveolar oxygen tension (PAO2 ) should be measured by sampling the expired gas; 5) a finite specific conductance in the blood for NO (θNO) should be assumed as 4...
February 2017: European Respiratory Journal: Official Journal of the European Society for Clinical Respiratory Physiology
J M B Hughes, A T Dinh-Xuan
DLNO/DLCO directly measures the ratio of the diffusing capacities of the lung for nitric oxide (NO) and carbon monoxide (CO). In terms of the Roughton and Forster (1957) equation, 1/DL=1/Dm+1/θVc, where Dm is the membrane (Dm) and θVc is the red cell component of the overall diffusing conductance (DL); DLNO mostly reflects the Dm component and DLCO the θVc red cell component. The DLNO/DLCO ratio is positively related to the DmCO/Vc ratio and the CO red cell resistance (1/θCOVc) as a percentage of the total resistance (1/DLCO), independent of the absolute values of DLNO or DLCO...
January 11, 2017: Respiratory Physiology & Neurobiology
Bamodi Simaga, Kevin Forton, Yoshiki Motoji, Robert Naeije, Vitalie Faoro
Single breath measurements of lung diffusing capacity (DL) for carbon monoxide (CO) and nitric oxide (NO) were performed in age-, sex-, weight- and height-matched 32 sub-Saharan Africans (13 women) and 32 Caucasian Europeans, and repeated in 14 of each group at 80% of maximum exercise capacity. In Africans versus Caucasians respectively, DLNO was 153±31 vs 176±38ml/mmHg/min at rest (P<0.001) and 210±48 vs 241±52ml/mmHg/min at exercise (P<0.01) while hemoglobin-adjusted DLCO was 29±6 vs 34±6ml/mmHg/min at rest (P<0...
January 10, 2017: Respiratory Physiology & Neurobiology
M-Y Kang, D Grebenkov, H Guénard, I Katz, B Sapoval
Roughton and Forster (RF) proposed to split the lung diffusing capacity into two contributions describing first, diffusion to red blood cells (RBC), and second, capture by diffusion from the RBC surface and reaction with haemoglobin. Solving the diffusion-reaction equations for simplified capillary-RBC structures, we investigate the RF interpretation. This reveals first that the conventional extrapolation to zero pressure of 1/DLCO on PO2 is not a correct measure of the diffusive component. Consequently the capillary volumes deduced from this extrapolation are erroneous...
December 31, 2016: Respiratory Physiology & Neurobiology
Kirsten E Coffman, Steven C Chase, Bryan J Taylor, Bruce D Johnson
Whether the specific blood transfer conductance for nitric oxide (NO) with hemoglobin (θNO) is finite or infinite is controversial but important in the calculation of alveolar capillary membrane conductance (DmCO) and pulmonary capillary blood volume (VC) from values of lung diffusing capacity for carbon monoxide (DLCO) and nitric oxide (DLNO). In this review, we discuss the background associated with θNO, explore the resulting values of DmCO and VC when applying either assumption, and investigate the mathematical underpinnings of DmCO and VC calculations...
July 2017: Respiratory Physiology & Neurobiology
Gerald S Zavorsky, Ivo van der Lee
Pulmonary diffusing capacity for carbon monoxide (DLCO) has been an important pulmonary function test used since the 1950's. It measures the uptake of CO from the alveolar space into pulmonary capillary blood, following the same path as oxygen. It's used to evaluate/follow the progress of various lung diseases. In the eighties, a new test was developed similar to the DLCO test: pulmonary diffusing capacity for nitric oxide (DLNO). About 81-90% of the variance in DLNO is shared by DLCO in patients with cardiopulmonary disease and in healthy subjects...
November 21, 2016: Respiratory Physiology & Neurobiology
Natalie E Taylor, Sarah E Baker, Thomas P Olson, Sophie Lalande, Bruce D Johnson, Eric M Snyder
BACKGROUND: Beta-2 adrenergic receptors (β2ARs) are located throughout the body including airway and alveolar cells. The β2ARs regulate lung fluid clearance through a variety of mechanisms including ion transport on alveolar cells and relaxation of the pulmonary lymphatics. We examined the effect of an inhaled β2-agonist (albuterol) on alveolar-capillary membrane conductance (DM) and pulmonary capillary blood volume (VC) in healthy humans. METHODS: We assessed the diffusing capacity of the lungs for carbon monoxide (DLCO) and nitric oxide (DLNO) at baseline, 30 minutes, and 60 minutes following nebulized albuterol (2...
2016: Clinical Medicine Insights. Circulatory, Respiratory and Pulmonary Medicine
Laurent Godinas, David Amar, David Montani, Edmund M Lau, Xavier Jaïs, Laurent Savale, Mitja Jevnikar, Olivier Sitbon, Gérald Simonneau, Marc Humbert, Pierantonio Laveneziana, Gilles Garcia
BACKGROUND: Combined diffusion capacity of the lung for carbon monoxide (DLco) and nitric oxide (DLno) measurements allow for the estimation of pulmonary capillary blood volume (Vc) and alveolar membrane diffusion (Dm). The clinical usefulness of these measurements in pulmonary hypertension (PH) is unclear. METHODS: Combined DLco and DLno were measured in 290 consecutive patients with precapillary PH (pulmonary arterial hypertension (PAH), n = 153; pulmonary veno-occlusive disease (PVOD), n = 33; and chronic thromboembolic pulmonary hypertension (CTEPH), n = 104)...
May 2016: Journal of Heart and Lung Transplantation
Giovanni Barisione, Claudia Brusasco, Alessandro Garlaschi, Michele Baroffio, Vito Brusasco
Lung diffusing capacity for carbon monoxide (DLCO) is decreased in both usual interstitial pneumonia-idiopathic pulmonary fibrosis (UIP-IPF) and nonspecific interstitial pneumonia (NSIP), but is moderately related to computed tomography (CT)-determined fibrotic changes. This may be due to the relative insensitivity of DLCO to changes in alveolar membrane diffusive conductance (DMCO). The purpose of this study was to determine whether measurement of lung diffusing capacity for nitric oxide (DLNO) better reflects fibrotic changes than DLCO DLNO-DLCO were measured simultaneously in 30 patients with UIP-IPF and 30 with NSIP...
May 1, 2016: Journal of Applied Physiology
Min-Yeong Kang, Bernard Sapoval
Capture of CO and NO by blood requires molecules to travel by diffusion from alveolar gas to haemoglobin molecules inside RBCs and then to react. One can attach to these processes two times, a time for diffusion and a time for reaction. This reaction time is known from chemical kinetics and, therefore, constitutes a unique physical clock. This paper presents a time-based bottom-up theory that yields a simple expression for DLCO and DLNO that produces quantitative predictions which compare successfully with experiments...
May 2016: Respiratory Physiology & Neurobiology
Bryan J Taylor, Kirsten E Coffman, Douglas T Summerfield, Amine N Issa, Alex J Kasak, Bruce D Johnson
PURPOSE: We determined whether well-acclimatized humans have a reserve to recruit pulmonary capillaries in response to exercise at high altitude. METHODS: At sea level, lung diffusing capacity for carbon monoxide (DLCO), alveolar-capillary membrane conductance (DmCO), and pulmonary capillary blood volume (V c) were measured at rest before maximal oxygen consumption ([Formula: see text]) was determined in seven adults. Then, DLCO, DmCO and V c were measured pre- and post-exhaustive incremental exercise at 5150 m after ~40 days of acclimatization...
February 2016: European Journal of Applied Physiology
A Le Bourgeois, F Malard, P Chevallier, G Urbistandoy, T Guillaume, J Delaunay, P Peterlin, P Lemarchand, P Germaud, M Mohty, P Moreau, A Chambellan
No abstract text is available yet for this article.
April 2016: Bone Marrow Transplantation
Jean Benoit Martinot, Hervé Guénard, Anh-Tuan Dinh-Xuan, Henri Gin, Claire Dromer
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 (DmCO and 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 )...
July 2017: Clinical Physiology and Functional Imaging
Kirsten E Coffman, Bryan J Taylor, Alex R Carlson, Robert J Wentz, Bruce D Johnson
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...
January 15, 2016: Respiratory Physiology & Neurobiology
Courtney M Wheatley, Sarah E Baker, Mary A Morgan, Marina G Martinez, Wayne J Morgan, Eric C Wong, Stephen R Karpen, Eric M Snyder
BACKGROUND: Although exercise is a vital component of the therapy prescribed to individuals with cystic fibrosis (CF), it is not a priority due to a finite amount of treatment time and the view that exercise is not as beneficial as pharmacological treatments by many individuals with CF. We sought to compare the therapeutic benefits of exercise and their prescribed bronchodilator albuterol. METHODS: CF (n = 14) and healthy (n = 16) subjects completed three visits, a baseline screening with VO2 max test and two treatment visits...
April 2015: Respiratory Medicine
U Schulz, S Langwieler, S Riedel, J Schreiber
Reduced pulmonary diffusion capacity is a hallmark of COPD, although the relative contribution of the subcomponents of pulmonary diffusion--membranous component (Dm) and capillary volume (Vc)--is unknown. These components can be measured with the method of NO single-breath diffusion (DLNO). In a prospective study, pulmonary function tests including spirometry, body plethysmography and single-breath measurements of diffusion capacity with CO and NO were performed in 183 patients with COPD of varying severity...
April 2014: Pneumologie
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