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Pulmonary function tests in systemic sclerosis-associated interstitial lung disease: new directions and future prospects. CURRENT OPINION IN PHYSIOLOGY 2021. [DOI: 10.1016/j.cophys.2021.05.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Barisione G, Brusasco V. Lung diffusing capacity for nitric oxide and carbon monoxide following mild-to-severe COVID-19. Physiol Rep 2021; 9:e14748. [PMID: 33625799 PMCID: PMC7903940 DOI: 10.14814/phy2.14748] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 01/07/2021] [Accepted: 01/13/2021] [Indexed: 02/06/2023] Open
Abstract
A decreased lung diffusing capacity for carbon monoxide (DLCO ) has been reported in a variable proportion of subjects over the first 3 months of recovery from severe coronavirus disease 2019 (COVID-19). In this study, we investigated whether measurement of lung diffusing capacity for nitric oxide (DLNO ) offers additional insights on the presence and mechanisms of gas transport abnormalities. In 94 subjects, recovering from mild-to-severe COVID-19 pneumonia, we measured DLNO and DLCO between 10 and 266 days after each patient was tested negative for severe acute respiratory syndrome coronavirus 2. In 38 subjects, a chest computed tomography (CT) was available for semiquantitative analysis at six axial levels and automatic quantitative analysis of entire lungs. DLNO was abnormal in 57% of subjects, independent of time of lung function testing and severity of COVID-19, whereas standard DLCO was reduced in only 20% and mostly within the first 3 months. These differences were not associated with changes of simultaneous DLNO /DLCO ratio, while DLCO /VA and DLNO /VA were within normal range or slightly decreased. DLCO but not DLNO positively correlated with recovery time and DLCO was within the normal range in about 90% of cases after 3 months, while DLNO was reduced in more than half of subjects. Both DLNO and DLCO inversely correlated with persisting CT ground glass opacities and mean lung attenuation, but these were more frequently associated with DLNO than DLCO decrease. These data show that an impairment of DLNO exceeding standard DLCO may be present during the recovery from COVID-19, possibly due to loss of alveolar units with alveolar membrane damage, but relatively preserved capillary volume. Alterations of gas transport may be present even in subjects who had mild COVID-19 pneumonia and no or minimal persisting CT abnormalities. TRIAL REGISTRY: ClinicalTrials.gov PRS: No.: NCT04610554 Unique Protocol ID: SARS-CoV-2_DLNO 2020.
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Affiliation(s)
- Giovanni Barisione
- Struttura Semplice Fisiopatologia Respiratoria, Clinica Malattie Respiratorie e Allergologia, Dipartimento di Medicina Interna e Specialità Mediche, Università di Genova, IRCCS Ospedale Policlinico San Martino, Genova, Italy
| | - Vito Brusasco
- Centro Polifunzionale di Scienze Motorie, Dipartimento di Medicina Sperimentale, Università di Genova, IRCCS Ospedale Policlinico San Martino, Genova, Italy
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Abstract
This overview presents the recent progress in our understanding of gas transfer by the lungs during the respiratory cycle and during breath holding. Different phenomena intervene in gas transfer, convection and diffusion in the gas, dissolution, diffusion across the alveolar-capillary membrane, diffusion across blood plasma, and finally diffusion and reaction with hemoglobin inside blood cells. The different gases, O2 , CO, and NO, have very different reaction times with hemoglobin ranging from a few microseconds to tens of milliseconds. This is leading to different outcomes. For O2 , the solutions to the coupled nonlinear gas and blood equations are obtained at the acinus level. They include the fact that the acinar internal ventilation is strongly heterogeneous due to the arborescent structure. Also, in the dynamic calculation, one takes care of the delay between the start of inhalation and arrival of fresh air in the acinus. This "dead" time is the dynamic equivalent of the dead space ventilation. The question of the dependence of Vo2 on ventilation and perfusion takes a different form. The results show that Vo2 is not only a function of the ventilation/perfusion ratio but also depends on the variables: acinar ventilation VEac and perfusion Qac . The ratio VEac /Qac roughly determines arterial O2 saturation and arterial and alveolar O2 partial pressure. The classic Roughton-Forster interpretation of DLCO (separation between independent membrane and blood resistance) was a mathematical conjecture. It was shown recently that this conjecture was violated. This article presents an alternative interpretation that uses time concepts instead of resistance. © 2021 American Physiological Society. Compr Physiol 11:1289-1314, 2021.
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Affiliation(s)
- Bernard Sapoval
- Laboratoire de Physique de la Matière Condensée, CNRS, Ecole Polytechnique, Palaiseau, France
| | - Min-Yeong Kang
- Laboratoire de Physique de la Matière Condensée, CNRS, Ecole Polytechnique, Palaiseau, France
| | - Anh Tuan Dinh-Xuan
- Service de Physiologie-Explorations Fonctionnelles, Hôpital Cochin, AP-HP, Université Paris Descartes, Paris, France
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Yamaguchi K, Tsuji T, Aoshiba K, Nakamura H, Abe S. Can DL NO/DL CO ratio offset prejudicial effects of functional heterogeneities in acinar regions? Respir Physiol Neurobiol 2020; 282:103517. [PMID: 32805419 DOI: 10.1016/j.resp.2020.103517] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Accepted: 08/03/2020] [Indexed: 02/07/2023]
Abstract
OBJECTIVES (1) To establish the general equation that describes relationship of DMCO/Vc versus DLNO/DLCO under conditions with no functional heterogeneities. (2) To examine the effects of functional heterogeneities, including parallel and series (stratified) heterogeneities, on DLNO/DLCO. RESULTS AND DISCUSSIONS (1) Given that "true" θNO in pulmonary capillaries is represented by surface absorption-related θNO, relationship between DMCO/Vc and DLNO/DLCO does not differ significantly from that obtained on premise of infinite θNO. DLNO/DLCO decided physiologically may mirror morphometric DMCO/Vc actually working for gas exchange but not "total" morphometric ratio of DMCO/Vc. (2) There are three parallel heterogeneities that affect diffusing capacity (D)-related parameters. Of them, only the heterogeneity of D/VA, where VA is alveolar volume, underestimates DLCO and DLNO. DLNO/DLCO does not alleviate negative impact of D/VA heterogeneity, indicating that DMCO/Vc estimated from DLNO/DLCO does not mirror "true" morphometric DMCO/Vc in diseased lungs with D/VA maldistribution. (3) Stratified heterogeneity underrates morphometric DMCO, DMNO, and DMNO/DMCO maximally by 1.4 %, 2.8 %, and 1.4 %, respectively, under conditions similar to single-breath D measurements, suggesting that effect of stratified heterogeneity on D measures is no longer needed to be considered in normal subjects but may be in patients having lung diseases with destructive lesions of acinar structures.
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Affiliation(s)
- Kazuhiro Yamaguchi
- Department of Respiratory Medicine, Tokyo Medical University, Tokyo 160-0023, Japan.
| | - Takao Tsuji
- Department of Respiratory Medicine, Tokyo Medical University, Tokyo 160-0023, Japan
| | - Kazutetsu Aoshiba
- Department of Respiratory Medicine, Tokyo Medical University Ibaraki Medical Center, Ibaraki 300-0395, Japan
| | - Hiroyuki Nakamura
- Department of Respiratory Medicine, Tokyo Medical University Ibaraki Medical Center, Ibaraki 300-0395, Japan
| | - Shinji Abe
- Department of Respiratory Medicine, Tokyo Medical University, Tokyo 160-0023, Japan
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Barisione G, Garlaschi A, Occhipinti M, Baroffio M, Pistolesi M, Brusasco V. Value of lung diffusing capacity for nitric oxide in systemic sclerosis. Physiol Rep 2020; 7:e14149. [PMID: 31264386 PMCID: PMC6603284 DOI: 10.14814/phy2.14149] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Accepted: 06/01/2019] [Indexed: 01/08/2023] Open
Abstract
A decreased lung diffusing capacity for carbon monoxide (DLCO ) in systemic sclerosis (SSc) is considered to reflect losses of alveolar membrane diffusive conductance for CO (DMCO ), due to interstitial lung disease, and/or pulmonary capillary blood volume (VC ), due to vasculopathy. However, standard DLCO does not allow separate DMCO from VC . Lung diffusing capacity for nitric oxide (DLNO ) is considered to be more sensitive to decrement of alveolar membrane diffusive conductance than DLCO . Standard DLCO and DLNO were compared in 96 SSc subjects with or without lung restriction. Data showed that DLNO was reduced in 22% of subjects with normal lung volumes and DLCO , whereas DLCO was normal in 30% of those with decreased DLNO . In 30 subjects with available computed tomography of the chest, both DLCO and DLNO were negatively correlated with the extent of pulmonary fibrosis. However, DLNO but not DLCO was always reduced in subjects with ≥ 5% fibrosis, and also decreased in some subjects with < 5% fibrosis. DMCO and VC partitioning and Doppler ultrasound-determined systolic pulmonary artery pressure could not explain individual differences in DLCO and DLNO . DLNO may be of clinical value in SSc because it is more sensitive to DMCO loss than standard DLCO , even in nonrestricted subjects without fibrosis, whereas DLCO partitioning into its subcomponents does not provide information on whether diffusion limitation is primarily due to vascular or interstitial lung disease in individual subjects. Moreover, decreased DLCO in the absence of lung restriction does not allow to suspect pulmonary arterial hypertension without fibrosis.
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Affiliation(s)
- Giovanni Barisione
- Unità Operativa Fisiopatologia Respiratoria, Dipartimento di Medicina Interna, Università di Genova, Genova, Italy
| | - Alessandro Garlaschi
- Dipartimento della Diagnostica per Immagini e Radioterapia, Ospedale Policlinico San Martino - IRCCS, Genova, Italy
| | - Mariaelena Occhipinti
- Dipartimento di Medicina Sperimentale e Clinica, Azienda Ospedaliero-Universitaria Careggi, Firenze, Italy
| | - Michele Baroffio
- Unità Operativa Fisiopatologia Respiratoria, Dipartimento di Medicina Interna, Università di Genova, Genova, Italy
| | - Massimo Pistolesi
- Dipartimento di Medicina Sperimentale e Clinica, Azienda Ospedaliero-Universitaria Careggi, Firenze, Italy
| | - Vito Brusasco
- Unità Operativa Fisiopatologia Respiratoria, Dipartimento di Medicina Interna, Università di Genova, Genova, Italy
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Yamaguchi K, Tsuji T, Aoshiba K, Nakamura H, Abe S. What are appropriate values of relative krogh diffusion Constant of NO against CO and of theta-NO in alveolar septa? Respir Physiol Neurobiol 2020; 276:103415. [PMID: 32068129 DOI: 10.1016/j.resp.2020.103415] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2019] [Revised: 02/11/2020] [Accepted: 02/14/2020] [Indexed: 02/07/2023]
Abstract
OBJECTIVES To propose new physical constants for NO and CO (Krogh diffusion constant ratio (KDNO/CO) and specific blood conductance for NO (θNO)) for calculating DMCO and Vc, according to Roughton-Forster's equation (Roughton and Forster, J. Appl. Physiol. 11: 290-302, 1957) from simultaneous DLNO and DLCO measurements. RESULTS AND CONCLUSIONS (1) The Graham's law is unacceptable for determining KDNO/CO because CO does not fulfil all the conditions of an "ideal" gas. We have re-estimated KDNO/CO in a new way based on difference in molar volumes of two gases (molar volume theory). The KDNO/CO thus decided is 2.34. (2) θNO measured with rapid-reaction, constant-flow method by Carlsen and Comroe (J. Gen. Physiol. 42: 83-107, 1958) may be underestimated by about 40 % due to unstirred water layer surrounding the erythrocyte. (3) Erythrocyte θO2 can be harvested from O2 release kinetics in presence of high concentration of dithionite, which effectively removes the unstirred water layer-elicited effect. Multiplication of erythrocyte θO2 by erythrocyte KDNO/O2 equals erythrocyte θNO, the value of which is 6.2 mL/min/mmHg/(mL⋅blood). According to the concepts of Kang et al. (RESPNB. 241: 62-71, 2017) and Borland et al. (RESPNB. 241: 58-61, 2017), in vitro θNO decided from rapid-mixing experiments may mirror bulk absorption of NO by erythrocytes. (4) In pulmonary capillaries, NO uptake takes place predominantly in the surface rim of the erythrocyte. This surface absorption of NO increases the θNO 10-fold versus bulk absorption of NO to about 60 mL/min/mmHg/(mL⋅blood).
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Affiliation(s)
- Kazuhiro Yamaguchi
- Department of Respiratory Medicine, Tokyo Medical University, Tokyo 160-0023, Japan.
| | - Takao Tsuji
- Department of Respiratory Medicine, Tokyo Medical University, Tokyo 160-0023, Japan.
| | - Kazutetsu Aoshiba
- Department of Respiratory Medicine, Tokyo Medical University Ibaraki Medical Center, Ibaraki 300-0395, Japan.
| | - Hiroyuki Nakamura
- Department of Respiratory Medicine, Tokyo Medical University Ibaraki Medical Center, Ibaraki 300-0395, Japan.
| | - Shinji Abe
- Department of Respiratory Medicine, Tokyo Medical University, Tokyo 160-0023, Japan.
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D R Borland C, B Hughes JM. Lung Diffusing Capacities (D L ) for Nitric Oxide (NO) and Carbon Monoxide (CO): The Evolving Story. Compr Physiol 2019; 10:73-97. [PMID: 31853952 DOI: 10.1002/cphy.c190001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Nitric oxide and carbon monoxide diffusing capacities (DLNO and DLCO ) obey Fick's First Law of Diffusion and the basic principles of chemical kinetic theory. NO gas transfer is dominated by membrane diffusion (DM ), whereas CO transfer is limited by diffusion plus chemical reaction within the red cell. Marie Krogh, who pioneered the single-breath measurement of DLCO in 1915, believed that the combination of CO with red cell hemoglobin (Hb) was instantaneous. Roughton and colleagues subsequently showed, in vitro, that the reaction rate was finite, and prolonged in the presence of high P O 2 . Roughton and Forster (R-F) proposed that the resistance to transfer (1/DL ) was the sum of the membrane resistance (1/DM ) and (1/θVc), the red cell resistance (θ being the CO or NO conductance for blood uptake and Vc the capillary volume). From this R-F equation, DM for CO and Vc can be solved with simultaneous NO and CO inhalation. At near maximum exercise, DMCO and Vc for normal subjects were 88% and 79%, respectively, of morphometric values. The validity of these calculations depends on the values chosen for θ for CO and NO, and on the diffusivity of NO versus CO. Recent mathematical modeling suggests that θ for NO is "effectively" infinite because NO reacts only with Hb in the outer 0.1 μM of the red cell. An "infinite θNO " recalculation reduced DMCO to 53% and increased Vc to 95% of morphometric values. © 2020 American Physiological Society. Compr Physiol 10:73-97, 2020.
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Affiliation(s)
| | - J Mike B Hughes
- National Heart and Lung Institute, Imperial College, London, UK
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Beretta E, Lanfranconi F, Grasso GS, Bartesaghi M, Alemayehu HK, Pratali L, Catuzzo B, Giardini G, Miserocchi G. Air blood barrier phenotype correlates with alveolo-capillary O 2 equilibration in hypobaric hypoxia. Respir Physiol Neurobiol 2017; 246:53-58. [DOI: 10.1016/j.resp.2017.08.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 08/02/2017] [Accepted: 08/04/2017] [Indexed: 10/19/2022]
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Kang MY, Guénard H, Sapoval B. Diffusion Reaction of Carbon Monoxide in the Human Lung. PHYSICAL REVIEW LETTERS 2017; 119:078101. [PMID: 28949676 DOI: 10.1103/physrevlett.119.078101] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Indexed: 06/07/2023]
Abstract
The capture of CO, a standard lung function test, results from diffusion-reaction processes of CO with hemoglobin inside red blood cells (RBCs). In its current understanding, suggested by Roughton and Forster in 1957, the capture is represented by two independent resistances in series, one for diffusion from the gas to the RBC periphery, the second for internal diffusion reaction. Numerical studies in 3D model structures described here contradict the independence hypothesis. This results from two different theoretical reasons: (i) The RBC peripheries are not equi-concentrations; (ii) diffusion times in series are not additive.
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Affiliation(s)
- M-Y Kang
- Laboratoire de Physique de la Matière Condensée, Ecole Polytechnique, CNRS, Université Paris-Saclay, 91128 Palaiseau Cedex, France
| | - H Guénard
- Laboratoire de Physiologie, Université Bordeaux 2, 33076 Bordeaux, France
| | - B Sapoval
- Laboratoire de Physique de la Matière Condensée, Ecole Polytechnique, CNRS, Université Paris-Saclay, 91128 Palaiseau Cedex, France
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Hypothesis: Why θNO could be finite in vitro but infinite in vivo. Respir Physiol Neurobiol 2017; 241:58-61. [DOI: 10.1016/j.resp.2017.02.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2016] [Revised: 02/23/2017] [Accepted: 02/24/2017] [Indexed: 11/24/2022]
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The Roughton-Forster equation for DL CO and DL NO re-examined. Respir Physiol Neurobiol 2017; 241:62-71. [DOI: 10.1016/j.resp.2016.12.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Revised: 12/19/2016] [Accepted: 12/28/2016] [Indexed: 11/19/2022]
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Reappraisal of DLCO adjustment to interpret the adaptive response of the air-blood barrier to hypoxia. Respir Physiol Neurobiol 2016; 238:59-65. [PMID: 27595980 DOI: 10.1016/j.resp.2016.08.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Revised: 08/11/2016] [Accepted: 08/29/2016] [Indexed: 11/21/2022]
Abstract
DLCO measured in hypoxia must be corrected due to the higher affinity (increase in coefficient θ) of CO with Hb. We propose an adjustment accounting for individual changes in the equation relating DLCO to subcomponents Dm (membrane diffusive capacity) and Vc (lung capillary volume): 1/DLCO=1/Dm+1/θVc. We adjusted the individual DLCO measured in hypoxia (HA, 3269m) by interpolating the 1/DLCO to the sea level (SL) 1/θ value. Nineteen healthy subjects were studied at SL and HA. Based on the proposed adjustment, DLCO increased in HA in 53% of subjects, reflecting the increase in Dm that largely overruled the decrease in Vc. We hypothesize that a decrease in Vc (buffering microvascular filtration) and the increase in Dm (possibly resulting from a decrease in thickness of the air-blood barrier) represent the anti-edemagenic adaptation of the lung to hypoxia exposure. The efficiency of this adaptation varied among subjects as DLCO did not change in 31% of subjects and decreased in 16%.
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