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Bozier J, Jeagal E, Robinson PD, Prisk GK, Chapman DG, King GG, Thamrin C, Rutting S. The effect of O 2 and CO 2 cross-sensitivity sensor error in the Eco Medics Exhalyzer D device on measures of conductive and acinar airway function. ERJ Open Res 2022; 8:00614-2021. [PMID: 35854872 PMCID: PMC9289373 DOI: 10.1183/23120541.00614-2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Accepted: 02/17/2022] [Indexed: 11/13/2022] Open
Abstract
Introduction The multiple breath nitrogen washout (MBNW) test provides important clinical information in obstructive airways diseases. Recently, a significant cross-sensitivity error in the O2 and CO2 sensors of a widely used commercial MBNW device (Exhalyzer D, Eco Medics AG, Duernten, Switzerland) was detected, which leads to overestimation of N2 concentrations. Significant errors in functional residual capacity (FRC) and lung clearance index (LCI) have been reported in infants and children. This study investigated the impact in adults, and on additional important indices reflecting conductive (Scond) and acinar (Sacin) ventilation heterogeneity, in health and disease. Methods Existing MBNW measurements of 27 healthy volunteers, 20 participants with asthma and 16 smokers were reanalysed using SPIROWARE V 3.3.1, which incorporates an error correction algorithm. Uncorrected and corrected indices were compared using paired t-tests and Bland–Altman plots. Results Correction of the sensor error significantly lowered FRC (mean difference 9%) and LCI (8–10%) across all three groups. Scond was higher following correction (11%, 14% and 36% in health, asthma and smokers, respectively) with significant proportional bias. Sacin was significantly lower following correction in the asthma and smoker groups, but the effect was small (2–5%) and with no proportional bias. Discussion The O2 and CO2 cross-sensitivity sensor error significantly overestimated FRC and LCI in adults, consistent with data in infants and children. There was a high degree of underestimation of Scond but minimal impact on Sacin. The presence of significant proportional bias indicates that previous studies will require reanalysis to confirm previous findings and to allow comparability with future studies. O2 and CO2 cross-sensitivity sensor error in the Exhalyzer D device significantly overestimates FRC and LCI in adults, consistent with infants and children. Importantly, there was a high degree of underestimation of Scond, but minimal impact on Sacin.https://bit.ly/3HcH3Tp
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Koucký V. Multiple breath washout test in infants-still in search for technical ideal. Pediatr Pulmonol 2021; 56:2397-2398. [PMID: 34126000 DOI: 10.1002/ppul.25531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 06/03/2021] [Indexed: 11/07/2022]
Affiliation(s)
- Václav Koucký
- Department of Pediatrics, 2nd Faculty of Medicine, Charles University and University Hospital Motol, Prague, Czech Republic
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3
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Rutting S, Chapman DG, Thamrin C, Tang FSM, Dame Carroll JR, Bailey DL, Trifunovic M, Magnussen JS, King GG, Farrow CE. Effect of combination inhaled therapy on ventilation distribution measured by SPECT/CT imaging in uncontrolled asthma. J Appl Physiol (1985) 2021; 131:621-629. [PMID: 34166109 DOI: 10.1152/japplphysiol.01068.2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Asthma is characterized by heterogeneous ventilation as measured by three-dimensional ventilation imaging. Combination inhaled corticosteroid/long-acting β2-agonist (ICS/LABA) treatment response is variable in asthma, and effects on regional ventilation are unknown. Our aims were to determine whether regional ventilation defects decrease after ICS/LABA treatment and whether small airways dysfunction predicts response in uncontrolled asthma. Twenty-two symptomatic participants with asthma underwent single-photon emission computed tomography (SPECT)/CT imaging with Technegas, before and after 8-wk fluticasone/formoterol (1,000/40 µg/day) treatment. Lung regions that were nonventilated, low ventilated, or well ventilated were calculated using an adaptive threshold method and were expressed as a percentage of total lung volume. Multiple-breath nitrogen washout (MBNW) was used to measure diffusion-dependent and convection-dependent small airways function (Sacin and Scond, respectively). Forced oscillation technique (FOT) was used to measure respiratory system resistance and reactance. At baseline and posttreatment, Scond z-score was related to percentage of nonventilated lung, whereas Sacin z-score was related to percentage of low-ventilated lung. Although symptoms, spirometry, FOT, and MBNW improved following treatment, there was no mean change in ventilation measured by SPECT. There was, however, a wide range of changes in SPECT ventilation such that greater percentage of nonventilated lung, older age, and higher Scond predicted a reduction in nonventilated lung after treatment. SPECT ventilation defects are overall unresponsive to ICS/LABA, but the response is variable, with improvement occurring when small airways dysfunction and ventilation defects are more severe. Persistent ventilation defects that correlate with Scond suggest that mechanisms such as non-ICS responsive inflammation or remodeling underlie these defects.NEW & NOTEWORTHY This study provides insights into the mechanisms of high-dose ICS treatment in uncontrolled asthma. Ventilation defects as measured by SPECT/CT imaging respond heterogeneously to increased ICS/LABA treatment, with improvement occurring when ventilation defects and impairment of convection-dependent small airways function are more severe. Persistent correlations between ventilation defects and measures of small airways function suggest the potential presence of ICS nonresponsive inflammation and/or remodeling.
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Affiliation(s)
- Sandra Rutting
- Department of Respiratory Medicine, Royal North Shore Hospital, St. Leonards, New South Wales, Australia.,Airway Physiology and Imaging Group, The Woolcock Institute of Medical Research, The University of Sydney, Sydney, New South Wales, Australia.,National Health and Medical Research Council Centre of Excellence in Severe Asthma, New Lambton Heights, New South Wales, Australia
| | - David G Chapman
- Airway Physiology and Imaging Group, The Woolcock Institute of Medical Research, The University of Sydney, Sydney, New South Wales, Australia.,Faculty of Science, School of Life Sciences, University of Technology Sydney, Ultimo, New South Wales, Australia
| | - Cindy Thamrin
- Airway Physiology and Imaging Group, The Woolcock Institute of Medical Research, The University of Sydney, Sydney, New South Wales, Australia
| | - Francesca S M Tang
- Department of Respiratory Medicine, Royal North Shore Hospital, St. Leonards, New South Wales, Australia.,Airway Physiology and Imaging Group, The Woolcock Institute of Medical Research, The University of Sydney, Sydney, New South Wales, Australia
| | - Jessica R Dame Carroll
- Airway Physiology and Imaging Group, The Woolcock Institute of Medical Research, The University of Sydney, Sydney, New South Wales, Australia
| | - Dale L Bailey
- Department of Nuclear Medicine, Royal North Shore Hospital, St. Leonards, New South Wales, Australia.,Faculty of Health and Medicine, Northern Clinical School, University of Sydney, New South Wales, Australia
| | - Marko Trifunovic
- Macquarie Medical Imaging, Macquarie University Hospital, Macquarie University, New South Wales, Australia
| | - John S Magnussen
- Macquarie Medical Imaging, Macquarie University Hospital, Macquarie University, New South Wales, Australia.,Faculty of Medicine and Health Sciences, Macquarie University, New South Wales, Australia
| | - Gregory G King
- Department of Respiratory Medicine, Royal North Shore Hospital, St. Leonards, New South Wales, Australia.,Airway Physiology and Imaging Group, The Woolcock Institute of Medical Research, The University of Sydney, Sydney, New South Wales, Australia.,National Health and Medical Research Council Centre of Excellence in Severe Asthma, New Lambton Heights, New South Wales, Australia.,Faculty of Health and Medicine, Northern Clinical School, University of Sydney, New South Wales, Australia
| | - Catherine E Farrow
- Airway Physiology and Imaging Group, The Woolcock Institute of Medical Research, The University of Sydney, Sydney, New South Wales, Australia.,Department of Respiratory Medicine, Westmead Hospital, Westmead, New South Wales, Australia
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4
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Handley BM, Jeagal E, Schoeffel RE, Badal T, Chapman DG, Farrow CE, King GG, Robinson PD, Milne S, Thamrin C. Controlled versus free breathing for multiple breath nitrogen washout in healthy adults. ERJ Open Res 2021; 7:00435-2020. [PMID: 33532457 PMCID: PMC7836463 DOI: 10.1183/23120541.00435-2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 10/16/2020] [Indexed: 11/18/2022] Open
Abstract
Multiple breath nitrogen washout (MBNW) quantifies ventilation heterogeneity. Two distinct protocols are currently used for MBNW testing: “controlled breathing”, with targeted tidal volume (VT) and respiratory rate (RR); and “free breathing”, with no constraints on breathing pattern. Indices derived from the two protocols (functional residual capacity (FRC), lung clearance index (LCI), Scond, Sacin) have not been directly compared in adults. We aimed to determine whether MBNW indices are comparable between protocols, to identify factors underlying any between-protocol differences and to determine the between-session variabilities of each protocol. We performed MBNW testing by both protocols in 27 healthy adult volunteers, applying the currently proposed correction for VT to Scond and Sacin derived from free breathing. To establish between-session variability, we repeated testing in 15 volunteers within 3 months. While FRC was comparable between controlled versus free breathing (3.17 (0.98) versus 3.18 (0.94) L, p=0.88), indices of ventilation heterogeneity derived from the two protocols were not, with poor correlation for Scond (r=0.18, p=0.36) and significant bias for Sacin (0.057 (0.021) L−1versus 0.085 (0.038) L−1, p=0.0004). Between-protocol differences in Sacin were related to differences in the breathing pattern, i.e. VT (p=0.004) and RR (p=0.01), rather than FRC. FRC and LCI showed good between-session repeatability, but Scond and Sacin from free breathing showed poor repeatability with wide limits of agreement. These findings have implications for the ongoing clinical implementation of MBNW, as they demonstrate that Scond and Sacin from free breathing, despite VT correction, are not equivalent to the controlled breathing protocol. The poor between-session repeatability of Scond during free breathing may limit its clinical utility. Phase 3 slopes indices derived from “free breathing” and “controlled breathing” MBNW protocols are not comparable, and differences are related to breathing patterns. These findings have implications for the ongoing clinical implementation of MBNW.https://bit.ly/35oQYnW
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Affiliation(s)
- Blake M Handley
- Dept of Respiratory Medicine, Royal North Shore Hospital, St Leonards, NSW, Australia.,Woolcock Institute of Medical Research, University of Sydney, Glebe, NSW, Australia
| | - Edward Jeagal
- Woolcock Institute of Medical Research, University of Sydney, Glebe, NSW, Australia
| | - Robin E Schoeffel
- Dept of Respiratory Medicine, Royal North Shore Hospital, St Leonards, NSW, Australia
| | - Tanya Badal
- Woolcock Institute of Medical Research, University of Sydney, Glebe, NSW, Australia
| | - David G Chapman
- Woolcock Institute of Medical Research, University of Sydney, Glebe, NSW, Australia.,Translational Airways Group, School of Life Sciences, Faculty of Science, University of Technology Sydney, Ultimo, NSW, Australia
| | - Catherine E Farrow
- Woolcock Institute of Medical Research, University of Sydney, Glebe, NSW, Australia.,Dept of Respiratory and Sleep Medicine, Westmead Hospital, Westmead, NSW, Australia
| | - Gregory G King
- Dept of Respiratory Medicine, Royal North Shore Hospital, St Leonards, NSW, Australia.,Woolcock Institute of Medical Research, University of Sydney, Glebe, NSW, Australia.,Faculty of Medicine and Health, University of Sydney, Camperdown, NSW, Australia
| | - Paul D Robinson
- Dept of Respiratory Medicine, The Children's Hospital at Westmead, Westmead, NSW, Australia
| | - Stephen Milne
- Faculty of Medicine and Health, University of Sydney, Camperdown, NSW, Australia.,Centre for Heart Lung Innovation, St Paul's Hospital and Division of Respiratory Medicine, University of British Columbia, Vancouver, BC, Canada.,These authors contributed equally
| | - Cindy Thamrin
- Woolcock Institute of Medical Research, University of Sydney, Glebe, NSW, Australia.,Faculty of Medicine and Health, University of Sydney, Camperdown, NSW, Australia.,These authors contributed equally
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5
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Isaac SM, Jensen R, Anagnostopoulou P, Davies JC, Gappa M, Latzin P, Saunders C, Short C, Singer F, Stanojevic S, Zwitserloot A, Ratjen F. Evaluation of a multiple breath nitrogen washout system in children. Pediatr Pulmonol 2020; 55:2108-2114. [PMID: 32437013 DOI: 10.1002/ppul.24862] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 05/13/2020] [Indexed: 11/10/2022]
Abstract
INTRODUCTION The multiple breath nitrogen washout (MBW) test offers a sensitive measure of airway function. In this study we aim to (a) assess the validity of the EasyOne Pro LAB (MBWndd ) in an in vitro lung model, (b) assess the feasibility, repeatability, and reproducibility of MBWndd and (c) compare outcomes with the Exhalyzer D (MBWEM ) and body plethysmography. METHODS In vitro, functional residual capacity (FRC) measurements were assessed using a lung model under quasi-physiological conditions and compared to measured FRC. In vivo plethysmography and MBW were performed in a prospective study of children at two visits (n = 45 healthy; n = 41 cystic fibrosis [CF]). Bland-Altman plots were used to compare agreement between FRC and lung clearance index (LCI) measurements. RESULTS In vitro FRCndd measurements were repeatable but lung volumes were underestimated (mean relative difference -5.4% (limits of agreement [LA] -9.6%; -1.1%), 95% confidence interval (CI) -6.27; -4.45). In vivo, compared to plethysmography, FRCndd was consistently lower (-19.3% [-40.5; 1.9], 95% CI [-23.9; -14.7]), and showed a volume dependency. LCIndd values were also higher in children with smaller lung volumes. The within-test coefficient of variation of the FRCndd and LCIndd were 4.9% in health, and 5.6% and 6.9% in CF respectively. LCIndd was reproducible between-visits (mean relative difference [LA] -3.7% [-14.8, -7.5; 95% CI -6.6; -0.73] in health [n = 17] and 0.34% [-13.2, 22.8; 95% CI -5.0; 5.69] in CF [n = 23]). When calculated using the same algorithm, LCIndd was similar to LCIEM in health. CONCLUSIONS MBWndd measurements are feasible, repeatable, and reproducible, however, MBW-derived outcomes are not interchangeable with MBWEM .
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Affiliation(s)
- Sarah M Isaac
- Translational Medicine, Research Institute, Hospital for Sick Children, Toronto, Canada
| | - Renee Jensen
- Translational Medicine, Research Institute, Hospital for Sick Children, Toronto, Canada
| | - Pinelopi Anagnostopoulou
- Division of Respiratory Medicine, Department of Pediatrics, University Children's Hospital of Bern, University of Bern, Bern, Switzerland.,Institute of Anatomy, University of Bern, Bern, Switzerland
| | - Jane C Davies
- National Heart & Lung Institute, Imperial College London and Royal Brompton Hospital, London, UK
| | - Monika Gappa
- Evangelisches Krankenhaus Düsseldorf, Formerly Marienhospital Wesel, Germany
| | - Philipp Latzin
- Division of Respiratory Medicine, Department of Pediatrics, University Children's Hospital of Bern, University of Bern, Bern, Switzerland
| | - Clare Saunders
- National Heart & Lung Institute, Imperial College London and Royal Brompton Hospital, London, UK
| | - Christopher Short
- National Heart & Lung Institute, Imperial College London and Royal Brompton Hospital, London, UK
| | - Florian Singer
- Division of Respiratory Medicine, Department of Pediatrics, University Children's Hospital of Bern, University of Bern, Bern, Switzerland
| | - Sanja Stanojevic
- Translational Medicine, Research Institute, Hospital for Sick Children, Toronto, Canada.,University of Toronto, Toronto, Ontario, Canada
| | - Annelies Zwitserloot
- University Medical Centre Groningen, Beatrix Children's Hospital, The Netherlands
| | - Felix Ratjen
- Translational Medicine, Research Institute, Hospital for Sick Children, Toronto, Canada.,University of Toronto, Toronto, Ontario, Canada.,Division of Respiratory Medicine, Hospital for Sick Children, Toronto, Ontario, Canada
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Zwitserloot AM, van den Born EJ, Raaijmakers LHA, Stalman WE, van Smaalen M, van den Berge M, Gappa M, Koppelman GH, Willemse BWM. Differences in lung clearance index and functional residual capacity between two commercial multiple-breath nitrogen washout devices in healthy children and adults. ERJ Open Res 2020; 6:00247-2019. [PMID: 32613018 PMCID: PMC7322914 DOI: 10.1183/23120541.00247-2019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 04/07/2020] [Indexed: 11/21/2022] Open
Abstract
Multiple-breath nitrogen washout (MBNW) and its clinical parameter lung clearance index (LCI) are gaining increasing attention for the assessment of small airway function. Measurement of LCI relies on accurate assessment of functional residual capacity (FRC). The EasyOne Pro LAB (ndd) and Exhalyzer D (EM) are two commercially available MBNW devices. The aim of the study was to compare these two devices in vitro and in vivo in healthy subjects with regard to FRC, LCI and secondary outcome parameters and to relate FRCMBNW to FRC measured by body plethysmography (pleth) and helium dilution technique. MBNW measurements were performed using a lung model (FRC between 500 and 4000 mL) in vitro and in 38 subjects aged 6–65 years followed by helium dilution and pleth in vivo using fixed and relaxed breathing techniques. In vitro accuracy within 5% of lung model FRC was 67.3% for ndd, FRC was >5% higher for EM in all tests. In vivo, FRCpleth ranged from 1.2 to 5.6 L. Mean differences (limits of agreement) between FRCpleth and FRCMBNW were −7.0%, (−23.2 to 9.2%) and 5.7% (−11.2 to 22.6%) using ndd and EM, respectively. FRCndd was consistently lower than FRCEM (−11.8% (−25.6 to 2%)). LCI was comparable between the two devices (−1.3% (−21.9 to 19.3%)). There was a difference of >10 % in LCI in 12 of 38 subjects. Using the most recent software updates, both devices show relevant deviations in FRC measurement both in vitro and in vivo and individual differences in LCI in a significant proportion of subjects. The devices are therefore not interchangeable. MBNW measurements with the Exhalyzer D and EasyOne Pro LAB cannot be used interchangeably for FRC and LCI measurements. FRC measured on both devices showed deviations from in vitro and in vivo measurements.https://bit.ly/2xyyUuJ
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Affiliation(s)
- Annelies M Zwitserloot
- University of Groningen, University Medical Center Groningen, Beatrix Children's Hospital, Dept of Paediatric Pulmonology and Paediatric Allergy, Groningen, The Netherlands.,University of Groningen, University Medical Center Groningen, Groningen Research Institute for Asthma and COPD, Groningen, The Netherlands
| | - Evelyne J van den Born
- University of Groningen, University Medical Center Groningen, Beatrix Children's Hospital, Dept of Paediatric Pulmonology and Paediatric Allergy, Groningen, The Netherlands
| | - Lena H A Raaijmakers
- Radboud University Medical Center, Radboud Institute for Health Sciences, Dept of Primary and Community Care, Nijmegen, The Netherlands
| | - Wouter E Stalman
- University of Groningen, University Medical Center Groningen, Beatrix Children's Hospital, Dept of Paediatric Pulmonology and Paediatric Allergy, Groningen, The Netherlands
| | - Marjanne van Smaalen
- University of Groningen, University Medical Center Groningen, Beatrix Children's Hospital, Dept of Paediatric Pulmonology and Paediatric Allergy, Groningen, The Netherlands
| | - Maarten van den Berge
- University of Groningen, University Medical Center Groningen, Groningen Research Institute for Asthma and COPD, Groningen, The Netherlands.,University of Groningen, University Medical Center Groningen, Dept of Pulmonary Diseases, Groningen, The Netherlands
| | - Monika Gappa
- Evangelisches Krankenhaus Düsseldorf, Children's Hospital, Düsseldorf, Germany
| | - Gerard H Koppelman
- University of Groningen, University Medical Center Groningen, Beatrix Children's Hospital, Dept of Paediatric Pulmonology and Paediatric Allergy, Groningen, The Netherlands.,University of Groningen, University Medical Center Groningen, Groningen Research Institute for Asthma and COPD, Groningen, The Netherlands
| | - Brigitte W M Willemse
- University of Groningen, University Medical Center Groningen, Beatrix Children's Hospital, Dept of Paediatric Pulmonology and Paediatric Allergy, Groningen, The Netherlands.,University of Groningen, University Medical Center Groningen, Groningen Research Institute for Asthma and COPD, Groningen, The Netherlands
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Chapman DG, King GG, Robinson PD, Farah CS, Thamrin C. The need for physiological phenotyping to develop new drugs for airways disease. Pharmacol Res 2020; 159:105029. [PMID: 32565310 DOI: 10.1016/j.phrs.2020.105029] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 06/01/2020] [Accepted: 06/12/2020] [Indexed: 11/25/2022]
Abstract
Asthma and COPD make up the majority of obstructive airways diseases (OADs), which affects ∼11 % of the population. The main drugs used to treat OADs have not changed in the past five decades, with advancements mainly comprising variations on existing treatments. The recent biologics are beneficial to only specific subsets of patients. Part of this may lie in our inability to adequately characterise the tremendous heterogeneity in every aspect of OAD. The field is currently moving towards the concept of personalised medicine, based on a focus on treatable traits that are objective, measurable and modifiable. We propose extending this concept via the use of emerging clinical tools for comprehensive physiological phenotyping. We describe, based on published data, the evidence for the use of functional imaging, gas washout techniques and oscillometry, as well as potential future applications, to more comprehensively assess and predict treatment response in OADs. In this way, we hope to demonstrate how physiological phenotyping tools will improve the way in which drugs are prescribed, but most importantly, will facilitate development of new drugs for OADs.
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Affiliation(s)
- David G Chapman
- Airway Physiology and Imaging Group and Woolcock Emphysema Centre, The Woolcock Institute of Medical Research, The University of Sydney, Glebe NSW 2037, Australia; School of Life Sciences, Faculty of Science, University of Technology Sydney, Ultimo NSW 2007, Australia.
| | - G G King
- Airway Physiology and Imaging Group and Woolcock Emphysema Centre, The Woolcock Institute of Medical Research, The University of Sydney, Glebe NSW 2037, Australia; Department of Respiratory Medicine, Royal North Shore Hospital, St. Leonards, NSW 2065, Australia; NHMRC Centre of Excellence in Severe Asthma, New Lambton Heights NSW 2305, Australia; Faculty of Medicine and Health Sciences, The University of Sydney, NSW 2006, Australia
| | - Paul D Robinson
- Airway Physiology and Imaging Group and Woolcock Emphysema Centre, The Woolcock Institute of Medical Research, The University of Sydney, Glebe NSW 2037, Australia; Department of Respiratory Medicine, The Children's Hospital at Westmead, Westmead, NSW 2145, Australia; Faculty of Medicine and Health Sciences, The University of Sydney, NSW 2006, Australia
| | - Claude S Farah
- Airway Physiology and Imaging Group and Woolcock Emphysema Centre, The Woolcock Institute of Medical Research, The University of Sydney, Glebe NSW 2037, Australia; Faculty of Medicine and Health Sciences, The University of Sydney, NSW 2006, Australia; Department of Thoracic Medicine, Concord Repatriation General Hospital, Concord, NSW 2137, Australia
| | - Cindy Thamrin
- Airway Physiology and Imaging Group and Woolcock Emphysema Centre, The Woolcock Institute of Medical Research, The University of Sydney, Glebe NSW 2037, Australia; Faculty of Medicine and Health Sciences, The University of Sydney, NSW 2006, Australia
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Tang FSM, Rutting S, Farrow CE, Tonga KO, Watts J, Dame-Carrol JR, Bertolin A, King GG, Thamrin C, Chapman DG. Ventilation heterogeneity and oscillometry predict asthma control improvement following step-up inhaled therapy in uncontrolled asthma. Respirology 2020; 25:827-835. [PMID: 32026586 DOI: 10.1111/resp.13772] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Revised: 12/17/2019] [Accepted: 01/14/2020] [Indexed: 02/06/2023]
Abstract
BACKGROUND AND OBJECTIVE Abnormal peripheral airway function is an important feature of asthma and relates to asthma symptoms and poor asthma control. We aimed to determine whether peripheral airway function, as measured by forced oscillatory impedance and multiple-breath nitrogen washout (MBNW), relates to symptom improvement in asthmatic participants with uncontrolled asthma, after stepping up to high-dose ICS/LABA treatment. METHODS A total of 19 subjects (14 females, mean age: 29.9 ± 13.6 years) with uncontrolled asthma, as defined by an ACQ5 > 1.5, taking 500 μg/day fluticasone equivalent or less, underwent spirometry, plethysmography, fractional exhaled FeNO, forced oscillatory resistance (Rrs5Hz ) and reactance (Xrs5Hz ), and indices of MBNW ventilation heterogeneity (lung clearance index (LCI), diffusion-convection-dependent (Sacin) and convection-dependent (Scond)). Measurements were made before and after 8 weeks of treatment with fluticasone/formoterol combination inhaler 250/10 μg, 2 puffs twice daily. RESULTS Treatment improved ACQ5 (P = 0.0002), FEV1 (P = 0.02), FVC (P = 0.04), FeNO (P = 0.0008), Xrs5Hz (P = 0.01), LCI (P = 0.0002), Sacin (P = 0.006) and Scond (P = 0.01). At baseline, ACQ5 correlated with Xrs5Hz (rs = 0.52, P = 0.03) and Rrs5Hz (rs = 0.55, P = 0.02). The improvement in ACQ5 was predicted by more abnormal baseline LCI (P = 0.03), Scond (P = 0.02) and Rrs5Hz (P = 0.006). Baseline Scond was the best predictor of a clinically meaningful improvement in asthma control (ΔACQ > 0.5, ROC-AUC = 0.91, P = 0.007). CONCLUSION Step-up to high-dose combination treatment in uncontrolled asthma is associated with improved peripheral airway function as measured by Xrs5Hz and MBNW. Baseline MBNW and FOT parameters correlated with the improvement in symptoms and may predict a positive response to up-titration in uncontrolled asthmatic patients.
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Affiliation(s)
- Francesca S M Tang
- Department of Respiratory Medicine, Royal North Shore Hospital, Sydney, NSW, Australia.,Airway Physiology and Imaging Group, The Woolcock Institute of Medical Research, The University of Sydney, Sydney, NSW, Australia
| | - Sandra Rutting
- Department of Respiratory Medicine, Royal North Shore Hospital, Sydney, NSW, Australia.,Airway Physiology and Imaging Group, The Woolcock Institute of Medical Research, The University of Sydney, Sydney, NSW, Australia.,NHMRC Centre of Excellence in Severe Asthma, Newcastle, NSW, Australia
| | - Catherine E Farrow
- Airway Physiology and Imaging Group, The Woolcock Institute of Medical Research, The University of Sydney, Sydney, NSW, Australia.,Department of Respiratory and Sleep Medicine, Westmead Hospital, Sydney, NSW, Australia.,Faculty of Medicine and Health Sciences, The University of Sydney, Sydney, NSW, Australia
| | - Katrina O Tonga
- Department of Respiratory Medicine, Royal North Shore Hospital, Sydney, NSW, Australia.,Airway Physiology and Imaging Group, The Woolcock Institute of Medical Research, The University of Sydney, Sydney, NSW, Australia.,Faculty of Medicine and Health Sciences, The University of Sydney, Sydney, NSW, Australia.,Department of Thoracic and Transplant Medicine, St Vincent's Hospital, Sydney, NSW, Australia.,St Vincent's Clinical School, University of New South Wales, Sydney, NSW, Australia
| | - Joanna Watts
- Airway Physiology and Imaging Group, The Woolcock Institute of Medical Research, The University of Sydney, Sydney, NSW, Australia
| | - Jessica R Dame-Carrol
- Airway Physiology and Imaging Group, The Woolcock Institute of Medical Research, The University of Sydney, Sydney, NSW, Australia
| | - Amy Bertolin
- Airway Physiology and Imaging Group, The Woolcock Institute of Medical Research, The University of Sydney, Sydney, NSW, Australia
| | - Gregory G King
- Department of Respiratory Medicine, Royal North Shore Hospital, Sydney, NSW, Australia.,Airway Physiology and Imaging Group, The Woolcock Institute of Medical Research, The University of Sydney, Sydney, NSW, Australia.,NHMRC Centre of Excellence in Severe Asthma, Newcastle, NSW, Australia
| | - Cindy Thamrin
- Airway Physiology and Imaging Group, The Woolcock Institute of Medical Research, The University of Sydney, Sydney, NSW, Australia
| | - David G Chapman
- Airway Physiology and Imaging Group, The Woolcock Institute of Medical Research, The University of Sydney, Sydney, NSW, Australia.,School of Life Sciences, Faculty of Science, University of Technology Sydney, Sydney, NSW, Australia
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9
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Petousi N, Talbot NP, Pavord I, Robbins PA. Measuring lung function in airways diseases: current and emerging techniques. Thorax 2019; 74:797-805. [PMID: 31036773 DOI: 10.1136/thoraxjnl-2018-212441] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 02/14/2019] [Accepted: 02/25/2019] [Indexed: 12/12/2022]
Abstract
Chronic airways diseases, including asthma, COPD and cystic fibrosis, cause significant morbidity and mortality and are associated with high healthcare expenditure, in the UK and worldwide. For patients with these conditions, improvements in clinical outcomes are likely to depend on the application of precision medicine, that is, the matching of the right treatment to the right patient at the right time. In this context, the identification and targeting of 'treatable traits' is an important priority in airways disease, both to ensure the appropriate use of existing treatments and to facilitate the development of new disease-modifying therapy. This requires not only better understanding of airway pathophysiology but also an enhanced ability to make physiological measurements of disease activity and lung function and, if we are to impact on the natural history of these diseases, reliable measures in early disease. In this article, we outline some of the key challenges faced by the respiratory community in the management of airways diseases, including early diagnosis, disease stratification and monitoring of therapeutic response. In this context, we review the advantages and limitations of routine physiological measurements of respiratory function including spirometry, body plethysmography and diffusing capacity and discuss less widely used methods such as forced oscillometry, inert gas washout and the multiple inert gas elimination technique. Finally, we highlight emerging technologies including imaging methods such as quantitative CT and hyperpolarised gas MRI as well as quantification of lung inhomogeneity using precise in-airway gas analysis and mathematical modelling. These emerging techniques have the potential to enhance existing measures in the assessment of airways diseases, may be particularly valuable in early disease, and should facilitate the efforts to deliver precision respiratory medicine.
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Affiliation(s)
- Nayia Petousi
- Nuffield Department of Clinical Medicine Division of Experimental Medicine, University of Oxford, Oxford, UK .,Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK.,Oxford Centre for Respiratory Medicine, Oxford University Hospitals NHS Trust, Oxford, UK
| | - Nick P Talbot
- Nuffield Department of Clinical Medicine Division of Experimental Medicine, University of Oxford, Oxford, UK.,Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK.,Oxford Centre for Respiratory Medicine, Oxford University Hospitals NHS Trust, Oxford, UK
| | - Ian Pavord
- Nuffield Department of Clinical Medicine Division of Experimental Medicine, University of Oxford, Oxford, UK.,Oxford Centre for Respiratory Medicine, Oxford University Hospitals NHS Trust, Oxford, UK
| | - Peter A Robbins
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
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10
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Zimmermann SC, Tonga KO, Thamrin C. Dismantling airway disease with the use of new pulmonary function indices. Eur Respir Rev 2019; 28:28/151/180122. [PMID: 30918023 PMCID: PMC9488242 DOI: 10.1183/16000617.0122-2018] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2018] [Accepted: 02/15/2019] [Indexed: 11/27/2022] Open
Abstract
We are currently limited in our abilities to diagnose, monitor disease status and manage chronic airway disease like asthma and chronic obstructive pulmonary disease (COPD). Conventional lung function measures often poorly reflect patient symptoms or are insensitive to changes, particularly in the small airways where disease may originate or manifest. Novel pulmonary function tests are becoming available which help us better characterise and understand chronic airway disease, and their translation and adoption from the research arena would potentially enable individualised patient care. In this article, we aim to describe two emerging lung function tests yielding novel pulmonary function indices, the forced oscillation technique (FOT) and multiple breath nitrogen washout (MBNW). With a particular focus on asthma and COPD, this article demonstrates how chronic airway disease mechanisms have been dismantled with the use of the FOT and MBNW. We describe their ability to assess detailed pulmonary mechanics for diagnostic and management purposes including response to bronchodilation and other treatments, relationship with symptoms, evaluation of acute exacerbations and recovery, and telemonitoring. The current limitations of both tests, as well as open questions/directions for further research, are also discussed. Spirometry is used to diagnose and manage airway disease such as asthma and COPD, but relates poorly to symptoms, lacks sensitivity and is effort dependent. FOT and MBNW are emerging clinical lung function tests that help us dismantle disease mechanisms.http://ow.ly/nM0G30nS6Ct
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Affiliation(s)
- Sabine C Zimmermann
- Airway Physiology and Imaging Group, Woolcock Institute of Medical Research, The University of Sydney, Sydney, Australia.,Dept of Respiratory Medicine, Royal North Shore Hospital, Sydney, Australia.,Sydney Medical School Northern, The University of Sydney, Sydney, Australia.,Woolcock Emphysema Centre, Woolcock Institute of Medical Research, The University of Sydney, Sydney, Australia
| | - Katrina O Tonga
- Airway Physiology and Imaging Group, Woolcock Institute of Medical Research, The University of Sydney, Sydney, Australia.,Dept of Respiratory Medicine, Royal North Shore Hospital, Sydney, Australia.,Sydney Medical School Northern, The University of Sydney, Sydney, Australia.,Woolcock Emphysema Centre, Woolcock Institute of Medical Research, The University of Sydney, Sydney, Australia.,Dept of Thoracic and Transplant Medicine, St Vincent's Hospital, Sydney, Australia.,Faculty of Medicine, The University of New South Wales, Sydney, Australia
| | - Cindy Thamrin
- Airway Physiology and Imaging Group, Woolcock Institute of Medical Research, The University of Sydney, Sydney, Australia .,Woolcock Emphysema Centre, Woolcock Institute of Medical Research, The University of Sydney, Sydney, Australia
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11
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Poncin W, Lebecque P. [Lung clearance index in cystic fibrosis]. Rev Mal Respir 2019; 36:377-395. [PMID: 30686561 DOI: 10.1016/j.rmr.2018.03.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2017] [Accepted: 03/28/2018] [Indexed: 01/03/2023]
Abstract
INTRODUCTION Small airways' involvement in cystic fibrosis (CF) pulmonary disease is a very early event, which can progress sub-clinically and insidiously since it is poorly reflected by commonly used lung function tests. STATE OF ART Sensitive and discriminative tools are available to investigate small airways function. However their complexity and/or invasiveness has confined their use to research purposes and to some specialized research teams. By contrast, the multiple breath washout (MBW) test is more affordable and non-invasive. Lung clearance index (LCI), which is the most used derived parameter, is reproducible and much more sensitive than spirometry in detecting small airways disease. However, MBW is operator dependent. PERSPECTIVES The recent commercialization of devices assessing LCI launches MBW as a potential tool in routine clinical care, although its use currently remains mostly dedicated to research purposes. However, important differences in LCI between various equipment settings raise a number of theoretical questions. Specific algorithms should be refined and more transparent. Standardization of MBW is still an ongoing process. Whether other MBW derived indices can prove superior over LCI deserves further study. CONCLUSIONS In CF, LCI is now a well-established outcome in research settings to detect early lung function abnormalities and new treatment effects, especially in patients with mild lung disease. In these patients, LCI seems an attractive tool for clinicians too. Yet, further investigation is needed to define clinically significant changes in LCI and to which extent this index can be useful in guiding clinical decisions remains to be studied.
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Affiliation(s)
- W Poncin
- Pôle de pneumologie, ORL et dermatologie, université Catholique de Louvain, institut de recherche expérimentale et clinique (IREC), 1200 Bruxelles, Belgique; Service de médecine physique et réadaptation, cliniques universitaires Saint-Luc, 1200 Bruxelles, Belgique.
| | - P Lebecque
- Pneumologie pédiatrique & centre de référence pour la mucoviscidose, cliniques universitaires Saint-Luc, 1200 Bruxelles, Belgique
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Guglani L, Kasi A, Starks M, Pedersen KE, Nielsen JG, Weiner DJ. Difference between SF6 and N2 multiple breath washout kinetics is due to N2 back diffusion and error in N2 offset. J Appl Physiol (1985) 2018; 125:1257-1265. [DOI: 10.1152/japplphysiol.00326.2018] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Measurement of lung clearance index (LCI) by multiple breath washout (MBW) is a sensitive method for monitoring lung disease in patients with cystic fibrosis (CF). To compare nitrogen MBW (N2-MBW) and sulfur hexafluoride MBW (SF6-MBW), we connected these two gas analysis systems in series to obtain truly simultaneous measurements, with no differences other than the gas used. Nonsmoking healthy controls (HC) and subjects with CF were recruited at two institutions. The Exhalyzer-D (for N2-MBW measurement) was connected in series with the Innocor (for SF6-MBW measurement). Subjects washed in SF6 from a Douglas bag with tidal breathing and washed out SF6 and nitrogen with 100% oxygen provided as bias flow. Washout of both gases was continued past the LCI point (1/40th of equilibration concentration) in triplicate. N2-MBW resulted in higher cumulative exhaled volume, functional residual capacity (FRC), and LCI when compared with SF6-derived parameters in HC subjects ( P < 0.0001 for all comparisons). All N2-MBW parameters were also significantly higher than SF6-MBW parameters in subjects with CF ( P < 0.01 for all comparisons). After recalculation with a common FRC, N2-MBW LCI was higher than SF6-MBW LCI in subjects with CF (19.73 vs. 11.39; P < 0.0001) and in HC (8.12 vs. 6.78; P < 0.0001). Adjusting for N2 back diffusion and an offset error in the nitrogen measurement resulted in near complete agreement between the two methodologies. We found significant differences in LCI and FRC measurements using two different gases for MBW. This may have significant implications for the future use and interpretation of LCI data in clinical trials and routine clinical care. NEW & NOTEWORTHY This study provides important insights into the differences between the two techniques used for measuring lung clearance index (LCI): N2 and SF6 multiple breath washout. Differences between measurements made by these two methods in subjects with cystic fibrosis and healthy controls could be explained by nitrogen back diffusion and N2 offset error. This is important for use and interpretation of LCI data as an outcome measure for clinical trials and in routine clinical care.
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Affiliation(s)
- Lokesh Guglani
- Center for Cystic Fibrosis and Airways Disease Research, Emory University, Atlanta, Georgia
| | - Ajay Kasi
- Center for Cystic Fibrosis and Airways Disease Research, Emory University, Atlanta, Georgia
| | - Miah Starks
- Center for Cystic Fibrosis and Airways Disease Research, Emory University, Atlanta, Georgia
| | | | | | - Daniel J. Weiner
- Division of Pulmonary Medicine, Allergy & Immunology, Department of Pediatrics, University of Pittsburgh, Pittsburgh, Pennsylvania
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