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Riley M, Arigliani M, Davies G, Aurora P. Looking beyond LCI: Multiple breath washout phase III slope derived indices and their application in chronic respiratory disease in children. Pediatr Pulmonol 2024. [PMID: 39031489 DOI: 10.1002/ppul.27177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Revised: 06/17/2024] [Accepted: 07/06/2024] [Indexed: 07/22/2024]
Abstract
The multiple breath washout (MBW) test is widely reported in the context of Lung Clearance Index (LCI). LCI reflects global ventilation inhomogeneity but does not provide information regarding the localization of disease along the respiratory tree. The MBW-derived normalized phase III slope (SnIII) indices (Scond and Sacin), instead, can distinguish between convective-dependent and diffusion-convection-dependent ventilation inhomogeneity considered to occur within the conductive and acinar airways, respectively. In cystic fibrosis, Scond tends to become abnormal even earlier than LCI and spirometry. The value of Scond and Sacin in clinical practice has been recently explored in other respiratory conditions, including asthma, primary ciliary dyskinesia, bronchopulmonary dysplasia, bronchiolitis obliterans, and sickle cell disease. In this narrative review we offer an overview on the theoretical background, potentialities, and limitations of SnIII analysis in children, including challenges and feasibility aspects. Moreover, we summarize current evidence on the use of SnIII-derived indices across different groups of pediatric chronic respiratory disease and we highlight the gaps in knowledge that need to be addressed in future studies.
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Affiliation(s)
- Mollie Riley
- Infection, Immunity and Inflammation Research and Teaching Department, UCL Great Ormond Street Institute of Child Health (UCL GOS ICH), London, UK
- Heart and Lung Directorate, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Michele Arigliani
- Infection, Immunity and Inflammation Research and Teaching Department, UCL Great Ormond Street Institute of Child Health (UCL GOS ICH), London, UK
- Department of Respiratory Paediatrics, Royal Brompton Hospital, London, UK
| | - Gwyneth Davies
- Heart and Lung Directorate, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
- Population, Policy and Practice Research and Teaching Department, UCL GOS ICH, London, UK
| | - Paul Aurora
- Infection, Immunity and Inflammation Research and Teaching Department, UCL Great Ormond Street Institute of Child Health (UCL GOS ICH), London, UK
- Heart and Lung Directorate, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
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Bayfield KJ, Weinheimer O, Middleton A, Boyton C, Fitzpatrick R, Kennedy B, Blaxland A, Jayasuriya G, Caplain N, Wielpütz MO, Yu L, Galban CJ, Robinson TE, Bartholmai B, Gustafsson P, Fitzgerald D, Selvadurai H, Robinson PD. Comparative sensitivity of early cystic fibrosis lung disease detection tools in school aged children. J Cyst Fibros 2024:S1569-1993(24)00075-4. [PMID: 38969602 DOI: 10.1016/j.jcf.2024.05.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2023] [Revised: 05/05/2024] [Accepted: 05/20/2024] [Indexed: 07/07/2024]
Abstract
BACKGROUND Effective detection of early lung disease in cystic fibrosis (CF) is critical to understanding early pathogenesis and evaluating early intervention strategies. We aimed to compare ability of several proposed sensitive functional tools to detect early CF lung disease as defined by CT structural disease in school aged children. METHODS 50 CF subjects (mean±SD 11.2 ± 3.5y, range 5-18y) with early lung disease (FEV1≥70 % predicted: 95.7 ± 11.8 %) performed spirometry, Multiple breath washout (MBW, including trapped gas assessment), oscillometry, cardiopulmonary exercise testing (CPET) and simultaneous spirometer-directed low-dose CT imaging. CT data were analysed using well-evaluated fully quantitative software for bronchiectasis and air trapping (AT). RESULTS CT bronchiectasis and AT occurred in 24 % and 58 % of patients, respectively. Of the functional tools, MBW detected the highest rates of abnormality: Scond 82 %, MBWTG RV 78 %, LCI 74 %, MBWTG IC 68 % and Sacin 51 %. CPET VO2peak detected slightly higher rates of abnormality (9 %) than spirometry-based FEV1 (2 %). For oscillometry AX (14 %) performed better than Rrs (2 %) whereas Xrs and R5-19 failed to detect any abnormality. LCI and Scond correlated with bronchiectasis (r = 0.55-0.64, p < 0.001) and AT (r = 0.73-0.74, p < 0.001). MBW-assessed trapped gas was detectable in 92 % of subjects and concordant with CT-assessed AT in 74 %. CONCLUSIONS Significant structural and functional deficits occur in early CF lung disease, as detected by CT and MBW. For MBW, additional utility, beyond that offered by LCI, was suggested for Scond and MBW-assessed gas trapping. Our study reinforces the complementary nature of these tools and the limited utility of conventional oscillometry and CPET in this setting.
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Affiliation(s)
- Katie J Bayfield
- The Children's Hospital at Westmead, Westmead, New South Wales, Australia
| | - Oliver Weinheimer
- Department of Diagnostic and Interventional Radiology, University Hospital of Heidelberg, Heidelberg, Germany; Translational Lung Research Center Heidelberg, German Center for Lung Research DZL, Heidelberg, Germany
| | - Anna Middleton
- The Children's Hospital at Westmead, Westmead, New South Wales, Australia
| | - Christie Boyton
- The Children's Hospital at Westmead, Westmead, New South Wales, Australia
| | - Rachel Fitzpatrick
- The Children's Hospital at Westmead, Westmead, New South Wales, Australia
| | - Brendan Kennedy
- The Children's Hospital at Westmead, Westmead, New South Wales, Australia
| | - Anneliese Blaxland
- The Children's Hospital at Westmead, Westmead, New South Wales, Australia
| | - Geshani Jayasuriya
- The Children's Hospital at Westmead, Westmead, New South Wales, Australia; Woolcock Institute of Medical Research, Sydney, New South Wales, Australia
| | - Neil Caplain
- The Children's Hospital at Westmead, Westmead, New South Wales, Australia
| | - Mark O Wielpütz
- Department of Diagnostic and Interventional Radiology, University Hospital of Heidelberg, Heidelberg, Germany; Translational Lung Research Center Heidelberg, German Center for Lung Research DZL, Heidelberg, Germany
| | - Lifeng Yu
- Division of Radiology, Mayo Clinic Rochester, Rochester, MN, USA
| | - Craig J Galban
- Department of Radiology, Michigan Medicine, Ann Arbor, MI, USA
| | - Terry E Robinson
- Department of Pediatrics, Center of Excellence in Pulmonary Biology, Stanford University School of Medicine, Stanford, CA, USA
| | - Brian Bartholmai
- Division of Radiology, Mayo Clinic Rochester, Rochester, MN, USA
| | - Per Gustafsson
- Department of Paediatrics, Central Hospital, Skövde, Sweden
| | - Dominic Fitzgerald
- The Children's Hospital at Westmead, Westmead, New South Wales, Australia; The University of Sydney, Sydney, New South Wales, Australia
| | - Hiran Selvadurai
- The Children's Hospital at Westmead, Westmead, New South Wales, Australia; The University of Sydney, Sydney, New South Wales, Australia
| | - Paul D Robinson
- The Children's Hospital at Westmead, Westmead, New South Wales, Australia; Woolcock Institute of Medical Research, Sydney, New South Wales, Australia; The University of Sydney, Sydney, New South Wales, Australia; Children's Health and Environment Program, Child Health Research Centre, University of Queensland, South Brisbane, Australia.
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Abstract
Rationale: Lung clearance index (LCI) has good intravisit repeatability with better sensitivity in detecting lung disease on computed tomography scan compared with forced expiratory volume in 1 second (FEV1) in adults with bronchiectasis. Alternative multiple-breath washout parameters have not been systematically studied in bronchiectasis. Objectives: To determine the validity, repeatability, sensitivity, specificity, and feasibility of standard LCI (LCI2.5), shortened LCI (LCI5.0), ventilation heterogeneity arising within proximal conducting airways (ScondVT), and ventilation heterogeneity arising within the acinar airways (SacinVT) in a cross-sectional observational cohort of adults with bronchiectasis. Methods: Cross-sectional multiple-breath nitrogen washout data (Exhalyzer D; Eco Medics AG) from 132 patients with bronchiectasis across five United Kingdom centers (BronchUK Clinimetrics study) and 88 healthy control subjects were analyzed. Results: Within-test repeatability (mean coefficient of variation) was <5% for both LCI2.5 and LCI5.0 in patients with bronchiectasis, and there was no difference in mean coefficient of variation for LCI2.5 and LCI5.0 in patients with bronchiectasis compared with healthy volunteers. Moderate-strength correlations were seen between FEV1 and LCI2.5 (r = -0.54), LCI5.0 (r = -0.53), ScondVT (r = -0.35), and SacinVT (r = -0.38) z-scores. The proportion of subjects with abnormal multiple-breath washout (z-score > 2) but in normal FEV1 (z-score < -2) was 42% (LCI2.5) and 36% (LCI5.0). Overall results from the receiver operating characteristic curve analysis indicated that LCI2.5 had the greatest combined sensitivity and specificity to discriminate between bronchiectasis and control subjects, followed by LCI5.0, FEV1, and ScondVT z-scores. There was a 57% time saving with LCI5.0. Conclusions: LCI2.5 and LCI5.0 had good within-test repeatability and superior sensitivity compared with spirometry measures in differentiating between health and bronchiectasis disease. LCI5.0 is quicker and more feasible than LCI2.5. Clinical trial registered with www.clinicaltrials.gov (NCT02468271).
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Whitfield CA, Horsley A, Jensen OE, Horn FC, Collier GJ, Smith LJ, Wild JM. Model-based Bayesian inference of the ventilation distribution in patients with cystic fibrosis from multiple breath washout, with comparison to ventilation MRI. Respir Physiol Neurobiol 2022; 302:103919. [PMID: 35562095 DOI: 10.1016/j.resp.2022.103919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 04/06/2022] [Accepted: 05/05/2022] [Indexed: 10/18/2022]
Abstract
BACKGROUND Indices of ventilation heterogeneity (VH) from multiple breath washout (MBW) have been shown to correlate well with VH indices derived from hyperpolarised gas ventilation MRI. Here we report the prediction of ventilation distributions from MBW data using a mathematical model, and the comparison of these predictions with imaging data. METHODS We developed computer simulations of the ventilation distribution in the lungs to model MBW measurement with 3 parameters: σV, determining the extent of VH; V0, the lung volume; and VD, the dead-space volume. These were inferred for each individual from supine MBW data recorded from 25 patients with cystic fibrosis (CF) using approximate Bayesian computation. The fitted models were used to predict the distribution of gas imaged by 3He ventilation MRI measurements collected from the same visit. RESULTS The MRI indices measured (I1/3, the fraction of pixels below one-third of the mean intensity and ICV, the coefficient of variation of pixel intensity) correlated strongly with those predicted by the MBW model fits (r=0.93,0.88 respectively). There was also good agreement between predicted and measured MRI indices (mean bias ± limits of agreement: I1/3:-0.003±0.118 and ICV:-0.004±0.298). Fitted model parameters were robust to truncation of MBW data. CONCLUSION We have shown that the ventilation distribution in the lung can be inferred from an MBW signal, and verified this using ventilation MRI. The Bayesian method employed extracts this information with fewer breath cycles than required for LCI, reducing acquisition time required, and gives uncertainty bounds, which are important for clinical decision making.
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Affiliation(s)
- Carl A Whitfield
- Division of Infection, Immunity and Respiratory Medicine, University of Manchester, Manchester, UK; Department of Mathematics, University of Manchester, Manchester, UK.
| | - Alexander Horsley
- Division of Infection, Immunity and Respiratory Medicine, University of Manchester, Manchester, UK
| | - Oliver E Jensen
- Department of Mathematics, University of Manchester, Manchester, UK
| | - Felix C Horn
- POLARIS, Imaging Sciences, Department of Infection, Immunity & Cardiovascular Disease, University of Sheffield, UK
| | - Guilhem J Collier
- POLARIS, Imaging Sciences, Department of Infection, Immunity & Cardiovascular Disease, University of Sheffield, UK
| | - Laurie J Smith
- POLARIS, Imaging Sciences, Department of Infection, Immunity & Cardiovascular Disease, University of Sheffield, UK
| | - Jim M Wild
- POLARIS, Imaging Sciences, Department of Infection, Immunity & Cardiovascular Disease, University of Sheffield, UK
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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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Verbanck S, Schuermans D, Paiva M, Robinson PD, Vanderhelst E. Mitigating increased variability of multiple breath washout indices due to tidal breathing. Eur Respir J 2020; 57:13993003.02765-2020. [PMID: 32994196 DOI: 10.1183/13993003.02765-2020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 09/14/2020] [Indexed: 11/05/2022]
Affiliation(s)
- Sylvia Verbanck
- Respiratory Division, University Hospital UZ Brussel, Vrije Universiteit Brussel, Brussels, Belgium
| | - Daniel Schuermans
- Respiratory Division, University Hospital UZ Brussel, Vrije Universiteit Brussel, Brussels, Belgium
| | - Manuel Paiva
- Respiratory Division, University Hospital Erasme, Université Libre de Bruxelles, Brussels, Belgium
| | - Paul D Robinson
- Dept of Respiratory Medicine, The Children's Hospital at Westmead, Sydney, Australia
| | - Eef Vanderhelst
- Respiratory Division, University Hospital UZ Brussel, Vrije Universiteit Brussel, Brussels, Belgium
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Verger N, Arigliani M, Raywood E, Duncan J, Negreskul Y, Bush A, Aurora P. Limitations of regional ventilation inhomogeneity indices in children with cystic fibrosis. Pediatr Pulmonol 2020; 55:2315-2322. [PMID: 32441886 DOI: 10.1002/ppul.24863] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 05/18/2020] [Accepted: 05/19/2020] [Indexed: 01/25/2023]
Abstract
BACKGROUND Scond is a multiple breath washout (MBW) index that measures convection-dependent ventilation inhomogeneity (CDI) arising within conductive airways, but the calculation method is unreliable in subjects with advanced cystic fibrosis (CF) lung disease. A new CDI index, Scond *, has been proposed for use in adults with CF and moderate to severe ventilation inhomogeneity. We aimed to evaluate the most appropriate CDI index in children and adolescents with CF and various degrees of inhomogeneity, and from that the most appropriate diffusion-convection-interaction index (Sacin or Sacin *). METHODS Scond , Sacin and the alternative indices, Scond *, and Sacin * were retrospectively calculated in subjects with CF aged 3 to 18 years and age-matched controls, who underwent sulfur hexafluoride MBW between 2003 and 2015. The upper limit of normal was based on 95th percentile of the control population. RESULTS One hundred and twenty-seven subjects with CF (44% male; mean age ± SD: 7.5 years ± 4.9) and 94 controls (53% male; 7.9 years ± 5.1) were included in the final analysis. All measures of ventilation inhomogeneity were significantly higher in children with CF. As predicted, Scond reached a maximum value at lung clearance index (LCI) values of approximately 9. In subjects with LCI ≥ 9 Scond * showed good correlation with LCI, whilst Scond had no relationship with LCI (Spearman rank correlation Scond */LCI, 0.49; P < .01; Scond /LCI, -0.068; P = .46). In subjects with mild disease (LCI < 9) Scond was more frequently abnormal than Scond * (37% vs 16%; P = .01). CONCLUSIONS Scond and Sacin are sensitive indices of early regional inhomogeneity, but are of no value when LCI ≥ 9. In these subjects, Scond * & Sacin * are potential alternatives.
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Affiliation(s)
- Nicolas Verger
- Respiratory, Critical Care and Anaesthesia Section, Infection Inflammation and Immunity Programme, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Michele Arigliani
- Division of Pediatrics, Department of Medicine, University Hospital of Udine, Udine, Italy
| | - Emma Raywood
- Respiratory, Critical Care and Anaesthesia Section, Infection Inflammation and Immunity Programme, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Julie Duncan
- Respiratory, Critical Care and Anaesthesia Section, Infection Inflammation and Immunity Programme, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Yulia Negreskul
- Respiratory, Critical Care and Anaesthesia Section, Infection Inflammation and Immunity Programme, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Andrew Bush
- Respiratory Division, The National Heart and Lung Institute, Imperial College, London, UK
| | - Paul Aurora
- Respiratory, Critical Care and Anaesthesia Section, Infection Inflammation and Immunity Programme, UCL Great Ormond Street Institute of Child Health, London, UK.,Department of Respiratory Medicine, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
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Arigliani M, Valentini E, Stocco C, De Pieri C, Castriotta L, Barbato V, Cuberli E, Orsaria M, Cattarossi L, Cogo P. Regional ventilation inhomogeneity in survivors of extremely preterm birth. Pediatr Pulmonol 2020; 55:1366-1374. [PMID: 32212328 DOI: 10.1002/ppul.24742] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 03/13/2020] [Indexed: 11/08/2022]
Abstract
INTRODUCTION Survivors of extreme prematurity may have disrupted lung development. We hypothesized that the multiple breath washout (MBW) index Scond, which is intended to reflect ventilation inhomogeneity from the conducting airways, could be a sensitive marker of respiratory impairment in this group. METHODS Spirometry, TLco, and MBW were cross-sectionally evaluated at 8 to 14 years of age in children born at <28 weeks between 2004 and 2010 in Udine, Italy. Age-matched controls born at term were also included. Bronchopulmonary dysplasia (BPD) was defined as oxygen-dependence at 36 weeks postmenstrual age. The limits of normal were the 5th percentile of the reference population (Global Lung Initiative) for spirometry and TLco and the 95th percentile of controls for Lung Clearance Index, Scond, and Sacin from MBW. RESULTS Results were obtained in 47 extremely preterm children (53% boys, mean ± standard deviation age 11.3 ± 2.0 years, 40% with BPD) and 60 controls (50% boys, 11.6 ± 1.9 years). There were significant differences between preterm children and controls in all lung function outcomes, except for Sacin. Among children born <28 weeks, Scond tended to be frequently abnormal than FEV1 z-score (29% vs 14%, P = .06). At multivariable linear regression, in the preterm group, current asthma was significantly associated with a higher Scond (B = 0.019, 95% confidence interval, 0.000-0.038), whereas BPD was not. CONCLUSION Almost a third of extremely preterm children at school age showed Scond alterations that affected also children without BPD. Longitudinal studies should clarify the prognostic meaning of Scond abnormalities in this group.
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Affiliation(s)
- Michele Arigliani
- Department of Medicine, Division of Pediatrics, University Hospital of Udine, Udine, Italy
| | - Elena Valentini
- Department of Medicine, Division of Pediatrics, University Hospital of Udine, Udine, Italy
| | - Chiara Stocco
- Department of Medicine, Division of Pediatrics, University Hospital of Udine, Udine, Italy
| | - Carlo De Pieri
- Department of Medicine, Division of Pediatrics, University Hospital of Udine, Udine, Italy
| | - Luigi Castriotta
- Institute of Hygiene and Clinical Epidemiology, University Hospital of Udine, Udine, Italy
| | - Vincenzo Barbato
- Department of Medicine, Division of Pediatrics, University Hospital of Udine, Udine, Italy
| | - Elisa Cuberli
- Department of Medicine, Division of Pediatrics, University Hospital of Udine, Udine, Italy
| | - Maria Orsaria
- Department of Medicine, Surgical Pathology Section, University Hospital of Udine, Udine, Italy
| | - Luigi Cattarossi
- Department of Medicine, Neonatal Intensive Care Unit, University Hospital of Udine, Udine, Italy
| | - Paola Cogo
- Department of Medicine, Division of Pediatrics, University Hospital of Udine, Udine, Italy
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Yammine S, Ramsey KA, Skoric B, King L, Latzin P, Rosenow T, Hall GL, Ranganathan SC. Single-breath washout and association with structural lung disease in children with cystic fibrosis. Pediatr Pulmonol 2019; 54:587-594. [PMID: 30758143 DOI: 10.1002/ppul.24271] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 01/16/2019] [Indexed: 11/09/2022]
Abstract
BACKGROUND In children with cystic fibrosis (CF) lung clearance index (LCI) from multiple-breath washout (MBW) correlates with structural lung disease. As a shorter test, single-breath washout (SBW) represents an attractive alternative to assess the ventilation distribution, however, data for the correlation with lung imaging are lacking. METHODS We assessed correlations between phase III slope (SIII) of double-tracer gas SBW, nitrogen MBW indices (LCI and moment ratios for overall ventilation distribution, Scond, and Sacin for conductive and mainly acinar ventilation, respectively) and structural lung disease assessed by chest computed tomography (CT) in children with CF. RESULTS In a prospective cross-sectional study data from MBW, SBW, and chest CT were obtained in 32 children with CF with a median (range) age of 8.2 (5.2-16.3) years. Bronchiectasis was present in 24 (75%) children and air trapping was present in 29 (91%). Median (IQR) SIII of SBW was -138.4 (150.6) mg/mol. We found no association between SIII with either the MBW outcomes or CT scores (n = 23, association with bronchiectasis extent r = 0.10, P = 0.64). LCI and Scond were associated with bronchiectasis extent (n = 23, r = 0.57, P = 0.004; r = 0.60, P = 0.003, respectively). CONCLUSIONS Acinar ventilation inhomogeneity measured by SBW was not associated with structural lung disease on CT. Double-tracer SBW added no benefit to indices measured by MBW.
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Affiliation(s)
| | - Kathryn A Ramsey
- University Children's Hospital Bern, Bern, Switzerland.,Telethon Kids Institute, Subiaco, Australia
| | - Billy Skoric
- Respiratory Medicine, Royal Children's Hospital, Melbourne, Victoria, Australia.,Murdoch Children's Research Institute, Melbourne, Victoria, Australia
| | - Louise King
- Respiratory Medicine, Royal Children's Hospital, Melbourne, Victoria, Australia.,Murdoch Children's Research Institute, Melbourne, Victoria, Australia
| | | | - Tim Rosenow
- Telethon Kids Institute, Subiaco, Australia.,Centre for Child Health Research, University of Western Australia, Subiaco, Australia
| | - Graham L Hall
- Telethon Kids Institute, Subiaco, Australia.,Centre for Child Health Research, University of Western Australia, Subiaco, Australia.,School of Physiotherapy and Exercise Science, Curtin University, Western Australia, Australia
| | - Sarath C Ranganathan
- Respiratory Medicine, Royal Children's Hospital, Melbourne, Victoria, Australia.,Murdoch Children's Research Institute, Melbourne, Victoria, Australia.,Department of Paediatrics, University of Melbourne, Australia
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10
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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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11
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Whitfield CA, Horsley A, Jensen OE. Modelling structural determinants of ventilation heterogeneity: A perturbative approach. PLoS One 2018; 13:e0208049. [PMID: 30496317 PMCID: PMC6264152 DOI: 10.1371/journal.pone.0208049] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Accepted: 11/09/2018] [Indexed: 01/19/2023] Open
Abstract
We have developed a computational model of gas mixing and ventilation in the human lung represented as a bifurcating network. We have simulated multiple-breath washout (MBW), a clinical test for measuring ventilation heterogeneity (VH) in patients with obstructive lung conditions. By applying airway constrictions inter-regionally, we have predicted the response of MBW indices to obstructions and found that they detect a narrow range of severe constrictions that reduce airway radius to 10%–30% of healthy values. These results help to explain the success of the MBW test to distinguish obstructive lung conditions from healthy controls. Further, we have used a perturbative approach to account for intra-regional airway heterogeneity that avoids modelling each airway individually. We have found, for random airway heterogeneity, that the variance in MBW indices is greater when indices are already elevated due to constrictions. By quantifying this effect, we have shown that variability in lung structure and mechanical properties alone can lead to clinically significant variability in MBW indices (specifically the Lung Clearance Index—LCI, and the gradient of phase-III slopes—Scond), but only in cases simulating obstructive lung conditions. This method is a computationally efficient way to probe the lung’s sensitivity to structural changes, and to quantify uncertainty in predictions due to random variations in lung mechanical and structural properties.
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Affiliation(s)
- Carl A. Whitfield
- Division of Infection, Immunity and Respiratory Medicine, University of Manchester, Southmoor Road, Manchester, United Kingdom, M23 9LT
- School of Mathematics, University of Manchester, Oxford Road, Manchester, United Kingdom, M13 9PL
- * E-mail:
| | - Alex Horsley
- Division of Infection, Immunity and Respiratory Medicine, University of Manchester, Southmoor Road, Manchester, United Kingdom, M23 9LT
| | - Oliver E. Jensen
- School of Mathematics, University of Manchester, Oxford Road, Manchester, United Kingdom, M13 9PL
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12
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Nyilas S, Bigler A, Yammine S, Kieninger E, Rochat I, Ramsey K, Casaulta C, Moeller A, Latzin P, Singer F. Alternate gas washout indices: Assessment of ventilation inhomogeneity in mild to moderate pediatric cystic fibrosis lung disease. Pediatr Pulmonol 2018; 53:1485-1491. [PMID: 30168294 DOI: 10.1002/ppul.24149] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Revised: 07/06/2018] [Accepted: 07/29/2018] [Indexed: 12/20/2022]
Abstract
INTRODUCTION Normalized phase III slope (SnIII ) indices from multiple breath washout (MBW) estimate ventilation inhomogeneity. Alternate (*) protocols for SnIII indices exist, however the utility of these outcomes in children with mild-to-moderate cystic fibrosis (CF) is unknown. METHODS We measured nitrogen MBW and spirometry in 135 children (43 controls) aged 4-18 years. We assessed validity, practicability, and reliability of SnIII protocols. Outcomes included the ability to detect abnormal lung function, test agreement, measurement duration, intra-test repeatability, and quality. RESULTS Lung clearance index (LCI) was abnormal in 80 (87%), Scond in 55 (60%), Scond* in 17 (19%), Sacin in 10 (11%), Sacin* in 11 (12%), and FEV1 in 28 (30%). Alternate protocols reduced measurement duration. Agreement of indices to detect abnormal lung function was poor. The quality of analysis and repeatability deteriorated with the alternate technique compared to standard. CONCLUSION In children with mild-to-moderate CF lung disease, alternate protocols seem practical but clinimetric properties of standard SnIII protocols are preferable.
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Affiliation(s)
- Sylvia Nyilas
- Division of Paediatric Pulmonology, University Children's Hospital Zurich, Zurich, Switzerland.,Division of Respiratory Medicine, Department of Pediatrics, University Children's Hospital of Bern, University of Bern, Bern, Switzerland
| | - Anja Bigler
- Division of Respiratory Medicine, Department of Pediatrics, University Children's Hospital of Bern, University of Bern, Bern, Switzerland
| | - Sophie Yammine
- Division of Respiratory Medicine, Department of Pediatrics, University Children's Hospital of Bern, University of Bern, Bern, Switzerland
| | - Elisabeth Kieninger
- Division of Respiratory Medicine, Department of Pediatrics, University Children's Hospital of Bern, University of Bern, Bern, Switzerland
| | - Isabelle Rochat
- Department of Paediatric Pulmonology, University Children's Hospital of Lausanne, Lausanne, Switzerland
| | - Kathryn Ramsey
- Division of Respiratory Medicine, Department of Pediatrics, University Children's Hospital of Bern, University of Bern, Bern, Switzerland
| | - Carmen Casaulta
- Division of Respiratory Medicine, Department of Pediatrics, University Children's Hospital of Bern, University of Bern, Bern, Switzerland
| | - Alexander Moeller
- Division of Paediatric Pulmonology, University Children's Hospital Zurich, Zurich, Switzerland
| | - Philipp Latzin
- Division of Respiratory Medicine, Department of Pediatrics, University Children's Hospital of Bern, University of Bern, Bern, Switzerland
| | - Florian Singer
- Division of Paediatric Pulmonology, University Children's Hospital Zurich, Zurich, Switzerland.,Division of Respiratory Medicine, Department of Pediatrics, University Children's Hospital of Bern, University of Bern, Bern, Switzerland
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13
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Smith LJ, Collier GJ, Marshall H, Hughes PJ, Biancardi AM, Wildman M, Aldag I, West N, Horsley A, Wild JM. Patterns of regional lung physiology in cystic fibrosis using ventilation magnetic resonance imaging and multiple-breath washout. Eur Respir J 2018; 52:13993003.00821-2018. [DOI: 10.1183/13993003.00821-2018] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Accepted: 09/10/2018] [Indexed: 11/05/2022]
Abstract
Hyperpolarised helium-3 (3He) ventilation magnetic resonance imaging (MRI) and multiple-breath washout (MBW) are sensitive methods for detecting lung disease in cystic fibrosis (CF). We aimed to explore their relationship across a broad range of CF disease severity and patient age, as well as assess the effect of inhaled lung volume on ventilation distribution.32 children and adults with CF underwent MBW and 3He-MRI at a lung volume of end-inspiratory tidal volume (EIVT). In addition, 28 patients performed 3He-MRI at total lung capacity. 3He-MRI scans were quantitatively analysed for ventilation defect percentage (VDP), ventilation heterogeneity index (VHI) and the number and size of individual contiguous ventilation defects. From MBW, the lung clearance index, convection-dependent ventilation heterogeneity (Scond) and convection–diffusion-dependent ventilation heterogeneity (Sacin) were calculated.VDP and VHI at EIVT strongly correlated with lung clearance index (r=0.89 and r=0.88, respectively), Sacin (r=0.84 and r=0.82, respectively) and forced expiratory volume in 1 s (FEV1) (r=−0.79 and r=−0.78, respectively). Two distinct 3He-MRI patterns were highlighted: patients with abnormal FEV1 had significantly (p<0.001) larger, but fewer, contiguous defects than those with normal FEV1, who tended to have numerous small volume defects. These two MRI patterns were delineated by a VDP of ∼10%. At total lung capacity, when compared to EIVT, VDP and VHI reduced in all subjects (p<0.001), demonstrating improved ventilation distribution and regions of volume-reversible and nonreversible ventilation abnormalities.
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14
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Nyilas S, Bauman G, Sommer G, Stranzinger E, Pusterla O, Frey U, Korten I, Singer F, Casaulta C, Bieri O, Latzin P. Novel magnetic resonance technique for functional imaging of cystic fibrosis lung disease. Eur Respir J 2017; 50:50/6/1701464. [DOI: 10.1183/13993003.01464-2017] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Accepted: 08/31/2017] [Indexed: 11/05/2022]
Abstract
Lung function tests are commonly used to monitor lung disease in cystic fibrosis (CF). While practical, they cannot locate the exact origin of functional impairment. Contemporary magnetic resonance imaging (MRI) techniques provide information on the location of disease but the need for contrast agents constrains their repeated application. We examined the correlation between functional MRI, performed without administration of contrast agent, and lung clearance index (LCI) from nitrogen multiple-breath washout (N2-MBW).40 children with CF (median (range) age 12.0 (6–18) years) and 12 healthy age-matched controls underwent functional and structural MRI and lung function tests on the same day. Functional MRI provided semiquantitative measures of perfusion (RQ) and ventilation (RFV) impairment as percentages of affected lung volume. Morphological MRI was evaluated using CF-specific scores. LCI measured global ventilation inhomogeneity.MRI detected functional impairment in CF:RFV19–38% andRQ16–35%.RFVandRQcorrelated strongly with LCI (r=0.76, p<0.0001 and r=0.85, p<0.0001, respectively), as did total morphology score (r=0.81, p<0.0001). All indices differed significantly between patients with CF and healthy controls (p<0.001).Noninvasive functional MRI is a promising method to detect and visualise perfusion and ventilation impairment in CF without the need for contrast agents.
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15
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Chelabi R, Soumagne T, Guillien A, Puyraveau M, Degano B. In cystic fibrosis, lung clearance index is sensitive to detecting abnormalities appearing at exercise in children with normal spirometry. Respir Physiol Neurobiol 2017; 247:9-11. [PMID: 28882651 DOI: 10.1016/j.resp.2017.08.017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 08/21/2017] [Accepted: 08/26/2017] [Indexed: 10/18/2022]
Abstract
Symptom-limited incremental cardiopulmonary exercise test was performed in school-age children with clinically stable cystic fibrosis (CF), all with normal spirometry. Physiological parameters were compared between patients with normal lung clearance index (LCI; n=6) and patients with elevated LCI (n=6). Dyspnoea ratings during exercise were similar in both groups. Although no patient had significant dynamic hyperinflation, end-expiratory lung volumes were higher throughout exercise in patients with elevated LCI. In addition, alveolar-arterial oxygen gradient at peak exercise was higher, and SpO2 was lower in patients with elevated LCI. LCI can thus be regarded as a test performed at rest that predicts some abnormalities appearing at exercise in CF children with normal spirometry.
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Affiliation(s)
- Riyadh Chelabi
- University Hospital, Department of Paediatrics, Besançon, France
| | - Thibaud Soumagne
- University Hospital, Department of Pulmonology, Besançon, France; University Hospital, Department of Physiology, Besançon, France
| | - Alicia Guillien
- University Hospital, Department of Physiology, Besançon, France; University of Bourgogne-Franche-Comté, EA 3920, Besançon, France
| | - Marc Puyraveau
- University Hospital, Department of Statistics and Methodology, Besançon, France
| | - Bruno Degano
- University Hospital, Department of Physiology, Besançon, France; University of Bourgogne-Franche-Comté, EA 3920, Besançon, France.
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16
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Intra-session and inter-session variability of nitric oxide pulmonary diffusing capacity in adults with cystic fibrosis. Respir Physiol Neurobiol 2017; 246:33-38. [PMID: 28782664 DOI: 10.1016/j.resp.2017.08.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 07/30/2017] [Accepted: 08/01/2017] [Indexed: 11/24/2022]
Abstract
We evaluated the intra-session and inter-session variability of the diffusing capacity of nitric oxide (DLNO), carbon monoxide (DLCO), alveolar-capillary membrane diffusing capacity for carbon monoxide (DMCO) and pulmonary capillary blood volume (Vc) in patients with cystic fibrosis (CF). Patients performed single-breath diffusing capacity measurements during all of 3 consecutive study visits. Precision of gas diffusing parameters was quantified by within-subject standard deviation (SDws) and coefficient of variation (CV). Intra-session and inter-session reproducibility was determined by SDws*2.77. 15 clinically stable patients were included. The intra-session precision of gas diffusing parameters improved over the study visits. The inter-session SDws for DLNO, DLCO, DMCO, and Vc was 4.8, 1.3, 2.4, and 4.3, respectively. Reproducibility was 13.3, 3.8, 6.7 and 12.0mLmin-1mmHg-1; CV was 4.4, 4.7, 4.4 and 5.8%, respectively. The intra-session variability of DLNO, DLCO, DMCO and Vc improves with breath-hold maneuver training in test-naïve patients with CF, indicating a learning effect. Inter-session reproducibility data are lower than those previously reported in healthy subjects.
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17
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Saunders C, Bayfield K, Irving S, Short C, Bush A, Davies JC. Developments in multiple breath washout testing in children with cystic fibrosis. Curr Med Res Opin 2017; 33:613-620. [PMID: 27931123 DOI: 10.1080/03007995.2016.1268999] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
BACKGROUND Lung clearance index (LCI) is becoming recognized as an important addition in the monitoring of pediatric cystic fibrosis (CF). The non-invasive technique is easy to perform in all ages, reproducible and increasingly being used in clinical trials. There is interest in utilizing it within the clinic setting but its current use is mostly as a research tool. The procedure is highly dependent on skilled operators and a relaxed testing environment is key to obtaining good quality measurements. CONCLUSIONS Standardization of LCI is part of an ongoing collaborative, multicenter process. This review describes the background to LCI, discusses technical issues and limitations and provides examples of its utility in clinical and research contexts.
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Affiliation(s)
- Clare Saunders
- a NHLI, Imperial College London , UK
- b Royal Brompton and Harefield NHS Foundation Trust , London , UK
| | - Katie Bayfield
- a NHLI, Imperial College London , UK
- b Royal Brompton and Harefield NHS Foundation Trust , London , UK
| | - Samantha Irving
- a NHLI, Imperial College London , UK
- b Royal Brompton and Harefield NHS Foundation Trust , London , UK
| | - Christopher Short
- a NHLI, Imperial College London , UK
- b Royal Brompton and Harefield NHS Foundation Trust , London , UK
| | - Andrew Bush
- a NHLI, Imperial College London , UK
- b Royal Brompton and Harefield NHS Foundation Trust , London , UK
| | - Jane C Davies
- a NHLI, Imperial College London , UK
- b Royal Brompton and Harefield NHS Foundation Trust , London , UK
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18
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Marshall H, Horsley A, Taylor CJ, Smith L, Hughes D, Horn FC, Swift AJ, Parra-Robles J, Hughes PJ, Norquay G, Stewart NJ, Collier GJ, Teare D, Cunningham S, Aldag I, Wild JM. Detection of early subclinical lung disease in children with cystic fibrosis by lung ventilation imaging with hyperpolarised gas MRI. Thorax 2017; 72:760-762. [DOI: 10.1136/thoraxjnl-2016-208948] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2016] [Revised: 01/11/2017] [Accepted: 02/03/2017] [Indexed: 11/04/2022]
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19
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Nyilas S, Schlegtendal A, Singer F, Goutaki M, Kuehni CE, Casaulta C, Latzin P, Koerner-Rettberg C. Alternative inert gas washout outcomes in patients with primary ciliary dyskinesia. Eur Respir J 2017; 49:49/1/1600466. [DOI: 10.1183/13993003.00466-2016] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The lung clearance index (LCI) derived from a nitrogen multiple breath washout test (N2-MBW) is a promising tool to assess small airways disease in primary ciliary dyskinesia, but it is difficult to apply in routine clinical settings because of its long measuring time. In this study, we aimed to assess alternative indices derived from shorter washout protocols.49 patients with primary ciliary dyskinesia (mean age 14.7±6.6 years) and 37 controls (mean age 14.3±1.4 years) performed N2-MBW and double-tracer gas (DTG) single-breath washout tests. Global (LCI and moment ratio (M2/M0)), conductive (Scond) and acinar ventilation inhomogeneity (DTG Slope III (SIII-DTG)) were determined for each individual. The main outcomes were 1) the ability to detect abnormal lung function from washout indices (>1.64 z-scores) and 2) measurement duration.The prevalence of abnormal values for LCI2.5% was 37 out of 47 (79%), for LCI5% was 34 out of 47 (72%), for M2/M0 was 34 out of 47 (72%), for Scond was 36 out of 46 (78%) and for SIII-DTG was 12 out of 35 (34%). Mean±sd duration of measurement was 19.8±11.2 min for LCI2.5%, 10.8±4.6 min for LCI5% and 8.6±2.3 min for Scond.Compared to standard LCI2.5%, ventilation inhomogeneity was detected by LCI5%, moment ratio and Scond with comparable sensitivity while measurement duration was significantly shorter. Longitudinal studies will show which outcome is most suitable and practical in terms of sensitivity, duration and variability within the course of primary ciliary dyskinesia lung disease.
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20
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O’Neill K, Tunney MM, Johnston E, Rowan S, Downey DG, Rendall J, Reid A, Bradbury I, Elborn JS, Bradley JM. Lung Clearance Index in Adults and Children With Cystic Fibrosis. Chest 2016; 150:1323-1332. [DOI: 10.1016/j.chest.2016.06.029] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 04/20/2016] [Accepted: 06/01/2016] [Indexed: 02/08/2023] Open
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Theilmann RJ, Darquenne C, Elliott AR, Bailey BA, Conrad DJ. Characterizing Lung Disease in Cystic Fibrosis with Magnetic Resonance Imaging and Airway Physiology. PLoS One 2016; 11:e0157177. [PMID: 27337056 PMCID: PMC4919047 DOI: 10.1371/journal.pone.0157177] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 05/25/2016] [Indexed: 11/30/2022] Open
Abstract
Translational investigations in cystic fibrosis (CF) have a need for improved quantitative and longitudinal measures of disease status. To establish a non-invasive quantitative MRI technique to monitor lung health in patients with CF and correlate MR metrics with airway physiology as measured by multiple breath washout (MBW). Data were collected in 12 CF patients and 12 healthy controls. Regional (central and peripheral lung) measures of fractional lung water density (FLD: air to 100% fluid) were acquired both at FRC and TLC on a 1.5T MRI. The median FLD (mFLD) and the FRC-to-TLC mFLD ratio were calculated for each region at both lung volumes. Spirometry and MBW data were also acquired for each subject. Ventilation inhomogeneities were quantified by the lung clearance index (LCI) and by indices Scond* and Sacin* that assess inhomogeneities in the conducting (central) and acinar (peripheral) lung regions, respectively. MBW indices and mFLD at TLC (both regions) were significantly elevated in CF (p<0.01) compared to controls. The mFLD at TLC (central: R = 0.82) and the FRC-to-TLC mFLD ratio (peripheral: R = -0.77) were strongly correlated with Scond* and LCI. CF patients had high lung water content at TLC when compared to controls. This is likely due to the presence of retained airway secretions and airway wall edema (more water) and to limited expansions of air trapping areas (less air) in CF subjects. FRC-to-TLC ratios of mFLD strongly correlated with central ventilation inhomogeneities. These combined measures may provide a useful marker of both retained mucus and air trapping in CF lungs.
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Affiliation(s)
- Rebecca J. Theilmann
- Department of Radiology, University of California San Diego, San Diego, California, United States of America
- * E-mail:
| | - Chantal Darquenne
- Department of Medicine, University of California San Diego, San Diego, California, United States of America
| | - Ann R. Elliott
- Department of Medicine, University of California San Diego, San Diego, California, United States of America
| | - Barbara A. Bailey
- Department of Mathematics and Statistics, San Diego State University, San Diego, California, United States of America
| | - Douglas J. Conrad
- Department of Medicine, University of California San Diego, San Diego, California, United States of America
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22
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Multiple-Breath Washout as a Lung Function Test in Cystic Fibrosis. A Cystic Fibrosis Foundation Workshop Report. Ann Am Thorac Soc 2016; 12:932-9. [PMID: 26075554 DOI: 10.1513/annalsats.201501-021fr] [Citation(s) in RCA: 88] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The lung clearance index (LCI) is a lung function parameter derived from the multiple-breath washout (MBW) test. Although first developed 60 years ago, the technique was not widely used for many years. Recent technological advances in equipment design have produced gains in popularity for this test among cystic fibrosis (CF) researchers and clinicians, particularly for testing preschool-aged children. LCI has been shown to be feasible and sensitive to early CF lung disease in patients of all ages from infancy to adulthood. A workshop was convened in January 2014 by the North American Cystic Fibrosis Foundation to determine the readiness of the LCI for use in multicenter clinical trials as well as clinical care. The workshop concluded that the MBW text is a valuable potential outcome measure for CF clinical trials in preschool-aged patients and in older patients with FEV1 in the normal range. However, gaps in knowledge about the choice of device, gas, and standardization across systems are key issues precluding its use as a clinical trial end point in infants. Based on the current evidence, there are insufficient data to support the use of LCI or MBW parameters in the routine clinical management of patients with CF.
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23
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Yammine S, Schmidt A, Sutter O, Fouzas S, Singer F, Frey U, Latzin P. Functional evidence for continued alveolarisation in former preterms at school age? Eur Respir J 2015; 47:147-55. [PMID: 26493788 DOI: 10.1183/13993003.00478-2015] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Accepted: 08/18/2015] [Indexed: 11/05/2022]
Abstract
Prematurity is the most common disruptor of lung development. The aim of our study was to examine the function of the more vulnerable peripheral airways in former preterm children by multiple-breath washout (MBW) measurements.86 school-aged children, born between 24 and 35 weeks of gestation and 49 term-born children performed nitrogen MBW. Lung clearance index (LCI), and slope III-derived Scond and Sacin were assessed as markers for global, convection-dependent and diffusion-convection-dependent ventilation inhomogeneity, respectively.We analysed the data of 77 former preterm (mean (range) age 9.5 (7.2-12.8) years) and 46 term-born children (mean age 9.9 (6.0-15.9) years). LCI and Sacin did not differ between preterm and term-born children. Scond was significantly elevated in preterm compared to term-born participants (mean difference z-score 1.74, 95% CI 1.17-2.30; p<0.001), with 54% of former preterm children showing elevated Scond. In multivariable regression analysis Scond was significantly related only to gestational age (R(2)=0.37).Normal Sacin provides evidence for a functionally normal alveolar compartment, while elevated Scond indicates impaired function of more proximal conducting airways. Together, our findings support the concept of continued alveolarisation, albeit with "dysanaptic" lung growth in former preterm children.
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Affiliation(s)
- Sophie Yammine
- University Children's Hospital of Basel (UKBB), Basel, Switzerland Division of Respiratory Medicine, Department of Paediatrics, University Children's Hospital Bern, Bern, Switzerland
| | - Anne Schmidt
- University Children's Hospital of Basel (UKBB), Basel, Switzerland Division of Respiratory Medicine, Department of Paediatrics, University Children's Hospital Bern, Bern, Switzerland
| | - Oliver Sutter
- Division of Respiratory Medicine, Department of Paediatrics, University Children's Hospital Bern, Bern, Switzerland
| | - Sotirios Fouzas
- Paediatric Respiratory Unit, University Hospital of Patras, Patras, Greece
| | - Florian Singer
- Division of Respiratory Medicine, Department of Paediatrics, University Children's Hospital Bern, Bern, Switzerland University Children's Hospital Zurich, Zurich, Switzerland
| | - Urs Frey
- University Children's Hospital of Basel (UKBB), Basel, Switzerland
| | - Philipp Latzin
- University Children's Hospital of Basel (UKBB), Basel, Switzerland Division of Respiratory Medicine, Department of Paediatrics, University Children's Hospital Bern, Bern, Switzerland
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24
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Ventilation heterogeneity and the benefits and challenges of multiple breath washout testing in patients with cystic fibrosis. Paediatr Respir Rev 2015; 16 Suppl 1:15-8. [PMID: 26420586 DOI: 10.1016/j.prrv.2015.07.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Multiple breath inert gas washout tests offer a simple and non-invasive method of measuring the effects of peripheral airway disease on ventilation efficiency, and have been the subject of intense research and commercial interest in the last decade. Although highly sensitive, these tests are not specific to disease in the small airways and are not suited to all patients with cystic fibrosis. They are harder to perform in subjects with more severe lung disease, with longer test time and poorer reproducibility in this population. The clinical advantages are more obvious in those with milder airways disease, where they are more sensitive to early changes than spirometry. In this population they are also quicker to complete and reproducible. A particular advantage in children is a stable range of normal which does not change during adolescence. Different inert gases give different washout results, and the technology to measure MBW is itself still evolving. Newer technologies such as hyperpolarised gas MRI are now helping us to understand how disease-related changes in lung ventilation influences inert gas washout.
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25
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Bigler A, Yammine S, Singer F, Riedel T, Latzin P. Feasibility of automated slope III and Scond analysis in children. Pediatr Pulmonol 2015; 50:805-13. [PMID: 25056098 DOI: 10.1002/ppul.23080] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Revised: 05/08/2014] [Accepted: 05/28/2014] [Indexed: 11/11/2022]
Abstract
BACKGROUND Multiple breath washout (MBW) derived Scond is an established index of ventilation inhomogeneity. Time-consuming post hoc calculations of the expirogram's slope of alveolar phase III (SIII) and the lack of available software hampered widespread application of Scond. METHODS Seventy-two school-aged children (45 with cystic fibrosis; CF) performed 3 nitrogen MBW. We tested a new automated algorithm for Scond analysis (Scondauto ) which comprised breath selection for SIII detection, calculation and reporting of test quality. We compared Scondauto to (i) standard Scond analysis (Scondmanual ) with manual breath selection and to (ii) pragmatic Scond analysis including all breaths (Scondall ). Primary outcomes were success rate and agreement between different Scond protocols, and Scond fitting quality (linear regression R(2) ). RESULTS Average Scondauto (0.06 for CF and 0.01 for controls) was not different from Scondmanual (0.06 for CF and 0.01 for controls) and showed comparable fitting quality (R(2) 0.53 for CF and 0.13 for controls vs. R(2) 0.54 for CF and 0.13 for controls). Scondall was similar in CF and controls but with inferior fitting quality compared to Scondauto and Scondmanual . CONCLUSIONS Automated Scond calculation is feasible and produces robust results comparable to the standard manual way of Scond calculation. This algorithm provides a valid, fast and objective tool for regular use, even in children.
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Affiliation(s)
- Anja Bigler
- University Children's Hospital Bern, Bern, Switzerland
| | - Sophie Yammine
- University Children's Hospital Bern, Bern, Switzerland.,University Children's Hospital Basel, UKBB, Basel, Switzerland
| | - Florian Singer
- University Children's Hospital Bern, Bern, Switzerland.,University Children's Hospital Zurich, Zurich, Switzerland
| | - Thomas Riedel
- University Children's Hospital Bern, Bern, Switzerland
| | - Philipp Latzin
- University Children's Hospital Bern, Bern, Switzerland.,University Children's Hospital Basel, UKBB, Basel, Switzerland
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Gustafsson PM, Robinson PD, Gilljam M, Lindblad A, Houltz BK. Slow and fast lung compartments in cystic fibrosis measured by nitrogen multiple-breath washout. J Appl Physiol (1985) 2014; 117:720-9. [DOI: 10.1152/japplphysiol.01274.2013] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Imaging studies describe significant ventilation defects across a wide range of cystic fibrosis (CF) related lung disease severity. These are unfortunately poorly reflected by phase III slope analysis–derived Scond and Sacin from multiple-breath washout (MBW). Methodology extending previous two-lung compartment model-based analysis is presented describing size and function of fast- and slow-ventilating lung compartments from nitrogen (N2) MBW and correlation to obstructive lung disease severity. In 37 CF subjects (forced expiratory volume in 1 s [FEV1] mean [SD] 84.8 [19.9] % predicted; abnormal lung clearance index [LCI] in 36/37, range 7.28–18.9) and 74 matched healthy controls, volume and specific ventilation of both fast and slowly ventilated lung compartments were derived from N2-based MBW with commercial equipment. In healthy controls lung emptying was characterized by a large compartment constituting 75.6 (8.4)% of functional residual capacity (FRC) with a specific ventilation (regional alveolar tidal volume/regional lung volume) of 13.9 (3.7)% and a small compartment with high specific ventilation (48.4 [15.7]%). In CF the slowly ventilated lung compartment constituted 51.9(9.1)% of FRC, with low specific ventilation of 5.3 (2.4)%. Specific ventilation of the slowly ventilated lung compartment showed stronger correlation with LCI (r2 = 0.70, P < 0.001) vs. Sacin (r2 = 0.44, P < 0.001) or Scond (no significant correlation). Overventilation of the fast lung compartment was no longer seen in severe CF lung disease. Magnitude and function of under- and overventilated lung volumes can be derived from routine N2 MBW in CF. Reported values agree with previous modelling-derived estimates of impaired ventilation and offer improved correlation to disease severity, compared with SnIII analysis.
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Affiliation(s)
- P. M. Gustafsson
- Department of Pediatrics, Central Hospital, Skövde, Sweden
- The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - P. D. Robinson
- Department of Respiratory Medicine, The Children's Hospital at Westmead, Sydney, New South Wales, Australia
- Discipline of Paediatrics and Child Health, Sydney Medical School, University of Sydney, Australia
| | - M. Gilljam
- The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
- Department of Chest Medicine and Allergology, The Sahlgrenska University Hospital, Gothenburg, Sweden
| | - A. Lindblad
- The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
- Queen Silvia Children's Hospital, Gothenburg, Sweden; and
| | - B. K. Houltz
- The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
- Department of Clinical Physiology, The Sahlgrenska University Hospital/East, Gothenburg, Sweden
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27
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Horsley A, Siddiqui S. Putting lung function and physiology into perspective: cystic fibrosis in adults. Respirology 2014; 20:33-45. [PMID: 25219816 DOI: 10.1111/resp.12382] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Revised: 07/22/2014] [Accepted: 07/23/2014] [Indexed: 11/30/2022]
Abstract
Adult cystic fibrosis (CF) is notable for the wide heterogeneity in severity of disease expression, both between patients and within the lungs of individuals. Although CF airways disease appears to start in the small airways, in adults there is typically widespread bronchiectasis, increased airway secretions, and extensive obstruction and inflammation of the small airways. The complexity and heterogeneity of airways disease in CF means that although there are many different methods of assessing and describing lung 'function', none of these single-dimensional tests is able to provide a comprehensive assessment of lung physiology across the spectrum seen in adult CF. The most widely described measure, the forced expiratory volume in 1 s, remains a useful and simple clinical tool, but is insensitive to early changes and may be dissociated from other more detailed assessments of disease severity such as computed tomography. In this review, we also discuss the use of more sensitive novel assessments such as multiple breath washout tests and impulse oscillometry, as well as the role of cardiopulmonary exercise testing. In the future, hyperpolarized gas magnetic resonance imaging techniques that combine regional structural and functional information may help us to better understand these measures, their applications and limitations.
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Affiliation(s)
- Alex Horsley
- Respiratory Research Group, Institute of Inflammation and Repair, University of Manchester, Manchester, UK; Manchester Adult Cystic Fibrosis Centre, North West Lung Centre, University Hospital of South Manchester, Manchester, UK
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Husemann K, Berg N, Engel J, Port J, Joppek C, Tao Z, Singer F, Schulz H, Kohlhäufl M. Double tracer gas single-breath washout: reproducibility in healthy subjects and COPD. Eur Respir J 2014; 44:1210-22. [PMID: 25102960 DOI: 10.1183/09031936.00085713] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The applicability and interpretation of inert tracer gas washout tests is hampered by the lack of feasible protocols and reproducibility data. We assessed feasibility, variability and reproducibility of a new easy to perform double tracer gas (DTG) single-breath washout (SBW) test and compared this with conventional nitrogen washouts. In 40 healthy nonsmokers and 20 patients with stable chronic obstructive pulmonary disease (COPD), we performed three N2 vital capacity SBWs, three N2 multiple-breath washouts and three tidal DTG-SBW tests. Follow-up was after 1 week, 1 month and 6 months. Main outcomes were the lung clearance index (LCI) (N2 multiple-breath washout), slope of phase III (dN2) (N2 vital capacity SBW) and slope of phase III (SIIIDTG) (DTG-SBW). In healthy subjects, mean±sd LCI at baseline was 6.94±0.61, dN2 0.99±0.42% N2 per litre and SIIIDTG -0.206±0.108 g·mol(-1)·L(-1). In COPD, LCI and dN2 were significantly higher (LCI 12.23±2.67, dN2 7.43±5.38% N2 per litre; p<0.001) and SIIIDTG significantly steeper (-0.653±0.428 g·mol(-1)·L(-1), p<0.001). Reproducibility was high for main outcome parameters: the intraclass correlation coefficient over 6 months was 0.77 (0.86 in COPD) for LCI, 0.82 (0.89) for dN2 and 0.83 (0.93) for SIIIDTG. The tidal DTG-SBW is a reproducible test in healthy and COPD subjects that seems attractive for use in routine clinical settings.
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Affiliation(s)
- Kim Husemann
- Klinik Schillerhöhe, Center for Respiratory Medicine and Thoracic Surgery, Robert-Bosch-Krankenhaus-GmbH, Stuttgart, Germany
| | - Nina Berg
- Klinik Schillerhöhe, Center for Respiratory Medicine and Thoracic Surgery, Robert-Bosch-Krankenhaus-GmbH, Stuttgart, Germany
| | - Jennifer Engel
- Klinik Schillerhöhe, Center for Respiratory Medicine and Thoracic Surgery, Robert-Bosch-Krankenhaus-GmbH, Stuttgart, Germany
| | - Johannes Port
- University of Stuttgart, Dept of Biomedical Engineering, Stuttgart, Germany
| | - Christoph Joppek
- University of Stuttgart, Dept of Biomedical Engineering, Stuttgart, Germany
| | - Ziran Tao
- University of Stuttgart, Dept of Biomedical Engineering, Stuttgart, Germany
| | | | - Holger Schulz
- Helmholtz Zentrum Munich, Institute of Epidemiology I, Neuherberg, Germany
| | - Martin Kohlhäufl
- Klinik Schillerhöhe, Center for Respiratory Medicine and Thoracic Surgery, Robert-Bosch-Krankenhaus-GmbH, Stuttgart, Germany
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29
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Hannon D, Bradley JM, Bradbury I, Bell N, Elborn JS, O'Neill K. Shortened Lung Clearance Index is a repeatable and sensitive test in children and adults with cystic fibrosis. BMJ Open Respir Res 2014; 1:e000031. [PMID: 25478180 PMCID: PMC4212720 DOI: 10.1136/bmjresp-2014-000031] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Revised: 06/27/2014] [Accepted: 06/30/2014] [Indexed: 11/16/2022] Open
Abstract
Background Lung clearance index (LCI) derived from sulfur hexafluoride (SF6) multiple breath washout (MBW) is a sensitive measure of lung disease in people with cystic fibrosis (CF). However, it can be time-consuming, limiting its use clinically. Aim To compare the repeatability, sensitivity and test duration of LCI derived from washout to 1/30th (LCI1/30), 1/20th (LCI1/20) and 1/10th (LCI1/10) to ‘standard’ LCI derived from washout to 1/40th initial concentration (LCI1/40). Methods Triplicate MBW test results from 30 clinically stable people with CF and 30 healthy controls were analysed retrospectively. MBW tests were performed using 0.2% SF6 and a modified Innocor device. All LCI end points were calculated using SimpleWashout software. Repeatability was assessed using coefficient of variation (CV%). The proportion of people with CF with and without abnormal LCI and forced expiratory volume in 1 s (FEV1) % predicted was compared. Receiver operating characteristic (ROC) curve statistics were calculated. Test duration of all LCI end points was compared using paired t tests. Results In people with CF, LCI1/40 CV% (p=0.16), LCI1/30 CV%, (p=0.53), LCI1/20 CV% (p=0.14) and LCI1/10 CV% (p=0.25) was not significantly different to controls. The sensitivity of LCI1/40, LCI1/30 and LCI1/20 to the presence of CF was equal (67%). The sensitivity of LCI1/10 and FEV1% predicted was lower (53% and 47% respectively). Area under the ROC curve (95% CI) for LCI1/40, LCI1/30, LCI1/20, LCI1/10 and FEV1% predicted was 0.89 (0.80 to 0.97), 0.87 (0.77 to 0.96), 0.87 (0.78 to 0.96), 0.83 (0.72 to 0.94) and 0.73 (0.60 to 0.86), respectively. Test duration of LCI1/30, LCI1/20 and LCI1/10 was significantly shorter compared with the test duration of LCI1/40 in people with CF (p<0.0001) equating to a 5%, 9% and 15% time saving, respectively. Conclusions In this study, LCI1/20 was a repeatable and sensitive measure with equal diagnostic performance to LCI1/40. LCI1/20 was shorter, potentially offering a more feasible research and clinical measure.
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Affiliation(s)
- David Hannon
- Centre for Infection and Immunity, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast , Belfast , UK
| | - Judy M Bradley
- Centre for Health and Rehabilitation Technologies (CHART), University of Ulster , Belfast , UK
| | - Ian Bradbury
- Centre for Health and Rehabilitation Technologies (CHART), University of Ulster , Belfast , UK
| | - Nicholas Bell
- Respiratory Medicine Department , Bristol Adult Cystic Fibrosis Centre, Bristol Royal Infirmary, University Hospitals Bristol , Bristol , UK
| | - J Stuart Elborn
- Centre for Infection and Immunity, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast , Belfast , UK
| | - Katherine O'Neill
- Centre for Infection and Immunity, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast , Belfast , UK
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Gonem S, Scadding A, Soares M, Singapuri A, Gustafsson P, Ohri C, Range S, Brightling CE, Pavord I, Horsley A, Siddiqui S. Lung clearance index in adults with non-cystic fibrosis bronchiectasis. Respir Res 2014; 15:59. [PMID: 24884343 PMCID: PMC4035904 DOI: 10.1186/1465-9921-15-59] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Accepted: 05/08/2014] [Indexed: 12/03/2022] Open
Abstract
Background Lung clearance index (LCI) is a measure of abnormal ventilation distribution derived from the multiple breath inert gas washout (MBW) technique. We aimed to determine the clinical utility of LCI in non-CF bronchiectasis, and to assess two novel MBW parameters that distinguish between increases in LCI due to specific ventilation inequality (LCIvent) and increased respiratory dead space (LCIds). Methods Forty-three patients with non-CF bronchiectasis and 18 healthy control subjects underwent MBW using the sulphur hexafluoride wash-in technique, and data from 40 adults with CF were re-analysed. LCIvent and LCIds were calculated using a theoretical two-compartment lung model, and represent the proportional increase in LCI above its ideal value due to specific ventilation inequality and increased respiratory dead space, respectively. Results LCI was significantly raised in patients with non-CF bronchiectasis compared to healthy controls (9.99 versus 7.28, p < 0.01), and discriminated well between these two groups (area under receiver operating curve = 0.90, versus 0.83 for forced expiratory volume in one second [% predicted]). LCI, LCIvent and LCIds were repeatable (intraclass correlation coefficient > 0.75), and correlated significantly with measures of spirometric airflow obstruction. Conclusion LCI is repeatable, discriminatory, and is associated with spirometric airflow obstruction in patients with non-CF bronchiectasis. LCIvent and LCIds are a practical and repeatable alternative to phase III slope analysis and may allow a further level of mechanistic information to be extracted from the MBW test in patients with severe ventilation heterogeneity.
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Affiliation(s)
- Sherif Gonem
- Institute for Lung Health, University of Leicester, Leicester, UK.
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31
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Kraemer R. Ventilation inhomogeneities in patients with cystic fibrosis: which target lung function parameters offer valuable evaluation? Respiration 2014; 87:459-61. [PMID: 24801562 DOI: 10.1159/000362675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Affiliation(s)
- Richard Kraemer
- Department of Clinical Research, University of Bern, Bern, Switzerland
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32
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Horsley A. Author's response: heterogeneity of change in LCI in patients with cystic fibrosis following antibiotic treatment. Thorax 2014; 69:184. [DOI: 10.1136/thoraxjnl-2013-204359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Kent L, Reix P, Innes JA, Zielen S, Le Bourgeois M, Braggion C, Lever S, Arets HGM, Brownlee K, Bradley JM, Bayfield K, O'Neill K, Savi D, Bilton D, Lindblad A, Davies JC, Sermet I, De Boeck K. Lung clearance index: evidence for use in clinical trials in cystic fibrosis. J Cyst Fibros 2013; 13:123-38. [PMID: 24315208 DOI: 10.1016/j.jcf.2013.09.005] [Citation(s) in RCA: 148] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Revised: 09/10/2013] [Accepted: 09/23/2013] [Indexed: 02/09/2023]
Abstract
The ECFS-CTN Standardisation Committee has undertaken this review of lung clearance index as part of the group's work on evaluation of clinical endpoints with regard to their use in multicentre clinical trials in CF. The aims were 1) to review the literature on reliability, validity and responsiveness of LCI in patients with CF, 2) to gain consensus of the group on feasibility of LCI and 3) to gain consensus on answers to key questions regarding the promotion of LCI to surrogate endpoint status. It was concluded that LCI has an attractive feasibility and clinimetric properties profile and is particularly indicated for multicentre trials in young children with CF and patients with early or mild CF lung disease. This is the first article to collate the literature in this manner and support the use of LCI in clinical trials in CF.
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Affiliation(s)
- L Kent
- Centre for Health and Rehabilitation Technologies (CHaRT), Institute for Nursing and Health Research, University of Ulster, Newtownabbey, UK; Regional Cystic Fibrosis Centre, Belfast Health and Social Care Trust, Belfast, UK
| | - P Reix
- Centre de Référence de la Mucoviscidose, Hospices Civils de Lyon, Lyon, France
| | - J A Innes
- Scottish Adult Cystic Fibrosis Service, Western General Hospital, Edinburgh, UK; Molecular and Clinical Medicine, University of Edinburgh, UK
| | - S Zielen
- Department of Paediatrics, J.W. Goethe-Universität Frankfurt, Germany
| | - M Le Bourgeois
- Centre de Référence de la Mucoviscidose, Hôpital Necker-Enfants Malades, Paris, France
| | - C Braggion
- Cystic Fibrosis Center, Pediatric Department, Meyer Children's Hospital, Florence, Italy
| | - S Lever
- Erasmus MC, Rotterdam, The Netherlands
| | - H G M Arets
- Department of Pediatric Pulmonology, Wilhelmina Children's Hospital, University Medical Center Utrecht, The Netherlands
| | - K Brownlee
- Children's Cystic Fibrosis Centre, Leeds Teaching Hospitals, Leeds, UK
| | - J M Bradley
- Centre for Health and Rehabilitation Technologies (CHaRT), Institute for Nursing and Health Research, University of Ulster, Newtownabbey, UK; Regional Cystic Fibrosis Centre, Belfast Health and Social Care Trust, Belfast, UK
| | - K Bayfield
- Department of Gene Therapy, Imperial College London, UK
| | - K O'Neill
- Centre for Infection and Immunity, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, UK
| | - D Savi
- Department of Pediatrics and Pediatric Neurology, Cystic Fibrosis Center, Sapienza University of Rome, Italy
| | - D Bilton
- Royal Brompton & Harefield NHS Foundation Trust, London, UK
| | - A Lindblad
- Gothenburg CF Centre, Queen Silvia Children's Hospital, Göteborg, Sweden
| | - J C Davies
- Department of Gene Therapy, Imperial College London, UK; Royal Brompton & Harefield NHS Foundation Trust, London, UK
| | - I Sermet
- Centre de Référence de la Mucoviscidose, Hôpital Necker-Enfants Malades, Paris, France; Université Paris Descartes, Paris, France
| | - K De Boeck
- Pediatric Pulmonology, University Hospitals Leuven and KU Leuven, Leuven, Belgium.
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Abbas C, Singer F, Yammine S, Casaulta C, Latzin P. Treatment response of airway clearance assessed by single-breath washout in children with cystic fibrosis. J Cyst Fibros 2013; 12:567-74. [DOI: 10.1016/j.jcf.2013.05.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Revised: 03/30/2013] [Accepted: 05/26/2013] [Indexed: 11/15/2022]
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35
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Acinar and conductive ventilation heterogeneity in severe CF lung disease: Back to the model. Respir Physiol Neurobiol 2013; 188:124-32. [DOI: 10.1016/j.resp.2013.05.011] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Revised: 05/07/2013] [Accepted: 05/13/2013] [Indexed: 11/19/2022]
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36
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Henry FS, Llapur CJ, Tsuda A, Tepper RS. Numerical modelling and analysis of peripheral airway asymmetry and ventilation in the human adult lung. J Biomech Eng 2013; 134:061001. [PMID: 22757498 DOI: 10.1115/1.4006809] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We present a new one-dimensional model of gas transport in the human adult lung. The model comprises asymmetrically branching airways, and heterogeneous interregional ventilation. Our model differs from previous models in that we consider the asymmetry in both the conducting and the acinar airways in detail. Another novelty of our model is that we use simple analytical relationships to produce physiologically realistic models of the conducting and acinar airway trees. With this new model, we investigate the effects of airway asymmetry and heterogeneous interregional ventilation on the phase III slope in multibreath washouts. The model predicts the experimental trend of the increase in the phase III slope with breath number in multibreath washout studies for nitrogen, SF(6) and helium. We confirm that asymmetrical branching in the acinus controls the magnitude of the first-breath phase III slope and find that heterogeneous interregional ventilation controls the way in which the slope changes with subsequent breaths. Asymmetry in the conducting airways appears to have little effect on the phase III slope. That the increase in slope appears to be largely controlled by interregional ventilation inhomogeneities should be of interest to those wishing to use multibreath washouts to detect the location of the structural abnormalities within the lung.
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Affiliation(s)
- F S Henry
- Molecular and Integrative Physiological Sciences, Harvard School of Public Health, Boston, MA 02115, USA.
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37
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Abstract
Noninvasive physiological measurements are reviewed that have been reported in the literature with the specific aim being to study the small airways in lung disease. This has mostly involved at-the-mouth noninvasive measurement of flow, pressure or inert gas concentration, with the intent of deriving one or more indices that are representative of small airway structure and function. While these measurements have remained relatively low-tech, the effort and sophistication increasingly reside with the interpretation of such indices. When aspiring to derive information at the mouth about structural and mechanical processes occurring several airway generations away in a complex cyclically changing cul-de-sac structure, conceptual or semi-quantitative lung models can be valuable. Two assumptions that are central to small airway structure-function measurement are that of an average airway change at a given peripheral lung generation and of a parallel heterogeneity in airway changes. While these are complementary pieces of information, they can affect certain small airways tests in confounding ways. We critically analyzed the various small airway tests under review, while contending that negative outcomes of these tests are probably a true reflection of the fact that no change occurred in the small airways. Utmost care has been taken to not favor one technique over another, given that most current small airways tests still have room for improvement in terms of rendering their content more specific to the small airways. One way to achieve this could consist of the coupling of signals collected at the mouth to spatial information gathered from imaging in the same patient.
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Affiliation(s)
- Sylvia Verbanck
- Respiratory Division, University Hospital UZ Brussel, Brussels, Belgium.
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38
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Stuart-Andrews CR, Kelly VJ, Sands SA, Lewis AJ, Ellis MJ, Thompson BR. Automated detection of the phase III slope during inert gas washout testing. J Appl Physiol (1985) 2011; 112:1073-81. [PMID: 22174406 DOI: 10.1152/japplphysiol.00372.2011] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We describe a method to determine the phase III slope for the purpose of calculating indexes of ventilation heterogeneity, S(acin) and S(cond), from the multiple breath nitrogen washout test (MBNW). Our automated method applies a recursive, segmented linear regression technique to each breath of the MBNW test and determines the best point of transition, or breakpoint, between each phase of the washout. A sample set of 50 MBNW tests (controls, asthma, and COPD) was used to establish the conditions in which the phase III slope obtained from the automated technique best matched that obtained by two manual interpreters. We then applied our technique to a test set of 30 subjects (with an even number of subjects in each of the above groups) and compared these results against the manual analysis of a third independent manual interpreter. Indexes of ventilation heterogeneity were determined using both methods and compared. The phase III slopes determined by the automatic technique best matched the manual interpreter when the phase III slope was calculated from the phase II-III transition point plus the addition of 50% of the phase II volume to the end of the expiration. Calculation of the indexes S(acin) and S(cond) showed no overall difference between analysis methods in either S(acin) (P = 0.14) or S(cond) (P = 0.59) when the set threshold was applied to our automated analysis. Our analysis method provides an alternate means for rapid quantification of the MBNW test, removing operator dependence without alteration in either S(acin) or S(cond).
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Affiliation(s)
- Christopher R Stuart-Andrews
- Physiology Service, Department of Allergy, Immunology and Respiratory Medicine, The Alfred Hospital, Melbourne, VIC, Australia.
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39
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Verbanck S, Paiva M, Schuermans D, Hanon S, Vincken W, Van Muylem A. Relationships between the lung clearance index and conductive and acinar ventilation heterogeneity. J Appl Physiol (1985) 2011; 112:782-90. [PMID: 22162528 DOI: 10.1152/japplphysiol.01221.2011] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The lung clearance index (LCI) derived from a multiple breath washout test has regained considerable popularity in recent years, alternatively being promoted as an early detection tool or a marker of small airways function. In this study, we systematically investigated the link between LCI and indexes of acinar and conductive airways ventilation heterogeneity (Sacin, Scond) to assess potential contributions from both lung zones. Relationships were examined in 55 normal subjects after provocation, where only Scond is known to be markedly increased, and in 55 asthma patients after bronchodilation, in whom both Scond and Sacin ranged between normal and abnormal. LCI was correlated to Scond in both groups (R = 0.37-0.43; P < 0.01 for both); in the asthma group, LCI was also tightly correlated to Sacin (R = 0.70; P < 0.001). Potential mechanisms operational at various levels of the bronchial tree were identified by considering washout curvilinearity in addition to LCI to distinguish specific ventilation and dead space effects (also illustrated by simple 2-compartment model simulations). Although the asthma data clearly demonstrate that LCI can reflect very peripheral ventilation heterogeneities, the normal provocation data also convincingly show that LCI increases may be the exclusive result of far more proximal ventilation heterogeneities. Because LCI potentially includes heterogeneities at all length scales, it is suggested that ventilation imaging in combination with LCI measurement at the mouth could identify the scale of relevant ventilation heterogeneities. In the meantime, interpretations of LCI results in the clinic based on washout curves collected at the mouth should be handled with caution.
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Affiliation(s)
- Sylvia Verbanck
- Respiratory Division, Univ. Hospital UZ Brussel, Laarbeeklaan 101, 1090 Brussels, Belgium.
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