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Salem Y, Jakob J, Steinberg R, Gorlanova O, Fuchs O, Müller L, Usemann J, Frey U, Latzin P, Yammine S. Cohort Profile Update: The Bern Basel Infant Lung Development Cohort. Int J Epidemiol 2024; 53:dyad164. [PMID: 38061036 DOI: 10.1093/ije/dyad164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 12/05/2023] [Indexed: 02/12/2024] Open
Affiliation(s)
- Yasmin Salem
- Division of Pediatric Respiratory Medicine and Allergology, Department of Pediatrics, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
- Graduate School for Health Sciences, University of Bern, Bern, Switzerland
| | - Julian Jakob
- Division of Pediatric Respiratory Medicine and Allergology, Department of Pediatrics, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
- Graduate School for Health Sciences, University of Bern, Bern, Switzerland
- Institute of Primary Health Care (BIHAM), University of Bern, Bern, Switzerland
| | - Ruth Steinberg
- Division of Pediatric Respiratory Medicine and Allergology, Department of Pediatrics, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
- Graduate School for Biomedical Science, University of Bern, Bern, Switzerland
| | - Olga Gorlanova
- University Children's Hospital Basel (UKBB), Basel, Switzerland
| | - Oliver Fuchs
- Division of Pediatric Respiratory Medicine and Allergology, Department of Pediatrics, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
- Allergology, Department of Medicine, Lucerne Cantonal Hospital and University of Lucerne, Lucerne, Switzerland
| | - Loretta Müller
- Division of Pediatric Respiratory Medicine and Allergology, Department of Pediatrics, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
- Department for BioMedical Research (DBMR), University of Bern, Bern, Switzerland
| | - Jakob Usemann
- University Children's Hospital Basel (UKBB), Basel, Switzerland
| | - Urs Frey
- University Children's Hospital Basel (UKBB), Basel, Switzerland
| | - Philipp Latzin
- Division of Pediatric Respiratory Medicine and Allergology, Department of Pediatrics, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Sophie Yammine
- Division of Pediatric Respiratory Medicine and Allergology, Department of Pediatrics, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
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Stanojevic S, Bowerman C, Robinson P. Multiple breath washout: measuring early manifestations of lung pathology. Breathe (Sheff) 2022; 17:210016. [PMID: 35035543 PMCID: PMC8753656 DOI: 10.1183/20734735.0016-2021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 07/13/2021] [Indexed: 11/05/2022] Open
Abstract
The multiple breath washout (MBW) test measures the efficiency of gas mixing in the lungs and has gained significant interest over the past 20 years. MBW outcomes detect early lung function impairment and peripheral airway pathology, through its main outcome measure lung clearance index (LCI). LCI measures the number of lung turnovers required to washout an inert tracer gas. MBW is performed during normal (tidal) breathing, making it particularly suitable for young children or those who have trouble performing forced manoeuvres. Additionally, research in chronic respiratory disease populations has shown that MBW can detect acute clinically relevant changes before conventional lung function tests, such as spirometry, thus enabling early intervention. The development of technical standards for MBW and commercial devices have allowed MBW to be implemented in clinical research and potentially routine clinical practice. Although studies have summarised clinimetric properties of MBW indices, additional research is required to establish the clinical utility of MBW and, if possible, shorten testing time. Sensitive, feasible measures of early lung function decline will play an important role in early intervention for people living with respiratory diseases. Educational aim To describe the multiple breath washout test, its applications to lung pathology and respiratory disease, as well as directions for future research.
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Affiliation(s)
- Sanja Stanojevic
- Dept of Community Health and Epidemiology, Dalhousie University, Halifax, NS, Canada
| | - Cole Bowerman
- Dept of Community Health and Epidemiology, Dalhousie University, Halifax, NS, Canada
| | - Paul Robinson
- Dept of Respiratory Medicine, Children's Hospital at Westmead, Sydney, Australia.,The Children's Hospital at Westmead Clinical School, The University of Sydney, Sydney, Australia
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Oestreich MA, Wyler F, Latzin P, Ramsey KA. Shedding light into the black box of infant multiple-breath washout. Pediatr Pulmonol 2021; 56:2642-2653. [PMID: 33991038 DOI: 10.1002/ppul.25464] [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: 07/16/2020] [Revised: 04/22/2021] [Accepted: 05/08/2021] [Indexed: 11/10/2022]
Abstract
BACKGROUND Multiple-breath inert gas washout (MBW) is a sensitive technique to assess lung volumes and ventilation inhomogeneity in infancy. Poor agreement amongst commercially available setups and a lack of transparency in the underlying algorithms for the computation of infant MBW outcomes currently limit the widespread application of MBW as a surveillance tool in early lung disease. METHODS We determined all computational steps in signal processing and the calculation of MBW outcomes in the current infant WBreath/Exhalyzer D setup (Exhalyzer D device, Eco Medics AG; WBreath software version 3.28.0, ndd Medizintechnik AG; Switzerland). We developed a revised WBreath version based on current consensus guidelines and compared outcomes between the current (3.28.0) and revised (3.52.3) WBreath version. We analyzed 60 visits from 40 infants with cystic fibrosis (CF) and 20 healthy controls at 6 weeks and 1 year of age. RESULTS Investigation into the algorithms in WBreath 3.28.0 revealed discrepancies from current consensus guidelines, which resulted in a potential overestimation of functional residual capacity (FRC) and underestimation of lung clearance index (LCI). We developed a revised WBreath version (3.52.3), which overall resulted in 6.7% lower FRC (mean (SD) -1.78 (0.99) mL/kg) and 14.1% higher LCI (1.11 (0.57) TO) than WBreath version 3.28.0. CONCLUSION Comprehensive investigation into the signal processing and algorithms used for analysis of MBW measurements improves the transparency and robustness of infant MBW data. The revised software version calculates outcomes according to consensus guidelines. Future work is needed to validate and compare outcomes between infant MBW setups.
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Affiliation(s)
- Marc-Alexander Oestreich
- Pediatric Respiratory Medicine, Inselspital, University Children's Hospital of Bern, University of Bern, Bern, Switzerland.,Graduate School for Health Sciences, University of Bern, Bern, Switzerland
| | - Florian Wyler
- Pediatric Respiratory Medicine, Inselspital, University Children's Hospital of Bern, University of Bern, Bern, Switzerland
| | - Philipp Latzin
- Pediatric Respiratory Medicine, Inselspital, University Children's Hospital of Bern, University of Bern, Bern, Switzerland
| | - Kathryn A Ramsey
- Pediatric Respiratory Medicine, Inselspital, University Children's Hospital of Bern, University of Bern, Bern, Switzerland
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Isaac SM, Jensen R, Anagnostopoulou P, Davies JC, Gappa M, Latzin P, Saunders C, Short C, Singer F, Stanojevic S, Zwitserloot A, Ratjen F. Evaluation of a multiple breath nitrogen washout system in children. Pediatr Pulmonol 2020; 55:2108-2114. [PMID: 32437013 DOI: 10.1002/ppul.24862] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 05/13/2020] [Indexed: 11/10/2022]
Abstract
INTRODUCTION The multiple breath nitrogen washout (MBW) test offers a sensitive measure of airway function. In this study we aim to (a) assess the validity of the EasyOne Pro LAB (MBWndd ) in an in vitro lung model, (b) assess the feasibility, repeatability, and reproducibility of MBWndd and (c) compare outcomes with the Exhalyzer D (MBWEM ) and body plethysmography. METHODS In vitro, functional residual capacity (FRC) measurements were assessed using a lung model under quasi-physiological conditions and compared to measured FRC. In vivo plethysmography and MBW were performed in a prospective study of children at two visits (n = 45 healthy; n = 41 cystic fibrosis [CF]). Bland-Altman plots were used to compare agreement between FRC and lung clearance index (LCI) measurements. RESULTS In vitro FRCndd measurements were repeatable but lung volumes were underestimated (mean relative difference -5.4% (limits of agreement [LA] -9.6%; -1.1%), 95% confidence interval (CI) -6.27; -4.45). In vivo, compared to plethysmography, FRCndd was consistently lower (-19.3% [-40.5; 1.9], 95% CI [-23.9; -14.7]), and showed a volume dependency. LCIndd values were also higher in children with smaller lung volumes. The within-test coefficient of variation of the FRCndd and LCIndd were 4.9% in health, and 5.6% and 6.9% in CF respectively. LCIndd was reproducible between-visits (mean relative difference [LA] -3.7% [-14.8, -7.5; 95% CI -6.6; -0.73] in health [n = 17] and 0.34% [-13.2, 22.8; 95% CI -5.0; 5.69] in CF [n = 23]). When calculated using the same algorithm, LCIndd was similar to LCIEM in health. CONCLUSIONS MBWndd measurements are feasible, repeatable, and reproducible, however, MBW-derived outcomes are not interchangeable with MBWEM .
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Affiliation(s)
- Sarah M Isaac
- Translational Medicine, Research Institute, Hospital for Sick Children, Toronto, Canada
| | - Renee Jensen
- Translational Medicine, Research Institute, Hospital for Sick Children, Toronto, Canada
| | - Pinelopi Anagnostopoulou
- Division of Respiratory Medicine, Department of Pediatrics, University Children's Hospital of Bern, University of Bern, Bern, Switzerland.,Institute of Anatomy, University of Bern, Bern, Switzerland
| | - Jane C Davies
- National Heart & Lung Institute, Imperial College London and Royal Brompton Hospital, London, UK
| | - Monika Gappa
- Evangelisches Krankenhaus Düsseldorf, Formerly Marienhospital Wesel, Germany
| | - Philipp Latzin
- Division of Respiratory Medicine, Department of Pediatrics, University Children's Hospital of Bern, University of Bern, Bern, Switzerland
| | - Clare Saunders
- National Heart & Lung Institute, Imperial College London and Royal Brompton Hospital, London, UK
| | - Christopher Short
- National Heart & Lung Institute, Imperial College London and Royal Brompton Hospital, London, UK
| | - Florian Singer
- Division of Respiratory Medicine, Department of Pediatrics, University Children's Hospital of Bern, University of Bern, Bern, Switzerland
| | - Sanja Stanojevic
- Translational Medicine, Research Institute, Hospital for Sick Children, Toronto, Canada.,University of Toronto, Toronto, Ontario, Canada
| | - Annelies Zwitserloot
- University Medical Centre Groningen, Beatrix Children's Hospital, The Netherlands
| | - Felix Ratjen
- Translational Medicine, Research Institute, Hospital for Sick Children, Toronto, Canada.,University of Toronto, Toronto, Ontario, Canada.,Division of Respiratory Medicine, Hospital for Sick Children, Toronto, Ontario, Canada
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Robinson PD, Latzin P, Ramsey KA, Stanojevic S, Aurora P, Davis SD, Gappa M, Hall GL, Horsley A, Jensen R, Lum S, Milla C, Nielsen KG, Pittman JE, Rosenfeld M, Singer F, Subbarao P, Gustafsson PM, Ratjen F. Preschool Multiple-Breath Washout Testing. An Official American Thoracic Society Technical Statement. Am J Respir Crit Care Med 2019; 197:e1-e19. [PMID: 29493315 DOI: 10.1164/rccm.201801-0074st] [Citation(s) in RCA: 85] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
BACKGROUND Obstructive airway disease is nonuniformly distributed throughout the bronchial tree, although the extent to which this occurs can vary among conditions. The multiple-breath washout (MBW) test offers important insights into pediatric lung disease, not available through spirometry or resistance measurements. The European Respiratory Society/American Thoracic Society inert gas washout consensus statement led to the emergence of validated commercial equipment for the age group 6 years and above; specific recommendations for preschool children were beyond the scope of the document. Subsequently, the focus has shifted to MBW applications within preschool subjects (aged 2-6 yr), where a "window of opportunity" exists for early diagnosis of obstructive lung disease and intervention. METHODS This preschool-specific technical standards document was developed by an international group of experts, with expertise in both custom-built and commercial MBW equipment. A comprehensive review of published evidence was performed. RESULTS Recommendations were devised across areas that place specific age-related demands on MBW systems. Citing evidence where available in the literature, recommendations are made regarding procedures that should be used to achieve robust MBW results in the preschool age range. The present work also highlights the important unanswered questions that need to be addressed in future work. CONCLUSIONS Consensus recommendations are outlined to direct interested groups of manufacturers, researchers, and clinicians in preschool device design, test performance, and data analysis for the MBW technique.
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Anagnostopoulou P, Vomsattel S, Kentgens AC, Guidi M, Binggeli S, Kohler L, Singer F, Latzin P, Obrist D. An innovative lung model for multiple breath washout testing in health and disease. Clin Biomech (Bristol, Avon) 2019; 66:74-80. [PMID: 29157654 DOI: 10.1016/j.clinbiomech.2017.11.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 11/02/2017] [Accepted: 11/06/2017] [Indexed: 02/07/2023]
Abstract
BACKGROUND Multiple breath washout (MBW) is a lung function test that identifies the degree of ventilation inhomogeneity (VI) in the lungs. In vitro validation of MBW devices is recommended. So far, plastic lung models for MBW validation ignored variable degrees of VI. Our primary aim was to create a plastic lung model applicable for physiological lung volumes and variable VI. METHODS A plastic box divided in two chambers was filled with water and ventilated in various lung volumes and respiratory rates. A ventilator was used for efficient gas distribution (model with low VI). An additional divider was inserted to create a model with high VI. The model was connected to commercial MBW devices and measurements were performed using different tracer gases and conditions. Primary outcome was the precision of generated functional residual capacity (FRC) and the ability to generate variable VI. The latter was estimated by lung clearance index (LCI) and expiratory phase III slopes (SIII). LCI was also compared to a mathematical model. FINDINGS The intra-test variability for FRC was minimal, mean(SD) coefficient of variation 0.96(0.63)%, using different tracer gases under different conditions. Compared to the model with low VI, in the model with high VI LCI and washout SIII were significantly increased. LCI compared well to the mathematical model. INTERPRETATION This novel lung model shows excellent precision in lung volumes and VI estimates independent of tracer gases and conditions. The model can mimic the lungs of patients with uneven gas distribution.
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Affiliation(s)
- Pinelopi Anagnostopoulou
- Pediatric Respiratory Medicine, Department of Pediatrics, Inselspital, Bern University Hospital, University of Bern, Switzerland.
| | - Sarah Vomsattel
- Pediatric Respiratory Medicine, Department of Pediatrics, Inselspital, Bern University Hospital, University of Bern, Switzerland
| | - Anne-Christiane Kentgens
- Pediatric Respiratory Medicine, Department of Pediatrics, Inselspital, Bern University Hospital, University of Bern, Switzerland; Department of Respiratory Medicine and Allergy, Radboud University Medical Centre, Amalia Children's Hospital, Nijmegen, Netherlands
| | - Marisa Guidi
- Pediatric Respiratory Medicine, Department of Pediatrics, Inselspital, Bern University Hospital, University of Bern, Switzerland
| | - Severin Binggeli
- Pediatric Respiratory Medicine, Department of Pediatrics, Inselspital, Bern University Hospital, University of Bern, Switzerland
| | - Lena Kohler
- Pediatric Respiratory Medicine, Department of Pediatrics, Inselspital, Bern University Hospital, University of Bern, Switzerland
| | - Florian Singer
- Pediatric Respiratory Medicine, Department of Pediatrics, Inselspital, Bern University Hospital, University of Bern, Switzerland
| | - Philipp Latzin
- Pediatric Respiratory Medicine, Department of Pediatrics, Inselspital, Bern University Hospital, University of Bern, Switzerland
| | - Dominik Obrist
- ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland
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A modified CO2/O2 Guedel airway improves capnographic accuracy compared with a CO2/O2 nasal cannula: An infant manikin study. Eur J Anaesthesiol 2018; 35:566-572. [PMID: 29757925 DOI: 10.1097/eja.0000000000000818] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Capnography via a CO2/O2 nasal cannula is commonly used for respiratory monitoring during sedation. However, signal disturbances are frequently encountered, especially in young children. OBJECTIVE Sampling ports placed closer to the trachea have been shown to result in improved signal quality. In a manikin model of a 6-month-old infant we compared capnography from a modified Guedel airway with a CO2 port located at the tip with that from a CO2/O2 nasal cannula. DESIGN A comparison study using an artificial model of a breathing 6-month-old infant. SETTING Department of Paediatrics, Inselspital Bern, Switzerland, from March 2016 to June 2016. MATERIAL Modified CO2/O2 Guedel airway. INTERVENTIONS Capnography using a modified CO2/O2 Guedel airway or a CO2/O2 nasal cannula was performed for tidal volumes of 20 to 80 ml (in steps of 20 ml), respiratory rates of 20 to 60 min (in steps of 10 min) and with different O2 flows (0 to 2 l min, in steps of 0.5 l). MAIN OUTCOME MEASURES Comparison of differences between tracheal and device CO2. Secondary outcomes included the effect of various respiratory settings and O2 flows on the CO2 difference. RESULTS The tracheal to device CO2 difference was significantly smaller when using a modified CO2/O2 Guedel airway vs. a CO2/O2 nasal cannula: Mean ± SD, 16.8 ± 4.9 vs. 24.1 ± 5.9 mmHg, P less than 0.0001. An O2 flow of 0.5 to 2 l min did not influence the tracheal to device CO2 difference with the modified CO2/O2 Guedel airway in contrast to the CO2/O2 nasal cannula where there were significant differences (P < 0.0001). The effect of various tidal volumes and respiratory rates proved to be similar in both devices. CONCLUSION Capnography traces derived from a sample port at the tip of a modified CO2/O2 Guedel airway were more accurate than those obtained from a CO2/O2 nasal cannula. TRIAL REGISTRATION Not applicable.
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Kentgens AC, Guidi M, Korten I, Kohler L, Binggeli S, Singer F, Latzin P, Anagnostopoulou P. Infant multiple breath washout using a new commercially available device: Ready to replace the previous setup? Pediatr Pulmonol 2018; 53:628-635. [PMID: 29418075 DOI: 10.1002/ppul.23959] [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: 04/06/2017] [Accepted: 01/08/2018] [Indexed: 11/11/2022]
Abstract
INTRODUCTION Multiple breath washout (MBW) is a sensitive test to measure lung volumes and ventilation inhomogeneity from infancy on. The commonly used setup for infant MBW, based on ultrasonic flowmeter, requires extensive signal processing, which may reduce robustness. A new setup may overcome some previous limitations but formal validation is lacking. AIM We assessed the feasibility of infant MBW testing with the new setup and compared functional residual capacity (FRC) values of the old and the new setup in vivo and in vitro. METHODS We performed MBW in four healthy infants and four infants with cystic fibrosis, as well as in a Plexiglas lung simulator using realistic lung volumes and breathing patterns, with the new (Exhalyzer D, Spiroware 3.2.0, Ecomedics) and the old setup (Exhalyzer D, WBreath 3.18.0, ndd) in random sequence. RESULTS The technical feasibility of MBW with the new device-setup was 100%. Intra-subject variability in FRC was low in both setups, but differences in FRC between the setups were considerable (mean relative difference 39.7%, range 18.9; 65.7, P = 0.008). Corrections of software settings decreased FRC differences (14.0%, -6.4; 42.3, P = 0.08). Results were confirmed in vitro. CONCLUSION MBW measurements with the new setup were feasible in infants. However, despite attempts to correct software settings, outcomes between setups were not interchangeable. Further work is needed before widespread application of the new setup can be recommended.
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Affiliation(s)
- Anne-Christianne Kentgens
- Pediatric Respiratory Medicine, Department of Pediatrics, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.,Department of Respiratory Medicine and Allergy, Radboud University Medical Centre, Amalia Children's Hospital, Nijmegen, The Netherlands
| | - Marisa Guidi
- Pediatric Respiratory Medicine, Department of Pediatrics, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Insa Korten
- Pediatric Respiratory Medicine, Department of Pediatrics, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Lena Kohler
- Pediatric Respiratory Medicine, Department of Pediatrics, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Severin Binggeli
- Pediatric Respiratory Medicine, Department of Pediatrics, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Florian Singer
- Pediatric Respiratory Medicine, Department of Pediatrics, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.,Division of Respiratory Medicine, University Children's Hospital of Zurich, Zurich, Switzerland
| | - Philipp Latzin
- Pediatric Respiratory Medicine, Department of Pediatrics, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Pinelopi Anagnostopoulou
- Pediatric Respiratory Medicine, Department of Pediatrics, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
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Lenherr N, Ramsey KA, Jost K, Hornwall L, Singer F, Yammine S, Latzin P. Leaks during multiple-breath washout: characterisation and influence on outcomes. ERJ Open Res 2018; 4:00012-2017. [PMID: 29497618 PMCID: PMC5827412 DOI: 10.1183/23120541.00012-2017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2017] [Accepted: 12/13/2017] [Indexed: 11/19/2022] Open
Abstract
Nitrogen multiple-breath washout (N2MBW) is increasingly used in patients with cystic fibrosis. The current European Respiratory Society/American Thoracic Society consensus statement for MBW recommends the rejection of measurements with leaks. However, it is unclear whether this is necessary for all types of leaks. Here, our aim was to 1) model and 2) apply air leaks, and 3) to assess their influence on the primary MBW outcomes of lung clearance index and functional residual capacity. We investigated the influence of air leaks at various locations (pre-, intra- and post-capillary), sizes, durations and stages of the washout. Modelled leaks were applied to existing N2MBW data from 10 children by modifying breath tables. In addition, leaks were applied to the equipment during N2MBW measurements performed by one healthy adolescent. All modelled and applied leaks resulted in statistically significant but heterogeneous effects on lung clearance index and functional residual capacity. In all types of continuous inspiratory leaks exceeding a certain size, the end of the washout was not reached. For practical application, we illustrated six different “red flags”, i.e. signs that enable easy identification of leaks during measurements. Air leaks during measurement significantly influence N2MBW outcomes. The influence of leaks on MBW outcomes is dependent on the location, relation to breath cycle, duration, stage of washout and size of the leak. We identified a range of signs to help distinguish leaks from physiological noise. The influence of leaks on nitrogen MBW outcomes is complex, dynamic and dependent on the size, duration, location and position of leaks during the washout and breathing cyclehttp://ow.ly/PbHV30hB91H
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Affiliation(s)
- Nina Lenherr
- Dept of Pediatric Pneumology, University Children's Hospital Basel (UKBB), Basel, Switzerland
| | - Kathryn A Ramsey
- Pediatric Respiratory Medicine, Dept of Pediatrics, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Kerstin Jost
- Dept of Pediatric Pneumology, University Children's Hospital Basel (UKBB), Basel, Switzerland
| | - Linn Hornwall
- Dept of Pediatric Pneumology, University Children's Hospital Basel (UKBB), Basel, Switzerland
| | - Florian Singer
- Pediatric Respiratory Medicine, Dept of Pediatrics, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.,Division of Respiratory Medicine, University Children's Hospital Zurich, Zurich, Switzerland
| | - Sophie Yammine
- Pediatric Respiratory Medicine, Dept of Pediatrics, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Philipp Latzin
- Pediatric Respiratory Medicine, Dept of Pediatrics, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
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10
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Tonga KO, Robinson PD, Farah CS, King GG, Thamrin C. In vitro and in vivo functional residual capacity comparisons between multiple-breath nitrogen washout devices. ERJ Open Res 2017; 3:00011-2017. [PMID: 29204436 PMCID: PMC5703358 DOI: 10.1183/23120541.00011-2017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2017] [Accepted: 06/23/2017] [Indexed: 11/25/2022] Open
Abstract
Functional residual capacity (FRC) accuracy is essential for deriving multiple-breath nitrogen washout (MBNW) indices, and is the basis for device validation. Few studies have compared existing MBNW devices. We evaluated in vitro and in vivo FRC using two commercial MBNW devices, the Exhalyzer D (EM) and the EasyOne Pro LAB (ndd), and an in-house device (Woolcock in-house device, WIMR). FRC measurements were performed using a novel syringe-based lung model and in adults (20 healthy and nine with asthma), followed by plethysmography (FRCpleth). The data were analysed using device-specific software. Following the results seen with ndd, we also compared its standard clinical software (ndd v.2.00) with a recent upgrade (ndd v.2.01). WIMR and EM fulfilled formal in vitro FRC validation recommendations (>95% of FRC within 5% of known volume). Ndd v.2.00 underestimated in vitro FRC by >20%. Reanalysis using ndd v.2.01 reduced this to 11%, with 36% of measurements ≤5%. In vivo differences from FRCpleth (mean±sd) were 4.4±13.1%, 3.3±11.8%, −20.6±11% (p<0.0001) and −10.5±10.9% (p=0.005) using WIMR, EM, ndd v.2.00 and ndd v.2.01, respectively. Direct device comparison highlighted important differences in measurement accuracy. FRC discrepancies between devices were larger in vivo, compared to in vitro results; however, the pattern of difference was similar. These results represent progress in ongoing standardisation efforts. Multiple-breath washout devices are not yet comparablehttp://ow.ly/bB7b30eAs0c
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Affiliation(s)
- Katrina O Tonga
- Woolcock Institute of Medical Research, University of Sydney, Sydney, Australia.,Sydney Medical School, University of Sydney, Sydney, Australia.,Dept of Respiratory Medicine, Royal North Shore Hospital, Sydney, Australia.,Dept of Respiratory Medicine, Concord Hospital, Sydney, Australia
| | - Paul D Robinson
- Woolcock Institute of Medical Research, University of Sydney, Sydney, Australia.,Sydney Medical School, University of Sydney, Sydney, Australia.,Dept of Respiratory Medicine, The Children's Hospital at Westmead, Sydney, Australia
| | - Claude S Farah
- Woolcock Institute of Medical Research, University of Sydney, Sydney, Australia.,Sydney Medical School, University of Sydney, Sydney, Australia.,Dept of Respiratory Medicine, Concord Hospital, Sydney, Australia
| | - Greg G King
- Woolcock Institute of Medical Research, University of Sydney, Sydney, Australia.,Sydney Medical School, University of Sydney, Sydney, Australia.,Dept of Respiratory Medicine, Royal North Shore Hospital, Sydney, Australia
| | - Cindy Thamrin
- Woolcock Institute of Medical Research, University of Sydney, Sydney, Australia.,Sydney Medical School, University of Sydney, Sydney, Australia
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11
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Foong RE, Harper AJ, Hall GL, Ramsey KA. The effect of 100% oxygen on tidal breathing parameters in preschool children. Eur Respir J 2017; 49:49/6/1601959. [DOI: 10.1183/13993003.01959-2016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Accepted: 03/05/2017] [Indexed: 11/05/2022]
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12
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Davies G, Aurora P. The use of multiple breath washout for assessing cystic fibrosis in infants. Expert Rev Respir Med 2016; 11:21-28. [DOI: 10.1080/17476348.2017.1269604] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Gwyneth Davies
- Respiratory Critical Care and Anaesthesia Section, Infection, Immunity and Inflammation Programme, UCL Great Ormond Street Institute of Child Health, London, UK
- Respiratory Medicine, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Paul Aurora
- Respiratory Critical Care and Anaesthesia Section, Infection, Immunity and Inflammation Programme, UCL Great Ormond Street Institute of Child Health, London, UK
- Respiratory Medicine, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
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Yammine S, Summermatter S, Singer F, Lauener R, Latzin P. Feasibility of nitrogen multiple-breath washout in inexperienced children younger than 7 years. Pediatr Pulmonol 2016; 51:1183-1190. [PMID: 27132707 DOI: 10.1002/ppul.23431] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Revised: 01/16/2016] [Accepted: 02/15/2016] [Indexed: 11/06/2022]
Abstract
BACKGROUND Multiple breath washout (MBW) is an attractive test to assess ventilation inhomogeneity, a marker of peripheral lung disease. Systematic research on MBW feasibility in preschool children is scanty. OBJECTIVES We assessed feasibility of nitrogen MBW in children aged 3-7 years in a clinical setting applying current ERS/ATS consensus. METHODS Sixty-two children with asthma were enrolled in the Swiss rehabilitation center Hochgebirgsklinik Davos without MBW experience and prior to consensus release. Age range was 3.1-6.7 years. All children were naïve to MBW, received training, and then aimed for triplicate nitrogen MBW within 20 min. We afterward assessed the number of MBW attempts and successful tests according to consensus asking for three technically acceptable trials with functional residual capacity (FRC) measurements within 25% of median FRC. Secondly, factors related to success rate and FRC variability were assessed. RESULTS Out of 205 MBW attempts in 62 children, 103 trials (50%) in 51 children were successful. Only 15 children (24%) achieved three valid trials as suggested by consensus. At least two valid trials were obtained in 37 children (60%). Age was positively correlated with success rate. FRC variability was inversely correlated with variability of tidal volume. CONCLUSIONS MBW was only feasible in one quarter of inexperienced children <7 years applying strict consensus criteria. Low FRC variability and low breathing variability seem to be mutually exclusive at this age group. Specific consensus recommendations for MBW in preschool children seem, thus, warranted. Pediatr Pulmonol. 2016;51:1183-1190. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Sophie Yammine
- University Children's Hospital Basel, UKBB, Basel, 4031, Switzerland.,Department of Pediatrics, Inselspital, Bern University Hospital, University of Bern, Switzerland
| | - Selina Summermatter
- University Children's Hospital Basel, UKBB, Basel, 4031, Switzerland.,Christine Kühne-Center for Allergy and Research Education, CK-CARE, Davos-Wolfgang, 7265, Switzerland.,Hochgebirgsklinik Davos, Davos-Wolfgang, 7265, Switzerland
| | - Florian Singer
- University Children's Hospital Zurich, Zurich, 8032, Switzerland
| | - Roger Lauener
- Christine Kühne-Center for Allergy and Research Education, CK-CARE, Davos-Wolfgang, 7265, Switzerland.,Hochgebirgsklinik Davos, Davos-Wolfgang, 7265, Switzerland.,Children's Hospital of Eastern Switzerland, St. Gallen, 9000, Switzerland
| | - Philipp Latzin
- University Children's Hospital Basel, UKBB, Basel, 4031, Switzerland. .,Department of Pediatrics, Inselspital, Bern University Hospital, University of Bern, Switzerland.
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14
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Gustafsson PM, Robinson PD, Lindblad A, Oberli D. Novel methodology to perform sulfur hexafluoride (SF6)-based multiple-breath wash-in and washout in infants using current commercially available equipment. J Appl Physiol (1985) 2016; 121:1087-1097. [DOI: 10.1152/japplphysiol.00115.2016] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 08/01/2016] [Indexed: 11/22/2022] Open
Abstract
Multiple-breath inert gas washout (MBW) is ideally suited for early detection and monitoring of serious lung disease, such as cystic fibrosis, in infants and young children. Validated commercial options for the MBW technique are limited, and suitability of nitrogen (N2)-based MBW is of concern given the detrimental effect of exposure to pure O2 on infant breathing pattern. We propose novel methodology using commercially available N2 MBW equipment to facilitate 4% sulfur hexafluoride (SF6) multiple-breath inert gas wash-in and washout suitable for the infant age range. CO2, O2, and sidestream molar mass sensor signals were used to accurately calculate SF6 concentrations. An improved dynamic method for synchronization of gas and respiratory flow was developed to take into account variations in sidestream sample flow during MBW measurement. In vitro validation of triplicate functional residual capacity (FRC) assessments was undertaken under dry ambient conditions using lung models ranging from 90 to 267 ml, with tidal volumes of 28-79 ml, and respiratory rates 20–60 per minute. The relative mean (SD, 95% confidence interval) error of triplicate FRC determinations by washout was −0.26 (1.84, −3.86 to +3.35)% and by wash-in was 0.57 (2.66, −4.66 to +5.79)%. The standard deviations [mean (SD)] of percentage error among FRC triplicates were 1.40 (1.14) and 1.38 (1.32) for washout and wash-in, respectively. The novel methodology presented achieved FRC accuracy as outlined by current MBW consensus recommendations (95% of measurements within 5% accuracy). Further clinical evaluation is required, but this new technique, using existing commercially available equipment, has exciting potential for research and clinical use.
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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
| | - A. Lindblad
- The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
- CF Centre, Queen Silvia Children's Hospital, Gothenburg, Sweden; and
| | - D. Oberli
- ECO MEDICS AG, Duernten, Switzerland
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15
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Gur M, Yaacoby-Bianu K, Ilivitzki A, Bar-Yoseph R, Nir V, Hakim F, Toukan Y, Bentur L. Lung Clearance Index (LCI) in Patients with Bronchiolitis Obliterans: A Preliminary Report and Comparison to Cystic Fibrosis Patients. Lung 2016; 194:1007-1013. [PMID: 27645685 DOI: 10.1007/s00408-016-9934-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2016] [Accepted: 08/17/2016] [Indexed: 11/30/2022]
Abstract
INTRODUCTION Bronchiolitis obliterans (BO) is a chronic airway disease following an insult to the lower respiratory tract. Lung clearance index (LCI) measures ventilation inhomogeneity and has been studied in cystic fibrosis (CF). We aimed to evaluate LCI in BO and to compare it to LCI in CF patients. METHODS LCI was measured in BO patients, compared to CF patients, and correlated with spirometry and CT findings. RESULTS Twenty BO patients and 26 CF patients (with similar mean age and BMI) underwent evaluation. FEV1 % and FEF25-75 % predicted were significantly lower in the BO group (60.5 ± 17.8 vs. 72.7 ± 20.7, p = 0.041, and 42.8 ± 22.8 vs. 66.4 ± 37.4, p = 0.017, respectively). In both groups, LCI was inversely correlated with FVC %, FEV1 %, and FEF25-75 % predicted. LCI % was slightly higher (190.4 ± 63.5 vs. 164.9 ± 39.4, p = 0.1) and FRC gas % (measured by multiple breath washout) was significantly higher in the BO group (92.5 ± 35.9 vs. 71.3 ± 18, p = 0.014). The strength of statistical association between the lower FEF25-75 % values and the higher LCI values was stronger in BO patients. CONCLUSIONS Similar to CF, LCI may provide estimation of ventilation inhomogeneity in BO. The results indicate greater small airway involvement and air trapping in BO. Further prospective longitudinal studies evaluating the correlation of LCI measurements with multiple clinical and physiological parameters should be performed to assess the clinical benefit of LCI measurement in BO.
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Affiliation(s)
- Michal Gur
- Pediatric Pulmonary Institute and CF Center, Ruth Rappaport Children's Hospital, Rambam Health Care Campus, PO Box 9602, 31092, Haifa, Israel
| | - Karin Yaacoby-Bianu
- Pediatric Pulmonary Institute and CF Center, Ruth Rappaport Children's Hospital, Rambam Health Care Campus, PO Box 9602, 31092, Haifa, Israel
| | - Anat Ilivitzki
- Pediatric Radiology Unit, Ruth Rappaport Children's Hospital, Rambam Health Care Campus, Haifa, Israel
| | - Ronen Bar-Yoseph
- Pediatric Pulmonary Institute and CF Center, Ruth Rappaport Children's Hospital, Rambam Health Care Campus, PO Box 9602, 31092, Haifa, Israel
| | - Vered Nir
- Pediatric Pulmonary Institute and CF Center, Ruth Rappaport Children's Hospital, Rambam Health Care Campus, PO Box 9602, 31092, Haifa, Israel
| | - Fahed Hakim
- Pediatric Pulmonary Institute and CF Center, Ruth Rappaport Children's Hospital, Rambam Health Care Campus, PO Box 9602, 31092, Haifa, Israel.,Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
| | - Yazeed Toukan
- Pediatric Pulmonary Institute and CF Center, Ruth Rappaport Children's Hospital, Rambam Health Care Campus, PO Box 9602, 31092, Haifa, Israel.,Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
| | - Lea Bentur
- Pediatric Pulmonary Institute and CF Center, Ruth Rappaport Children's Hospital, Rambam Health Care Campus, PO Box 9602, 31092, Haifa, Israel. .,Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel.
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16
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Jost K, Lenherr N, Singer F, Schulzke S, Frey U, Latzin P, Yammine S. Changes in breathing pattern upon 100% oxygen in children at early school age. Respir Physiol Neurobiol 2016; 228:9-15. [DOI: 10.1016/j.resp.2016.03.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Revised: 03/04/2016] [Accepted: 03/06/2016] [Indexed: 10/22/2022]
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17
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Shawcross A, Murray CS, Goddard N, Gupta R, Watson S, Horsley A. Accurate lung volume measurements in vitro using a novel inert gas washout method suitable for infants. Pediatr Pulmonol 2016; 51:491-7. [PMID: 26623550 DOI: 10.1002/ppul.23348] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Revised: 11/04/2015] [Accepted: 11/16/2015] [Indexed: 11/08/2022]
Abstract
BACKGROUND Multiple breath washout (MBW) in infants presents a number of technical challenges. Conventional MBW is based on simultaneous measurement of flow and gas concentrations. These two signals are aligned and combined to derive expired gas volumes from which lung volumes and measures of ventilation inhomogeneity are calculated. Accuracy of measurement becomes increasingly vulnerable to errors in gas signal alignment at fast respiratory rates. In this paper we describe an alternative method of performing MBW in infants. Expired gas is collected and analyzed to derive functional residual capacity (FRC) and lung clearance index (LCI). This eliminates the need for simultaneous measurement of flow, and integration of flow and gas signals, and significantly reduces deadspace. METHODS A highly accurate lung model incorporating BTPS conditions was used to generate realistic infant breathing parameters: FRC of 100-250 mls with respiratory rate of 20-60 min(-1) . In vitro accuracy of FRC measurement using the novel MBW method was assessed using the model. RESULTS Overall mean error (standard deviation) of FRC measurement was -1.0 (3.3)% with 90% of tests falling within ±5%. DISCUSSION FRC measurement using the novel method has superior accuracy in vitro than previously described systems. By uncoupling the measurement of gas volumes from real-time flow and gas measurement, this system offers an alternative method of MBW which is well suited to infants.
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Affiliation(s)
- Anna Shawcross
- Centre for Respiratory Medicine and Allergy, Institute of Inflammation and Repair, Manchester Academic Health Science Centre, The University of Manchester and University Hospital of South Manchester, NHS Foundation Trust, Manchester, United Kingdom.,Department of Paediatric Respiratory Medicine, Royal Manchester Children's Hospital, Manchester, United Kingdom.,Manchester Adult Cystic Fibrosis Centre, University Hospital of South Manchester, Manchester, United Kingdom
| | - Clare S Murray
- Centre for Respiratory Medicine and Allergy, Institute of Inflammation and Repair, Manchester Academic Health Science Centre, The University of Manchester and University Hospital of South Manchester, NHS Foundation Trust, Manchester, United Kingdom.,Department of Paediatric Respiratory Medicine, Royal Manchester Children's Hospital, Manchester, United Kingdom
| | - Nicholas Goddard
- University of Manchester Institute of Biotechnology, Manchester, United Kingdom
| | - Ruchi Gupta
- Department of Chemistry, University of Hull, Manchester, United Kingdom
| | - Stuart Watson
- Department of Medical Physics, Salford Royal NHS Foundation Trust, Manchester, United Kingdom
| | - Alexander Horsley
- Centre for Respiratory Medicine and Allergy, Institute of Inflammation and Repair, Manchester Academic Health Science Centre, The University of Manchester and University Hospital of South Manchester, NHS Foundation Trust, Manchester, United Kingdom.,Manchester Adult Cystic Fibrosis Centre, University Hospital of South Manchester, Manchester, United Kingdom
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18
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Impact of Software Settings on Multiple-Breath Washout Outcomes. PLoS One 2015; 10:e0132250. [PMID: 26167682 PMCID: PMC4500401 DOI: 10.1371/journal.pone.0132250] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Accepted: 06/11/2015] [Indexed: 11/19/2022] Open
Abstract
Background and Objectives Multiple-breath washout (MBW) is an attractive test to assess ventilation inhomogeneity, a marker of peripheral lung disease. Standardization of MBW is hampered as little data exists on possible measurement bias. We aimed to identify potential sources of measurement bias based on MBW software settings. Methods We used unprocessed data from nitrogen (N2) MBW (Exhalyzer D, Eco Medics AG) applied in 30 children aged 5–18 years: 10 with CF, 10 formerly preterm, and 10 healthy controls. This setup calculates the tracer gas N2 mainly from measured O2 and CO2concentrations. The following software settings for MBW signal processing were changed by at least 5 units or >10% in both directions or completely switched off: (i) environmental conditions, (ii) apparatus dead space, (iii) O2 and CO2 signal correction, and (iv) signal alignment (delay time). Primary outcome was the change in lung clearance index (LCI) compared to LCI calculated with the settings as recommended. A change in LCI exceeding 10% was considered relevant. Results Changes in both environmental and dead space settings resulted in uniform but modest LCI changes and exceeded >10% in only two measurements. Changes in signal alignment and O2 signal correction had the most relevant impact on LCI. Decrease of O2 delay time by 40 ms (7%) lead to a mean LCI increase of 12%, with >10% LCI change in 60% of the children. Increase of O2 delay time by 40 ms resulted in mean LCI decrease of 9% with LCI changing >10% in 43% of the children. Conclusions Accurate LCI results depend crucially on signal processing settings in MBW software. Especially correct signal delay times are possible sources of incorrect LCI measurements. Algorithms of signal processing and signal alignment should thus be optimized to avoid susceptibility of MBW measurements to this significant measurement bias.
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Horsley A, Macleod K, Gupta R, Goddard N, Bell N. Enhanced photoacoustic gas analyser response time and impact on accuracy at fast ventilation rates during multiple breath washout. PLoS One 2014; 9:e98487. [PMID: 24892522 PMCID: PMC4043749 DOI: 10.1371/journal.pone.0098487] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Accepted: 05/03/2014] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The Innocor device contains a highly sensitive photoacoustic gas analyser that has been used to perform multiple breath washout (MBW) measurements using very low concentrations of the tracer gas SF6. Use in smaller subjects has been restricted by the requirement for a gas analyser response time of <100 ms, in order to ensure accurate estimation of lung volumes at rapid ventilation rates. METHODS A series of previously reported and novel enhancements were made to the gas analyser to produce a clinically practical system with a reduced response time. An enhanced lung model system, capable of delivering highly accurate ventilation rates and volumes, was used to assess in vitro accuracy of functional residual capacity (FRC) volume calculation and the effects of flow and gas signal alignment on this. RESULTS 10-90% rise time was reduced from 154 to 88 ms. In an adult/child lung model, accuracy of volume calculation was -0.9 to 2.9% for all measurements, including those with ventilation rate of 30/min and FRC of 0.5 L; for the un-enhanced system, accuracy deteriorated at higher ventilation rates and smaller FRC. In a separate smaller lung model (ventilation rate 60/min, FRC 250 ml, tidal volume 100 ml), mean accuracy of FRC measurement for the enhanced system was minus 0.95% (range -3.8 to 2.0%). Error sensitivity to flow and gas signal alignment was increased by ventilation rate, smaller FRC and slower analyser response time. CONCLUSION The Innocor analyser can be enhanced to reliably generate highly accurate FRC measurements down at volumes as low as those simulating infant lung settings. Signal alignment is a critical factor. With these enhancements, the Innocor analyser exceeds key technical component recommendations for MBW apparatus.
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Affiliation(s)
- Alex Horsley
- Institute of Inflammation and Repair, University of Manchester, Manchester, United Kingdom
- Manchester Adult Cystic Fibrosis Centre, University Hospital of South Manchester, Manchester, United Kingdom
- * E-mail:
| | - Kenneth Macleod
- Department of Respiratory Medicine, Great Ormond Street Hospital, London, United Kingdom
| | - Ruchi Gupta
- School of Chemical Engineering and Analytical Science, University of Manchester, Manchester, United Kingdom
| | - Nick Goddard
- School of Chemical Engineering and Analytical Science, University of Manchester, Manchester, United Kingdom
| | - Nicholas Bell
- Department of Respiratory Medicine, Bristol Royal Infirmary, University Hospitals Bristol NHS Foundation Trust, Bristol, United Kingdom
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Latzin P, Thompson B. Validation of Multiple-Breath Washout Equipment: From Bench to Clinic and Possible Pitfalls. Respiration 2014; 87:456-8. [DOI: 10.1159/000362420] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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