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Darquenne C, Theilmann RJ, Fine JM, Verbanck SAB. Nitrogen-based lung clearance index: a valid physiological biomarker for the clinic. J Appl Physiol (1985) 2022; 132:1290-1296. [PMID: 35446597 PMCID: PMC9126222 DOI: 10.1152/japplphysiol.00511.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Multiple breath washout (MBW) testing is increasingly used as a physiological measurement in the clinic, due in part to the availability of commercial equipment and reference values for MBW indices. Commercial N2 washout devices are usually based on indirect measurement of N2 concentration (CN2), by directly measuring either molar mass and O2 and CO2, or molar mass and CO2. We aim to elucidate the role of two potential pitfalls associated with N2-MBW testing that could override its physiological content: indirect N2 measurement and blood-solubility of N2. We performed MBW in 12 healthy adult subjects using a commercial device (MBWindirect) with simultaneous direct gas concentration measurements by mass spectrometry (MBWdirect) and compared CN2 between MBWdirect and MBWindirect. We also measured argon concentration during the same washouts to verify the maximal effect gas solubility can have on N2-based functional residual capacity (FRC) and lung clearance index (LCI). Continuous N2 concentration traces were very similar for MBWindirect and MBWdirect, resulting in comparable breath-by-breath washout plots of expired concentration and in no significant differences in FRCN2, LCIN2, Scond, and Sacin between the two methods. Argon washouts were slightly slower than N2 washouts, as expected for a less diffusive and more soluble gas. Finally, comparison between LCIN2 and LCIAr indicates that the maximum impact from blood-tissue represents less than half a LCI unit in normal subjects. In conclusion, we have demonstrated by direct measurement of N2 and twice as soluble argon, that indirect N2 measurement can be safely used as a meaningful physiological measurement.NEW & NOTEWORTHY The physiological content of N2 multibreath washout testing has been questioned due to N2 indirect measurement accuracy and N2 blood solubility. With direct measurement of N2 and twice as soluble argon, we show that these effects are largely outweighed by ease of use.
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Affiliation(s)
- Chantal Darquenne
- Department of Medicine, University of California, San Diego, California
| | | | - Janelle M Fine
- Department of Medicine, University of California, San Diego, California
| | - Sylvia A B Verbanck
- Respiratory Division, Vrije Universiteit Brussel (VUB), Universitair Ziekenhuis Brussel (UZ Brussel), Brussels, Belgium
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2
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Sandvik RM, Gustafsson PM, Lindblad A, Buchvald F, Olesen HV, Olsen JH, Skov M, Schmidt MN, Thellefsen MR, Robinson PD, Rubak S, Pressler T, Nielsen KG. Contemporary N 2 and SF 6 multiple breath washout in infants and toddlers with cystic fibrosis. Pediatr Pulmonol 2022; 57:945-955. [PMID: 35029068 DOI: 10.1002/ppul.25830] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 12/20/2021] [Accepted: 01/12/2022] [Indexed: 11/10/2022]
Abstract
INTRODUCTION Multiple breath washout (MBW) is used for early detection of cystic fibrosis (CF) lung disease, with SF6 MBW commonly viewed as the reference method. The use of N2 MBW in infants and toddlers has been questioned for technical and physiological reasons, but a new correction of the N2 signal has minimized the technical part. The present study aimed to assess the remaining differences and the contributing mechanisms for the differences between SF6 and N2 MBW,corrected-such as tidal volume reduction during N2 washout with pure O2 . METHOD This was a longitudinal multicenter cohort study. SF6 MBW and N2 MBW were performed prospectively at three CF centers in the same visits on 154 test occasions across 62 children with CF (mean age: 22.7 months). Offline analysis using identical algorithms to the commercially available program provided outcomes of N2,original and N2,corrected for comparison with SF6 MBW. RESULTS Mean functional residual capacity, FRCN2,corrected was 14.3% lower than FRCN2, original , and 1.0% different from FRCSF6 . Lung clearance index, LCIN2,corrected was 25.2% lower than LCIN2,original , and 7.3% higher than LCISF6 . Mean (SD) tidal volume decreased significantly during N2 MBWcorrected , compared to SF6 MBW (-13.1 ml [-30.7; 4.6], p < 0.0001, equal to -12.0% [-25.7; 1.73]), but this tidal volume reduction did not correlate to the differences between LCIN2,corrected and LCISF6 . The absolute differences in LCI increased significantly with higher LCISF6 (0.63/LCISF6 ) and (0.23/LCISF6 ), respectively, for N2,original and N2,corrected , but the relative differences were stable across disease severity for N2,corrected , but not for N2,original . CONCLUSION Only minor residual differences between FRCN2,corrected and FRCSF6 remained to show that the two methods measure gas volumes very similar in this age range. Small differences in LCI were found. Tidal volume reduction during N2 MBW did not affect differences. The corrected N2 MBW can now be used with confidence in young children with CF, although not interchangeably with SF6 .
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Affiliation(s)
- Rikke M Sandvik
- Danish Paediatric Pulmonary Service, CF Centre Copenhagen, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Per M Gustafsson
- Department of Paediatrics, Central Hospital, Skövde, Sweden.,Institute of Clinical Science, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Anders Lindblad
- Institute of Clinical Science, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.,Department of Pediatrics, CF Center, Queen Silvia Children's Hospital, Gothenburg, Sweden
| | - Frederik Buchvald
- Danish Paediatric Pulmonary Service, CF Centre Copenhagen, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Hanne V Olesen
- Department of Paediatrics and Adolescent Medicine, Danish Center of Pediatric Pulmonology and Allergology, Cystic Fibrosis Centre Aarhus, Aarhus University Hospital, Aarhus, Denmark
| | - Jørgen H Olsen
- Department of Paediatrics and Adolescent Medicine, Danish Center of Pediatric Pulmonology and Allergology, Cystic Fibrosis Centre Aarhus, Aarhus University Hospital, Aarhus, Denmark
| | - Marianne Skov
- Danish Paediatric Pulmonary Service, CF Centre Copenhagen, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Marika N Schmidt
- Danish Paediatric Pulmonary Service, CF Centre Copenhagen, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Mette R Thellefsen
- Danish Paediatric Pulmonary Service, CF Centre Copenhagen, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Paul D Robinson
- Department of Respiratory Medicine, The Children's Hospital at Westmead, Sydney, New South Wales, Australia
| | - Sune Rubak
- Department of Paediatrics and Adolescent Medicine, Danish Center of Pediatric Pulmonology and Allergology, Cystic Fibrosis Centre Aarhus, Aarhus University Hospital, Aarhus, Denmark
| | - Tacjana Pressler
- Danish Paediatric Pulmonary Service, CF Centre Copenhagen, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Kim G Nielsen
- Danish Paediatric Pulmonary Service, CF Centre Copenhagen, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark.,Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
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Rayment JH, Sandoval RA, Roden JP, Schultz KR. Multiple breath washout testing to identify pulmonary chronic graft versus host disease in children after haematopoietic stem cell transplantation. Transplant Cell Ther 2022; 28:328.e1-328.e7. [DOI: 10.1016/j.jtct.2022.02.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 02/02/2022] [Accepted: 02/03/2022] [Indexed: 10/19/2022]
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4
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Marpole R, Ohn M, O'Dea CA, von Ungern-Sternberg BS. Clinical utility of preoperative pulmonary function testing in pediatrics. Paediatr Anaesth 2022; 32:191-201. [PMID: 34875135 DOI: 10.1111/pan.14356] [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: 10/26/2021] [Revised: 11/30/2021] [Accepted: 12/01/2021] [Indexed: 11/28/2022]
Abstract
Perioperative respiratory adverse events pose a significant risk in pediatric anesthesia, and identifying these risks is vital. Traditionally, this is assessed using history and examination. However, the perioperative risk is multifactorial, and children with complex medical backgrounds such as chronic lung disease or obesity may benefit from additional objective preoperative pulmonary function tests. This article summarizes the utility of available pulmonary function assessment tools as preoperative tests in improving post-anesthetic outcomes. Currently, there is no evidence to support or discourage any pulmonary function assessment as a routine preoperative test for children undergoing anesthesia. In addition, there is uncertainty about which patients with the known or suspected respiratory disease require preoperative pulmonary function tests, what time period prior to surgery these are required, and whether spirometry or more sophisticated tests are indicated. Therefore, the need for any test should be based on information obtained from the history and examination, the child's age, and the complexity of the surgery.
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Affiliation(s)
- Rachael Marpole
- Department of Respiratory and Sleep Medicine, Perth Children's Hospital, Nedlands, WA, Australia.,Division of Paediatrics, School of Medical, University of Western Australia, Crawley, WA, Australia
| | - Mon Ohn
- Department of Respiratory and Sleep Medicine, Perth Children's Hospital, Nedlands, WA, Australia.,Division of Paediatrics, School of Medical, University of Western Australia, Crawley, WA, Australia.,Perioperative Medicine Team, Telethon Kids Institute, Nedlands, WA, Australia
| | - Christopher A O'Dea
- Department of Respiratory and Sleep Medicine, Perth Children's Hospital, Nedlands, WA, Australia
| | - Britta S von Ungern-Sternberg
- Perioperative Medicine Team, Telethon Kids Institute, Nedlands, WA, Australia.,Division of Emergency Medicine, Anaesthesia and Pain Medicine, School of Medical, University of Western Australia, Crawley, WA, Australia.,Department of Anaesthesia and Pain Management, Perth Children's Hospital, Nedlands, WA, Australia
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Horsley A, Darquenne C. Better late than never: correcting the error in the Exhalyzer nitrogen washout system. J Appl Physiol (1985) 2021; 131:1286-1287. [PMID: 34528460 PMCID: PMC8560394 DOI: 10.1152/japplphysiol.00581.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- Alexander Horsley
- 1Division of Infection, Immunity and Respiratory Medicine, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Chantal Darquenne
- 2Department of Medicine, University of California, San Diego, La Jolla, California
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6
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Robinson PD, Jensen R, Seeto RA, Stanojevic S, Saunders C, Short C, Davies JC, Ratjen F. Impact of cross-sensitivity error correction on representative nitrogen-based multiple breath washout data from clinical trials. J Cyst Fibros 2021; 21:e204-e207. [PMID: 34526221 DOI: 10.1016/j.jcf.2021.08.033] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 08/27/2021] [Accepted: 08/27/2021] [Indexed: 01/09/2023]
Affiliation(s)
- Paul D Robinson
- Dept of Respiratory Medicine, The Children's Hospital at Westmead, Respiratory Medicine, Locked Bag 4001, Westmead, Sydney, Australia; Discipline of Paediatrics and Child Health, Sydney Medical School, University of Sydney, Australia.
| | - Renee Jensen
- Translational Medicine, Division of Respiratory Medicine, Sellers Chair of Cystic Fibrosis, Hospital for Sick Children, 555 University Avenue, Toronto Ontario M5G 1 × 8, Canada
| | - Ryan A Seeto
- Translational Medicine, Division of Respiratory Medicine, Sellers Chair of Cystic Fibrosis, Hospital for Sick Children, 555 University Avenue, Toronto Ontario M5G 1 × 8, Canada
| | - Sanja Stanojevic
- Dept of Community Health and Epidemiology, Dalhousie University, Halifax, Canada
| | - Clare Saunders
- National Heart and Lung Institute, Imperial College London, United Kingdom; Royal Brompton Hospital, Guys & St Thomas' NHS Foundation Trust, London, United Kingdom
| | - Christopher Short
- National Heart and Lung Institute, Imperial College London, United Kingdom; Royal Brompton Hospital, Guys & St Thomas' NHS Foundation Trust, London, United Kingdom
| | - Jane C Davies
- National Heart and Lung Institute, Imperial College London, United Kingdom; Royal Brompton Hospital, Guys & St Thomas' NHS Foundation Trust, London, United Kingdom
| | - Felix Ratjen
- Translational Medicine, Division of Respiratory Medicine, Sellers Chair of Cystic Fibrosis, Hospital for Sick Children, 555 University Avenue, Toronto Ontario M5G 1 × 8, Canada; University of Toronto, Toronto, Canada.
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7
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Wyler F, Oestreich MAH, Frauchiger BS, Ramsey KA, Latzin PT. Correction of sensor crosstalk error in Exhalyzer D multiple-breath washout device significantly impacts outcomes in children with cystic fibrosis. J Appl Physiol (1985) 2021; 131:1148-1156. [PMID: 34351818 DOI: 10.1152/japplphysiol.00338.2021] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
RATIONALE Nitrogen multiple-breath washout is an established technique to assess functional residual capacity and ventilation inhomogeneity in the lung. Accurate measurement of gas concentrations is essential for the appropriate calculation of clinical outcomes. OBJECTIVES We investigated the accuracy of oxygen and carbon dioxide gas sensor measurements used for the indirect calculation of nitrogen concentration in a commercial multiple-breath washout device (Exhalyzer D, Eco Medics AG, Duernten, Switzerland) and its impact on functional residual capacity and lung clearance index. METHODS High precision calibration gas mixtures and mass spectrometry were used to evaluate sensor output. We assessed the impact of corrected signal processing on multiple-breath washout outcomes in a dataset of healthy children and children with cystic fibrosis using custom analysis software. RESULTS We found inadequate correction for the cross sensitivity of the oxygen and carbon dioxide sensors in the Exhalyzer D device. This results in an overestimation of expired nitrogen concentration, and consequently multiple-breath washout outcomes. Breath-by-breath correction of this error reduced the mean (SD) cumulative expired volume by 19.6 (5.0)%, functional residual capacity by 8.9 (2.2)%, and lung clearance index by 11.9 (4.0)%. It also substantially reduced the level of the tissue nitrogen signal at the end of measurements. CONCLUSIONS Inadequate correction for cross sensitivity in the oxygen and carbon dioxide gas sensors of the Exhalyzer D device leads to an overestimation of functional residual capacity and lung clearance index. Correction of this error is possible and could be applied by re-analyzing the measurements in an updated software version.
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Affiliation(s)
- Florian Wyler
- Division of Paediatric Respiratory Medicine and Allergology, Department of Paediatrics, Inselspital, Bern University Hospital, University of Bern, Switzerland
| | - Marc-Alexander H Oestreich
- Division of Paediatric Respiratory Medicine and Allergology, Department of Paediatrics, Inselspital, Bern University Hospital, University of Bern, Switzerland.,Graduate School for Health Sciences, University of Bern, Switzerland
| | - Bettina Sarah Frauchiger
- Division of Paediatric Respiratory Medicine and Allergology, Department of Paediatrics, Inselspital, Bern University Hospital, University of Bern, Switzerland.,Graduate School of Cellular and Biomedical Sciences, University of Bern, Switzerland
| | - Kathryn A Ramsey
- Division of Paediatric Respiratory Medicine and Allergology, Department of Paediatrics, Inselspital, Bern University Hospital, University of Bern, Switzerland
| | - Philipp T Latzin
- Division of Paediatric Respiratory Medicine and Allergology, Department of Paediatrics, Inselspital, Bern University Hospital, University of Bern, Switzerland
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8
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Sandvik R, Gustafsson PM, Lindblad A, Robinson PD, Nielsen K. Improved agreement between N 2 and SF 6 multiple-breath washout in healthy infants and toddlers with improved EXHALYZER D sensor performance. J Appl Physiol (1985) 2021; 131:107-118. [PMID: 34043468 DOI: 10.1152/japplphysiol.00129.2021] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Recent studies indicate limited utility of nitrogen multiple-breath washout (N2MBW) in infancy and advocate for using sulfur hexafluoride (SF6) MBW in this age-group. Modern N2MBW systems, such as EXHALYZER D (ECO MEDICS AG, Duernten, Switzerland), use O2 and CO2 sensors to calculate N2 concentrations (in principle, N2% = 100 - CO2% - O2%). High O2 and CO2 concentrations have now been shown to significantly suppress signal output from the other sensor, raising apparent N2 concentrations. We examined whether improved EXHALYZER D N2 signal, accomplished after thorough examination of this CO2 and O2 interaction on gas sensors and its correction, leads to better agreement between N2MBW and SF6MBW in healthy infants and toddlers. Within the same session, 52 healthy children aged 1-36 mo [mean = 1.30 (SD = 0.72) yr] completed SF6MBW and N2MBW recordings (EXHALYZER D, SPIROWARE version 3.2.1) during supine quiet sleep. SF6 and N2 SPIROWARE files were reanalyzed offline with in-house software using identical algorithms as in SPIROWARE with or without application of the new correction factors for N2MBW provided by ECO MEDICS AG. Applying the improved N2 signal significantly reduced mean [95% confidence interval (CI)] differences between N2MBW and SF6MBW recorded functional residual capacity (FRC) and lung clearance index (LCI): for FRC, from 26.1 (21.0, 31.2) mL, P < 0.0001, to 1.18 (-2.3, 4.5) mL, P = 0.5, and for LCI, from 1.86 (1.68, 2.02), P < 0.001, to 0.44 (0.33, 0.55), P < 0.001. Correction of N2 signal for CO2 and O2 interactions on gas sensors resulted in markedly closer agreement between N2MBW and SF6MBW outcomes in healthy infants and toddlers.NEW & NOTEWORTHY Modern nitrogen multiple-breath washout (N2MBW) systems such as EXHALYZER D use O2 and CO2 sensors to calculate N2 concentrations. New corrections for interactions between high O2 and CO2 concentrations on the gas sensors now provide accurate N2 signals. The correct N2 signal led to much improved agreement between N2MBW and sulfur hexafluoride (SF6) MBW functional residual capacity (FRC) and lung clearance index (LCI) in 52 sleeping healthy infants and toddlers, suggesting a role for N2MBW in this age-group.
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Affiliation(s)
- Rikke Sandvik
- Danish Paediatric Pulmonary Service, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Per M Gustafsson
- Department of Paediatrics, Central Hospital, Skövde, Sweden.,Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Anders Lindblad
- Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.,Gothenburg CF Centre, Queen Silvia Children's Hospital, Gothenburg, Sweden
| | - Paul D Robinson
- Department of Respiratory Medicine, The Children's Hospital at Westmead, Westmead, New South Wales, Australia.,The Discipline of Paediatrics and Child Health, The University of Sydney, Sydney, New South Wales, Australia
| | - Kim Nielsen
- Danish Paediatric Pulmonary Service, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark.,Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
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9
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Magor-Elliott SRM, Fullerton CJ, Richmond G, Ritchie GAD, Robbins PA. A dynamic model of the body gas stores for carbon dioxide, oxygen, and inert gases that incorporates circulatory transport delays to and from the lung. J Appl Physiol (1985) 2021; 130:1383-1397. [PMID: 33475459 PMCID: PMC8354828 DOI: 10.1152/japplphysiol.00764.2020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Many models of the body’s gas stores have been generated for specific purposes. Here, we seek to produce a more general purpose model that: 1) is relevant for both respiratory (CO2 and O2) and inert gases; 2) is based firmly on anatomy and not arbitrary compartments; 3) can be scaled to individuals; and 4) incorporates arterial and venous circulatory delays as well as tissue volumes so that it can reflect rapid transients with greater precision. First, a “standard man” of 11 compartments was produced, based on data compiled by the International Radiation Protection Commission. Each compartment was supplied via its own parallel circulation, the arterial and venous volumes of which were based on reported tissue blood volumes together with data from a detailed anatomical model for the large arteries and veins. A previously published model was used for the blood gas chemistry of CO2 and O2. It was not permissible ethically to insert pulmonary artery catheters into healthy volunteers for model validation. Therefore, validation was undertaken by comparing model predictions with previously published data and by comparing model predictions with experimental data for transients in gas exchange at the mouth following changes in alveolar gas composition. Overall, model transients were fastest for O2, intermediate for CO2, and slowest for N2. There was good agreement between model estimates and experimentally measured data. Potential applications of the model include estimation of closed-loop gain for the ventilatory chemoreflexes and improving the precision associated with multibreath washout testing and respiratory measurement of cardiac output. NEW & NOTEWORTHY A model for the body gas stores has been generated that is applicable to both respiratory gases (CO2 and O2) and inert gases. It is based on anatomical details for organ volumes and blood contents together with anatomical details of the large arteries. It can be scaled to the body size and composition of different individuals. The model enables mixed venous gas compositions to be predicted from the systemic arterial compositions.
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Affiliation(s)
| | | | - Graham Richmond
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, United Kingdom
| | - Grant A D Ritchie
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, United Kingdom
| | - Peter A Robbins
- Department of Physiology, Anatomy and Genetics, University of Oxford, United Kingdom
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10
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Sandhu D, Ritchie GAD, Robbins PA. The differing physiology of nitrogen and tracer gas multiple-breath washout techniques. ERJ Open Res 2021; 7:00858-2020. [PMID: 33898618 PMCID: PMC8053910 DOI: 10.1183/23120541.00858-2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Accepted: 03/02/2021] [Indexed: 11/08/2022] Open
Abstract
Background Multiple-breath washout techniques are increasingly used to assess lung function. The principal statistic obtained is the lung clearance index (LCI), but values obtained for LCI using the nitrogen (N2)-washout technique are higher than those obtained using an exogenous tracer gas such as sulfur hexafluoride. This study explored whether the pure oxygen (O2) used for the N2 washout could underlie these higher values. Methods A model of a homogenous, reciprocally ventilated acinus was constructed. Perfusion was kept constant, and ventilation adjusted by varying the swept volume during the breathing cycle. The blood supplying the acinus had a standard mixed-venous composition. Carbon dioxide and O2 exchange between the blood and acinar gas proceeded to equilibrium. The model was initialised with either air or air plus tracer gas as the inspirate. Washouts were conducted with pure O2 for the N2 washout or with air for the tracer gas washout. Results At normal ventilation/perfusion (V′/Q′) ratios, the rate of washout of N2 and exogenous tracer gas was almost indistinguishable. At low V′/Q′, the N2 washout lagged the tracer gas washout. At very low V′/Q′, N2 became trapped in the acinus. Under low V′/Q′ conditions, breathing pure O2 introduced a marked asymmetry between the inspiratory and expiratory gas flow rates that was not present when breathing air. Discussion The use of pure O2 to washout N2 increases O2 uptake in low V′/Q′ units. This generates a background gas flow into the acinus that opposes flow out of the acinus during expiration, and so delays the washout of N2. Differences in lung clearance index between nitrogen and exogenous tracer gas multiple-breath washout tests can be explained by the oxygen used to wash out nitrogen generating convective flows of gas into low ventilation/perfusion unitshttps://bit.ly/3l0xq0G
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Affiliation(s)
- Dominic Sandhu
- Dept of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford, UK
| | - Grant A D Ritchie
- Dept of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford, UK
| | - Peter A Robbins
- Dept of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
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11
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Trinkmann F, Maros M, Roth K, Hermanns A, Schäfer J, Gawlitza J, Saur J, Akin I, Borggrefe M, Herth FJF, Ganslandt T. Multiple breath washout (MBW) testing using sulfur hexafluoride: reference values and influence of anthropometric parameters. Thorax 2021; 76:380-386. [PMID: 33593931 DOI: 10.1136/thoraxjnl-2020-214717] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 01/07/2021] [Accepted: 01/20/2021] [Indexed: 11/04/2022]
Abstract
BACKGROUND Multiple breath washout (MBW) using sulfur hexafluoride (SF6) has the potential to reveal ventilation heterogeneity which is frequent in patients with obstructive lung disease and associated small airway dysfunction. However, reference data are scarce for this technique and mostly restricted to younger cohorts. We therefore set out to evaluate the influence of anthropometric parameters on SF6-MBW reference values in pulmonary healthy adults. METHODS We evaluated cross-sectional data from 100 pulmonary healthy never-smokers and smokers (mean 51 (SD 20), range 20-88 years). Lung clearance index (LCI), acinar (Sacin) and conductive (Scond) ventilation heterogeneity were derived from triplicate SF6-MBW measurements. Global ventilation heterogeneity was calculated for the 2.5% (LCI2.5) and 5% (LCI5) stopping points. Upper limit of normal (ULN) was defined as the 95th percentile. RESULTS Age was the only meaningful parameter influencing SF6-MBW parameters, explaining 47% (CI 33% to 59%) of the variance in LCI, 32% (CI 18% to 47%) in Sacin and 10% (CI 2% to 22%) in Scond. Mean LCI increases from 6.3 (ULN 7.4) to 8.8 (ULN 9.9) in subjects between 20 and 90 years. Smoking accounted for 2% (CI 0% to 8%) of the variability in LCI, 4% (CI 0% to 13%) in Sacin and 3% (CI 0% to 13%) in Scond. CONCLUSION SF6-MBW outcome parameters showed an age-dependent increase from early adulthood to old age. The effect was most pronounced for global and acinar ventilation heterogeneity and smaller for conductive ventilation heterogeneity. No influence of height, weight and sex was seen. Reference values can now be provided for all important SF6-MBW outcome parameters over the whole age range. TRIAL REGISTRATION NUMBER NCT04099225.
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Affiliation(s)
- Frederik Trinkmann
- 1st Department of Medicine, University Medical Centre Mannheim, Mannheim, Baden-Württemberg, Germany .,Department of Pneumology and Critical Care Medicine, Thoraxklinik at University Hospital Heidelberg, Translational Lung Research Centre Heidelberg (TLRC), Member of German Centre for Lung Research (DZL), Heidelberg, Baden-Württemberg, Germany.,Department of Biomedical Informatics, Centre for Preventive Medicine & Digital Health Baden-Württemberg, University Medical Centre Mannheim, Mannheim, Germany
| | - Máté Maros
- Department of Biomedical Informatics, Centre for Preventive Medicine & Digital Health Baden-Württemberg, University Medical Centre Mannheim, Mannheim, Germany.,Department of Neuroradiology, University Medical Centre Mannheim, Mannheim, Germany
| | - Katharina Roth
- 1st Department of Medicine, University Medical Centre Mannheim, Mannheim, Baden-Württemberg, Germany
| | - Arne Hermanns
- 1st Department of Medicine, University Medical Centre Mannheim, Mannheim, Baden-Württemberg, Germany
| | - Julia Schäfer
- 1st Department of Medicine, University Medical Centre Mannheim, Mannheim, Baden-Württemberg, Germany
| | - Joshua Gawlitza
- Institute for Clinical Radiology and Nuclear Medicine, University Medical Centre Mannheim, Mannheim, Germany
| | - Joachim Saur
- 1st Department of Medicine, University Medical Centre Mannheim, Mannheim, Baden-Württemberg, Germany
| | - Ibrahim Akin
- 1st Department of Medicine, University Medical Centre Mannheim, Mannheim, Baden-Württemberg, Germany.,DZHK (German Centre for Cardiovascular Research), Mannheim, Germany
| | - Martin Borggrefe
- 1st Department of Medicine, University Medical Centre Mannheim, Mannheim, Baden-Württemberg, Germany.,DZHK (German Centre for Cardiovascular Research), Mannheim, Germany
| | - Felix J F Herth
- Department of Pneumology and Critical Care Medicine, Thoraxklinik at University Hospital Heidelberg, Translational Lung Research Centre Heidelberg (TLRC), Member of German Centre for Lung Research (DZL), Heidelberg, Baden-Württemberg, Germany
| | - Thomas Ganslandt
- Department of Biomedical Informatics, Centre for Preventive Medicine & Digital Health Baden-Württemberg, University Medical Centre Mannheim, Mannheim, Germany
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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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Gustafsson PM, Kadar L, Kjellberg S, Andersson L, Lindblad A, Robinson PD. End-expiratory lung volume remains stable during N 2 MBW in healthy sleeping infants. Physiol Rep 2020; 8:e14477. [PMID: 32845567 PMCID: PMC7448799 DOI: 10.14814/phy2.14477] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Accepted: 05/13/2020] [Indexed: 11/24/2022] Open
Abstract
We have previously shown that functional residual capacity (FRC) and lung clearance index were significantly greater in sleeping healthy infants when measured by N2 (nitrogen) washout using 100% O2 (oxygen) versus 4% SF6 (sulfur hexafluoride) washout using air. Following 100% O2 exposure, tidal volumes decreased by over 30%, while end-expiratory lung volume (EELV, i.e., FRC) rose markedly based on ultrasonic flow meter assessments. In the present study to investigate the mechanism behind the observed changes, N2 MBW was performed in 10 separate healthy full-term spontaneously sleeping infants, mean (range) 26 (18-31) weeks, with simultaneous EELV monitoring (respiratory inductance plethysmography, RIP) and oxygen uptake (V´O2 ) assessment during prephase air breathing, during N2 washout by exposure to 100% O2 , and subsequently during air breathing. While flow meter signals suggested a rise in ELLV by mean (SD) 26 (9) ml over the washout period, RIP signals demonstrated no EELV change. V'O2 /FRC ratio during air breathing was mean (SD) 0.43 (0.08)/min, approximately seven times higher than that calculated from adult data. We propose that our previously reported flow meter-based overestimation of EELV was in fact a physiological artifact caused by rapid and marked movement of O2 across the alveolar capillary membrane into the blood and tissue during 100% O2 exposure, without concomitant transfer of N2 to the same degree in the opposite direction. This may be driven by the high observed O2 consumption and resulting cardiac output encountered in infancy. Furthermore, the low resting lung volume in infancy may make this error in lung volume determination by N2 washout relatively large.
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Affiliation(s)
- Per M. Gustafsson
- Department of PediatricsCentral HospitalSkövdeSweden
- The Sahlgrenska Academy at the University of GothenburgGothenburgSweden
| | - Laszlo Kadar
- Department of PediatricsCentral HospitalSkövdeSweden
| | | | | | - Anders Lindblad
- The Sahlgrenska Academy at the University of GothenburgGothenburgSweden
- CF CentreQueen Silvia Children's HospitalGothenburgSweden
| | - Paul D. Robinson
- Department of Respiratory MedicineThe Children’s Hospital at WestmeadSydneyNSWAustralia
- Discipline of Paediatrics and Child HealthSydney Medical SchoolUniversity of SydneySydneyNSWAustralia
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14
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Horsley AR, Alrumuh A, Bianco B, Bayfield K, Tomlinson J, Jones A, Maitra A, Cunningham S, Smith J, Fullwood C, Pandyan A, Gilchrist FJ. Lung clearance index in healthy volunteers, measured using a novel portable system with a closed circuit wash-in. PLoS One 2020; 15:e0229300. [PMID: 32097445 PMCID: PMC7041809 DOI: 10.1371/journal.pone.0229300] [Citation(s) in RCA: 3] [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: 09/26/2019] [Accepted: 02/03/2020] [Indexed: 11/18/2022] Open
Abstract
Introduction Lung clearance index (LCI) is a sensitive measure of early lung disease, but adoption into clinical practice has been slow. Challenges include the time taken to perform each test. We recently described a closed-circuit inert gas wash-in method that reduces overall testing time by decreasing the time to equilibration. The aim of this study was to define a normative range of LCI in healthy adults and children derived using this method. We were also interested in the feasibility of using this system to measure LCI in a community setting. Methods LCI was assessed in healthy volunteers at three hospital sites and in two local primary schools. Volunteers completed three washout repeats at a single visit using the closed circuit wash-in method (0.2% SF6 wash-in tracer gas to equilibrium, room air washout). Results 160 adult and paediatric subjects successfully completed LCI assessment (95%) (100 in hospital, 60 in primary schools). Median coefficient of variation was 3.4% for LCI repeats and 4.3% for FRC. Mean (SD) LCI for the analysis cohort (n = 53, age 5–39 years) was 6.10 (0.42), making the upper limit of normal LCI 6.8. There was no relationship between LCI and multiple demographic variables. Median (interquartile range) total test time was 18.7 (16.0–22.5) minutes. Conclusion The closed circuit method of LCI measurement can be successfully and reproducibly measured in healthy volunteers, including in out-of-hospital settings. Normal range appears stable up to 39 years. With few subjects older than 40 years, further work is required to define the normal limits above this age.
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Affiliation(s)
- Alex R. Horsley
- Division of Infection, Immunity & Respiratory Medicine, Faculty of Biology Medicine and Health, University of Manchester, Manchester, United Kingdom
- Manchester Adult CF Centre, Manchester University NHS Foundation Trust, Manchester, United Kingdom
- * E-mail:
| | - Amnah Alrumuh
- Institute of Applied Clinical Science, Keele University, Newcastle-under-Lyme, United Kingdom
- Royal Stoke University Hospital, University Hospitals of North Midlands NHS Trust, Stoke-on-Trent, United Kingdom
| | - Brooke Bianco
- Manchester Adult CF Centre, Manchester University NHS Foundation Trust, Manchester, United Kingdom
- NIHR Manchester Clinical Research Facility, Manchester, United Kingdom
| | - Katie Bayfield
- NIHR Manchester Clinical Research Facility, Manchester, United Kingdom
| | - Joanne Tomlinson
- Royal Stoke University Hospital, University Hospitals of North Midlands NHS Trust, Stoke-on-Trent, United Kingdom
| | - Andrew Jones
- Division of Infection, Immunity & Respiratory Medicine, Faculty of Biology Medicine and Health, University of Manchester, Manchester, United Kingdom
- Manchester Adult CF Centre, Manchester University NHS Foundation Trust, Manchester, United Kingdom
| | - Anirban Maitra
- Royal Manchester Children’s Hospital, Manchester University NHS Foundation Trust, Manchester, United Kingdom
| | - Steve Cunningham
- Centre for Inflammation Research, University of Edinburgh, Edinburgh, United Kingdom
| | - Jaclyn Smith
- Division of Infection, Immunity & Respiratory Medicine, Faculty of Biology Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Catherine Fullwood
- Research and Innovation, Manchester University NHS Foundation Trust, Manchester, United Kingdom
- Centre for Biostatistics, Faculty of Biology Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Anand Pandyan
- Institute of Applied Clinical Science, Keele University, Newcastle-under-Lyme, United Kingdom
| | - Francis J. Gilchrist
- Institute of Applied Clinical Science, Keele University, Newcastle-under-Lyme, United Kingdom
- Royal Stoke University Hospital, University Hospitals of North Midlands NHS Trust, Stoke-on-Trent, United Kingdom
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Trinkmann F, Lenz SA, Schäfer J, Gawlitza J, Schroeter M, Gradinger T, Akin I, Borggrefe M, Ganslandt T, Saur J. Feasibility and clinical applications of multiple breath wash-out (MBW) testing using sulphur hexafluoride in adults with bronchial asthma. Sci Rep 2020; 10:1527. [PMID: 32001782 PMCID: PMC6992773 DOI: 10.1038/s41598-020-58538-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Accepted: 01/15/2020] [Indexed: 11/17/2022] Open
Abstract
Ventilation heterogeneity is frequent in bronchial asthma and can be assessed using multiple breath wash-out testing (MBW). Most data is available in paediatric patients and using nitrogen as a tracer gas. We aimed to evaluate sulphur hexafluoride (SF6) MBW in adult asthmatics. Spirometry, whole-body plethysmography, impulse oscillometry and SF6-MBW were prospectively performed. MBW parameters reflecting global (lung clearance index, LCI), acinar (Sacin) and conductive (Scond) ventilation heterogeneity were derived from three consecutive wash-outs. LCI was calculated for the traditional 2.5% and an earlier 5% stopping point that has the potential to reduce wash-out times. 91 asthmatics (66%) and 47 non-asthmatic controls (34%) were included in final analysis. LCI2.5 and LCI5 were higher in asthmatics (p < 0.001). Likewise, Sacin and Scond were elevated (p < 0.001 and p < 0.01). Coefficient of variation was 3.4% for LCI2.5 and 3.5% for LCI5 in asthmatics. Forty-one asthmatic patients had normal spirometry. ROC analysis revealed an AUC of 0.906 for the differentiation from non-asthmatic controls exceeding diagnostic performance of individual and conventional parameters (AUC = 0.819, p < 0.05). SF6-MBW is feasible and reproducible in adult asthmatics. Ventilation heterogeneity is increased as compared to non-asthmatic controls persisting in asthmatic patients with normal spirometry. Diagnostic performance is not affected using an earlier LCI stopping point while reducing wash-out duration considerably.
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Affiliation(s)
- Frederik Trinkmann
- 1st Department of Medicine (Cardiology, Angiology, Pulmonary and Intensive Care), University Medical Centre Mannheim, Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany. .,Department of Biomedical Informatics of the Heinrich-Lanz-Centre, University Medical Centre Mannheim, Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany.
| | - Steffi A Lenz
- 1st Department of Medicine (Cardiology, Angiology, Pulmonary and Intensive Care), University Medical Centre Mannheim, Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany
| | - Julia Schäfer
- 1st Department of Medicine (Cardiology, Angiology, Pulmonary and Intensive Care), University Medical Centre Mannheim, Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany
| | - Joshua Gawlitza
- Institute of Clinical Radiology and Nuclear Medicine, University Medical Centre Mannheim, Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany
| | - Michele Schroeter
- 1st Department of Medicine (Cardiology, Angiology, Pulmonary and Intensive Care), University Medical Centre Mannheim, Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany
| | - Tobias Gradinger
- Department of Biomedical Informatics of the Heinrich-Lanz-Centre, University Medical Centre Mannheim, Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany
| | - Ibrahim Akin
- 1st Department of Medicine (Cardiology, Angiology, Pulmonary and Intensive Care), University Medical Centre Mannheim, Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany.,DZHK (German Centre for Cardiovascular Research), partner site Mannheim, University Medical Centre Mannheim, Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany
| | - Martin Borggrefe
- 1st Department of Medicine (Cardiology, Angiology, Pulmonary and Intensive Care), University Medical Centre Mannheim, Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany.,DZHK (German Centre for Cardiovascular Research), partner site Mannheim, University Medical Centre Mannheim, Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany
| | - Thomas Ganslandt
- Department of Biomedical Informatics of the Heinrich-Lanz-Centre, University Medical Centre Mannheim, Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany
| | - Joachim Saur
- 1st Department of Medicine (Cardiology, Angiology, Pulmonary and Intensive Care), University Medical Centre Mannheim, Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany
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Nielsen JG. Nitrogen offset in N 2 multiple washout method. ERJ Open Res 2020; 6:00335-2019. [PMID: 32201687 PMCID: PMC7073414 DOI: 10.1183/23120541.00335-2019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 12/04/2019] [Indexed: 11/18/2022] Open
Abstract
In a recent study of the nitrogen multiple breath washout (MBW) method to measure lung clearance index (LCI) using the Exhalyzer device (Eco Medics AG, Dürnten, Switzerland), Bayfieldet al. [1] reported an N2 offset signal of ∼1.4%, slightly higher than reported in several previous studies. There was no similar offset using sulfur hexafluoride as the tracer gas measured with the Innocor device (Innovision ApS, Glamsbjerg, Denmark), a finding that is in line with previous reports. The results of this and other studies are extremely important as the Exhalyzer is the device that is currently used in ≥100 cystic fibrosis centres in the European Cystic Fibrosis Society Clinical Trial Network and the Cystic Fibrosis Foundation Therapeutics Development Network in various drug trials [2]. An offset in the nitrogen signal significantly affects LCI measured by the N2 MBW methodhttp://bit.ly/35hwOuH
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Bayfield KJ, Horsley A, Alton E, Irving S, Bush A, Davies JC. Simultaneous sulfur hexafluoride and nitrogen multiple-breath washout (MBW) to examine inherent differences in MBW outcomes. ERJ Open Res 2019; 5:00234-2018. [PMID: 31720295 PMCID: PMC6826248 DOI: 10.1183/23120541.00234-2018] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Accepted: 08/27/2019] [Indexed: 11/10/2022] Open
Abstract
Multiple-breath washout (MBW) can be performed with different gases (sulfur hexafluoride (SF6) and nitrogen (N2)) and different devices, all of which give discrepant results. This study aimed to confirm previously reported differences and explore factors influencing discrepant results; equipment factors or the physical properties of gases used. Inherent differences in simultaneous SF6 and N2 washout on the mass spectrometer show why results are never comparablehttp://bit.ly/34k52Oo
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Affiliation(s)
- Katie J Bayfield
- Imperial College London, London, UK.,Royal Brompton and Harefield NHS Foundation Trust, London, UK.,European Cystic Fibrosis Society Clinical Trials Network, Lung Clearance Index Core Facility, London, UK.,The Children's Hospital at Westmead, Sydney, Australia
| | - Alex Horsley
- Institute of Inflammation and repair, Education and Research centre, University of Manchester, University Hospital of South Manchester, Manchester, UK
| | - Eric Alton
- Imperial College London, London, UK.,Royal Brompton and Harefield NHS Foundation Trust, London, UK
| | - Samantha Irving
- Imperial College London, London, UK.,Royal Brompton and Harefield NHS Foundation Trust, London, UK
| | - Andrew Bush
- Imperial College London, London, UK.,Royal Brompton and Harefield NHS Foundation Trust, London, UK
| | - Jane C Davies
- Imperial College London, London, UK.,Royal Brompton and Harefield NHS Foundation Trust, London, UK.,European Cystic Fibrosis Society Clinical Trials Network, Lung Clearance Index Core Facility, London, UK
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Horsley A, Nissenbaum C, Guglani L, Weiner D. Comment on Comparison of lung clearance index determined by washout of N2 and SF6 in infants and preschool children with cystic fibrosis. J Cyst Fibros 2019; 18:e26-e27. [DOI: 10.1016/j.jcf.2018.12.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 12/17/2018] [Accepted: 12/17/2018] [Indexed: 11/15/2022]
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