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Noble PB, Donovan GM. If your patient with asthma wheezes when sitting or lying quietly, lung function testing may reveal small airway disease. Eur Respir J 2023; 61:61/3/2202307. [PMID: 36997235 DOI: 10.1183/13993003.02307-2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Accepted: 02/06/2023] [Indexed: 04/01/2023]
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2
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Handley BM, Jeagal E, Schoeffel RE, Badal T, Chapman DG, Farrow CE, King GG, Robinson PD, Milne S, Thamrin C. Controlled versus free breathing for multiple breath nitrogen washout in healthy adults. ERJ Open Res 2021; 7:00435-2020. [PMID: 33532457 PMCID: PMC7836463 DOI: 10.1183/23120541.00435-2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 10/16/2020] [Indexed: 11/18/2022] Open
Abstract
Multiple breath nitrogen washout (MBNW) quantifies ventilation heterogeneity. Two distinct protocols are currently used for MBNW testing: “controlled breathing”, with targeted tidal volume (VT) and respiratory rate (RR); and “free breathing”, with no constraints on breathing pattern. Indices derived from the two protocols (functional residual capacity (FRC), lung clearance index (LCI), Scond, Sacin) have not been directly compared in adults. We aimed to determine whether MBNW indices are comparable between protocols, to identify factors underlying any between-protocol differences and to determine the between-session variabilities of each protocol. We performed MBNW testing by both protocols in 27 healthy adult volunteers, applying the currently proposed correction for VT to Scond and Sacin derived from free breathing. To establish between-session variability, we repeated testing in 15 volunteers within 3 months. While FRC was comparable between controlled versus free breathing (3.17 (0.98) versus 3.18 (0.94) L, p=0.88), indices of ventilation heterogeneity derived from the two protocols were not, with poor correlation for Scond (r=0.18, p=0.36) and significant bias for Sacin (0.057 (0.021) L−1versus 0.085 (0.038) L−1, p=0.0004). Between-protocol differences in Sacin were related to differences in the breathing pattern, i.e. VT (p=0.004) and RR (p=0.01), rather than FRC. FRC and LCI showed good between-session repeatability, but Scond and Sacin from free breathing showed poor repeatability with wide limits of agreement. These findings have implications for the ongoing clinical implementation of MBNW, as they demonstrate that Scond and Sacin from free breathing, despite VT correction, are not equivalent to the controlled breathing protocol. The poor between-session repeatability of Scond during free breathing may limit its clinical utility. Phase 3 slopes indices derived from “free breathing” and “controlled breathing” MBNW protocols are not comparable, and differences are related to breathing patterns. These findings have implications for the ongoing clinical implementation of MBNW.https://bit.ly/35oQYnW
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Affiliation(s)
- Blake M Handley
- Dept of Respiratory Medicine, Royal North Shore Hospital, St Leonards, NSW, Australia.,Woolcock Institute of Medical Research, University of Sydney, Glebe, NSW, Australia
| | - Edward Jeagal
- Woolcock Institute of Medical Research, University of Sydney, Glebe, NSW, Australia
| | - Robin E Schoeffel
- Dept of Respiratory Medicine, Royal North Shore Hospital, St Leonards, NSW, Australia
| | - Tanya Badal
- Woolcock Institute of Medical Research, University of Sydney, Glebe, NSW, Australia
| | - David G Chapman
- Woolcock Institute of Medical Research, University of Sydney, Glebe, NSW, Australia.,Translational Airways Group, School of Life Sciences, Faculty of Science, University of Technology Sydney, Ultimo, NSW, Australia
| | - Catherine E Farrow
- Woolcock Institute of Medical Research, University of Sydney, Glebe, NSW, Australia.,Dept of Respiratory and Sleep Medicine, Westmead Hospital, Westmead, NSW, Australia
| | - Gregory G King
- Dept of Respiratory Medicine, Royal North Shore Hospital, St Leonards, NSW, Australia.,Woolcock Institute of Medical Research, University of Sydney, Glebe, NSW, Australia.,Faculty of Medicine and Health, University of Sydney, Camperdown, NSW, Australia
| | - Paul D Robinson
- Dept of Respiratory Medicine, The Children's Hospital at Westmead, Westmead, NSW, Australia
| | - Stephen Milne
- Faculty of Medicine and Health, University of Sydney, Camperdown, NSW, Australia.,Centre for Heart Lung Innovation, St Paul's Hospital and Division of Respiratory Medicine, University of British Columbia, Vancouver, BC, Canada.,These authors contributed equally
| | - Cindy Thamrin
- Woolcock Institute of Medical Research, University of Sydney, Glebe, NSW, Australia.,Faculty of Medicine and Health, University of Sydney, Camperdown, NSW, Australia.,These authors contributed equally
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3
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Verbanck S, Schuermans D, Paiva M, Robinson PD, Vanderhelst E. Mitigating increased variability of multiple breath washout indices due to tidal breathing. Eur Respir J 2020; 57:13993003.02765-2020. [PMID: 32994196 DOI: 10.1183/13993003.02765-2020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 09/14/2020] [Indexed: 11/05/2022]
Affiliation(s)
- Sylvia Verbanck
- Respiratory Division, University Hospital UZ Brussel, Vrije Universiteit Brussel, Brussels, Belgium
| | - Daniel Schuermans
- Respiratory Division, University Hospital UZ Brussel, Vrije Universiteit Brussel, Brussels, Belgium
| | - Manuel Paiva
- Respiratory Division, University Hospital Erasme, Université Libre de Bruxelles, Brussels, Belgium
| | - Paul D Robinson
- Dept of Respiratory Medicine, The Children's Hospital at Westmead, Sydney, Australia
| | - Eef Vanderhelst
- Respiratory Division, University Hospital UZ Brussel, Vrije Universiteit Brussel, Brussels, Belgium
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4
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Karlsson J, Fodor GH, Santos Rocha A, Lin N, Habre W, Wallin M, Hallbäck M, Peták F, Lönnqvist P. End-expiratory lung volume assessment using helium and carbon dioxide in an experimental model of pediatric capnoperitoneum. Acta Anaesthesiol Scand 2020; 64:1106-1113. [PMID: 32314349 DOI: 10.1111/aas.13607] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2019] [Revised: 02/08/2020] [Accepted: 04/08/2020] [Indexed: 12/12/2022]
Abstract
BACKGROUND Capnoperitoneum during laparoscopy leads to cranial shift of the diaphragm, loss in lung volume, and risk of impaired gas exchange. Infants are susceptible to these changes and bedside assessment of lung volume during laparoscopy might assist with optimizing the ventilation. Thus, the primary aim was to investigate the monitoring value of a continuous end-expiratory lung volume (EELV) assessment method based on CO2 dynamics ( EELV CO 2 ) in a pediatric capnoperitoneum model by evaluating the correlation and trending ability against helium washout (EELVHe ). METHODS Intra-abdominal pressure (IAP) was randomly varied between 0, 6, and 12 mm Hg with CO2 insufflation, while positive end-expiratory pressure (PEEP) levels of 3, 6, and 9 cm H2 O were randomly applied in eight anesthetized and mechanically ventilated chinchilla rabbits. Concomitant EELV CO 2 and EELVHe and lung clearance index (LCI) were obtained under each experimental condition. RESULTS Significant correlations were found between EELV CO 2 and EELVHe before capnoperitoneum (r = .85, P < .001), although increased IAP distorted this relationship. The negative influence of IAP was counteracted by the application of PEEP 9, which restored the correlation between EELV CO 2 and EELVHe and resulted in 100% concordance rate between the methods regarding changes in lung volume. EELVHe and LCI showed a curvilinear relationship, and an EELVHe of approximately 20 mL kg-1 , determined with a receiver operating characteristic curve, was associated with near-normal LCI values. CONCLUSION In this animal model of pediatric capnoperitoneum, reliable assessment of changes in EELV based on EELV CO 2 requires an open lung strategy, defined as EELV above approximately 20 mL kg-1 .
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Affiliation(s)
- Jacob Karlsson
- Department of Physiology and Pharmacology (FYFA) Eriksson I Lars group‐Section of Anesthesiology and Intensive Care Karolinska Institute Stockholm Sweden
- Pediatric Perioperative Medicine and Intensive Care Karolinska University Hospital Stockholm Sweden
| | - Gergely H. Fodor
- Unit for Anaesthesiological Investigations Department of Anesthesiology, Pharmacology, Intensive Care and Emergency Medicine University of Geneva Geneva Switzerland
| | - Andre Santos Rocha
- Unit for Anaesthesiological Investigations Department of Anesthesiology, Pharmacology, Intensive Care and Emergency Medicine University of Geneva Geneva Switzerland
| | - Na Lin
- Unit for Anaesthesiological Investigations Department of Anesthesiology, Pharmacology, Intensive Care and Emergency Medicine University of Geneva Geneva Switzerland
| | - Walid Habre
- Unit for Anaesthesiological Investigations Department of Anesthesiology, Pharmacology, Intensive Care and Emergency Medicine University of Geneva Geneva Switzerland
- Pediatric Anesthesia Unit Geneva Children's Hospital Geneva Switzerland
| | - Mats Wallin
- Department of Physiology and Pharmacology (FYFA) Eriksson I Lars group‐Section of Anesthesiology and Intensive Care Karolinska Institute Stockholm Sweden
- Maquet Critical Care AB Solna Sweden
| | | | - Ferenc Peták
- Departmenet of Medical Physics and Informatics University of Szeged Szeged Hungary
| | - Per‐Arne Lönnqvist
- Department of Physiology and Pharmacology (FYFA) Eriksson I Lars group‐Section of Anesthesiology and Intensive Care Karolinska Institute Stockholm Sweden
- Pediatric Perioperative Medicine and Intensive Care Karolinska University Hospital Stockholm Sweden
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5
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Zwitserloot AM, van den Born EJ, Raaijmakers LHA, Stalman WE, van Smaalen M, van den Berge M, Gappa M, Koppelman GH, Willemse BWM. Differences in lung clearance index and functional residual capacity between two commercial multiple-breath nitrogen washout devices in healthy children and adults. ERJ Open Res 2020; 6:00247-2019. [PMID: 32613018 PMCID: PMC7322914 DOI: 10.1183/23120541.00247-2019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 04/07/2020] [Indexed: 11/21/2022] Open
Abstract
Multiple-breath nitrogen washout (MBNW) and its clinical parameter lung clearance index (LCI) are gaining increasing attention for the assessment of small airway function. Measurement of LCI relies on accurate assessment of functional residual capacity (FRC). The EasyOne Pro LAB (ndd) and Exhalyzer D (EM) are two commercially available MBNW devices. The aim of the study was to compare these two devices in vitro and in vivo in healthy subjects with regard to FRC, LCI and secondary outcome parameters and to relate FRCMBNW to FRC measured by body plethysmography (pleth) and helium dilution technique. MBNW measurements were performed using a lung model (FRC between 500 and 4000 mL) in vitro and in 38 subjects aged 6–65 years followed by helium dilution and pleth in vivo using fixed and relaxed breathing techniques. In vitro accuracy within 5% of lung model FRC was 67.3% for ndd, FRC was >5% higher for EM in all tests. In vivo, FRCpleth ranged from 1.2 to 5.6 L. Mean differences (limits of agreement) between FRCpleth and FRCMBNW were −7.0%, (−23.2 to 9.2%) and 5.7% (−11.2 to 22.6%) using ndd and EM, respectively. FRCndd was consistently lower than FRCEM (−11.8% (−25.6 to 2%)). LCI was comparable between the two devices (−1.3% (−21.9 to 19.3%)). There was a difference of >10 % in LCI in 12 of 38 subjects. Using the most recent software updates, both devices show relevant deviations in FRC measurement both in vitro and in vivo and individual differences in LCI in a significant proportion of subjects. The devices are therefore not interchangeable. MBNW measurements with the Exhalyzer D and EasyOne Pro LAB cannot be used interchangeably for FRC and LCI measurements. FRC measured on both devices showed deviations from in vitro and in vivo measurements.https://bit.ly/2xyyUuJ
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Affiliation(s)
- Annelies M Zwitserloot
- University of Groningen, University Medical Center Groningen, Beatrix Children's Hospital, Dept of Paediatric Pulmonology and Paediatric Allergy, Groningen, The Netherlands.,University of Groningen, University Medical Center Groningen, Groningen Research Institute for Asthma and COPD, Groningen, The Netherlands
| | - Evelyne J van den Born
- University of Groningen, University Medical Center Groningen, Beatrix Children's Hospital, Dept of Paediatric Pulmonology and Paediatric Allergy, Groningen, The Netherlands
| | - Lena H A Raaijmakers
- Radboud University Medical Center, Radboud Institute for Health Sciences, Dept of Primary and Community Care, Nijmegen, The Netherlands
| | - Wouter E Stalman
- University of Groningen, University Medical Center Groningen, Beatrix Children's Hospital, Dept of Paediatric Pulmonology and Paediatric Allergy, Groningen, The Netherlands
| | - Marjanne van Smaalen
- University of Groningen, University Medical Center Groningen, Beatrix Children's Hospital, Dept of Paediatric Pulmonology and Paediatric Allergy, Groningen, The Netherlands
| | - Maarten van den Berge
- University of Groningen, University Medical Center Groningen, Groningen Research Institute for Asthma and COPD, Groningen, The Netherlands.,University of Groningen, University Medical Center Groningen, Dept of Pulmonary Diseases, Groningen, The Netherlands
| | - Monika Gappa
- Evangelisches Krankenhaus Düsseldorf, Children's Hospital, Düsseldorf, Germany
| | - Gerard H Koppelman
- University of Groningen, University Medical Center Groningen, Beatrix Children's Hospital, Dept of Paediatric Pulmonology and Paediatric Allergy, Groningen, The Netherlands.,University of Groningen, University Medical Center Groningen, Groningen Research Institute for Asthma and COPD, Groningen, The Netherlands
| | - Brigitte W M Willemse
- University of Groningen, University Medical Center Groningen, Beatrix Children's Hospital, Dept of Paediatric Pulmonology and Paediatric Allergy, Groningen, The Netherlands.,University of Groningen, University Medical Center Groningen, Groningen Research Institute for Asthma and COPD, Groningen, The Netherlands
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6
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Ratjen F, Jensen R, Klingel M, McDonald R, Moore C, Benseler N, Wilson D, Stanojevic S. Effect of changes in tidal volume on multiple breath washout outcomes. PLoS One 2019; 14:e0219309. [PMID: 31269068 PMCID: PMC6608950 DOI: 10.1371/journal.pone.0219309] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Accepted: 06/20/2019] [Indexed: 01/03/2023] Open
Abstract
The lung clearance index (LCI), measured by multiple breath washout (MBW), reflects global ventilation inhomogeneity and is a sensitive marker of early obstructive airway disease. For the MBW test to accurately reflect a subject's gas mixing within the lungs, the breathing pattern should represent physiologically appropriate tidal volumes (VT) and respiratory rate (RR). We aimed to assess whether changes in VT impact MBW outcome measures with a series of prospective and retrospective studies. MBW testing was performed using the Exhalyzer ® D (EcoMedics AG, Switzerland). Healthy adult subjects performed MBW with uninstructed tidal breathing and a series of instructed tidal breathing tests, designed to isolate specific features of the breathing pattern. In addition, we retrospectively analyzed MBW data from two pediatric multi-centre interventional studies of cystic fibrosis (CF) subjects to determine the range of VT observed during uninstructed breathing, and whether breathing outside this range impacted results. The LCI was lower, but not significantly different between deep breathing at 20 ml/kg body weight and uninstructed tidal breathing; whereas LCI was significantly higher during shallow breathing compared with normal tidal breathing. For the majority of subjects with CF (80%), VT ranged from 9-15mL/kg. Within the observed VT range, LCI was similar in trials with mean VT /kg below this range compared to trials with VT /kg within the range. If subjects breathe naturally and are not instructed to use specific targets, the range of VT is within physiologically appropriate limits and normal variations observed do not impact MBW outcomes.
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Affiliation(s)
- Felix Ratjen
- Translational Medicine Research Program, The Hospital for Sick Children, Toronto, Canada
- Division of Respiratory Medicine, The Hospital for Sick Children, Toronto, Canada
- University of Toronto, Toronto, Canada
| | - Renee Jensen
- Translational Medicine Research Program, The Hospital for Sick Children, Toronto, Canada
| | - Michelle Klingel
- Translational Medicine Research Program, The Hospital for Sick Children, Toronto, Canada
| | - Reginald McDonald
- Translational Medicine Research Program, The Hospital for Sick Children, Toronto, Canada
| | - Courtney Moore
- Translational Medicine Research Program, The Hospital for Sick Children, Toronto, Canada
| | - Nick Benseler
- Translational Medicine Research Program, The Hospital for Sick Children, Toronto, Canada
| | - David Wilson
- Division of Respiratory Medicine, The Hospital for Sick Children, Toronto, Canada
| | - Sanja Stanojevic
- Translational Medicine Research Program, The Hospital for Sick Children, Toronto, Canada
- University of Toronto, Toronto, Canada
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7
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Whitfield CA, Horsley A, Jensen OE. Modelling structural determinants of ventilation heterogeneity: A perturbative approach. PLoS One 2018; 13:e0208049. [PMID: 30496317 PMCID: PMC6264152 DOI: 10.1371/journal.pone.0208049] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Accepted: 11/09/2018] [Indexed: 01/19/2023] Open
Abstract
We have developed a computational model of gas mixing and ventilation in the human lung represented as a bifurcating network. We have simulated multiple-breath washout (MBW), a clinical test for measuring ventilation heterogeneity (VH) in patients with obstructive lung conditions. By applying airway constrictions inter-regionally, we have predicted the response of MBW indices to obstructions and found that they detect a narrow range of severe constrictions that reduce airway radius to 10%–30% of healthy values. These results help to explain the success of the MBW test to distinguish obstructive lung conditions from healthy controls. Further, we have used a perturbative approach to account for intra-regional airway heterogeneity that avoids modelling each airway individually. We have found, for random airway heterogeneity, that the variance in MBW indices is greater when indices are already elevated due to constrictions. By quantifying this effect, we have shown that variability in lung structure and mechanical properties alone can lead to clinically significant variability in MBW indices (specifically the Lung Clearance Index—LCI, and the gradient of phase-III slopes—Scond), but only in cases simulating obstructive lung conditions. This method is a computationally efficient way to probe the lung’s sensitivity to structural changes, and to quantify uncertainty in predictions due to random variations in lung mechanical and structural properties.
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Affiliation(s)
- Carl A. Whitfield
- Division of Infection, Immunity and Respiratory Medicine, University of Manchester, Southmoor Road, Manchester, United Kingdom, M23 9LT
- School of Mathematics, University of Manchester, Oxford Road, Manchester, United Kingdom, M13 9PL
- * E-mail:
| | - Alex Horsley
- Division of Infection, Immunity and Respiratory Medicine, University of Manchester, Southmoor Road, Manchester, United Kingdom, M23 9LT
| | - Oliver E. Jensen
- School of Mathematics, University of Manchester, Oxford Road, Manchester, United Kingdom, M13 9PL
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8
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Foy BH, Gonem S, Brightling C, Siddiqui S, Kay D. Modelling the effect of gravity on inert-gas washout outputs. Physiol Rep 2018; 6:e13709. [PMID: 29845761 PMCID: PMC5974727 DOI: 10.14814/phy2.13709] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 04/11/2018] [Accepted: 04/15/2018] [Indexed: 11/24/2022] Open
Abstract
Multiple-breath washout (MBW) is a pulmonary function test (PFT) that is used to infer lung function through measurement of ventilation heterogeneity (VH). However, the body position that a test is taken in may also influence VH, due to the "Slinky" effect of gravity on the lungs. In healthy subjects this has minimal effect, but in unhealthy groups, PFT outputs have been seen to change drastically with body position. In this study, we used a combined computational and clinical approach to better understand the response of outputs from the MBW to body position. A patient-specific model of the MBW was developed, then validated against clinically measured washout data, as well as broader results in the literature. This model was then used to compare changes in MBW outputs with respect to body position, showing that output changes sensitively predict regional airway size differences between lobes. We then highlight cases in which body position effects may bias MBW outputs, leading to elevated or masked responses to bronchoconstriction. We close by placing this result in context with broader clinical practice, and showing how it can help improve interpretation of test outputs.
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Affiliation(s)
- Brody H. Foy
- Department of Computer ScienceUniversity of OxfordOxfordOxfordshireUnited Kingdom
| | - Sherif Gonem
- Respiratory Biomedical Research CentreUniversity of Leicester/National Institute of Health ResearchLeicesterLeicestershireUnited Kingdom
| | - Chris Brightling
- Respiratory Biomedical Research CentreUniversity of Leicester/National Institute of Health ResearchLeicesterLeicestershireUnited Kingdom
| | - Salman Siddiqui
- Respiratory Biomedical Research CentreUniversity of Leicester/National Institute of Health ResearchLeicesterLeicestershireUnited Kingdom
| | - David Kay
- Department of Computer ScienceUniversity of OxfordOxfordOxfordshireUnited Kingdom
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9
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Jordan AR, Claxton D, Purvis A, Barnes A, Fysh M. Sprint interval training on the vertical treadmill improves aerobic and anaerobic running performance. J Exerc Rehabil 2018; 14:106-112. [PMID: 29511660 PMCID: PMC5833954 DOI: 10.12965/jer.1835122.561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Accepted: 01/13/2018] [Indexed: 11/22/2022] Open
Abstract
The vertical treadmill (VertiRun) is an unresearched mode of exercise where users engage in a “running-like” action whilst body weight is supported by a recumbent bench and overhanging resistance cables are tethered to the user’s ankles. The purpose of this study was to determine the effects of training on a VertiRun and any cross-training effect on running performance. Thirty active males (age, 22±4 years; stature, 1.79±0.08 m; body mass, 78.5±12.6 kg) volunteered for this study. Participants’ aerobic and anaerobic running performance were determined by incremental maximum rate of oxygen consumption (VO2max) treadmill test and a maximum anaerobic running test (MART), respectively. Participants were matched and then randomly assigned to either a VertiRun group, 20-m shuttle sprint group or control group. The intervention consisted of 4–6, 30-sec all-out efforts with 4-min recovery between bouts, 3 days a week for 6 weeks. The pre- and postintervention VO2max and MART were analysed using a mixed repeated measures analysis of variance. MART increased by 4.5% in the VertiRun group (P=0.006) and 4% in the sprint group (P<0.001). VO2max increased by 6.2% in the VertiRun group (P=0.009) and 5.5% in the sprint group (P=0.020). The MART and VO2max of the control group were unchanged (P=0.910 and P=0.915, respectively). These data suggest that the VertiRun could be an effective cross-training mode for running and could supplement training programmes. Also, as VertiRun is a low-impact exercise it might be useful in the physical preparation of athletes returning to sport following lower limb injury.
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Affiliation(s)
- Alastair Ross Jordan
- School of Sport, York St. John's University, Lord Mayor's Walk, York, United Kingdom
| | - David Claxton
- Academy of Sport and Physical Activity, Sheffield Hallam University, Sheffield, United Kingdom
| | - Alison Purvis
- Academy of Sport and Physical Activity, Sheffield Hallam University, Sheffield, United Kingdom
| | - Andrew Barnes
- Academy of Sport and Physical Activity, Sheffield Hallam University, Sheffield, United Kingdom
| | - Mary Fysh
- Academy of Sport and Physical Activity, Sheffield Hallam University, Sheffield, United Kingdom
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10
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Smith LJ, Macleod KA, Collier GJ, Horn FC, Sheridan H, Aldag I, Taylor CJ, Cunningham S, Wild JM, Horsley A. Supine posture changes lung volumes and increases ventilation heterogeneity in cystic fibrosis. PLoS One 2017; 12:e0188275. [PMID: 29176899 PMCID: PMC5703538 DOI: 10.1371/journal.pone.0188275] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Accepted: 11/03/2017] [Indexed: 12/28/2022] Open
Abstract
INTRODUCTION Lung Clearance Index (LCI) is recognised as an early marker of cystic fibrosis (CF) lung disease. The effect of posture on LCI however is important when considering longitudinal measurements from infancy and when comparing LCI to imaging studies. METHODS 35 children with CF and 28 healthy controls (HC) were assessed. Multiple breath washout (MBW) was performed both sitting and supine in triplicate and analysed for LCI, Scond, Sacin, and lung volumes. These values were also corrected for the Fowler dead-space to create 'alveolar' indices. RESULTS From sitting to supine there was a significant increase in LCI and a significant decrease in FRC for both CF and HC (p<0.01). LCI, when adjusted to estimate 'alveolar' LCI (LCIalv), increased the magnitude of change with posture for both LCIalv and FRCalv in both groups, with a greater effect of change in lung volume in HC compared with children with CF. The % change in LCIalv for all subjects correlated significantly with lung volume % changes, most notably tidal volume/functional residual capacity (Vtalv/FRCalv (r = 0.54,p<0.001)). CONCLUSION There is a significant increase in LCI from sitting to supine, which we believe to be in part due to changes in lung volume and also increasing ventilation heterogeneity related to posture. This may have implications in longitudinal measurements from infancy to older childhood and for studies comparing supine imaging methods to LCI.
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Affiliation(s)
- Laurie J. Smith
- POLARIS, Academic Radiology, University of Sheffield, Sheffield, United Kingdom
- Sheffield Children’s Hospital NHS Foundation Trust, Sheffield, United Kingdom
| | | | - Guilhem J. Collier
- POLARIS, Academic Radiology, University of Sheffield, Sheffield, United Kingdom
| | - Felix C. Horn
- POLARIS, Academic Radiology, University of Sheffield, Sheffield, United Kingdom
| | - Helen Sheridan
- Royal Hospital for Sick Children, Edinburgh, United Kingdom
| | - Ina Aldag
- Sheffield Children’s Hospital NHS Foundation Trust, Sheffield, United Kingdom
| | - Chris J. Taylor
- Sheffield Children’s Hospital NHS Foundation Trust, Sheffield, United Kingdom
| | | | - Jim M. Wild
- POLARIS, Academic Radiology, University of Sheffield, Sheffield, United Kingdom
| | - Alex Horsley
- Respiratory Research Group, Division of Infection, Immunity & Respiratory Medicine, University of Manchester, Manchester, United Kingdom
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11
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Ramsey KA, McGirr C, Stick SM, Hall GL, Simpson SJ. Effect of posture on lung ventilation distribution and associations with structure in children with cystic fibrosis. J Cyst Fibros 2017; 16:713-718. [PMID: 28188011 DOI: 10.1016/j.jcf.2017.01.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Revised: 01/23/2017] [Accepted: 01/24/2017] [Indexed: 11/30/2022]
Abstract
BACKGROUND We assessed the effect of posture on ventilation distribution and the impact on associations with structural lung disease. METHODS Multiple breath washout (MBW) was performed in seated and supine postures in 25 healthy children and 21 children with CF. Children with CF also underwent a chest CT scan. Functional residual capacity (FRC), lung clearance index (LCI) and moment ratios were calculated from the MBW test. CT scans were evaluated for CF-related structural lung disease. RESULTS FRC was lower in the supine than in the seated posture, whereas LCI was higher in the supine than in the seated posture. In children with CF, associations between LCI and the extent of structural lung disease were stronger when performed in the supine posture. CONCLUSIONS Body posture influences lung volumes and ventilation distribution in both healthy children and children with CF. MBW testing in the supine posture strengthened associations with structural lung damage.
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Affiliation(s)
- Kathryn A Ramsey
- Telethon Kids Institute, Subiaco, Western Australia, Australia; Centre for Child Health Research, University of Western Australia, Crawley, Western Australia, Australia; Cystic Fibrosis Research and Treatment Centre, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Caroline McGirr
- Telethon Kids Institute, Subiaco, Western Australia, Australia
| | - Stephen M Stick
- Telethon Kids Institute, Subiaco, Western Australia, Australia; Centre for Child Health Research, University of Western Australia, Crawley, Western Australia, Australia; Respiratory Medicine, Princess Margaret Hospital for Children, Subiaco, Western Australia, Australia
| | - Graham L Hall
- Telethon Kids Institute, Subiaco, Western Australia, Australia; Centre for Child Health Research, University of Western Australia, Crawley, Western Australia, Australia; School of Physiotherapy and Exercise Science, Curtin University, Bentley, Western Australia, Australia.
| | - Shannon J Simpson
- Telethon Kids Institute, Subiaco, Western Australia, Australia; Centre for Child Health Research, University of Western Australia, Crawley, Western Australia, Australia
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Horsley A, Siddiqui S. Putting lung function and physiology into perspective: cystic fibrosis in adults. Respirology 2014; 20:33-45. [PMID: 25219816 DOI: 10.1111/resp.12382] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Revised: 07/22/2014] [Accepted: 07/23/2014] [Indexed: 11/30/2022]
Abstract
Adult cystic fibrosis (CF) is notable for the wide heterogeneity in severity of disease expression, both between patients and within the lungs of individuals. Although CF airways disease appears to start in the small airways, in adults there is typically widespread bronchiectasis, increased airway secretions, and extensive obstruction and inflammation of the small airways. The complexity and heterogeneity of airways disease in CF means that although there are many different methods of assessing and describing lung 'function', none of these single-dimensional tests is able to provide a comprehensive assessment of lung physiology across the spectrum seen in adult CF. The most widely described measure, the forced expiratory volume in 1 s, remains a useful and simple clinical tool, but is insensitive to early changes and may be dissociated from other more detailed assessments of disease severity such as computed tomography. In this review, we also discuss the use of more sensitive novel assessments such as multiple breath washout tests and impulse oscillometry, as well as the role of cardiopulmonary exercise testing. In the future, hyperpolarized gas magnetic resonance imaging techniques that combine regional structural and functional information may help us to better understand these measures, their applications and limitations.
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Affiliation(s)
- Alex Horsley
- Respiratory Research Group, Institute of Inflammation and Repair, University of Manchester, Manchester, UK; Manchester Adult Cystic Fibrosis Centre, North West Lung Centre, University Hospital of South Manchester, Manchester, UK
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Kent L, Reix P, Innes JA, Zielen S, Le Bourgeois M, Braggion C, Lever S, Arets HGM, Brownlee K, Bradley JM, Bayfield K, O'Neill K, Savi D, Bilton D, Lindblad A, Davies JC, Sermet I, De Boeck K. Lung clearance index: evidence for use in clinical trials in cystic fibrosis. J Cyst Fibros 2013; 13:123-38. [PMID: 24315208 DOI: 10.1016/j.jcf.2013.09.005] [Citation(s) in RCA: 148] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Revised: 09/10/2013] [Accepted: 09/23/2013] [Indexed: 02/09/2023]
Abstract
The ECFS-CTN Standardisation Committee has undertaken this review of lung clearance index as part of the group's work on evaluation of clinical endpoints with regard to their use in multicentre clinical trials in CF. The aims were 1) to review the literature on reliability, validity and responsiveness of LCI in patients with CF, 2) to gain consensus of the group on feasibility of LCI and 3) to gain consensus on answers to key questions regarding the promotion of LCI to surrogate endpoint status. It was concluded that LCI has an attractive feasibility and clinimetric properties profile and is particularly indicated for multicentre trials in young children with CF and patients with early or mild CF lung disease. This is the first article to collate the literature in this manner and support the use of LCI in clinical trials in CF.
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Affiliation(s)
- L Kent
- Centre for Health and Rehabilitation Technologies (CHaRT), Institute for Nursing and Health Research, University of Ulster, Newtownabbey, UK; Regional Cystic Fibrosis Centre, Belfast Health and Social Care Trust, Belfast, UK
| | - P Reix
- Centre de Référence de la Mucoviscidose, Hospices Civils de Lyon, Lyon, France
| | - J A Innes
- Scottish Adult Cystic Fibrosis Service, Western General Hospital, Edinburgh, UK; Molecular and Clinical Medicine, University of Edinburgh, UK
| | - S Zielen
- Department of Paediatrics, J.W. Goethe-Universität Frankfurt, Germany
| | - M Le Bourgeois
- Centre de Référence de la Mucoviscidose, Hôpital Necker-Enfants Malades, Paris, France
| | - C Braggion
- Cystic Fibrosis Center, Pediatric Department, Meyer Children's Hospital, Florence, Italy
| | - S Lever
- Erasmus MC, Rotterdam, The Netherlands
| | - H G M Arets
- Department of Pediatric Pulmonology, Wilhelmina Children's Hospital, University Medical Center Utrecht, The Netherlands
| | - K Brownlee
- Children's Cystic Fibrosis Centre, Leeds Teaching Hospitals, Leeds, UK
| | - J M Bradley
- Centre for Health and Rehabilitation Technologies (CHaRT), Institute for Nursing and Health Research, University of Ulster, Newtownabbey, UK; Regional Cystic Fibrosis Centre, Belfast Health and Social Care Trust, Belfast, UK
| | - K Bayfield
- Department of Gene Therapy, Imperial College London, UK
| | - K O'Neill
- Centre for Infection and Immunity, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, UK
| | - D Savi
- Department of Pediatrics and Pediatric Neurology, Cystic Fibrosis Center, Sapienza University of Rome, Italy
| | - D Bilton
- Royal Brompton & Harefield NHS Foundation Trust, London, UK
| | - A Lindblad
- Gothenburg CF Centre, Queen Silvia Children's Hospital, Göteborg, Sweden
| | - J C Davies
- Department of Gene Therapy, Imperial College London, UK; Royal Brompton & Harefield NHS Foundation Trust, London, UK
| | - I Sermet
- Centre de Référence de la Mucoviscidose, Hôpital Necker-Enfants Malades, Paris, France; Université Paris Descartes, Paris, France
| | - K De Boeck
- Pediatric Pulmonology, University Hospitals Leuven and KU Leuven, Leuven, Belgium.
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Yammine S, Singer F, Gustafsson P, Latzin P. Impact of different breathing protocols on multiple-breath washout outcomes in children. J Cyst Fibros 2013; 13:190-7. [PMID: 24075581 DOI: 10.1016/j.jcf.2013.08.010] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Revised: 08/26/2013] [Accepted: 08/29/2013] [Indexed: 01/07/2023]
Abstract
BACKGROUND To standardize multiple-breath washout (MBW) measurements, 1L tidal volume (VT) protocols were suggested. The effect on MBW derived ventilation inhomogeneity (VI) indices is unclear. METHODS We compared VI indices from free breathing MBW at baseline to 1L VT MBW performed in triplicates in 35 children (20 with CF). Mean (range) age was 12.8 (7.0-16.7) years, weight 42 (20-64) kg and height 151 (117-170) cm. RESULTS Baseline lung clearance index (LCI) increased from mean (SD) 11.0 (2.2) to 13.0 (2.6), p = 0.011, in CF and from 6.8 (0.5) to 7.7 (1.4), p = 0.004, in controls. Moment ratio and Scond similarly increased. While change in VI indices was heterogeneous in individuals, decrease in functional residual capacity was most strongly associated with LCI increase. CONCLUSION MBW protocols strongly influence measures of VI. The 1L VT MBW protocol leads to overestimation of VI and is not recommended in children.
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Affiliation(s)
- Sophie Yammine
- Division of Respiratory Medicine, Department of Pediatrics, University Children's Hospital of Bern, Switzerland; University Children's Hospital of Basel UKBB, Switzerland
| | - Florian Singer
- Division of Respiratory Medicine, Department of Pediatrics, University Children's Hospital of Bern, Switzerland; University Children's Hospital of Zurich, Switzerland
| | - Per Gustafsson
- Department of Pediatrics, Central Hospital, Skoevde, Sweden
| | - Philipp Latzin
- Division of Respiratory Medicine, Department of Pediatrics, University Children's Hospital of Bern, Switzerland; University Children's Hospital of Basel UKBB, Switzerland.
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15
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Henry FS, Llapur CJ, Tsuda A, Tepper RS. Numerical modelling and analysis of peripheral airway asymmetry and ventilation in the human adult lung. J Biomech Eng 2013; 134:061001. [PMID: 22757498 DOI: 10.1115/1.4006809] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We present a new one-dimensional model of gas transport in the human adult lung. The model comprises asymmetrically branching airways, and heterogeneous interregional ventilation. Our model differs from previous models in that we consider the asymmetry in both the conducting and the acinar airways in detail. Another novelty of our model is that we use simple analytical relationships to produce physiologically realistic models of the conducting and acinar airway trees. With this new model, we investigate the effects of airway asymmetry and heterogeneous interregional ventilation on the phase III slope in multibreath washouts. The model predicts the experimental trend of the increase in the phase III slope with breath number in multibreath washout studies for nitrogen, SF(6) and helium. We confirm that asymmetrical branching in the acinus controls the magnitude of the first-breath phase III slope and find that heterogeneous interregional ventilation controls the way in which the slope changes with subsequent breaths. Asymmetry in the conducting airways appears to have little effect on the phase III slope. That the increase in slope appears to be largely controlled by interregional ventilation inhomogeneities should be of interest to those wishing to use multibreath washouts to detect the location of the structural abnormalities within the lung.
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Affiliation(s)
- F S Henry
- Molecular and Integrative Physiological Sciences, Harvard School of Public Health, Boston, MA 02115, USA.
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Wellman TJ, Winkler T, Costa ELV, Musch G, Harris RS, Venegas JG, Vidal Melo MF. Effect of regional lung inflation on ventilation heterogeneity at different length scales during mechanical ventilation of normal sheep lungs. J Appl Physiol (1985) 2012; 113:947-57. [PMID: 22678958 PMCID: PMC3472483 DOI: 10.1152/japplphysiol.01631.2011] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2012] [Accepted: 06/01/2012] [Indexed: 01/06/2023] Open
Abstract
Heterogeneous, small-airway diameters and alveolar derecruitment in poorly aerated regions of normal lungs could produce ventilation heterogeneity at those anatomic levels. We modeled the washout kinetics of (13)NN with positron emission tomography to examine how specific ventilation (sV) heterogeneity at different length scales is influenced by lung aeration. Three groups of anesthetized, supine sheep were studied: high tidal volume (Vt; 18.4 ± 4.2 ml/kg) and zero end-expiratory pressure (ZEEP) (n = 6); low Vt (9.2 ± 1.0 ml/kg) and ZEEP (n = 6); and low Vt (8.2 ± 0.2 ml/kg) and positive end-expiratory pressure (PEEP; 19 ± 1 cmH(2)O) (n = 4). We quantified fractional gas content with transmission scans, and sV with emission scans of infused (13)NN-saline. Voxel (13)NN-washout curves were fit with one- or two-compartment models to estimate sV. Total heterogeneity, measured as SD[log(10)(sV)], was divided into length-scale ranges by measuring changes in variance of log(10)(sV), resulting from progressive filtering of sV images. High-Vt ZEEP showed higher sV heterogeneity at <12- (P < 0.01), 12- to 36- (P < 0.01), and 36- to 60-mm (P < 0.05) length scales compared with low-Vt PEEP, with low-Vt ZEEP in between. Increased heterogeneity was associated with the emergence of low sV units in poorly aerated regions, with a high correlation (r = 0.95, P < 0.001) between total heterogeneity and the fraction of lung with slow washout. Regional mean fractional gas content was inversely correlated with regional sV heterogeneity at <12- (r = -0.67), 12- to 36- (r = -0.74), and >36-mm (r = -0.72) length scales (P < 0.001). We conclude that sV heterogeneity at length scales <60 mm increases in poorly aerated regions of mechanically ventilated normal lungs, likely due to heterogeneous small-airway narrowing and alveolar derecruitment. PEEP reduces sV heterogeneity by maintaining lung expansion and airway patency at those small length scales.
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Affiliation(s)
- Tyler J Wellman
- Department of Biomedical Engineering, Boston University, Boston, MA 02114, USA
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17
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Tidal volume single breath washout of two tracer gases--a practical and promising lung function test. PLoS One 2011; 6:e17588. [PMID: 21423739 PMCID: PMC3053358 DOI: 10.1371/journal.pone.0017588] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2010] [Accepted: 01/27/2011] [Indexed: 11/19/2022] Open
Abstract
Background Small airway disease frequently occurs in chronic lung diseases and may cause ventilation inhomogeneity (VI), which can be assessed by washout tests of inert tracer gas. Using two tracer gases with unequal molar mass (MM) and diffusivity increases specificity for VI in different lung zones. Currently washout tests are underutilised due to the time and effort required for measurements. The aim of this study was to develop and validate a simple technique for a new tidal single breath washout test (SBW) of sulfur hexafluoride (SF6) and helium (He) using an ultrasonic flowmeter (USFM). Methods The tracer gas mixture contained 5% SF6 and 26.3% He, had similar total MM as air, and was applied for a single tidal breath in 13 healthy adults. The USFM measured MM, which was then plotted against expired volume. USFM and mass spectrometer signals were compared in six subjects performing three SBW. Repeatability and reproducibility of SBW, i.e., area under the MM curve (AUC), were determined in seven subjects performing three SBW 24 hours apart. Results USFM reliably measured MM during all SBW tests (n = 60). MM from USFM reflected SF6 and He washout patterns measured by mass spectrometer. USFM signals were highly associated with mass spectrometer signals, e.g., for MM, linear regression r-squared was 0.98. Intra-subject coefficient of variation of AUC was 6.8%, and coefficient of repeatability was 11.8%. Conclusion The USFM accurately measured relative changes in SF6 and He washout. SBW tests were repeatable and reproducible in healthy adults. We have developed a fast, reliable, and straightforward USFM based SBW method, which provides valid information on SF6 and He washout patterns during tidal breathing.
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Effects of cystic fibrosis lung disease on gas mixing indices derived from alveolar slope analysis. Respir Physiol Neurobiol 2008; 162:197-203. [PMID: 18625345 DOI: 10.1016/j.resp.2008.06.014] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2008] [Revised: 06/16/2008] [Accepted: 06/17/2008] [Indexed: 11/21/2022]
Abstract
S(cond) and S(acin) are derived from analysis of concentration-normalized phase III slopes (Sn(III)) of a multiple breath inert gas washout. Studies in healthy and COPD subjects suggest these reflect ventilation heterogeneity in conducting and acinar airway zones respectively, but similar studies in cystic fibrosis (CF) are lacking. S(cond), S(acin) and lung clearance index (LCI, a measure of overall gas mixing efficiency) were measured in 22 adults and 18 children with CF and 17 adult and 29 child controls. Plethysmography and gas transfer measurements were performed in adults, and spirometry in all subjects. S(cond) was elevated in almost all CF patients, including children with mild disease and normal LCI. However, S(cond) did not correlate with other measurements and appeared to reach a maximum; further increase in ventilation heterogeneity being restricted to S(acin). The nature and/or severity of CF lung disease may invalidate assumptions underlying the ability to separate phase III slope analysis of ventilation heterogeneity into proximal and peripheral components, and LCI may be a better indicator of gas mixing in this population.
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Prediletto R, Fornai E, Catapano G, Carli C. Assessment of the alveolar volume when sampling exhaled gas at different expired volumes in the single breath diffusion test. BMC Pulm Med 2007; 7:18. [PMID: 18093300 PMCID: PMC2235885 DOI: 10.1186/1471-2466-7-18] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2007] [Accepted: 12/19/2007] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND Alveolar volume measured according to the American Thoracic Society-European Respiratory Society (ATS-ERS) guidelines during the single breath diffusion test can be underestimated when there is maldistribution of ventilation. Therefore, the alveolar volume calculated by taking into account the ATS-ERS guidelines was compared to the alveolar volume measured from sequentiallly collected samples of the expired volume in two groups of individuals: COPD patients and healthy individuals. The aim of this study was to investigate the effects of the maldistribution of ventilation on the real estimate of alveolar volume and to evaluate some indicators suggestive of the presence of maldistribution of ventilation. METHODS Thirty healthy individuals and fifty patients with moderate-severe COPD were studied. The alveolar volume was measured either according to the ATS-ERS guidelines or considering the whole expired volume subdivided into five quintiles. An index reflecting the non-uniformity of the distribution of ventilation was then derived (DeltaVA/VE). RESULTS Significant differences were found when comparing the two measurements and the alveolar volume by quintiles appeared to have increased progressively towards residual volume in healthy individuals and much more in COPD patients. Therefore, DeltaVA/VE resulted in an abnormal increase in COPD. CONCLUSION The results of our study suggest that the alveolar volume during the single breath diffusion test should be measured through the collection of a sample of expired volume which could be more representative of the overall gas composition, especially in the presence of uneven distribution of ventilation. Further studies aimed at clarifying the final effects of this way of calculating the alveolar volume on the measure of DLCO are needed. DeltaVA/VE is an index that can help assess the severity of inhomogeneity in COPD patients.
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Affiliation(s)
- Renato Prediletto
- Institute of Clinical Physiology, National Research Council of Italy, Pisa, Italy
| | - Edo Fornai
- Institute of Clinical Physiology, National Research Council of Italy, Pisa, Italy
| | - Giosuè Catapano
- Institute of Clinical Physiology, National Research Council of Italy, Pisa, Italy
| | - Cristina Carli
- Institute of Clinical Physiology, National Research Council of Italy, Pisa, Italy
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von Ungern-Sternberg BS, Petak F, Saudan S, Pellegrini M, Erb TO, Habre W. Effect of cardiopulmonary bypass and aortic clamping on functional residual capacity and ventilation distribution in children. J Thorac Cardiovasc Surg 2007; 134:1193-8. [DOI: 10.1016/j.jtcvs.2007.03.061] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2006] [Revised: 03/28/2007] [Accepted: 03/29/2007] [Indexed: 11/29/2022]
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von Ungern-Sternberg BS, Hammer J, Frei FJ, Jordi Ritz EM, Schibler A, Erb TO. Prone equals prone? Impact of positioning techniques on respiratory function in anesthetized and paralyzed healthy children. Intensive Care Med 2007; 33:1771-7. [PMID: 17558496 DOI: 10.1007/s00134-007-0670-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2006] [Accepted: 04/19/2007] [Indexed: 10/23/2022]
Abstract
OBJECTIVES Although the prone position is effectively used to improve oxygenation, its impact on functional residual capacity is controversial. Different techniques of body positioning might be an important confounding factor. The aim of this study was to determine the impact of two different prone positioning techniques on functional residual capacity and ventilation distribution in anesthetized, preschool-aged children. DESIGN Functional residual capacity and lung clearance index, a measure of ventilation homogeneity, were calculated using a sulfur-hexafluoride multibreath washout technique. After intubation, measurements were taken in the supine position and, in random order, in the flat prone position and the augmented prone position (gel pads supporting the pelvis and the upper thorax). SETTING Pediatric anesthesia unit of university hospital. PATIENTS AND PARTICIPANTS Thirty preschool children without cardiopulmonary disease undergoing elective surgery. MEASUREMENTS AND RESULTS Mean (range) age was 48.5 (24-80) months, weight 17.2 (10.5-26.9) kg, functional residual capacity (mean +/- SD) 22.9+/- 6.2 ml.kg (-1) in the supine position and 23.3 +/- 5.6 ml.kg (-1) in the flat prone position, while lung clearance indices were 8.1 +/- 2.3 vs. 7.9 +/- 2.3, respectively. In contrast, functional residual capacity increased to 27.6 +/- 6.5 ml.kg (-1) (p< 0.001) in the augmented prone position while at the same time the lung clearance index decreased to 6.7 +/- 0.9 (p< 0.001). CONCLUSIONS Functional residual capacity and ventilation distribution were similar in the supine and flat prone positions, while these parameters improved significantly in the augmented prone position, suggesting that the technique of prone positioning has major implications for pulmonary function.
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Regli A, Habre W, Saudan S, Mamie C, Erb TO, von Ungern-Sternberg BS. Impact of Trendelenburg positioning on functional residual capacity and ventilation homogeneity in anaesthetised children. Anaesthesia 2007; 62:451-5. [PMID: 17448055 DOI: 10.1111/j.1365-2044.2007.05030.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Trendelenburg positioning, a head-down tilt, is routinely used in anaesthesia when inserting a central venous catheter to increase the calibre of the jugular or subclavian veins and to prevent an air embolism. We investigated the impact of Trendelenburg positioning on functional residual capacity and ventilation homogeneity as well as the potential reversibility of these changes by repositioning and/or a recruitment manoeuvre in children with congenital heart disease. Functional residual capacity and ventilation homogeneity were assessed in 20 anaesthetised children between the ages of 3 months and 8 years who required central venous catheterisation before undergoing cardiac surgery. Functional residual capacity was measured (1) in the supine position, (2) in the Trendelenburg position, (3) after repositioning supine and (4) after a recruitment manoeuvre to total lung capacity which was performed by manually elevating the airway pressure to 40 cmH(2)O for ten consecutive breaths. Adopting the Trendelenburg position led to a significant decrease in functional residual capacity (median [range]- 12 (6-21)%) and increase in lung clearance index (12 (2-19)%). Baseline values were not reached after repositioning supine in any patient until after a standardised recruitment manoeuvre was performed.
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Affiliation(s)
- A Regli
- Department of Anaesthesia, Pharmacology and Intensive Care, University Hospitals of Geneva, Geneva, Switzerland
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23
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Abstract
Multiple-breath N2 washouts were performed before and after bronchodilation in 15 patients with moderately severe asthma (mean age 13 years), and in 11 patients with cystic fibrosis (CF; mean age 16 years) matched for FEV1. Eighteen healthy subjects (mean age 15 years) were studied before bronchodilation. The lung clearance index (LCI) was determined from the washout curve and gas trapping was assessed from five subsequent large breaths. Analysis of the progression of the concentration normalized phase III slopes (Sn(III)) over the washout was used to determine inhomogeneity in the conducting airways (S(cond)) and inhomogeneity close to or within the gas exchange zone (S(acin)). Before bronchodilation all washout indexes were abnormal in the CF group, and all but S(acin) in the asthma group. Two indexes were higher in CF than in asthma: LCI (11.5 (3.3) vs. 8.7 (1.3); P < 0.01), and S(acin) (0.307 (0.207) vs. 0.142 (0.071); P < 0.01), while gas trapping indexes and S(cond) (0.151 (0.071) vs. 0.127 (0.041)) did not differ significantly. After bronchodilation, all indexes improved in asthma and only S(cond) remained abnormally elevated. In CF, only a modest but statistically significant S(acin) improvement was seen and all indexes stayed abnormal. The study shows that overall ventilation inhomogeneity and particularly inhomogeneity in or close to the gas exchange zone are more pronounced in CF than in asthma matched for FEV1, while inhomogeneity in the conducting airway zone is similar. After bronchodilation, residual abnormalities of airway function are seen all through the airway tree in CF but only in the conducting airways in asthma.
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Affiliation(s)
- Per M Gustafsson
- Queen Silvia Children's Hospital, Sahlgrenska University Hospital, Göteborg, Sweden.
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Holmberg HC, Calbet JAL. Insufficient ventilation as a cause of impaired pulmonary gas exchange during submaximal exercise. Respir Physiol Neurobiol 2007; 157:348-59. [PMID: 17303477 DOI: 10.1016/j.resp.2006.12.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2006] [Revised: 12/18/2006] [Accepted: 12/20/2006] [Indexed: 11/27/2022]
Abstract
Pulmonary ventilation and gas exchange were determined during prolonged skiing (approximately 76% of V(O2, max); cardiac output=26-27 L min(-1)) using diagonal technique (DIA) for 40 min followed by 10 min of double poling (DPOL) and 10 min of leg skiing (LEG). Exercise caused approximately 2-5% reduction of arterial oxygen saturation Sa(O2). For a given cardiac output and V(O2), DPOL presented higher V(E), lower Pa(CO2) and a more efficient pulmonary gas exchange, revealed by higher PA(O2) and Pa(O2) and lower A-aD(O2). The A-aD(O2) widened 2 mmHg L(-1) of cardiac output increase. However, for a given cardiac output and V(O2), exercise mode had an important influence on pulmonary ventilation and gas exchange. Highly trained cross-country skiers' present about 2 units reduction in Sa(O2) from resting values during submaximal exercise at 76% of V(O2, max). Half of the reduction in saturation is accounted for by the rightward-shift of the oxygen dissociation curve of the haemoglobin. The exercise duration has almost no repercussion on pulmonary gas exchange in these athletes, with the small effect on Sa(O2) associated to the increase in body core temperature.
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Affiliation(s)
- H-C Holmberg
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.
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Aurora P, Kozlowska W, Stocks J. Gas mixing efficiency from birth to adulthood measured by multiple-breath washout. Respir Physiol Neurobiol 2005; 148:125-39. [PMID: 15993657 DOI: 10.1016/j.resp.2005.05.027] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2005] [Revised: 05/26/2005] [Accepted: 05/26/2005] [Indexed: 11/19/2022]
Abstract
Efficient mixing of inspired gas with the resident gas of the lung is an essential requirement of effective respiration. This review focuses on one method for quantifying ventilation inhomogeneity: the multiple-breath inert gas washout (MBW). MBW has been employed as a research tool in adults and school age children for more than 50 years. Modifications allowing data collection in infants and preschoolers have been described recently. Indices of overall ventilation inhomogeneity, such as the lung clearance index and moment ratios, are raised in many infants with lung disease of prematurity, and in young children with cystic fibrosis. These indices may be more sensitive than other lung function measures for the early detection of airway disease. We describe, for the first time, a development of the MBW analysis that allows calculation of acinar and conductive zone inhomogeneity indices in spontaneously breathing children. Although methodological and analytical issues remain, the future clinical and research applications of MBW justify accelerated research in this field.
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Affiliation(s)
- Paul Aurora
- Portex Anaesthesia, Intensive Therapy and Respiratory Medicine Unit, Institute of Child Health, London, UK. mailto:
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26
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Riedel T, Richards T, Schibler A. The value of electrical impedance tomography in assessing the effect of body position and positive airway pressures on regional lung ventilation in spontaneously breathing subjects. Intensive Care Med 2005; 31:1522-8. [PMID: 16195908 DOI: 10.1007/s00134-005-2734-x] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2004] [Accepted: 09/15/2005] [Indexed: 10/25/2022]
Abstract
OBJECTIVE Functional electrical impedance tomography (EIT) measures relative impedance changes in lung tissue during tidal breathing and creates images of local ventilation distribution. A novel approach to analyse the effect of body position and positive pressure ventilation on intrapulmonary tidal volume distribution was evaluated in healthy adult subjects. DESIGN AND SETTING Prospective experimental study in healthy adult subjects in the intensive care unit at university hospital. SUBJECTS Ten healthy male adults. INTERVENTIONS Change in body position from supine to prone, left and right lateral during spontaneous breathing and positive pressure support ventilation. MEASUREMENTS AND RESULTS EIT measurements and multiple-breath sulphur hexafluoride (SF6) washout were performed. Profiles of average relative impedance change in regional lung areas were calculated. Relative impedance time course analysis and Lissajous figure loop analysis were used to calculate phase angles between dependent or independent lung and total lung (phi). EIT data were compared to SF6 data washout measuring the lung clearance index (LCI). Proposed EIT profiles allowed inter-individual comparison of EIT data and identified areas with reduced regional tidal volume using pressure support ventilation. Phase angle phi of dependent lung in supine position was 11.7+/-1.4 degrees, in prone 5.3+/-0.5 degrees, in right lateral 11.0+/-1.3 degrees and in left lateral position 10.8+/-1.0 degree. LCI increased in supine position from 5.63+/-0.43 to 7.13+/-0.64 in prone position. Measured phi showed inverse relationship to LCI in the four different body positions. CONCLUSIONS EIT profiles and phi of functional EIT are new methods to describe regional ventilation distribution with EIT allowing inter-individual comparison.
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Affiliation(s)
- Thomas Riedel
- Queensland Paediatric Intensive Care Service, Mater Children's Hospital, Mater Misericordiae Hospitals, 41010, South Brisbane, QLD, Australia
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27
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Rousseau A, Bak Z, Janerot-Sjöberg B, Sjöberg F. Acute hyperoxaemia-induced effects on regional blood flow, oxygen consumption and central circulation in man. ACTA ACUST UNITED AC 2005; 183:231-40. [PMID: 15743383 DOI: 10.1111/j.1365-201x.2005.01405.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIM Despite numerous in vitro and animal studies, circulatory effects and mechanisms responsible for the vasoconstriction seen during hyperoxaemia are yet to be ascertained. The present study set out to: (i) set up a non-invasive human model for the study of hyperoxia-induced cardiovascular effects, (ii) describe the dynamics of this effect and (iii) determine whether hyperoxaemia also, by vasoconstriction alters oxygen consumption (O(2)). METHODS The study comprised four experiments (A, B, C and D) on healthy volunteers examined before, during and after 100% oxygen breathing. A: Blood flow (mL min(-1).100 mL(-1) tissue), venous occlusion plethysmography was assessed (n = 12). B: Blood flow was recorded with increasing transcutaneous oxygen tension (P(tc)O(2)) levels (dose-response) (n = 8). C: Heart rate (HR), stroke volume, cardiac output (CO) and systemic vascular resistance (SVR) was assessed using echocardiography (n = 8). D: O(2) was measured using an open circuit technique when breathing an air-O(2) mix (fraction of inhaled oxygen: F(i)O(2) = 0.58) (n = 8). RESULTS Calf blood flow decreased 30% during O(2) breathing. The decrease in calf blood flow was found to be oxygen dose dependent. A similar magnitude, as for the peripheral circulation, of the effect on central parameters (HR/CO and SVR) and in the time relationship was noted. Hyperoxia did not change O(2). An average of 207 (93) mL O(2) per subject was washed in during the experiments. CONCLUSION This model appears suitable for the investigation of O(2)-related effects on the central and peripheral circulation in man. Our findings, based on a more comprehensive (central/peripheral circulation examination) evaluation than earlier made, suggest significant circulatory effects of hyperoxia. Further studies are warranted to elucidate the underlying mechanisms.
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Affiliation(s)
- A Rousseau
- Department of Anaesthesiology and Intensive Care, University Hospital of Linköping, S-581 85 Linköping, Sweden
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28
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Olfert IM, Prisk GK. Effect of 60 degrees head-down tilt on peripheral gas mixing in the human lung. J Appl Physiol (1985) 2004; 97:827-34. [PMID: 15090487 DOI: 10.1152/japplphysiol.01379.2003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The phase III slope of sulfur hexafluoride (SF6) in a single-breath washout (SBW) is greater than that of helium (He) under normal gravity (i.e., 1G), thus resulting in a positive SF6-He slope difference. In microgravity (microG), SF6-He slope difference is smaller because of a greater fall in the phase III slope of SF6 than He. We sought to determine whether increasing thoracic fluid volume using 60 degrees head-down tilt (HDT) in 1G would produce a similar effect to microG on phase III slopes of SF6 and He. Single-breath vital capacity (SBW) and multiple-breath washout (MBW) tests were performed before, during, and 60 min after 1 h of HDT. Compared with baseline (SF6 1.050 +/- 0.182%/l, He 0.670 +/- 0.172%/l), the SBW phase III slopes for both SF6 and He tended to decrease during HDT, reaching nadir at 30 min (SF6 0.609 +/- 0.211%/l, He 0.248 +/- 0.138%/l; P = 0.08 and P = 0.06, respectively). In contrast to microG, the magnitude of the phase III slope decrease was similar for both SF6 and He; therefore, no change in SF6-He slope difference was observed. MBW analysis revealed a decrease in normalized phase III slopes at all time points during HDT, for both SF6 (P < 0.01) and He (P < 0.01). This decrease was due to changes in the acinar, and not the conductive, component of the normalized phase III slope. These findings support the notion that changes in thoracic fluid volume alter ventilation distribution in the lung periphery but also demonstrate that the effect during HDT does not wholly mimic that observed in microG.
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Affiliation(s)
- I Mark Olfert
- Department of Medicine, University of California, San Diego, La Jolla, California 92093-0623, USA.
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29
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Porra L, Monfraix S, Berruyer G, Le Duc G, Nemoz C, Thomlinson W, Suortti P, Sovijärvi ARA, Bayat S. Effect of tidal volume on distribution of ventilation assessed by synchrotron radiation CT in rabbit. J Appl Physiol (1985) 2004; 96:1899-908. [PMID: 14966018 DOI: 10.1152/japplphysiol.00866.2003] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
A respiration-gated synchrotron radiation computed tomography (SRCT) technique, which allows visualization and direct quantification of inhaled stable xenon gas, was used to study the effect of tidal volume (Vt) on regional lung ventilation. High-resolution maps (pixel size 0.35 x 0.35 mm) of local washin time constants (tau) and regional specific ventilation were obtained in five anesthetized, paralyzed, and mechanically ventilated rabbits in upright body position at the fourth, sixth, and eighth dorsal vertebral levels with a Vt from 4.9 +/- 0.3 to 7.9 +/- 0.4 ml/kg (means +/- SE). Increasing Vt without an increase in minute ventilation resulted in a proportional increase of mean specific ventilation up to 65% in all studied lung levels and reduced the scattering of washin tau values. The tau values had log-normal distributions. The results indicate that an increase in Vt decreases nonuniformity of intraregional ventilatory gas exchange. The findings suggest that (SRCT) provides a new quantitative tool with high spatial discrimination ability for assessment of changes in peripheral pulmonary gas distribution during mechanical ventilation.
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Affiliation(s)
- L Porra
- Department of Physical Sciences, University of Helsinki, Helsinki FIN 00014, Finland.
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30
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Gronkvist M, Bergsten E, Eiken O, Gustafsson PM. Inter- and intraregional ventilation inhomogeneity in hypergravity and after pressurization of an anti-G suit. J Appl Physiol (1985) 2003; 94:1353-64. [PMID: 12471045 DOI: 10.1152/japplphysiol.00612.2002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This study assessed the effects of increased gravity in the head-to-foot direction (+G(z)) and anti-G suit (AGS) pressurization on functional residual capacity (FRC), the volume of trapped gas (V(TG)), and ventilation distribution by using inert- gas washout. Normalized phase III slope (Sn(III)) analysis was used to determine the effects on inter- and intraregional ventilation inhomogeneity. Twelve men performed multiple-breath washouts of SF(6) and He in a human centrifuge at +1 to +3 G(z) wearing an AGS pressurized to 0, 6, or 12 kPa. Hypergravity produced moderately increased FRC, V(TG), and overall and inter- and intraregional inhomogeneities. In normogravity, AGS pressurization resulted in reduced FRC and increased V(TG), overall, and inter- and intraregional inhomogeneities. Inflation of the AGS to 12 kPa at +3 G(z) reduced FRC markedly and caused marked gas trapping and intraregional inhomogeneity, whereas interregional inhomogeneity decreased. In conclusion, increased +G(z) impairs ventilation distribution not only between widely separated lung regions, but also within small lung units. Pressurizing an AGS in hypergravity causes extensive gas trapping accompanied by reduced interregional inhomogeneity and, apparently, results in greater intraregional inhomogeneity.
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Affiliation(s)
- Mikael Gronkvist
- Swedish Defence Research Agency, Defence Medicine, S-580 13 Linköping, and Karolinska Institutet, S-171 77 Stockholm, Sweden.
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