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McCrabb T, Borg B, Gao CX, Smith C, O'Sullivan CF, Brown D, Ikin J, Makar A, Lane T, Abramson MJ, Thompson BR. Ventilation heterogeneity is increased in adults exposed to coal mine fire-related PM 2.5. Respirology 2024. [PMID: 39159074 DOI: 10.1111/resp.14817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Accepted: 07/22/2024] [Indexed: 08/21/2024]
Abstract
BACKGROUND AND OBJECTIVES The Hazelwood Health Study was set up to study long-term health effects of a mine fire that blanketed residents of the Latrobe Valley with smoke for 45 days in 2014. The Respiratory Stream specifically assessed the impact of fine particulate matter <2.5 μm diameter (PM2.5) exposure from mine fire smoke on lung health. The multiple breath nitrogen washout (MBW) test assesses ventilation heterogeneity, which may detect sub-clinical airways dysfunction not identified using standard tests such as spirometry. This analysis assessed the association of PM2.5 exposure with measures of ventilation heterogeneity. METHODS Exposed (Morwell) and unexposed (Sale) participants were recruited 3.5-4 years after the fire from those who had participated in an Adult Survey. MBW was performed to measure lung clearance index (LCI), functional residual capacity (FRC), acinar (Sacin) and conductive (Scond) ventilation heterogeneity. PM2.5 exposure was estimated with emission and chemical transport models. Multivariable linear regression models were fitted controlling for confounders. RESULTS We recruited 519 participants. MBW tests were conducted on 504 participants with 479 acceptable test results (40% male; 313 exposed, 166 unexposed). Exposure to mine fire-related PM2.5 was associated with increasing Scond (β = 1.57/kL, 95%CI: 0.20-2.95, p = 0.025), which was comparable to the estimated effect on Scond of 4.7 years of aging. No other MBW outcomes were statistically different. CONCLUSION Increasing exposure to PM2.5 was associated with increased ventilation heterogeneity in the conductive region of the lungs 4 years after the event.
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Affiliation(s)
- Thomas McCrabb
- School of Public Health & Preventive Medicine, Monash University, Melbourne, Victoria, Australia
- Respiratory Medicine, Alfred Health, Melbourne, Victoria, Australia
| | - Brigitte Borg
- School of Public Health & Preventive Medicine, Monash University, Melbourne, Victoria, Australia
- Respiratory Medicine, Alfred Health, Melbourne, Victoria, Australia
| | - Caroline X Gao
- School of Public Health & Preventive Medicine, Monash University, Melbourne, Victoria, Australia
- Centre for Youth Mental Health (Orygen), University of Melbourne, Melbourne, Victoria, Australia
| | - Catherine Smith
- School of Public Health & Preventive Medicine, Monash University, Melbourne, Victoria, Australia
- Centre for Youth Mental Health (Orygen), University of Melbourne, Melbourne, Victoria, Australia
| | - Claire F O'Sullivan
- School of Public Health & Preventive Medicine, Monash University, Melbourne, Victoria, Australia
- Respiratory Medicine, Alfred Health, Melbourne, Victoria, Australia
| | - David Brown
- School of Public Health & Preventive Medicine, Monash University, Melbourne, Victoria, Australia
| | - Jillian Ikin
- School of Public Health & Preventive Medicine, Monash University, Melbourne, Victoria, Australia
| | - Annie Makar
- Respiratory Medicine, Alfred Health, Melbourne, Victoria, Australia
| | - Tyler Lane
- School of Public Health & Preventive Medicine, Monash University, Melbourne, Victoria, Australia
| | - Michael J Abramson
- School of Public Health & Preventive Medicine, Monash University, Melbourne, Victoria, Australia
| | - Bruce R Thompson
- Melbourne School of Health Sciences, The University of Melbourne, Melbourne, Victoria, Australia
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2
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O'Sullivan CF, Nilsen K, Borg BM, Ellis MJ, Matsas P, Thien F, Douglass JA, Stuart-Andrews C, King GG, Prisk GK, Thompson BR. Small Airways Dysfunction is Associated with Increased Exacerbations in Patients with Asthma. J Appl Physiol (1985) 2022; 133:629-636. [PMID: 35861519 DOI: 10.1152/japplphysiol.00103.2022] [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
There is poor understanding of why some patients with asthma experience recurrent exacerbations despite high levels of treatment. We compared measurements of peripheral ventilation heterogeneity and respiratory system mechanics in participants with asthma who were differentiated according to exacerbation history, to ascertain whether peripheral airway dysfunction was related to exacerbations. Three asthmatic groups: "Stable" (no exacerbations for >12 months, n=18), "Exacerbation-prone" (≥1 exacerbation requiring systemic corticosteroids within the last 12 months, but stable for ≥1-month, n=9) and "Treated-exacerbation" (exacerbation requiring systemic corticosteroids within the last 1 month, n=12) were studied. All participants were current non-smokers with <10pack/years smoking history. Spirometry, static lung volumes, ventilation heterogeneity from multi-breath nitrogen washout (MBW) and respiratory system mechanics from oscillometry were measured. The Exacerbation-prone group compared to the Stable group had slightly worse spirometry (FEV1 Z-score -3.58(1.13) vs -2.32(1.06), p=0.03), however acinar ventilation heterogeneity (Sacin Z-score 7.43(8.59) vs 3.63(3.88), p=0.006) and respiratory system reactance (Xrs cmH2O.s.L-1 -2.74(3.82) vs -1.32(1.94), p=0.01) were much worse in this group. The Treated-exacerbation group had worse spirometry but similar small airway function, compared with the Stable group. Patients with asthma who exacerbate have worse small airway function as evidenced by increases in Sacin measured by MBW and delta Xrs from oscillometry, both markers of small airway dysfunction, compared with those that do not.
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Affiliation(s)
- Claire F O'Sullivan
- Respiratory Medicine, The Alfred Hospital, Melbourne, VIC, Australia.,Monash University, Melbourne, VIC, Australia
| | - Kris Nilsen
- Respiratory Medicine, The Alfred Hospital, Melbourne, VIC, Australia.,School of Health Science, Swinburne University of Technology, Melbourne, VIC, Australia
| | - Brigitte M Borg
- Respiratory Medicine, The Alfred Hospital, Melbourne, VIC, Australia.,Monash University, Melbourne, VIC, Australia
| | - Matthew J Ellis
- Respiratory Medicine, The Alfred Hospital, Melbourne, VIC, Australia
| | - Pam Matsas
- Respiratory Medicine, The Alfred Hospital, Melbourne, VIC, Australia
| | - Frank Thien
- Monash University, Melbourne, VIC, Australia.,Respiratory Medicine, Eastern Health, Melbourne, VIC, Australia
| | - Jo A Douglass
- The Department of Medicine, Royal Melbourne Hospital, University of Melbourne, Melbourne, VIC, Australia
| | | | - Gregory G King
- Airway Physiology and Imaging Group, The Woolcock Institute, Sydney, NSW, Australia
| | - Gordon Kim Prisk
- Department of Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Bruce R Thompson
- Respiratory Medicine, The Alfred Hospital, Melbourne, VIC, Australia.,School of Health Science, University of Melbourne, Melbourne, VIC, Australia
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3
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Commentaries on Viewpoint: Small airways vs. large airways in asthma: time for a new perspective. J Appl Physiol (1985) 2021; 131:1842-1848. [PMID: 34898290 DOI: 10.1152/japplphysiol.00762.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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4
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Holt NR, Gao CX, Borg BM, Brown D, Broder JC, Ikin J, Makar A, McCrabb T, Nilsen K, Thompson BR, Abramson MJ. Long-term impact of coal mine fire smoke on lung mechanics in exposed adults. Respirology 2021; 26:861-868. [PMID: 34181807 DOI: 10.1111/resp.14102] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 05/24/2021] [Accepted: 06/02/2021] [Indexed: 11/28/2022]
Abstract
BACKGROUND AND OBJECTIVE In 2014, a 6-week-long fire at the Hazelwood coal mine exposed residents in the adjacent town of Morwell to high concentrations of fine particulate matter with an aerodynamic diameter < 2.5 μm (PM2.5 ). The long-term health consequences are being evaluated as part of the Hazelwood Health Study. METHODS Approximately 3.5-4 years after the mine fire, adults from Morwell (n = 346) and the comparison town Sale (n = 173) participated in the longitudinal Respiratory Stream of the Study. Individual PM2.5 exposure was retrospectively modelled. Lung mechanics were assessed using the forced oscillation technique (FOT), utilizing pressure waves to measure respiratory system resistance (Rrs) and reactance (Xrs). Multivariate linear regression was used to evaluate associations between PM2.5 and transformed Rrs at 5 Hz, area under the reactance curve (AX5) and Xrs at 5 Hz controlling for key confounders. RESULTS There were clear dose-response relationships between increasing mine fire PM2.5 and worsening lung mechanics, including a reduction in post-bronchodilator (BD) Xrs5 and an increase in AX5. A 10 μg/m3 increase in mine fire-related PM2.5 was associated with a 0.015 (95% CI: 0.004, 0.027) reduction in exponential (Xrs5) post-BD, which was comparable to 4.7 years of ageing. Similarly, the effect of exposure was associated with a 0.072 (0.005, 0.138) increase in natural log (lnAX5) post-BD, equivalent to 3.9 years of ageing. CONCLUSION This is the first study using FOT in adults evaluating long-term respiratory outcomes after medium-term ambient PM2.5 exposure to coal mine fire smoke. These results should inform public health policies and planning for future events.
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Affiliation(s)
- Nicolette R Holt
- School of Public Health & Preventive Medicine, Monash University, Melbourne, Victoria, Australia.,Department of Anaesthetics, Perioperative Medicine & Pain Medicine, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia
| | - Caroline X Gao
- School of Public Health & Preventive Medicine, Monash University, Melbourne, Victoria, Australia.,Centre for Youth Mental Health (Orygen), University of Melbourne, Melbourne, Victoria, Australia
| | - Brigitte M Borg
- School of Public Health & Preventive Medicine, Monash University, Melbourne, Victoria, Australia.,Respiratory Medicine, The Alfred Hospital, Melbourne, Victoria, Australia
| | - David Brown
- School of Public Health & Preventive Medicine, Monash University, Melbourne, Victoria, Australia
| | - Jonathan C Broder
- School of Public Health & Preventive Medicine, Monash University, Melbourne, Victoria, Australia
| | - Jillian Ikin
- School of Public Health & Preventive Medicine, Monash University, Melbourne, Victoria, Australia
| | - Annie Makar
- Respiratory Medicine, The Alfred Hospital, Melbourne, Victoria, Australia
| | - Thomas McCrabb
- Respiratory Medicine, The Alfred Hospital, Melbourne, Victoria, Australia
| | - Kris Nilsen
- Respiratory Medicine, The Alfred Hospital, Melbourne, Victoria, Australia
| | - Bruce R Thompson
- School of Health Sciences, Swinburne University of Technology, Hawthorn, Victoria, Australia
| | - Michael J Abramson
- School of Public Health & Preventive Medicine, Monash University, Melbourne, Victoria, Australia
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Cottee AM, Seccombe LM, Thamrin C, Badal T, King GG, Peters MJ, Farah CS. Longitudinal monitoring of asthma in the clinic using respiratory oscillometry. Respirology 2021; 26:566-573. [PMID: 33797141 DOI: 10.1111/resp.14053] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2020] [Accepted: 02/23/2021] [Indexed: 01/18/2023]
Abstract
BACKGROUND AND OBJECTIVE Asthma guidelines emphasize the importance of assessing lung function and symptoms. The forced oscillation technique (FOT) and its longitudinal relationship with spirometry and symptoms are unresolved. We examined concordance between longitudinal spirometry, FOT and symptom control, and determined FOT limits of agreement in stable asthma. METHODS Over a 3-year period, adults with asthma attending a tertiary clinic completed the asthma control test (ACT), fraction of exhaled nitric oxide (FeNO), FOT and spirometry. Analysis included between-visit concordance for significant change using Cohen's kappa (κ) and stable asthma FOT limits of agreement. RESULTS Data (n = 186) from 855 visits (mean ± SD 4.6 ± 3.0 visits), 114 ± 95 days apart, were analysed. Between-visit concordance was moderate between reactance at 5 Hz (X5) and forced expiratory volume in 1 s (FEV1 ) (κ = 0.34, p = 0.001), and weak between ACT and FEV1 (κ = 0.18, p = 0.001). Change in FeNO did not correlate with lung function or ACT (κ < 0.05, p > 0.1). Stable asthma between visits (n = 75; 132 visits) had reduced lung function variability, but comparable concordance to the entire cohort. Limits of agreement for FEV1 (0.42 L), resistance at 5 Hz (2.06 cm H2 O s L-1 ) and X5 (2.75 cm H2 O s L-1 ) in stable asthma were at least twofold greater than published values in health. CONCLUSION In adults with asthma, there is moderate concordance between longitudinal change in FOT and spirometry. Both tests relate poorly to changes in asthma control, highlighting the need for multi-modal assessment in asthma rather than symptoms alone. The derivation of longitudinal FOT limits of agreement will assist in its clinical interpretation.
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Affiliation(s)
- Alice M Cottee
- Department of Respiratory Medicine, Concord Repatriation General Hospital, Concord, New South Wales, Australia.,Airway Physiology and Imaging Group and Woolcock Emphysema Centre, Woolcock Institute of Medical Research, Glebe, New South Wales, Australia.,Faculty of Medicine and Health, University of Sydney, Sydney, New South Wales, Australia
| | - Leigh M Seccombe
- Department of Respiratory Medicine, Concord Repatriation General Hospital, Concord, New South Wales, Australia.,Faculty of Medicine and Health, University of Sydney, Sydney, New South Wales, Australia
| | - Cindy Thamrin
- Airway Physiology and Imaging Group and Woolcock Emphysema Centre, Woolcock Institute of Medical Research, Glebe, New South Wales, Australia
| | - Tanya Badal
- Department of Respiratory Medicine, Concord Repatriation General Hospital, Concord, New South Wales, Australia.,Airway Physiology and Imaging Group and Woolcock Emphysema Centre, Woolcock Institute of Medical Research, Glebe, New South Wales, Australia.,Faculty of Medicine and Health, University of Sydney, Sydney, New South Wales, Australia
| | - Gregory G King
- Airway Physiology and Imaging Group and Woolcock Emphysema Centre, Woolcock Institute of Medical Research, Glebe, New South Wales, Australia.,Faculty of Medicine and Health, University of Sydney, Sydney, New South Wales, Australia.,Department of Respiratory Medicine, Royal North Shore Hospital, St Leonards, New South Wales, Australia
| | - Matthew J Peters
- Department of Respiratory Medicine, Concord Repatriation General Hospital, Concord, New South Wales, Australia.,Faculty of Medicine and Health, University of Sydney, Sydney, New South Wales, Australia.,Faculty of Medicine and Health Sciences, Macquarie University, North Ryde, New South Wales, Australia
| | - Claude S Farah
- Department of Respiratory Medicine, Concord Repatriation General Hospital, Concord, New South Wales, Australia.,Airway Physiology and Imaging Group and Woolcock Emphysema Centre, Woolcock Institute of Medical Research, Glebe, New South Wales, Australia.,Faculty of Medicine and Health, University of Sydney, Sydney, New South Wales, Australia.,Faculty of Medicine and Health Sciences, Macquarie University, North Ryde, New South Wales, Australia
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6
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Veneroni C, Van Muylem A, Malinovschi A, Michils A, Dellaca' RL. Closing volume detection by single-breath gas washout and forced oscillation technique. J Appl Physiol (1985) 2021; 130:903-913. [PMID: 33475458 DOI: 10.1152/japplphysiol.00440.2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Closing volume (CV) is commonly measured by single-breath nitrogen washout (CVSBW). A method based on the forced oscillation technique was recently introduced to detect a surrogate CV (CVFOT). As the two approaches are based on different physiological mechanisms, we aim to investigate CVFOT and CVSBW relationship at different degrees and patterns of airway obstruction. A mathematical model was developed to evaluate the CVSBW and CVFOT sensitivity to different patterns of airway obstruction, either located in a specific lung region or equally distributed throughout the lung. The two CVs were also assessed during slow vital capacity (VC) maneuvers in triplicate in 13 healthy subjects and pre- and postmethacholine challenge (Mch) in 12 subjects with mild-moderate asthma. Model simulations suggest that CVSBW is more sensitive than CVFOT to the presence of few flow-limited or closed airways that modify the contribution of tracer-poor and tracer-rich lung regions to the overall exhaled gas. Conversely, CVFOT occurs only when at least ∼65% of lung units are flow limited or closed, regardless of their regional distribution. CVSBW did not differ between healthy subjects and those with asthma (17 ± 9% VC vs. 22 ± 10% VC), whereas CVFOT did (16 ± 5% VC vs. 23 ± 6% VC, P < 0.01). In patients with asthma, both CVSBW and CVFOT increased post-Mch (33 ± 7% VC P < 0.001 and 43 ± 12% VC P < 0.001, respectively). CVSBW weakly correlated with CVFOT (r = 0.45, P < 0.01). The closing capacities (CV + residual volume) were correlated (r = 0.74, P < 0.001), but the changes with Mch in both CVs and closing capacities did not correlate. CVFOT is easy to measure and provides a reproducible parameter useful for describing airway impairment in obstructive respiratory diseases.NEW & NOTEWORTHY The forced oscillation technique can identify a surrogate of closing volume (CVFOT). We investigated its relationship with the one measured by single-breath washout (CVSBW). CVFOT weakly correlates with CVSBW. The respective closing capacities were correlated, but their increases after methacholine challenge in asthmatics did not. Our results suggest that CVFOT is less sensitive than CVSBW to few flow-limited/closed airways but more specific in detecting increases in flow-limited/closed airways involving the majority of the lung.
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Affiliation(s)
- Chiara Veneroni
- TechRes Lab, Department of Electronics, Information and Biomedical Engineering, Politecnico di Milano University, Milan, Italy
| | - Alain Van Muylem
- Chest Department, Erasme University Hospital/Université Libre de Bruxelles, Brussels, Belgium
| | - Andrei Malinovschi
- Department of Medical Sciences, Clinical Physiology, Uppsala University, Uppsala, Sweden
| | - Alain Michils
- Chest Department, Erasme University Hospital/Université Libre de Bruxelles, Brussels, Belgium
| | - Raffaele L Dellaca'
- TechRes Lab, Department of Electronics, Information and Biomedical Engineering, Politecnico di Milano University, Milan, Italy
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Bates JHT, Peters U, Daphtary N, MacLean ES, Hodgdon K, Kaminsky DA, Bhatawadekar S, Dixon AE. Altered airway mechanics in the context of obesity and asthma. J Appl Physiol (1985) 2021; 130:36-47. [PMID: 33119471 PMCID: PMC7944930 DOI: 10.1152/japplphysiol.00666.2020] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 10/27/2020] [Accepted: 10/27/2020] [Indexed: 12/29/2022] Open
Abstract
The obesity epidemic is causing a rise in asthma incidence due to the appearance of an obesity-specific late-onset nonallergic (LONA) phenotype. We investigated why only a subset of obese participants develop LONA asthma by determining how obesity, both alone and in combination with LONA asthma, affects the volume dependence of respiratory system impedance. We also determined how obesity and asthma affect impedance during and following challenge with the PC20 dose of methacholine. We found during passive exhalation that all obese participants, in contrast to lean controls and lean asthmatics, experienced similarly profound elevations in lung elastance as they approached functional residual capacity. We also found, however, that the LONA asthmatics had a greater negative dependence of airway resistance on lung volume over the middle of the volume range compared with the other groups. Methacholine challenge with the PC20 dose led to comparable changes in respiratory system impedance in the four study groups, but the doses themselves were substantially lower in both obese and lean asthmatic participants compared with obese and lean controls. Also, the obese LONA asthmatics had higher breathing frequencies and lower tidal volumes postchallenge compared with the other participants. Taken together, these results suggest that all obese individuals experience substantial lung collapse as they approach functional residual capacity, presumably due to the weight of the chest wall. It remains unclear why obese LONA asthmatics are hyperresponsive to methacholine while obese nonasthmatic individuals are not.NEW & NOTEWORTHY Why only a subset of severely obese subjects develop late-onset nonallergic (LONA) asthma remains unknown, although it is widely assumed that compression of the lungs by the chest wall is somehow involved. We show that lung compression is common to obese individuals both without asthma and with LONA asthma but that those with LONA asthma may have increased airway wall compliance and possibly also a reduced ability to recruit collapsed lung.
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Affiliation(s)
- Jason H T Bates
- Department of Medicine, Larner College of Medicine, University of Vermont, Burlington, Vermont
| | - Ubong Peters
- Department of Medicine, Larner College of Medicine, University of Vermont, Burlington, Vermont
| | - Nirav Daphtary
- Department of Medicine, Larner College of Medicine, University of Vermont, Burlington, Vermont
| | - Erick S MacLean
- Department of Medicine, Larner College of Medicine, University of Vermont, Burlington, Vermont
| | - Kevin Hodgdon
- Department of Medicine, Larner College of Medicine, University of Vermont, Burlington, Vermont
| | - David A Kaminsky
- Department of Medicine, Larner College of Medicine, University of Vermont, Burlington, Vermont
| | - Swati Bhatawadekar
- Department of Medicine, Larner College of Medicine, University of Vermont, Burlington, Vermont
| | - Anne E Dixon
- Department of Medicine, Larner College of Medicine, University of Vermont, Burlington, Vermont
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8
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Nilsen K, Thompson BR, Zajakovski N, Kean M, Harris B, Cowin G, Robinson P, Prisk GK, Thien F. Airway closure is the predominant physiological mechanism of low ventilation seen on hyperpolarized helium-3 MRI lung scans. J Appl Physiol (1985) 2020; 130:781-791. [PMID: 33332988 DOI: 10.1152/japplphysiol.00163.2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Hyperpolarized helium-3 MRI (3He MRI) provides detailed visualization of low- (hypo- and non-) ventilated lungs. Physiological measures of gas mixing may be assessed by multiple breath nitrogen washout (MBNW) and of airway closure by a forced oscillation technique (FOT). We hypothesize that in patients with asthma, areas of low-ventilated lung on 3He MRI are the result of airway closure. Ten control subjects, ten asthma subjects with normal spirometry (non-obstructed), and ten asthmatic subjects with reduced baseline lung function (obstructed) attended two testing sessions. On visit one, baseline plethysmography was performed followed by spirometry, MBNW, and FOT assessment pre and post methacholine challenge. On visit two, 3He MRI scans were conducted pre and post methacholine challenge. Post methacholine the volume of low-ventilated lung increased from 8.3% to 13.8% in the non-obstructed group (P = 0.012) and from 13.0% to 23.1% in the obstructed group (P = 0.001). For all subjects, the volume of low ventilation from 3He MRI correlated with a marker of airway closure in obstructive subjects, Xrs (6 Hz) and the marker of ventilation heterogeneity Scond with r2 values of 0.61 (P < 0.001) and 0.56 (P < 0.001), respectively. The change in Xrs (6 Hz) correlated well (r2 = 0.45, p < 0.001), whereas the change in Scond was largely independent of the change in low ventilation volume (r2 = 0.13, P < 0.01). The only significant predictor of low ventilation volume from the multi-variate analysis was Xrs (6 Hz). This is consistent with the concept that regions of poor or absent ventilation seen on 3He MRI are primarily the result of airway closure.NEW & NOTEWORTHY This study introduces a novel technique of generating high-resolution 3D ventilation maps from hyperpolarized helium-3 MRI. It is the first study to demonstrate that regions of poor or absent ventilation seen on 3He MRI are primarily the result of airway closure.
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Affiliation(s)
- Kris Nilsen
- The Alfred Hospital, Melbourne, Australia.,Swinburne University of Technology, Melbourne, Australia
| | - Bruce R Thompson
- Swinburne University of Technology, Melbourne, Australia.,Monash University, Melbourne, Australia
| | | | - Michael Kean
- The Royal Children's Hospital, Melbourne, Australia
| | - Benjamin Harris
- University of Sydney, Sydney, Australia.,Respiratory Medicine, Royal North Shore Hospital, Sydney, Australia
| | - Gary Cowin
- National Imaging Facility, Centre for Advanced Imaging, The University of Queensland, Brisbane, Australia
| | - Phil Robinson
- The Royal Children's Hospital, Melbourne, Australia.,University of Melbourne, Melbourne, Australia.,Murdoch Children's Research Institute, Melbourne, Australia
| | - G Kim Prisk
- University of California, San Diego, California
| | - Francis Thien
- Monash University, Melbourne, Australia.,Box Hill Hospital, Eastern Health, Melbourne, Australia
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9
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Abstract
This article will discuss in detail the pathophysiology of asthma from the point of view of lung mechanics. In particular, we will explain how asthma is more than just airflow limitation resulting from airway narrowing but in fact involves multiple consequences of airway narrowing, including ventilation heterogeneity, airway closure, and airway hyperresponsiveness. In addition, the relationship between the airway and surrounding lung parenchyma is thought to be critically important in asthma, especially as related to the response to deep inspiration. Furthermore, dynamic changes in lung mechanics over time may yield important information about asthma stability, as well as potentially provide a window into future disease control. All of these features of mechanical properties of the lung in asthma will be explained by providing evidence from multiple investigative methods, including not only traditional pulmonary function testing but also more sophisticated techniques such as forced oscillation, multiple breath nitrogen washout, and different imaging modalities. Throughout the article, we will link the lung mechanical features of asthma to clinical manifestations of asthma symptoms, severity, and control. © 2020 American Physiological Society. Compr Physiol 10:975-1007, 2020.
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Affiliation(s)
- David A Kaminsky
- University of Vermont Larner College of Medicine, Burlington, Vermont, USA
| | - David G Chapman
- University of Technology Sydney, Sydney, New South Wales, Australia
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10
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Chapman DG, King GG, Robinson PD, Farah CS, Thamrin C. The need for physiological phenotyping to develop new drugs for airways disease. Pharmacol Res 2020; 159:105029. [PMID: 32565310 DOI: 10.1016/j.phrs.2020.105029] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 06/01/2020] [Accepted: 06/12/2020] [Indexed: 11/25/2022]
Abstract
Asthma and COPD make up the majority of obstructive airways diseases (OADs), which affects ∼11 % of the population. The main drugs used to treat OADs have not changed in the past five decades, with advancements mainly comprising variations on existing treatments. The recent biologics are beneficial to only specific subsets of patients. Part of this may lie in our inability to adequately characterise the tremendous heterogeneity in every aspect of OAD. The field is currently moving towards the concept of personalised medicine, based on a focus on treatable traits that are objective, measurable and modifiable. We propose extending this concept via the use of emerging clinical tools for comprehensive physiological phenotyping. We describe, based on published data, the evidence for the use of functional imaging, gas washout techniques and oscillometry, as well as potential future applications, to more comprehensively assess and predict treatment response in OADs. In this way, we hope to demonstrate how physiological phenotyping tools will improve the way in which drugs are prescribed, but most importantly, will facilitate development of new drugs for OADs.
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Affiliation(s)
- David G Chapman
- Airway Physiology and Imaging Group and Woolcock Emphysema Centre, The Woolcock Institute of Medical Research, The University of Sydney, Glebe NSW 2037, Australia; School of Life Sciences, Faculty of Science, University of Technology Sydney, Ultimo NSW 2007, Australia.
| | - G G King
- Airway Physiology and Imaging Group and Woolcock Emphysema Centre, The Woolcock Institute of Medical Research, The University of Sydney, Glebe NSW 2037, Australia; Department of Respiratory Medicine, Royal North Shore Hospital, St. Leonards, NSW 2065, Australia; NHMRC Centre of Excellence in Severe Asthma, New Lambton Heights NSW 2305, Australia; Faculty of Medicine and Health Sciences, The University of Sydney, NSW 2006, Australia
| | - Paul D Robinson
- Airway Physiology and Imaging Group and Woolcock Emphysema Centre, The Woolcock Institute of Medical Research, The University of Sydney, Glebe NSW 2037, Australia; Department of Respiratory Medicine, The Children's Hospital at Westmead, Westmead, NSW 2145, Australia; Faculty of Medicine and Health Sciences, The University of Sydney, NSW 2006, Australia
| | - Claude S Farah
- Airway Physiology and Imaging Group and Woolcock Emphysema Centre, The Woolcock Institute of Medical Research, The University of Sydney, Glebe NSW 2037, Australia; Faculty of Medicine and Health Sciences, The University of Sydney, NSW 2006, Australia; Department of Thoracic Medicine, Concord Repatriation General Hospital, Concord, NSW 2137, Australia
| | - Cindy Thamrin
- Airway Physiology and Imaging Group and Woolcock Emphysema Centre, The Woolcock Institute of Medical Research, The University of Sydney, Glebe NSW 2037, Australia; Faculty of Medicine and Health Sciences, The University of Sydney, NSW 2006, Australia
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11
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Zimmermann SC, Thamrin C, Chan AS, Bertolin A, Chapman DG, King GG. Relationships Between Forced Oscillatory Impedance and 6-minute Walk Distance After Pulmonary Rehabilitation in COPD. Int J Chron Obstruct Pulmon Dis 2020; 15:157-166. [PMID: 32021155 PMCID: PMC6982450 DOI: 10.2147/copd.s225543] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 12/19/2019] [Indexed: 12/16/2022] Open
Abstract
Rationale Pulmonary rehabilitation for chronic obstructive pulmonary disease (COPD) reduces dyspnoea and improves exercise capacity and quality of life. The improvement in exercise capacity is variable and unpredictable, however. Respiratory system impedance obtained by forced oscillation technique (FOT) as a measure of ventilatory impairment in COPD may relate to improvement in exercise capacity with pulmonary rehabilitation. We aimed to determine if baseline FOT parameters relate to changes in exercise capacity following pulmonary rehabilitation. Methods At the start of rehabilitation, 15 COPD subjects (mean(SD) 75.2(6.1) years, FEV1 z-score −2.61(0.84)) had measurements by FOT, spirometry, plethysmographic lung volumes and 6-minute walk distance (6MWD). Respiratory system resistance (Rrs) and reactance (Xrs) parameters as the mean over all breaths (Rmean, Xmean), during inspiration only (Rinsp, Xinsp), and expiratory flow limitation (DeltaXrs = Xinsp−Xexp), were calculated. FOT and 6MWD measurements were repeated at completion of rehabilitation and 3 months after completion. Results At baseline, Xrs measures were unrelated to 6MWD. Xinsp improved significantly with rehabilitation (from mean(SD) −2.35(1.02) to −2.04(0.85) cmH2O.s.L−1, p=0.008), while other FOT parameters did not. No FOT parameters related to the change in 6MWD at program completion. Baseline Xmean, DeltaXrs, and FVC z-score correlated with the change in 6MWD between completion and 3 months after completion of rehabilitation (rs=0.62, p=0.03; rs=−0.65, p=0.02; and rs=0.62, p=0.03, respectively); with worse ventilatory impairment predicting loss of 6MWD. There were no relationships between Rrs parameters, FEV1 or FEV1/FVC z-scores and changes in 6MWD. Conclusion Baseline reactance parameters may be helpful in predicting those patients with COPD at most risk of loss of exercise capacity following completion of pulmonary rehabilitation.
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Affiliation(s)
- Sabine C Zimmermann
- The Woolcock Emphysema Centre, Woolcock Institute of Medical Research, The University of Sydney, Glebe, NSW 2037, Australia.,The Northern Clinical School, Faculty of Medicine and Health Sciences, The University of Sydney, Camperdown, NSW 2006, Australia.,Department of Respiratory Medicine, Royal North Shore Hospital, St Leonards, NSW 2065, Australia
| | - Cindy Thamrin
- The Woolcock Emphysema Centre, Woolcock Institute of Medical Research, The University of Sydney, Glebe, NSW 2037, Australia
| | - Andrew Sl Chan
- The Northern Clinical School, Faculty of Medicine and Health Sciences, The University of Sydney, Camperdown, NSW 2006, Australia.,Department of Respiratory Medicine, Royal North Shore Hospital, St Leonards, NSW 2065, Australia
| | - Amy Bertolin
- The Woolcock Emphysema Centre, Woolcock Institute of Medical Research, The University of Sydney, Glebe, NSW 2037, Australia
| | - David G Chapman
- The Woolcock Emphysema Centre, Woolcock Institute of Medical Research, The University of Sydney, Glebe, NSW 2037, Australia.,School of Life Sciences, Faculty of Science, University of Technology Sydney, Ultimo, NSW 2007, Australia
| | - Gregory G King
- The Woolcock Emphysema Centre, Woolcock Institute of Medical Research, The University of Sydney, Glebe, NSW 2037, Australia.,The Northern Clinical School, Faculty of Medicine and Health Sciences, The University of Sydney, Camperdown, NSW 2006, Australia.,Department of Respiratory Medicine, Royal North Shore Hospital, St Leonards, NSW 2065, Australia
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Takeichi N, Yamazaki H, Fujimoto K. Comparison of impedance measured by the forced oscillation technique and pulmonary functions, including static lung compliance, in obstructive and interstitial lung disease. Int J Chron Obstruct Pulmon Dis 2019; 14:1109-1118. [PMID: 31213791 PMCID: PMC6538254 DOI: 10.2147/copd.s198030] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 04/16/2019] [Indexed: 11/27/2022] Open
Abstract
Objective: To examine whether the parameters of impedance measured by the broadband frequency forced oscillation technique (FOT) were reflected by changes in lung compliance induced by emphysema and fibrosis, we retrospectively compared the parameters of FOT and pulmonary functions, including static lung compliance (Cst), in obstructive lung disease (OLD) and interstitial lung disease (ILD). Patients and methods: The data of 18 patients with OLD (16 with COPD, two with asthma COPD overlap), 11 with ILD, and 24 healthy volunteers, whose respiratory impedance was measured using a MostGraph-01 and other pulmonary functions including Cst and lung resistance (RL) were measured on the same day and were retrospectively collected and compared. Results: The parameters of resistance, reactance, and resonant frequency showed good correlations with ventilation unevenness (r=0.63, −0.89, 0.77, respectively) and lung elastic resistance (r=0.59, −0.80, 0.73, respectively) in all groups (N=53). These indices were significant determinants of increased respiratory resistance and more negative shift of respiratory reactance (Xrs) at lower frequency (P<0.001). Decreased functional residual capacity was also a determinant of Xrs at 5 Hz (X5) (P<0.05). The differences in mean X5 in the expiratory phase relative to those in the inspiratory phase (within-breath changes in X5) were associated with airflow obstruction (P<0.002) and lung elastic resistance (P<0.001). However, no significant correlations between Cst and any parameters of respiratory impedance were observed. Conclusions: These findings suggest that the impedance parameters measured by FOT are reflected by airway obstruction, ventilation unevenness, and lung resistance, but hardly reflected by changes in lung compliance due to emphysema or fibrosis in both CLD and ILD.
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Affiliation(s)
- Naoya Takeichi
- Department of Biomedical Laboratory Sciences, Graduate School of Medicine, Shinshu University, Matsumoto, Nagano, Japan
| | - Haruna Yamazaki
- Department of Biomedical Laboratory Sciences, Graduate School of Medicine, Shinshu University, Matsumoto, Nagano, Japan
| | - Keisaku Fujimoto
- Department of Clinical Laboratory Sciences, Shinshu University School of Health Sciences, Matsumoto, Nagano, Japan
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