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Coutu F, Malaeb D, Iorio OC, Nabavi S, McFarland T, Lundblad LKA, Dandurand RJ, Gottfried SB, Ross BA. Measuring lung mechanics in patients with COPD using the handheld portable rapid expiratory occlusion monitor (REOM): A cross-sectional study. Physiol Rep 2025; 13:e70307. [PMID: 40192097 PMCID: PMC11973731 DOI: 10.14814/phy2.70307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2024] [Revised: 02/14/2025] [Accepted: 03/24/2025] [Indexed: 04/10/2025] Open
Abstract
While conventional spirometry is associated with strenuous "forced" maximal respiratory maneuvers and infection control implications, oscillometry is not associated with these issues. However, portability, convenience of use, and interpretation remain common limitations to both techniques. This study tested the concordance and agreement between resistance measurements obtained from the handheld portable REOM device (Reo-f, Reo-s) with those from conventional oscillometry (R19, R5) in PFT-confirmed "mild" (GOLD 1) and "very severe" (GOLD 4) COPD. Unadjusted and adjusted concordance (Spearman correlation) and agreement (Bland-Altman tests) served as co-primary outcomes. Discrimination between GOLD 1 and 4 COPD (Wilcoxon rank sum test, Support Vector Machine (SVM) classifier) and patient user experience (System Utility Scale (SUS), Participant Satisfaction Survey (PSS)) served as secondary outcomes. In 17 participants (GOLD 1 n = 9, GOLD 4 n = 8), adjusted R5-Reo-s (0.95 [0.81, 0.98]) and R19-Reo-f (0.93 [0.79, 0.99]) correlations were very strong, as was agreement (mean differences: -0.07, 0.08, respectively). Statistically significant between-group differences were observed for all four resistance parameters. Reo-s in particular exhibited perfect discrimination between GOLD 1 and 4 disease, with some minor misclassification by Reo-f, R5 (n = 1 each) and R19 (n = 4). User experience scores were excellent. These results support the capacity for REOM as a novel, complementary diagnostic device in COPD.
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Affiliation(s)
- Felix‐Antoine Coutu
- Respiratory Epidemiology and Clinical Research Unit, Centre for Outcomes Research and EvaluationResearch Institute of the McGill University Health CentreMontrealQuebecCanada
- Department of MedicineMcGill UniversityMontrealQuebecCanada
| | - Dany Malaeb
- Respiratory Epidemiology and Clinical Research Unit, Centre for Outcomes Research and EvaluationResearch Institute of the McGill University Health CentreMontrealQuebecCanada
| | - Olivia C. Iorio
- Respiratory Epidemiology and Clinical Research Unit, Centre for Outcomes Research and EvaluationResearch Institute of the McGill University Health CentreMontrealQuebecCanada
- Department of MedicineMcGill UniversityMontrealQuebecCanada
| | - Seyedfakhreddin Nabavi
- Respiratory Epidemiology and Clinical Research Unit, Centre for Outcomes Research and EvaluationResearch Institute of the McGill University Health CentreMontrealQuebecCanada
| | - Tom McFarland
- Respiratory Epidemiology and Clinical Research Unit, Centre for Outcomes Research and EvaluationResearch Institute of the McGill University Health CentreMontrealQuebecCanada
- Department of MedicineMcGill UniversityMontrealQuebecCanada
| | - Lennart K. A. Lundblad
- Meakins‐Christie Laboratories, McGill UniversityMontrealQuebecCanada
- THORASYS Thoracic Medical Systems Inc.MontrealQuebecCanada
| | - Ron J. Dandurand
- Department of MedicineMcGill UniversityMontrealQuebecCanada
- Meakins‐Christie Laboratories, McGill UniversityMontrealQuebecCanada
- Montreal Chest Institute, McGill University Health CentreMontrealQuebecCanada
- Lakeshore General HospitalPointe‐ClaireQuebecCanada
- Ste‐Anne HospitalSte‐Anne‐de‐BellevueQuebecCanada
- Translation Research in Respiratory Diseases ProgramResearch Institute of the McGill University Health Centre, McGill UniversityMontrealQuebecCanada
| | - Stewart B. Gottfried
- Department of MedicineMcGill UniversityMontrealQuebecCanada
- Meakins‐Christie Laboratories, McGill UniversityMontrealQuebecCanada
- Montreal Chest Institute, McGill University Health CentreMontrealQuebecCanada
- Translation Research in Respiratory Diseases ProgramResearch Institute of the McGill University Health Centre, McGill UniversityMontrealQuebecCanada
| | - Bryan A. Ross
- Respiratory Epidemiology and Clinical Research Unit, Centre for Outcomes Research and EvaluationResearch Institute of the McGill University Health CentreMontrealQuebecCanada
- Department of MedicineMcGill UniversityMontrealQuebecCanada
- Montreal Chest Institute, McGill University Health CentreMontrealQuebecCanada
- Translation Research in Respiratory Diseases ProgramResearch Institute of the McGill University Health Centre, McGill UniversityMontrealQuebecCanada
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Aitken CR, Pathangey G, Stamos M, Kim CH, Johnson BD, Stewart GM. Reproducibility and responsiveness of airway impedance measures derived from the forced oscillation technique across different operating lung volumes. Respir Physiol Neurobiol 2024; 320:104200. [PMID: 38036081 DOI: 10.1016/j.resp.2023.104200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 11/21/2023] [Accepted: 11/22/2023] [Indexed: 12/02/2023]
Abstract
BACKGROUND The forced oscillation technique (FOT) enables non-invasive measurement of respiratory system impedance. Limited data exists on how changes in operating lung volume (OLV) impact FOT-derived measures of airway resistance (Rrs) and reactance (Xrs). OBJECTIVES This study examined the reproducibility and responsiveness of FOT-derived measures of Rrs and Xrs during simulated changes in OLV. METHODS Participants simulated breathing at six OLVs: total lung capacity (TLC), ∼50% of inspiratory reserve volume (IRV50), ∼two-times tidal volume (VT2), tidal volume (VT), ∼50% of expiratory reserve volume (ERV50), and residual volume (RV), on a commercially available FOT device. Each simulated OLV manuever was performed in triplicate and in random order. Total Rrs and Xrs were recorded at 5, 11, and 19 Hz. RESULTS Twelve healthy participants (2 female) completed the study (weight: 76.5 ± 13.6 kg, height: 178.6 ± 9.7 cm, body mass index: 23.9 ± 3.1 kg/m2). Reproducibility of Rrs and Xrs at VT, VT2 and IRV50 was good to excellent (Range: ICC: 0.89-0.98, 95% confidence interval (CI): 0.70-0.98), while reproducibility at TLC, RV, and ERV50 was poor to excellent (Range: ICC: 0.60-0.98, 95% CI: 0.36-0.97). Rrs and Xrs were not different between VT and VT2 at any frequency (P > .05). With lung hyperinflation from VT to TLC, Rrs and Xrs decreased at all three frequencies (e.g., At 5 Hz Rrs: mean difference (MD): - 0.89, 95%CI: - 0.03 to - 1.75, P = .04; Xrs: MD: - 0.56, 95%CI: - 0.25 to - 0.86, P < .01). With lung hypoinflated from VT to RV, Rrs increased, and Xrs decreased for all frequencies (e.g., MD at 5 Hz, Rrs: MD: 2.31, 95%CI: 0.94-3.67, P < .01; Xrs: MD: -2.53, 95%CI: -4.02 to -1.04, P < .01). CONCLUSION FOT-derived measures of airway Rrs and Xrs are reproducible across a range of OLV's, and are responsive to hyper- and hypo-inflation of the lung. To further understand the impact of lung hyper- and hypo-inflation on FOT-derived airway impedance additional study is required in individuals with pathological variations in operating lung volume.
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Affiliation(s)
- Craig R Aitken
- Menzies Health Institute Queensland, Griffith University, Gold Coast, QLD, Australia
| | | | - Mathew Stamos
- Depatment of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, USA
| | - Chul-Ho Kim
- Depatment of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, USA
| | - Bruce D Johnson
- Depatment of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, USA
| | - Glenn M Stewart
- Depatment of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, USA; Charles Perkins Centre and School of Medicine, Faculty of Medicine and Health, University of Sydney, Camberdown, NSW, Australia.
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Baydur A, Barbers R, May D. Effect of bronchial thermoplasty on static and dynamic lung compliance and resistance in patients with severe persistent asthma. Respir Med 2023; 217:107341. [PMID: 37429559 DOI: 10.1016/j.rmed.2023.107341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 06/21/2023] [Accepted: 06/25/2023] [Indexed: 07/12/2023]
Abstract
RATIONALE Bronchial thermoplasty (BT) reduces severity and frequency of bronchoconstriction and symptoms in severe, persistent asthmatics although it is usually not associated with change in spirometric variables. Other than spirometry. there are almost no data on changes in lung mechanics following BT. OBJECTIVE To assess lung static and dynamic lung compliance (Cst,L and Cdyn,L, respectively) and static and dynamic lung resistance (Rst,L and Rdyn,L, respectively) before and after BT in severe asthmatics using the esophageal balloon technique. METHODS Rdyn,L and Cdyn,L were measured at respiratory frequencies up to 145 breaths/min, using the esophageal balloon technique in 7 patients immediately before and 12-50 weeks after completing a series of 3 BT sessions. RESULTS All patients experienced improved symptoms within a few weeks following completion of BT. Pre-BT, all patients exhibited frequency dependency of lung compliance, with mean Cdyn,L decreasing to 63% of Cst,L at maximum respiratory rates. Post-BT, Cst,L did not change significantly from pre-thermoplasty values, while Cdyn,L diminished to 62%% of Cst,L. In 4 of 7 patients, post-BT values of Cdyn,L were consistently higher than pre-BT over the range of respiratory rates. RL in 4 of 7 patients during quiet breathing and at higher respiratory frequencies decreased following BT. CONCLUSIONS Patients with severe persistent asthma exhibit increased resting lung resistance and frequency dependence of compliance, the magnitudes of which are ameliorated in some patients following bronchial thermoplasty and associated with variable change in frequency dependence of lung resistance. These findings are related to asthma severity and may be related to the heterogeneous and variable nature of airway smooth muscle modeling and its response to BT.
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Affiliation(s)
- Ahmet Baydur
- Division of Pulmonary, Critical Care and Sleep Medicine, Keck School of Medicine, University of Southern California and Keck Medical Center, Los Angeles, CA, USA.
| | - Richard Barbers
- Division of Pulmonary, Critical Care and Sleep Medicine, Keck School of Medicine, University of Southern California and Keck Medical Center, Los Angeles, CA, USA
| | - Darren May
- Division of Pulmonary, Critical Care and Sleep Medicine, Keck School of Medicine, University of Southern California and Keck Medical Center, Los Angeles, CA, USA
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Sattari S, Mariano CA, Eskandari M. Pressure-volume mechanics of inflating and deflating intact whole organ porcine lungs. J Biomech 2023; 157:111696. [PMID: 37413822 DOI: 10.1016/j.jbiomech.2023.111696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 06/14/2023] [Accepted: 06/19/2023] [Indexed: 07/08/2023]
Abstract
Pressure-volume curves of the lung are classical measurements of lung function and are impacted by changes in lung structure due to disease or shifts in air-delivery volume or cycling rate. Diseased and preterm infant lungs have been found to show heterogeneous behavior which is highly frequency dependent. This breathing rate dependency has motivated the exploration of multi-frequency oscillatory ventilators to deliver volume oscillation with optimal frequencies for various portions of the lung to provide more uniform air distribution. The design of these advanced ventilators requires the examination of lung function and mechanics, and an improved understanding of the pressure-volume response of the lung. Therefore, to comprehensively analyze whole lung organ mechanics, we investigate six combinations of varying applied volumes and frequencies using ex-vivo porcine specimens and our custom-designed electromechanical breathing apparatus. Lung responses were evaluated through measurements of inflation and deflation slopes, static compliance, peak pressure and volume, as well as hysteresis, energy loss, and pressure relaxation. Generally, we observed that the lungs were stiffer when subjected to faster breathing rates and lower inflation volumes. The lungs exhibited greater inflation volume dependencies compared to frequency dependencies. This study's reported response of the lung to variations of inflation volume and breathing rate can help the optimization of conventional mechanical ventilators and inform the design of advanced ventilators. Although frequency dependency is found to be minimal in normal porcine lungs, this preliminary study lays a foundation for comparison with pathological lungs, which are known to demonstrate marked rate dependency.
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Affiliation(s)
- Samaneh Sattari
- Department of Mechanical Engineering, University of California at Riverside, Riverside, CA, USA
| | - Crystal A Mariano
- Department of Mechanical Engineering, University of California at Riverside, Riverside, CA, USA
| | - Mona Eskandari
- Department of Mechanical Engineering, University of California at Riverside, Riverside, CA, USA; BREATHE Center, School of Medicine, University of California at Riverside, Riverside, CA, USA; Department of Bioengineering, University of California at Riverside, Riverside, CA, USA.
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Darley DR, Nilsen K, Vazirani J, Borg BM, Levvey B, Snell G, Plit ML, Tonga KO. Airway oscillometry parameters in baseline lung allograft dysfunction: Associations from a multicenter study. J Heart Lung Transplant 2023; 42:767-777. [PMID: 36681528 DOI: 10.1016/j.healun.2022.12.026] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Revised: 12/09/2022] [Accepted: 12/30/2022] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Baseline lung allograft dysfunction (BLAD), the failure to achieve ≥80%-predicted spirometry after lung transplant (LTx), is associated with impaired survival. Physiologic abnormalities in BLAD are poorly understood. Airway oscillometry measures respiratory system mechanics and may provide insight into understanding the mechanisms of BLAD. OBJECTIVES This study aims to describe and measure the association between airway oscillometry parameters [Reactance (Xrs5, Ax), Resistance (Rrs5, Rrs5-19)] (1) stable LTx recipients, comparing those with normal spirometry and those with BLAD; and (2) in recipients with chronic lung allograft dysfunction (CLAD), comparing those with normal baseline spirometry and those with BLAD. METHODS A multi-center cross-sectional study was performed including bilateral LTx between January 2020 and June 2021. Participants performed concurrent airway oscillometry and spirometry. Multivariable logistic regression was performed to measure the association between oscillometry parameters and BLAD. RESULTS A total of 404 LTx recipients performed oscillometry and 253 were included for analysis. Stable allograft function was confirmed in 149 (50.2%) recipients (92 (61.7%) achieving normal spirometry and 57 (38.3%) with BLAD). Among stable LTx recipients, lower Xrs5 Z-Score (aOR 0.50 95% CI 0.37-0.76, p = 0.001) was independently associated with BLAD. CLAD was present in 104 (35.0%) recipients. Among recipients with CLAD, lower Xrs5 Z-Score (aOR 0.73 95% CI 0.56-0.95, p = 0.02) was associated with BLAD. CONCLUSIONS Oscillometry provides novel physiologic insights into mechanisms of BLAD. The independent association between Xrs5 and BLAD, in both stable recipients and those with CLAD suggests that respiratory mechanics, in particular abnormal elastance, is an important physiologic feature. Further longitudinal studies are needed to understand the trajectory of oscillometry parameters in relation to allograft outcomes.
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Affiliation(s)
- David Ross Darley
- Lung Transplant Unit, St Vincent's Hospital Sydney, Darlinghurst NSW, Australia; School of Clinical Medicine, St Vincent's Healthcare Clinical Campus, UNSW Medicine & Health, UNSW Sydney, Australia.
| | - Kris Nilsen
- Lung Transplant Service, The Alfred Hospital, Melbourne, Australia
| | - Jaideep Vazirani
- Lung Transplant Service, The Alfred Hospital, Melbourne, Australia
| | - Brigitte M Borg
- Respiratory Medicine, The Alfred Hospital, Melbourne, Australia
| | - Bronwyn Levvey
- Lung Transplant Service, The Alfred Hospital, Melbourne, Australia
| | - G Snell
- Lung Transplant Service, The Alfred Hospital, Melbourne, Australia
| | - Marshall Lawrence Plit
- Lung Transplant Unit, St Vincent's Hospital Sydney, Darlinghurst NSW, Australia; School of Clinical Medicine, St Vincent's Healthcare Clinical Campus, UNSW Medicine & Health, UNSW Sydney, Australia
| | - Katrina O Tonga
- School of Clinical Medicine, St Vincent's Healthcare Clinical Campus, UNSW Medicine & Health, UNSW Sydney, Australia; Thoracic Medicine Department, St Vincent's Hospital Darlinghurst, Sydney, Australia; Northern Clinical School, Sydney Medical School, Faculty of Medicine & Health, University of Sydney, Sydney, Australia
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Andrews P, Shiber J, Madden M, Nieman GF, Camporota L, Habashi NM. Myths and Misconceptions of Airway Pressure Release Ventilation: Getting Past the Noise and on to the Signal. Front Physiol 2022; 13:928562. [PMID: 35957991 PMCID: PMC9358044 DOI: 10.3389/fphys.2022.928562] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 06/21/2022] [Indexed: 12/16/2022] Open
Abstract
In the pursuit of science, competitive ideas and debate are necessary means to attain knowledge and expose our ignorance. To quote Murray Gell-Mann (1969 Nobel Prize laureate in Physics): "Scientific orthodoxy kills truth". In mechanical ventilation, the goal is to provide the best approach to support patients with respiratory failure until the underlying disease resolves, while minimizing iatrogenic damage. This compromise characterizes the philosophy behind the concept of "lung protective" ventilation. Unfortunately, inadequacies of the current conceptual model-that focuses exclusively on a nominal value of low tidal volume and promotes shrinking of the "baby lung" - is reflected in the high mortality rate of patients with moderate and severe acute respiratory distress syndrome. These data call for exploration and investigation of competitive models evaluated thoroughly through a scientific process. Airway Pressure Release Ventilation (APRV) is one of the most studied yet controversial modes of mechanical ventilation that shows promise in experimental and clinical data. Over the last 3 decades APRV has evolved from a rescue strategy to a preemptive lung injury prevention approach with potential to stabilize the lung and restore alveolar homogeneity. However, several obstacles have so far impeded the evaluation of APRV's clinical efficacy in large, randomized trials. For instance, there is no universally accepted standardized method of setting APRV and thus, it is not established whether its effects on clinical outcomes are due to the ventilator mode per se or the method applied. In addition, one distinctive issue that hinders proper scientific evaluation of APRV is the ubiquitous presence of myths and misconceptions repeatedly presented in the literature. In this review we discuss some of these misleading notions and present data to advance scientific discourse around the uses and misuses of APRV in the current literature.
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Affiliation(s)
- Penny Andrews
- R Adams Cowley Shock Trauma Center, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Joseph Shiber
- University of Florida College of Medicine, Jacksonville, FL, United States
| | - Maria Madden
- R Adams Cowley Shock Trauma Center, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Gary F. Nieman
- Department of Surgery, SUNY Upstate Medical University, Syracuse, NY, United States
| | - Luigi Camporota
- Department of Adult Critical Care, Guy’s and St Thomas’ NHS Foundation Trust, Health Centre for Human and Applied Physiological Sciences, London, United Kingdom
| | - Nader M. Habashi
- R Adams Cowley Shock Trauma Center, University of Maryland School of Medicine, Baltimore, MD, United States
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Sugawara H, Saito A, Yokoyama S, Tsunematsu K, Chiba H. Association between annual change in FEV1 and comorbidities or impulse oscillometry in chronic obstructive pulmonary disease. BMC Pulm Med 2022; 22:185. [PMID: 35527263 PMCID: PMC9080138 DOI: 10.1186/s12890-022-01980-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 04/18/2022] [Indexed: 11/16/2022] Open
Abstract
Background Chronic obstructive pulmonary disease (COPD) is characterized by persistent respiratory symptoms and airflow limitation. The decline in forced expiratory volume in one second (FEV1) is considered to be one of the most important outcome measures for evaluating disease progression. However, the only intervention proven to improve COPD prognosis is smoking cessation. This study therefore investigated the factors associated with annual FEV1 decline in COPD. Methods This retrospective study followed up 65 patients treated for COPD for 5 years: 13 current smokers and 52 former smokers, 25 with pneumonia, 24 with asthma, 18 with cancer, and 17 with cardiovascular disease. The patients were divided into groups based on clinical cutoff parameters of the impulse oscillometry system (IOS): 11 high and 54 low R5, 8 high and 57 low R20, 21 high and 44 low R5–R20, 26 high and 39 low X5, 38 high and 27 low Fres, and 36 high and 29 low AX. We investigated whether the decline in FEV1 was associated with comorbidities and IOS parameters. Results The annual change in FEV1 over 5 years was significantly affected by smoking status (current − 66.2 mL/year vs. former − 5.7 mL/year, p < 0.01), pneumonia (with − 31.5 mL/year vs. without − 8.9 mL/year, p < 0.05), asthma (with − 30.2 mL/year vs. − 10.8 mL/year, p < 0.01), but not by cancer and cardiovascular disease. In the groups defined by IOS results, only the high AX group had significantly more annual decline in FEV1 and %FEV1 than the low AX group (− 22.1 vs. − 12.8, p < 0.05 and − 0.20 vs. 0.40, p < 0.05, respectively). Conclusions Continuing smoking as well as complications in pneumonia and asthma would be risk factors for the progression of COPD. AX might be a suitable parameter to predict the prognosis of patients with COPD. Supplementary Information The online version contains supplementary material available at 10.1186/s12890-022-01980-6.
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Quiros KAM, Nelson TM, Sattari S, Mariano CA, Ulu A, Dominguez EC, Nordgren TM, Eskandari M. Mouse lung mechanical properties under varying inflation volumes and cycling frequencies. Sci Rep 2022; 12:7094. [PMID: 35501363 PMCID: PMC9059689 DOI: 10.1038/s41598-022-10417-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 03/30/2022] [Indexed: 01/23/2023] Open
Abstract
Respiratory pathologies alter the structure of the lung and impact its mechanics. Mice are widely used in the study of lung pathologies, but there is a lack of fundamental mechanical measurements assessing the interdependent effect of varying inflation volumes and cycling frequency. In this study, the mechanical properties of five male C57BL/6J mice (29-33 weeks of age) lungs were evaluated ex vivo using our custom-designed electromechanical, continuous measure ventilation apparatus. We comprehensively quantify and analyze the effect of loading volumes (0.3, 0.5, 0.7, 0.9 ml) and breathing rates (5, 10, 20 breaths per minute) on pulmonary inflation and deflation mechanical properties. We report means of static compliance between 5.4-16.1 µl/cmH2O, deflation compliance of 5.3-22.2 µl/cmH2O, percent relaxation of 21.7-39.1%, hysteresis of 1.11-7.6 ml•cmH2O, and energy loss of 39-58% for the range of four volumes and three rates tested, along with additional measures. We conclude that inflation volume was found to significantly affect hysteresis, static compliance, starting compliance, top compliance, deflation compliance, and percent relaxation, and cycling rate was found to affect only hysteresis, energy loss, percent relaxation, static compliance and deflation compliance.
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Affiliation(s)
- K A M Quiros
- Department of Mechanical Engineering, University of California, Riverside, CA, USA
| | - T M Nelson
- Department of Mechanical Engineering, University of California, Riverside, CA, USA
| | - S Sattari
- Department of Mechanical Engineering, University of California, Riverside, CA, USA
| | - C A Mariano
- Department of Mechanical Engineering, University of California, Riverside, CA, USA
| | - A Ulu
- BREATHE Center, School of Medicine, University of California, Riverside, CA, USA
- Division of Biomedical Sciences, School of Medicine, University of California Riverside, Riverside, CA, USA
| | - E C Dominguez
- BREATHE Center, School of Medicine, University of California, Riverside, CA, USA
- Division of Biomedical Sciences, School of Medicine, University of California Riverside, Riverside, CA, USA
| | - T M Nordgren
- BREATHE Center, School of Medicine, University of California, Riverside, CA, USA
- Division of Biomedical Sciences, School of Medicine, University of California Riverside, Riverside, CA, USA
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, USA
| | - M Eskandari
- Department of Mechanical Engineering, University of California, Riverside, CA, USA.
- BREATHE Center, School of Medicine, University of California, Riverside, CA, USA.
- Department of Bioengineering, University of California, Riverside, CA, USA.
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Hoshi D, Fukuie M, Tamai S, Momma R, Tarumi T, Sugawara J, Watanabe K. Influence of water immersion on the airway impedance measured by forced oscillation technique. Respir Physiol Neurobiol 2021; 295:103779. [PMID: 34455088 DOI: 10.1016/j.resp.2021.103779] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 08/18/2021] [Accepted: 08/23/2021] [Indexed: 11/27/2022]
Abstract
INTRODUCTION Few studies have examined the influence of different water depths on the airway impedance measured by forced oscillation technique in healthy adults. METHODS Eleven healthy men (23.2 ± 1.5 years old) participated in this study. We measured the respiratory impedance assessed with the resistance at frequency of 5 Hz and 20 Hz, the reactance at frequency of 5 Hz, and frequency of resonance. To compare the influence of water depths, we carried out one dryland (DL) and two water level conditions: clavicle level (CL) and xiphoid appendix level (XA). RESULTS The respiratory resistance at frequency of 5 Hz was higher in CL and XA than DL, and at 20 Hz was significantly higher in CL than DL. The respiratory reactance at 5 Hz was lower in CL and XA than DL, and frequency of resonance was higher in CL and XA than DL. CONCLUSION These results suggested that water immersion above xiphoid appendix level increase airway resistance.
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Affiliation(s)
- Daisuke Hoshi
- Doctoral Program in Sports Medicine, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan; Human Informatics and Interaction Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki, Japan
| | - Marina Fukuie
- Doctoral Program in Sports Medicine, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan; Human Informatics and Interaction Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki, Japan
| | - Shinsuke Tamai
- Doctoral Program in Sports Medicine, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Reiko Momma
- Doctoral Program in Sports Medicine, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Takashi Tarumi
- Human Informatics and Interaction Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki, Japan; Faculty of Health and Sports Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Jun Sugawara
- Human Informatics and Interaction Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki, Japan; Faculty of Health and Sports Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Koichi Watanabe
- Faculty of Health and Sports Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan.
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Lundblad LKA, Robichaud A. Oscillometry of the respiratory system: a translational opportunity not to be missed. Am J Physiol Lung Cell Mol Physiol 2021; 320:L1038-L1056. [PMID: 33822645 PMCID: PMC8203417 DOI: 10.1152/ajplung.00222.2020] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 03/23/2021] [Accepted: 04/01/2021] [Indexed: 12/18/2022] Open
Abstract
Airway oscillometry has become the de facto standard for quality assessment of lung physiology in laboratory animals and has demonstrated its usefulness in understanding diseases of small airways. Nowadays, it is seeing extensive use in daily clinical practice and research; however, a question that remains unanswered is how well physiological findings in animals and humans correlate? Methodological and device differences are obvious between animal and human studies. However, all devices deliver an oscillated airflow test signal and output respiratory impedance. In addition, despite analysis differences, there are ways to interpret animal and human oscillometry data to allow suitable comparisons. The potential with oscillometry is its ability to reveal universal features of the respiratory system across species, making translational extrapolation likely to be predictive. This means that oscillometry can thus help determine if an animal model displays the same physiological characteristics as the human disease. Perhaps more importantly, it can also be useful to determine whether an intervention is effective as well as to understand if it affects the desired region of the respiratory system, e.g., the periphery of the lung. Finally, findings in humans can also inform preclinical scientists and give indications as to what type of physiological changes should be observed in animal models to make them relevant as models of human disease. The present article will attempt to demonstrate the potential of oscillometry in respiratory research, an area where the development of novel therapies is plagued with a failure rate higher than in other disease areas.
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Affiliation(s)
- Lennart K A Lundblad
- Meakins-Christie Laboratories, McGill University, Montreal, Quebec, Canada
- THORASYS Thoracic Medical Systems Inc., Montreal, Quebec, Canada
| | - Annette Robichaud
- SCIREQ Scientific Respiratory Equipment Inc., Montreal, Quebec, Canada
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12
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Dahl MJ, Veneroni C, Lavizzari A, Bowen S, Emerson H, Rebentisch A, Dawson E, Summers K, Pettet L, Wang Z, Null DM, Yoder BA, Dellacà RL, Albertine KH. Early extubation to noninvasive respiratory support of former preterm lambs improves long-term respiratory outcomes. Am J Physiol Lung Cell Mol Physiol 2021; 321:L248-L262. [PMID: 34009031 DOI: 10.1152/ajplung.00051.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Invasive mechanical ventilation (IMV) and exposure to oxygen-rich gas during early postnatal life are contributing factors for long-term pulmonary morbidities faced by survivors of preterm birth and bronchopulmonary dysplasia. The duration of IMV that leads to long-term pulmonary morbidities is unknown. We compared two durations of IMV (3 h vs. 6 days) during the first 6-7 days of postnatal life in preterm lambs to test the hypothesis that minimizing the duration of IMV will improve long-term respiratory system mechanics and structural outcomes later in life. Moderately preterm (∼85% gestation) lambs were supported by IMV for either 3 h or 6 days before weaning from all respiratory support to become former preterm lambs. Respiratory system mechanics and airway reactivity were assessed monthly from 1 to 6 mo of chronological postnatal age by the forced oscillation technique. Quantitative morphological measurements were made for smooth muscle accumulation around terminal bronchioles and indices of alveolar formation. Minimizing IMV to 3 h led to significantly better (P < 0.05) baseline respiratory system mechanics and less reactivity to methacholine in the first 3 mo of chronological age (2 mo corrected age), significantly less (P < 0.05) accumulation of smooth muscle around peripheral resistance airways (terminal bronchioles), and significantly better (P < 0.05) alveolarization at the end of 5 mo corrected age compared with continuous IMV for 6 days. We conclude that limiting the duration of IMV following preterm birth of fetal lambs leads to better respiratory system mechanics and structural outcomes later in life.
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Affiliation(s)
- Mar Janna Dahl
- Division of Neonatology, Department of Pediatrics, University of Utah, Salt Lake City, Utah
| | - Chiara Veneroni
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano University, Milan, Italy
| | - Anna Lavizzari
- U.O. di Neonatologia e Terapia Intensiva Neonatale, Department of Clinical Sciences and Community Health, University of Milan Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Sydney Bowen
- Division of Neonatology, Department of Pediatrics, University of Utah, Salt Lake City, Utah
| | - Haleigh Emerson
- Division of Neonatology, Department of Pediatrics, University of Utah, Salt Lake City, Utah
| | - Andrew Rebentisch
- Division of Neonatology, Department of Pediatrics, University of Utah, Salt Lake City, Utah
| | - Elaine Dawson
- Division of Neonatology, Department of Pediatrics, University of Utah, Salt Lake City, Utah
| | - Kyle Summers
- Division of Neonatology, Department of Pediatrics, University of Utah, Salt Lake City, Utah
| | - Luke Pettet
- Division of Neonatology, Department of Pediatrics, University of Utah, Salt Lake City, Utah
| | - Zhengming Wang
- Division of Neonatology, Department of Pediatrics, University of Utah, Salt Lake City, Utah
| | - Donald M Null
- Division of Neonatology, University of California, Davis, California
| | - Bradley A Yoder
- Division of Neonatology, Department of Pediatrics, University of Utah, Salt Lake City, Utah
| | - Raffaele L Dellacà
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano University, Milan, Italy
| | - Kurt H Albertine
- Division of Neonatology, Department of Pediatrics, University of Utah, Salt Lake City, Utah
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13
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Day K, Ostridge K, Conway J, Cellura D, Watson A, Spalluto CM, Staples KJ, Thompson B, Wilkinson T. Interrelationships Among Small Airways Dysfunction, Neutrophilic Inflammation, and Exacerbation Frequency in COPD. Chest 2020; 159:1391-1399. [PMID: 33245876 DOI: 10.1016/j.chest.2020.11.018] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 11/03/2020] [Accepted: 11/08/2020] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Small airways disease (SAD) is a key component of COPD and is a main contributing factor to lung function decline. RESEARCH QUESTION Is SAD a key feature of frequent COPD exacerbators and is this related to airway inflammation? STUDY DESIGN AND METHODS Thirty-nine COPD patients defined as either frequent exacerbator (FE) group (≥ 2 exacerbations/y; n = 17) and infrequent exacerbator (IFE) group (≤ 1 exacerbation/y; n = 22) underwent the forced oscillation technique (resistance at 5 Hz minus 19 Hz [R5-R19], area of reactance [AX]), multiple breath nitrogen washout (conducting airways ventilation heterogeneity, acinar ventilation heterogeneity [Sacin]), plethysmography (ratio of residual volume to total lung capacity), single-breath transfer factor of the lung for carbon monoxide, spirometry (FEV1, FEV1/FVC), and paired inspiratory-expiratory CT scans to ascertain SAD. A subpopulation underwent bronchoscopy to enable enumeration of BAL cell proportions. RESULTS Sacin was significantly higher in the COPD FE group compared with the IFE group (P = .027). In the FE group, markers of SAD were associated strongly with BAL neutrophil proportions, R5-R19 (P = .001, r = 0.795), AX (P = .049, ρ = 0.560), residual volume to total lung capacity ratio (P = .004, r = 0.730), and the mean lung density of the paired CT scans (P = .018, r = 0.639). INTERPRETATION Increased Sacin may be a consequence of previous exacerbations or may highlight a group of patients prone to exacerbations. Measures of SAD were associated strongly with neutrophilic inflammation in the small airways of FE patients, supporting the hypothesis that frequent exacerbations are associated with SAD related to increased cellular inflammation.
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Affiliation(s)
- Kerry Day
- Faculty of Medicine, University of Southampton, Southampton; NIHR Southampton Biomedical Research Centre, University Hospital Southampton, Southampton.
| | - Kristoffer Ostridge
- Faculty of Medicine, University of Southampton, Southampton; NIHR Southampton Biomedical Research Centre, University Hospital Southampton, Southampton; Clinical Development, Research and Early Development, Respiratory & Immunology, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | | | | | | | | | - Karl J Staples
- Faculty of Medicine, University of Southampton, Southampton; NIHR Southampton Biomedical Research Centre, University Hospital Southampton, Southampton
| | - Bruce Thompson
- Swinburne University of Technology, Melbourne, Australia
| | - Tom Wilkinson
- Faculty of Medicine, University of Southampton, Southampton; NIHR Southampton Biomedical Research Centre, University Hospital Southampton, Southampton
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14
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Sattari S, Mariano CA, Vittalbabu S, Velazquez JV, Postma J, Horst C, Teh E, Nordgren TM, Eskandari M. Introducing a Custom-Designed Volume-Pressure Machine for Novel Measurements of Whole Lung Organ Viscoelasticity and Direct Comparisons Between Positive- and Negative-Pressure Ventilation. Front Bioeng Biotechnol 2020; 8:578762. [PMID: 33195138 PMCID: PMC7643401 DOI: 10.3389/fbioe.2020.578762] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 09/17/2020] [Indexed: 12/13/2022] Open
Abstract
Asthma, emphysema, COVID-19 and other lung-impacting diseases cause the remodeling of tissue structural properties and can lead to changes in conducting pulmonary volume, viscoelasticity, and air flow distribution. Whole organ experimental inflation tests are commonly used to understand the impact of these modifications on lung mechanics. Here we introduce a novel, automated, custom-designed device for measuring the volume and pressure response of lungs, surpassing the capabilities of traditional machines and built to range size-scales to accommodate both murine and porcine tests. The software-controlled system is capable of constructing standardized continuous volume-pressure curves, while accounting for air compressibility, yielding consistent and reproducible measures while eliminating the need for pulmonary degassing. This device uses volume-control to enable viscoelastic whole lung macromechanical insights from rate dependencies and pressure-time curves. Moreover, the conceptual design of this device facilitates studies relating the phenomenon of diaphragm breathing and artificial ventilation induced by pushing air inside the lungs. System capabilities are demonstrated and validated via a comparative study between ex vivo murine lungs and elastic balloons, using various testing protocols. Volume-pressure curve comparisons with previous pressure-controlled systems yield good agreement, confirming accuracy. This work expands the capabilities of current lung experiments, improving scientific investigations of healthy and diseased pulmonary biomechanics. Ultimately, the methodologies demonstrated in the manufacturing of this system enable future studies centered on investigating viscoelasticity as a potential biomarker and improvements to patient ventilators based on direct assessment and comparisons of positive- and negative-pressure mechanics.
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Affiliation(s)
- Samaneh Sattari
- Department of Mechanical Engineering, University of California, Riverside, Riverside, CA, United States
| | - Crystal A Mariano
- Department of Mechanical Engineering, University of California, Riverside, Riverside, CA, United States
| | - Swathi Vittalbabu
- Department of Mechanical Engineering, University of California, Riverside, Riverside, CA, United States
| | - Jalene V Velazquez
- BREATHE Center at the School of Medicine, University of California, Riverside, Riverside, CA, United States.,Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, CA, United States
| | | | - Caleb Horst
- CellScale Biomaterials Testing, Waterloo, ON, Canada
| | - Eric Teh
- CellScale Biomaterials Testing, Waterloo, ON, Canada
| | - Tara M Nordgren
- BREATHE Center at the School of Medicine, University of California, Riverside, Riverside, CA, United States.,Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, CA, United States
| | - Mona Eskandari
- Department of Mechanical Engineering, University of California, Riverside, Riverside, CA, United States.,BREATHE Center at the School of Medicine, University of California, Riverside, Riverside, CA, United States.,Department of Bioengineering, University of California, Riverside, Riverside, CA, United States
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15
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Using Novel Computed Tomography Analysis to Describe the Contribution and Distribution of Emphysema and Small Airways Disease in Chronic Obstructive Pulmonary Disease. Ann Am Thorac Soc 2020; 16:990-997. [PMID: 30892055 DOI: 10.1513/annalsats.201810-669oc] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Rationale: Chronic obstructive pulmonary disease (COPD) is characterized by airflow limitation, caused by emphysema and small airways disease (SAD). Computed tomography (CT) coupled with image analysis enables the quantification of these abnormalities; however, the optimum method for doing so has not been determined.Objectives: This study aims to compare two CT quantitative analysis techniques, disease probability measure (DPM) and parametric response mapping (PRM), and assess their relationship with specific physiological measures of SAD.Methods: Subjects with mild to moderate COPD, never smokers, and healthy ex-smokers were recruited. Each had airway oscillometry and multiple-breath nitrogen washout, measuring peripheral airway resistance, peripheral airway reactance, and acinar airway inhomogeneity. Subjects also had an inspiratory and expiratory chest CT, with DPM and PRM analysis performed by coregistering images and classifying each voxel as normal, emphysema, or nonemphysematous gas trapping related to SAD.Results: Thirty-eight subjects with COPD, 18 never smokers, and 23 healthy ex-smokers were recruited. There were strong associations between DPM and PRM analysis when measuring gas trapping (ρ = 0.87; P < 0.001) and emphysema (ρ = 0.99; P < 0.001). DPM assigned significantly more voxels as emphysema and gas trapped than PRM (P < 0.001). Both techniques showed significantly greater emphysema and gas trapping in subjects with COPD than in never smokers and ex-smokers (P < 0.001). All CT measures had significant associations with peripheral airway resistance and reactance, with disease probability measure of nonemphysematous gas trapping related to SAD having the strongest independent association with peripheral airway resistance (β = 0.42; P = 0.001) and peripheral airway reactance (β = 0.41; P = 0.001). Emphysema measures had the strongest associations with acinar airway inhomogeneity (β = 0.35-0.38).Conclusions: These results provide further validation for the use of DPM/PRM analysis in COPD by demonstrating significant relationships with specific physiological measures of SAD.
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16
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Calverley PMA, Farré R. Oscillometry: old physiology with a bright future. Eur Respir J 2020; 56:56/3/2001815. [PMID: 32912925 DOI: 10.1183/13993003.01815-2020] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 05/15/2020] [Indexed: 11/05/2022]
Affiliation(s)
- Peter M A Calverley
- Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, UK
| | - Ramon Farré
- Unitat de Biofísica i Bioenginyeria, Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, Barcelona, Spain.,CIBER de Enfermedades Respiratorias, Madrid, Spain.,Institut d'Investigacions Biomediques August Pi Sunyer, Barcelona, Spain
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17
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Cho E, Wu JKY, Birriel DC, Matelski J, Nadj R, DeHaas E, Huang Q, Yang K, Xu T, Cheung AB, Woo LN, Day L, Cypel M, Tikkanen J, Ryan C, Chow CW. Airway Oscillometry Detects Spirometric-Silent Episodes of Acute Cellular Rejection. Am J Respir Crit Care Med 2020; 201:1536-1544. [PMID: 32135068 DOI: 10.1164/rccm.201908-1539oc] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Rationale: Acute cellular rejection (ACR) is common during the initial 3 months after lung transplant. Patients are monitored with spirometry and routine surveillance transbronchial biopsies. However, many centers monitor patients with spirometry only because of the risks and insensitivity of transbronchial biopsy for detecting ACR. Airway oscillometry is a lung function test that detects peripheral airway inhomogeneity with greater sensitivity than spirometry. Little is known about the role of oscillometry in patient monitoring after a transplant.Objectives: To characterize oscillometry measurements in biopsy-proven clinically significant (grade ≥2 ACR) in the first 3 months after a transplant.Methods: We enrolled 156 of the 209 double lung transplant recipients between December 2017 and March 2019. Weekly outpatient oscillometry and spirometry and surveillance biopsies at Weeks 6 and 12 were conducted at our center.Measurements and Main Results: Of the 138 patients followed for 3 or more months, 15 patients had 16 episodes of grade 2 ACR (AR2) and 44 patients had 64 episodes of grade 0 ACR (AR0) rejection associated with stable and/or improving spirometry. In 15/16 episodes of AR2, spirometry was stable or improving in the weeks leading to transbronchial biopsy. However, oscillometry was markedly abnormal and significantly different from AR0 (P < 0.05), particularly in integrated area of reactance and the resistance between 5 and 19 Hz, the indices of peripheral airway obstruction. By 2 weeks after biopsy, after treatment for AR2, oscillometry in the AR2 group improved and was similar to the AR0 group.Conclusions: Oscillometry identified physiological changes associated with AR2 that were not discernible by spirometry and is useful for graft monitoring after a lung transplant.
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Affiliation(s)
- Elizabeth Cho
- Division of Respirology, Department of Medicine, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Joyce K Y Wu
- Division of Respirology, Department of Medicine, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.,Pulmonary Function Laboratory
| | - Daniella Cunha Birriel
- Division of Respirology, Department of Medicine, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.,Toronto Lung Transplant Programme, Multi-Organ Transplant Unit
| | | | - Richard Nadj
- Division of Respirology, Department of Medicine, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Emily DeHaas
- Division of Respirology, Department of Medicine, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Qian Huang
- Division of Respirology, Department of Medicine, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Kelsey Yang
- Division of Respirology, Department of Medicine, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Tong Xu
- Division of Respirology, Department of Medicine, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Aloysius B Cheung
- Division of Respirology, Department of Medicine, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Lindsay N Woo
- Division of Respirology, Department of Medicine, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Lauren Day
- Division of Respirology, Department of Medicine, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.,Pulmonary Function Laboratory
| | - Marcelo Cypel
- Toronto Lung Transplant Programme, Multi-Organ Transplant Unit.,Division of Thoracic Surgery, Department of Surgery, University Health Network, Toronto, Ontario, Canada
| | - Jussi Tikkanen
- Division of Respirology, Department of Medicine, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.,Toronto Lung Transplant Programme, Multi-Organ Transplant Unit
| | - Clodagh Ryan
- Division of Respirology, Department of Medicine, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.,Pulmonary Function Laboratory
| | - Chung-Wai Chow
- Division of Respirology, Department of Medicine, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.,Toronto Lung Transplant Programme, Multi-Organ Transplant Unit
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18
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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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19
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Veneroni C, Dahl MJ, Lavizzari A, Dawson E, Rebentisch A, Studstill S, Bowen S, Albertine KH, Dellaca RL. Non-invasive measurements of respiratory system mechanical properties by the forced oscillation technique in spontaneously breathing, mixed-breed, normal term lambs from birth to five months of age. Physiol Meas 2019; 40:105007. [PMID: 31341100 DOI: 10.1088/1361-6579/ab3493] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
OBJECTIVE To provide a non-invasive approach to monitoring lung function in spontaneously breathing lambs, from birth to five months of life, by the forced oscillation technique (FOT). This report describes the experimental set-up, data processing, and identification of normal predicted values of resistance (Rrs) and reactance (Xrs) of the respiratory system, along with normal bronchodilator response for bronchial reversibility testing. APPROACH Rrs and Xrs at 5, 11, and 19 Hz were measured monthly for five months in 20 normal term lambs that breathed spontaneously. In seven lambs, repeated measurements also were made within the first month of life (at 3, 7, 14, and 21 d of life). We determined the repeatability and reproducibility of the measurements and characterized the relationship between lung mechanics and age, sex, and body dimensions, using regression analysis, and measured changes in lung mechanics in response to inhaled bronchodilator. MAIN RESULTS The measurements provided repeatable and reproducible data. Rrs decreased, whereas Xrs increased, with growth from birth through the first two months of life, after which no statistically significant differences were detected. We identified normal value equations for Rrs and Xrs and for each of the measured anthropometric variables. Respiratory system mechanics were not affected by the bronchodilator. SIGNIFICANCE The FOT provides reliable non-invasive measurement of respiratory system mechanics in spontaneously breathing term lambs from birth to five months of age. The methods and normal reference values defined in this study will facilitate testing of the pathophysiological consequences of preterm birth and prolonged respiratory support on respiratory system mechanics.
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Affiliation(s)
- Chiara Veneroni
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano University, Milano, Italy. Co-first and co-last authors. Author to whom any correspondence should be addressed
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20
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Lundblad LKA, Siddiqui S, Bossé Y, Dandurand RJ. Applications of oscillometry in clinical research and practice. CANADIAN JOURNAL OF RESPIRATORY CRITICAL CARE AND SLEEP MEDICINE 2019. [DOI: 10.1080/24745332.2019.1649607] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Lennart K. A. Lundblad
- Meakins-Christie Labs, McGill University and THORASYS Thoracic Medical Systems Inc., Montréal, Québec, Canada
| | - Salman Siddiqui
- Department of Infection, Immunity and Inflammation, Leicester NIHR Biomedical Research Centre (Respiratory Theme) and University of Leicester, Leicester, UK
| | - Ynuk Bossé
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, University of Laval, Laval, Québec, Canada
| | - Ronald J. Dandurand
- CIUSSS de L’Ouest-de-L’Île-de-Montréal, Montreal Chest Institute, Meakins-Christie Labs, Oscillometry Unit and Centre for Innovative Medicine, McGill University Health Centre and Research Institute, and McGill University, Montreal, Québec, Canada
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21
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Capron T, Bourdin A, Perez T, Chanez P. COPD beyond proximal bronchial obstruction: phenotyping and related tools at the bedside. Eur Respir Rev 2019; 28:28/152/190010. [PMID: 31285287 DOI: 10.1183/16000617.0010-2019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2019] [Accepted: 05/04/2019] [Indexed: 11/05/2022] Open
Abstract
Chronic obstructive pulmonary disease (COPD) is characterised by nonreversible proximal bronchial obstruction leading to major respiratory disability. However, patient phenotypes better capture the heterogeneously reported complaints and symptoms of COPD. Recent studies provided evidence that classical bronchial obstruction does not properly reflect respiratory disability, and symptoms now form the new paradigm for assessment of disease severity and guidance of therapeutic strategies. The aim of this review was to explore pathways addressing COPD pathogenesis beyond proximal bronchial obstruction and to highlight innovative and promising tools for phenotyping and bedside assessment. Distal small airways imaging allows quantitative characterisation of emphysema and functional air trapping. Micro-computed tomography and parametric response mapping suggest small airways disease precedes emphysema destruction. Small airways can be assessed functionally using nitrogen washout, probing ventilation at conductive or acinar levels, and forced oscillation technique. These tests may better correlate with respiratory symptoms and may well capture bronchodilation effects beyond proximal obstruction.Knowledge of inflammation-based processes has not provided well-identified targets so far, and eosinophils probably play a minor role. Adaptative immunity or specific small airways secretory protein may provide new therapeutic targets. Pulmonary vasculature is involved in emphysema through capillary loss, microvascular lesions or hypoxia-induced remodelling, thereby impacting respiratory disability.
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Affiliation(s)
- Thibaut Capron
- Clinique des Bronches, Allergies et Sommeil, Hôpital Nord, Assistance Publique des Hôpitaux de Marseille, Aix Marseille Université, Marseille, France
| | - Arnaud Bourdin
- Université de Montpellier, PhyMedExp, INSERM, CNRS, CHU de Montpellier, Dept of Respiratory Diseases, Montpellier, France
| | - Thierry Perez
- Dept of Respiratory Diseases, CHU Lille, Center for Infection and Immunity of Lille, INSERM U1019 - CNRS UMR 8204, Université Lille Nord de France, Lille, France
| | - Pascal Chanez
- Clinique des Bronches, Allergies et Sommeil, Hôpital Nord, Assistance Publique des Hôpitaux de Marseille, Aix Marseille Université, Marseille, France .,Aix Marseille Université, INSERM, INRA, CV2N, Marseille, France
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22
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Petousi N, Talbot NP, Pavord I, Robbins PA. Measuring lung function in airways diseases: current and emerging techniques. Thorax 2019; 74:797-805. [PMID: 31036773 DOI: 10.1136/thoraxjnl-2018-212441] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 02/14/2019] [Accepted: 02/25/2019] [Indexed: 12/12/2022]
Abstract
Chronic airways diseases, including asthma, COPD and cystic fibrosis, cause significant morbidity and mortality and are associated with high healthcare expenditure, in the UK and worldwide. For patients with these conditions, improvements in clinical outcomes are likely to depend on the application of precision medicine, that is, the matching of the right treatment to the right patient at the right time. In this context, the identification and targeting of 'treatable traits' is an important priority in airways disease, both to ensure the appropriate use of existing treatments and to facilitate the development of new disease-modifying therapy. This requires not only better understanding of airway pathophysiology but also an enhanced ability to make physiological measurements of disease activity and lung function and, if we are to impact on the natural history of these diseases, reliable measures in early disease. In this article, we outline some of the key challenges faced by the respiratory community in the management of airways diseases, including early diagnosis, disease stratification and monitoring of therapeutic response. In this context, we review the advantages and limitations of routine physiological measurements of respiratory function including spirometry, body plethysmography and diffusing capacity and discuss less widely used methods such as forced oscillometry, inert gas washout and the multiple inert gas elimination technique. Finally, we highlight emerging technologies including imaging methods such as quantitative CT and hyperpolarised gas MRI as well as quantification of lung inhomogeneity using precise in-airway gas analysis and mathematical modelling. These emerging techniques have the potential to enhance existing measures in the assessment of airways diseases, may be particularly valuable in early disease, and should facilitate the efforts to deliver precision respiratory medicine.
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Affiliation(s)
- Nayia Petousi
- Nuffield Department of Clinical Medicine Division of Experimental Medicine, University of Oxford, Oxford, UK .,Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK.,Oxford Centre for Respiratory Medicine, Oxford University Hospitals NHS Trust, Oxford, UK
| | - Nick P Talbot
- Nuffield Department of Clinical Medicine Division of Experimental Medicine, University of Oxford, Oxford, UK.,Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK.,Oxford Centre for Respiratory Medicine, Oxford University Hospitals NHS Trust, Oxford, UK
| | - Ian Pavord
- Nuffield Department of Clinical Medicine Division of Experimental Medicine, University of Oxford, Oxford, UK.,Oxford Centre for Respiratory Medicine, Oxford University Hospitals NHS Trust, Oxford, UK
| | - Peter A Robbins
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
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23
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Miura E, Tsuchiya N, Igarashi Y, Arakawa R, Nikkuni E, Tamai T, Tabata M, Ohkouchi S, Irokawa T, Ogawa H, Takai-Igarashi T, Suzuki Y, Kuriyama S, Tamiya G, Hozawa A, Yamamoto M, Kurosawa H. Respiratory resistance among adults in a population-based cohort study in Northern Japan. Respir Investig 2019; 57:274-281. [PMID: 30770233 DOI: 10.1016/j.resinv.2018.12.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2018] [Revised: 12/14/2018] [Accepted: 12/21/2018] [Indexed: 10/27/2022]
Abstract
BACKGROUND Forced oscillation technique (FOT) is a noninvasive method used to measure respiratory system resistance (Rrs) and reactance (Xrs) during quiet breathing, which has been extensively studied in clinical settings. The distribution of measured FOT values was previously assessed in a community-based cohort study. In this study, we aimed to confirm the distribution of measured FOT values in a different cohort in order to investigate the relationship between these values and patient clinical and biological data. METHODS We reviewed FOT data and relevant patient clinical and biological information collected from the Community-Based Cohort Study (CommCohort Study), carried out between 2013 to 2016 as a part of the Tohoku Medical Megabank project (TMM). In total, 16,231 adults were enrolled in the study (Male/Female: 4886/11,345). RESULTS Significant gender differences were observed in distributions of Rrs and Xrs values at 5 Hz (termed R5 and X5, respectively). R5 values in males were lower than those in females, while X5 values in males were slightly less negative. High R5 values were strongly associated with high BMI, short height, smoking status in males, high serum IgE level, and high peripheral blood eosinophil count. CONCLUSION The present distribution values and their relation to clinical and biological data should provide useful insights for clinical settings and serve as a helpful guide in implementing FOT. Forced oscillation technique, respiratory system resistance, respiratory system reactance, gender difference, obesity.
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Affiliation(s)
- Emiri Miura
- Department of Occupational Health, Tohoku University Graduate School of Medicine, Japan
| | - Naho Tsuchiya
- Tohoku University Tohoku Medical Megabank Organization, Japan
| | - Yu Igarashi
- Department of Occupational Health, Tohoku University Graduate School of Medicine, Japan
| | - Ritsuko Arakawa
- Department of Occupational Health, Tohoku University Graduate School of Medicine, Japan
| | - Etsuhiro Nikkuni
- Department of Occupational Health, Tohoku University Graduate School of Medicine, Japan
| | - Tokiwa Tamai
- Department of Occupational Health, Tohoku University Graduate School of Medicine, Japan; Center for Environmental Conservation and Research Safety, Tohoku University, Japan
| | | | - Shinya Ohkouchi
- Department of Occupational Health, Tohoku University Graduate School of Medicine, Japan; Center for Environmental Conservation and Research Safety, Tohoku University, Japan
| | - Toshiya Irokawa
- Department of Occupational Health, Tohoku University Graduate School of Medicine, Japan; Center for Environmental Conservation and Research Safety, Tohoku University, Japan
| | - Hiromasa Ogawa
- Department of Occupational Health, Tohoku University Graduate School of Medicine, Japan; Center for Environmental Conservation and Research Safety, Tohoku University, Japan
| | | | - Yoichi Suzuki
- Tohoku University Tohoku Medical Megabank Organization, Japan
| | | | - Gen Tamiya
- Tohoku University Tohoku Medical Megabank Organization, Japan
| | - Atsushi Hozawa
- Tohoku University Tohoku Medical Megabank Organization, Japan
| | | | - Hajime Kurosawa
- Department of Occupational Health, Tohoku University Graduate School of Medicine, Japan; Tohoku University Tohoku Medical Megabank Organization, Japan; Center for Environmental Conservation and Research Safety, Tohoku University, Japan.
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Smith CJ, Spaeder MC, Sorkness RL, Teague WG. Disparate diagnostic accuracy of lung function tests as predictors of poor asthma control in children. J Asthma 2019; 57:327-334. [PMID: 30663912 DOI: 10.1080/02770903.2019.1566471] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Rationale: In practice, asthma control is assessed according to symptom burden and office spirometry. However, spirometry poorly tests peripheral lung function, which may be abnormal in asthma. Impluse oscillometry (IOS) and multiple-breath washout (MBW) are novel methods which measure reactance (X5) and ventilation heterogeneity (VH) in the peripheral lung, but how well these tests reflect asthma control is poorly understood. Objective: To compare the diagnostic accuracy of tests of large airways caliber (FEV1, FEV1/FVC, R20), peripheral zone properties (X5, VH), and airways inflammation (FeNO) as predictors of poor control in asthmatic children (44 poorly controlled/10 controlled). Methods: 54 children enriched in severe asthma completed a symptom-based control scale (ACT/cACT) and lung function tests after overnight bronchodilator withhold. The accuracy of each variable to predict poor control was ranked by area under the receiver operating characteristic (ROC) curve, sensitivity and specificity. Results: Among measures of large airways caliber, the FEV1% had the highest ROC curve area, with low sensitivity but perfect specificity. Among measures of peripheral lung function, X5 and VH in the conducting zone had fair curve areas with higher sensitivity but lower specificity compared to the FEV1%. VH in the acinar zone and FeNO both had poor accuracy. Conclusion: Tests of large airway and peripheral zone lung function performed disparately as predictors of poor control in a sample of children enriched in severe asthma. Further studies in a larger sample with more diverse phenotypic features are necessary to validate this preliminary conclusion.
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Affiliation(s)
- Clyde J Smith
- Division of Critical Care Medicine, Department of Pediatrics, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Michael C Spaeder
- Division of Critical Care Medicine, Department of Pediatrics, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Ronald L Sorkness
- School of Pharmacy and Departments of Medicine and Pediatrics, University of Wisconsin-Madison, Madison, WI, USA
| | - W Gerald Teague
- Child Health Research Center, Department of Pediatrics, University of Virginia School of Medicine, Charlottesville, VA, USA
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Eddy RL, Westcott A, Maksym GN, Parraga G, Dandurand RJ. Oscillometry and pulmonary magnetic resonance imaging in asthma and COPD. Physiol Rep 2019; 7:e13955. [PMID: 30632309 PMCID: PMC6328923 DOI: 10.14814/phy2.13955] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 11/23/2018] [Accepted: 11/26/2018] [Indexed: 12/14/2022] Open
Abstract
Developed over six decades ago, pulmonary oscillometry has re-emerged as a noninvasive and effort-independent method for evaluating respiratory-system impedance in patients with obstructive lung disease. Here, we evaluated the relationships between hyperpolarized 3 He ventilation-defect-percent (VDP) and respiratory-system resistance, reactance and reactance area (AX ) measurements in 175 participants including 42 never-smokers without respiratory disease, 56 ex-smokers with chronic-obstructive-pulmonary-disease (COPD), 28 ex-smokers without COPD and 49 asthmatic never-smokers. COPD participants were dichotomized based on x-ray computed-tomography (CT) evidence of emphysema (relative-area CT-density-histogram ≤ 950HU (RA950 ) ≥ 6.8%). In asthma and COPD subgroups, MRI VDP was significantly related to the frequency-dependence of resistance (R5-19 ; asthma: ρ = 0.48, P = 0.0005; COPD: ρ = 0.45, P = 0.0004), reactance at 5 Hz (X5 : asthma, ρ = -0.41, P = 0.004; COPD: ρ = -0.38, P = 0.004) and AX (asthma: ρ = 0.47, P = 0.0007; COPD: ρ = 0.43, P = 0.0009). MRI VDP was also significantly related to R5-19 in COPD participants without emphysema (ρ = 0.54, P = 0.008), and to X5 in COPD participants with emphysema (ρ = -0.36, P = 0.04). AX was weakly related to VDP in asthma (ρ = 0.47, P = 0.0007) and COPD participants with (ρ = 0.39, P = 0.02) and without (ρ = 0.43, P = 0.04) emphysema. AX is sensitive to obstruction but not specific to the type of obstruction, whereas the different relationships for MRI VDP with R5-19 and X5 may reflect the different airway and parenchymal disease-specific biomechanical abnormalities that lead to ventilation defects.
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Affiliation(s)
- Rachel L Eddy
- Robarts Research Institute, London, Ontario, Canada
- Department of Medical Biophysics, Western University, London, Ontario, Canada
| | - Andrew Westcott
- Robarts Research Institute, London, Ontario, Canada
- Department of Medical Biophysics, Western University, London, Ontario, Canada
| | - Geoffrey N Maksym
- School of Biomedical Engineering, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Grace Parraga
- Robarts Research Institute, London, Ontario, Canada
- Department of Medical Biophysics, Western University, London, Ontario, Canada
- School of Biomedical Engineering, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Ronald J Dandurand
- CIUSSS de l'Ouest-de-l'Île-de-Montréal, Montreal Chest Institute, Meakins-Christie Laboratories, Oscillometry Unit and Centre for Innovative Medicine, McGill University Health Centre and Research Institute, Montreal, Quebec, Canada
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Longitudinal changes in pulmonary function and respiratory impedance of rheumatoid arthritis. Respir Physiol Neurobiol 2018; 261:1-8. [PMID: 30583069 DOI: 10.1016/j.resp.2018.12.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 12/14/2018] [Accepted: 12/21/2018] [Indexed: 11/20/2022]
Abstract
The aim of this study was to examine long-term changes in pulmonary function and respiratory impedance (Zrs) as assessed by forced oscillation technique (FOT) of rheumatoid arthritis (RA)-related pulmonary disorders. Data of 42 RA patients who underwent pulmonary function tests and Zrs measurements at least twice at a >900-day interval were retrospectively reviewed. Zrs, respiratory resistance (Rrs) and reactance (Xrs), were measured as a function of oscillatory frequency from 4 to 36 Hz. The Rrs and difference between inspiratory and expiratory phases of Xrs were significantly decreased. Annual changes in Xrs parameters significantly correlated with those of spirometric parameters. Zrs parameters were significantly different between the low (the lower 75 percentile of incidence) and high (the top quartile) frequency of adverse respiratory event groups. The Zrs combined with spirometry may be beneficial to evaluate alterations in respiratory functions of RA.
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27
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Peters U, Dechman G, Hernandez P, Bhatawadekar SA, Ellsmere J, Maksym G. Improvement in upright and supine lung mechanics with bariatric surgery affects bronchodilator responsiveness and sleep quality. J Appl Physiol (1985) 2018; 125:1305-1314. [PMID: 30048205 DOI: 10.1152/japplphysiol.00694.2017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Obesity and weight-loss have complex effects on respiratory physiology, but these have been insufficiently studied, particularly at early time points following weight-loss surgery and in the supine position. We evaluated 15 severely obese female participants before, and 5 weeks and 6 months after bariatric surgery using the Pittsburgh Sleep Quality Index (PSQI), spirometry, plethysmography, and oscillometry to measure respiratory system mechanics. Oscillometry and spirometry were conducted in the upright and supine position, and pre- and post-bronchodilation with 200µg of salbutamol. At 5 weeks post-surgery, weight-loss was 11.9±2.7kg with no effect on spirometric outcomes and a slight effect on oscillometric outcomes. However, at 6 months, weight-loss was 21.4±7.1kg with a 14.1±6.1% and 17.8±5.4% reduction in upright and supine Rrs,6, respectively. Ers also decreased by 25.7±9.4% and 20.2±7.2% in the upright and supine positions. No changes were observed in spirometry, but sleep quality improved from PSQI of 8.4±3.5 to 4.1±2.9. Bronchodilator responsiveness was low at baseline but increased significantly post-surgery, and this response was comparable to the improvement in Rrs produced by weight-loss. Modeling the impedance spectra with a two-compartment model demonstrated that improvements in lung mechanics with weight-loss begin in the upper or central compartment of the lungs and progress to include the peripheral compartment. Respiratory mechanics are impaired in the severely obese and is associated with poor sleep quality, but these improved substantially with weight-loss. Our data provide new evidence that severely obese individuals may have poor sleep quality due to abnormal respiratory mechanics that weight-loss improves.
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Affiliation(s)
- Ubong Peters
- Larner College of Medicine, University of Vermont, United States
| | | | - Paul Hernandez
- Department of Medicine, University and Division of Respirology
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Wada Y, Kitaguchi Y, Yasuo M, Ueno F, Kawakami S, Fukushima K, Fujimoto K, Hanaoka M. Diversity of respiratory impedance based on quantitative computed tomography in patients with COPD. Int J Chron Obstruct Pulmon Dis 2018; 13:1841-1849. [PMID: 29892193 PMCID: PMC5993027 DOI: 10.2147/copd.s163129] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Introduction This study was conducted in order to investigate the diversity of respiratory physiology, including the respiratory impedance and reversibility of airway obstruction, based on quantitative computed tomography (CT) in patients with COPD. Patients and methods Medical records of 174 stable COPD patients were retrospectively reviewed to obtain the patients’ clinical data, including the pulmonary function and imaging data. According to the software-based quantification of the degree of emphysema and airway wall thickness, the patients were classified into the “normal by CT” phenotype, the airway-dominant phenotype, the emphysema-dominant phenotype, and the mixed phenotype. The pulmonary function, including the respiratory impedance evaluated by using the forced oscillation technique (FOT) and the reversibility of airway obstruction in response to inhaled short-acting β2-agonists, was then compared among the four phenotypes. Results The respiratory system resistance at 5 and 20 Hz (R5 and R20) was significantly higher, and the respiratory system reactance at 5 Hz (X5) was significantly more negative in the airway-dominant and mixed phenotypes than in the other phenotypes. The within-breath changes of X5 (ΔX5) were significantly greater in the mixed phenotype than in the “normal by CT” and emphysema-dominant phenotypes. The FOT parameters (R5, R20, and X5) were significantly correlated with indices of the degree of airway wall thickness and significantly but weakly correlated with the reversibility of airway obstruction. There was no significant correlation between the FOT parameters (R5, R20, and X5) and the degree of emphysema. Conclusion There is a diversity of respiratory physiology, including the respiratory impedance and reversibility of airway obstruction, based on quantitative CT in patients with COPD. The FOT measurements may reflect the degree of airway disease and aid in detecting airway remodeling in patients with COPD.
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Affiliation(s)
- Yosuke Wada
- First Department of Internal Medicine, Shinshu University School of Medicine, Matsumoto, Nagano, Japan
| | - Yoshiaki Kitaguchi
- First Department of Internal Medicine, Shinshu University School of Medicine, Matsumoto, Nagano, Japan
| | - Masanori Yasuo
- First Department of Internal Medicine, Shinshu University School of Medicine, Matsumoto, Nagano, Japan
| | - Fumika Ueno
- First Department of Internal Medicine, Shinshu University School of Medicine, Matsumoto, Nagano, Japan
| | - Satoshi Kawakami
- Department of Radiology, Shinshu University School of Medicine, Matsumoto, Nagano, Japan
| | - Kiyoyasu Fukushima
- Department of Respiratory Medicine, Japanese Red Cross Nagasaki Genbaku Isahaya Hospital, Isahaya, Nagasaki, Japan
| | - Keisaku Fujimoto
- Departments of Clinical Laboratory Sciences, Shinshu University School of Health Sciences, Matsumoto, Nagano, Japan
| | - Masayuki Hanaoka
- First Department of Internal Medicine, Shinshu University School of Medicine, Matsumoto, Nagano, Japan
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29
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Affiliation(s)
- Toshihiro Shirai
- Department of Respiratory Medicine, Shizuoka General Hospital, Shizuoka, Japan.
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30
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Finucane KE, Singh B. Role of bronchodilation and pattern of breathing in increasing tidal expiratory flow with progressive induced hypercapnia in chronic obstructive pulmonary disease. J Appl Physiol (1985) 2018; 124:91-98. [PMID: 28982946 DOI: 10.1152/japplphysiol.00752.2016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Hypercapnia (HC) in vitro relaxes airway smooth muscle; in vivo, it increases respiratory effort, tidal expiratory flows (V̇exp), and, by decreasing inspiratory duration (Ti), increases elastic recoil pressure (Pel) via lung viscoelasticity; however, its effect on airway resistance is uncertain. We examined the contributions of bronchodilation, Ti, and expiratory effort to increasing V̇exp with progressive HC in 10 subjects with chronic obstructive pulmonary disease (COPD): mean forced expiratory volume in 1 s (FEV1) 53% predicted. Lung volumes (Vl), V̇exp, esophageal pressure (Pes), Ti, and end-tidal Pco2 ([Formula: see text]) were measured during six tidal breaths followed by an inspiratory capacity (IC), breathing air, and at three levels of HC. V̇exp and V̇ with submaximal forced vital capacities breathing air (V̇sFVC) were compared. Pulmonary resistance ( Rl) was measured from the Pes-V̇ relationship. V̇exp and Pes at end-expiratory lung volume (EELV) + 0.3 tidal volume [V̇(0.3Vt) and Pes(0.3Vt), respectively], Ti, and Rl correlated with [Formula: see text] ( P < 0.001 for all) and were independent of tiotropium. [Formula: see text], Ti, and Pes(0.3Vt) predicted the increasing V̇(0.3Vt)/V̇sFVC(0.3Vt) [multiple regression analysis (MRA): P = 0.001, 0.004, and 0.025, respectively]. At [Formula: see text] ≥ 50 Torr, V̇(0.3Vt)/V̇sFVC(0.3Vt) exceeded unity in 30 of 36 measurements and was predicted by [Formula: see text] and Pes(0.3Vt) (MRA: P = 0.02 and 0.025, respectively). Rl decreased at [Formula: see text] 45 Torr ( P < 0.05) and did not change with further HC. IC and Vl(0.3Vt) did not change with HC. We conclude that in COPD HC increases V̇exp due to bronchodilation, increased Pel secondary to decreasing Ti, and increased expiratory effort, all promoting lung emptying and a stable EELV. NEW & NOTEWORTHY The response of airways to intrapulmonary hypercapnia (HC) is uncertain. In chronic obstructive pulmonary disease (COPD), progressive HC increases tidal expiratory flows by inducing bronchodilation and via an increased rate of inspiration and lung viscoelasticity, a probable increase in lung elastic recoil pressure, both changes increasing expiratory flows, promoting lung emptying and a stable end-expiratory volume. Bronchodilation with HC occurred despite optimal standard bronchodilator therapy, suggesting that in COPD further bronchodilation is possible.
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Affiliation(s)
- Kevin E Finucane
- Department of Pulmonary Physiology and Sleep Medicine, Sir Charles Gairdner Hospital , Nedlands, Western Australia , Australia.,West Australian Sleep Disorders Research Institute, Queen Elizabeth II Medical Centre , Perth, Western Australia , Australia
| | - Bhajan Singh
- Department of Pulmonary Physiology and Sleep Medicine, Sir Charles Gairdner Hospital , Nedlands, Western Australia , Australia.,West Australian Sleep Disorders Research Institute, Queen Elizabeth II Medical Centre , Perth, Western Australia , Australia.,Faculty of Science, University of Western Australia, Perth, Western Australia, Australia
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Alblooshi A, Alkalbani A, Albadi G, Narchi H, Hall G. Is forced oscillation technique the next respiratory function test of choice in childhood asthma. World J Methodol 2017; 7:129-138. [PMID: 29354485 PMCID: PMC5746666 DOI: 10.5662/wjm.v7.i4.129] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 10/08/2017] [Accepted: 11/02/2017] [Indexed: 02/06/2023] Open
Abstract
Respiratory diseases, especially asthma, are common in children. While spirometry contributes to asthma diagnosis and management in older children, it has a limited role in younger children whom are often unable to perform forced expiratory manoeuvre. The development of novel diagnostic methods which require minimal effort, such as forced oscillation technique (FOT) is, therefore, a welcome and promising addition. FOT involves applying external, small amplitude oscillations to the respiratory system during tidal breathing. Therefore, it requires minimal effort and cooperation. The FOT has the potential to facilitate asthma diagnosis and management in pre-school children by faciliting the objective measurement of baseline lung function and airway reactivity in children unable to successfully perform spirometry. Traditionally the use of FOT was limited to specialised centres. However, the availability of commercial equipment resulted in its use both in research and in clinical practice. In this article, we review the available literature on the use of FOT in childhood asthma. The technical aspects of FOT are described followed by a discussion of its practical aspects in the clinical field including the measurement of baseline lung function and associated reference ranges, bronchodilator responsiveness and bronchial hyper-responsiveness. We also highlight the difficulties and limitations that might be encountered and future research directions.
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Affiliation(s)
- Afaf Alblooshi
- Department of Pediatrics, United Arab Emirates University, Al-Ain, United Arab Emirates
| | - Alia Alkalbani
- Department of Pediatrics, Tawam Hospital, Al-Ain, United Arab Emirates
| | - Ghaya Albadi
- Department of Pediatrics, United Arab Emirates University, Al-Ain, United Arab Emirates
| | - Hassib Narchi
- Department of Pediatrics, United Arab Emirates University, Al-Ain, United Arab Emirates
| | - Graham Hall
- Department of Children’s Lung Health, Telethon Kids Institute, Perth 6000, Australia
- School of Physiotherapy and Exercise Science, Curtin University and Centre of Child Health Research, University of Western Australia, Perth 6000, Australia
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Foy BH, Kay D. A computational comparison of the multiple-breath washout and forced oscillation technique as markers of bronchoconstriction. Respir Physiol Neurobiol 2017; 240:61-69. [DOI: 10.1016/j.resp.2017.02.016] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Revised: 02/23/2017] [Accepted: 02/24/2017] [Indexed: 01/19/2023]
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Responsiveness to bronchodilator procaterol in COPD as assessed by forced oscillation technique. Respir Physiol Neurobiol 2017; 240:41-47. [PMID: 28238903 DOI: 10.1016/j.resp.2017.02.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Accepted: 02/21/2017] [Indexed: 12/23/2022]
Abstract
The aim of this retrospective study was to assess responses to a bronchodilator by forced oscillation technique (FOT) and to relate the results of respiratory impedance (Zrs) to spirometric parameters in patients with chronic obstructive pulmonary disease (COPD). Zrs was measured as a function of frequency from 4 to 36Hz before and after inhalation of procaterol, a short-acting β2-agonist (n=60). Respiratory resistance (Rrs) and reactance (Xrs) were significantly frequency-dependent, and inspiratory and expiratory phases were different both before and after procaterol inhalation. The Rrs at 4Hz and Xrs at 4-20Hz during a whole breath were significantly improved after procaterol inhalation. The response to procaterol inhalation varied among patients, and changes in Xrs at 4Hz significantly correlated with% change in forced expiratory volume in one second and changes in forced vital capacity. Taken together, Zrs, and specifically Xrs parameters, are sensitive to acute physiological responses to a bronchodilator in COPD.
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Lorx A, Czövek D, Gingl Z, Makan G, Radics B, Bartusek D, Szigeti S, Gál J, Losonczy G, Sly PD, Hantos Z. Airway dynamics in COPD patients by within-breath impedance tracking: effects of continuous positive airway pressure. Eur Respir J 2017; 49:49/2/1601270. [DOI: 10.1183/13993003.01270-2016] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2016] [Accepted: 11/08/2016] [Indexed: 11/05/2022]
Abstract
Tracking of the within-breath changes of respiratory mechanics using the forced oscillation technique may provide outcomes that characterise the dynamic behaviour of the airways during normal breathing.We measured respiratory resistance (Rrs) and reactance (Xrs) at 8 Hz in 55 chronic obstructive pulmonary disease (COPD) patients and 20 healthy controls, and evaluated Rrs and Xrs as functions of gas flow (V′) and volume (V) during normal breathing cycles. In 12 COPD patients, additional measurements were made at continuous positive airway pressure (CPAP) levels of 4, 8, 14 and 20 hPa.The Rrs and Xrsversus V′ and V relationships displayed a variety of loop patterns, allowing characterisation of physiological and pathological processes. The main outcomes emerging from the within-breath analysis were the Xrsversus V loop area (AXV) quantifying expiratory flow limitation, and the tidal change in Xrs during inspiration (ΔXI) reflecting alteration in lung inhomogeneity in COPD. With increasing CPAP, AXV and ΔXI approached the normal ranges, although with a large variability between individuals, whereas mean Rrs remained unchanged.Within-breath tracking of Rrs and Xrs allows an improved assessment of expiratory flow limitation and functional inhomogeneity in COPD; thereby it may help identify the physiological phenotypes of COPD and determine the optimal level of respiratory support.
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Airway reactivity in response to repeated emotional film clip presentation in asthma. Biol Psychol 2016; 123:1-7. [PMID: 27856329 DOI: 10.1016/j.biopsycho.2016.11.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 10/13/2016] [Accepted: 11/13/2016] [Indexed: 12/19/2022]
Abstract
Emotional stimuli elicit airway constriction in individuals with asthma and in healthy individuals, but little is known about effects of repeated stimulation. We therefore explored the effect of repeated emotion induction on respiratory resistance (Rrs) using unpleasant, high-arousal surgery films and investigated effects of respiration and emotional reactivity. Twenty-six participants (13 with asthma) watched a series of 12 short, 45-s surgery films followed by 2-min recovery periods. Rrs assessed with impulse oscillometry was significantly elevated during films in both groups compared to baseline and recovered quickly after that. No habituation of airway responses occurred. Rrs was higher in participants who felt more aroused and less in control when watching the films. Changes in Rrs remained significant when controlling for changes in respiration or emotional experience. Thus, although unpleasant stimuli lead to elevated Rrs, airway obstruction is not exacerbated with repeated stimulation due to a fast return to baseline after stimulation.
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Immediate effects of cigar smoking on respiratory mechanics and exhaled biomarkers; differences between young smokers with mild asthma and otherwise healthy young smokers. Tob Induc Dis 2016; 14:29. [PMID: 27547175 PMCID: PMC4990845 DOI: 10.1186/s12971-016-0095-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Accepted: 08/11/2016] [Indexed: 12/30/2022] Open
Abstract
Background We aimed to investigate the immediate respiratory effects of cigar smoking(CS), among young smokers with and without mild asthma. Materials and methods Forty-seven young smokers (18–31years old, 29 males, average pack-years = 3.6 ± 2.8) were enrolled. Twenty-two were mild asthmatics(MA-subgroup) and the remaining 25 were otherwise healthy smokers(HS-subgroup). Exhaled carbon monoxide(eCO), multi-frequency respiratory system impedance(Z), resistance(R), reactance(X), frequency-dependence of resistance(fdr = R5Hz - R20Hz), resonant frequency(fres), reactance area(AX) and exhaled nitric oxide(FENO) were measured at the aforementioned sequence, before and immediately after 30 min of CS, or equal session in the smoking area while using a sham cigar(control group). Chi-square, student’s t-tests, mixed linear models and Pearson correlation tests were used for the statistical analysis; level of significance was defined as p < 0.05. Results Immediately after CS, Z5Hz, R5Hz, R10Hz, R20Hz and eCO increased significantly in both subgroups(MA and HS). A greater increase was found for R20 in HS-subgroup. Fdr, fres and AX increased in MA, while decreased in HS. On the contrary, X10 decreased in MA and increased in HS, while X20 showed a greater decrease in MA. Changes in fdr, fres and AX were significantly correlated in both subgroups. No significant FENO alterations were detected in both subgroups. Conclusion CS has immediate effects on pulmonary function. Mild asthma predisposes to higher increase of peripheral resistance(increased fdr). In otherwise healthy smokers, central resistance(R20Hz) is more affected. FENO levels are not significantly affected by CS.
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Van Rhein T, Alzahrany M, Banerjee A, Salzman G. Fluid flow and particle transport in mechanically ventilated airways. Part I. Fluid flow structures. Med Biol Eng Comput 2016; 54:1085-96. [PMID: 26563199 DOI: 10.1007/s11517-015-1407-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Accepted: 10/19/2015] [Indexed: 11/30/2022]
Abstract
A large eddy simulation-based computational study of fluid flow and particle transport in upper tracheobronchial airways is carried out to investigate the effect of ventilation parameters on pulmonary fluid flow. Respiratory waveforms commonly used by commercial mechanical ventilators are used to study the effect of ventilation parameters and ventilation circuit on pulmonary fluid dynamics. A companion paper (Alzahrany et al. in Med Biol Eng Comput, 2014) reports our findings on the effect of the ventilation parameters and circuit on particle transport and aerosolized drug delivery. The endotracheal tube (ETT) was found to be an important geometric feature and resulted in a fluid jet that caused an increase in turbulence and created a recirculation zone with high wall shear stress in the main bronchi. Stronger turbulence was found in lower airways than would be found under normal breathing conditions due to the presence of the jet caused by the ETT. The pressure-controlled sinusoidal waveform induced the lowest wall shear stress on the airways wall.
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Affiliation(s)
- Timothy Van Rhein
- Department of Mechanical and Aerospace Engineering, Missouri University of Science and Technology, Rolla, MO, 65409, USA
| | - Mohammed Alzahrany
- Packard Laboratory, Department of Mechanical Engineering and Mechanics, Lehigh University, Bethlehem, PA, 18015, USA
| | - Arindam Banerjee
- Packard Laboratory, Department of Mechanical Engineering and Mechanics, Lehigh University, Bethlehem, PA, 18015, USA.
| | - Gary Salzman
- Respiratory and Critical Care Medicine, University of Missouri- Kansas City School of Medicine, Kansas City, MO, 64108, USA
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Czövek D, Shackleton C, Hantos Z, Taylor K, Kumar A, Chacko A, Ware RS, Makan G, Radics B, Gingl Z, Sly PD. Tidal changes in respiratory resistance are sensitive indicators of airway obstruction in children. Thorax 2016; 71:907-15. [PMID: 27178219 DOI: 10.1136/thoraxjnl-2015-208182] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Accepted: 04/17/2016] [Indexed: 11/04/2022]
Abstract
RATIONALE Individual assessment of airway obstruction in preschool-age children requires sensitive and specific lung function methods with low demand of cooperation. Although the forced oscillation technique (FOT) is feasible in young children, conventional measurements of respiratory impedance (Zrs) have limited diagnostic power in individuals. OBJECTIVE To find descriptors of within-breath Zrs that are sensitive indicators of airway obstruction during tidal breathing in children. METHODS Zrs was measured with (i) a standard multifrequency FOT (4-26 Hz) to assess the mean values of resistance and reactance for whole breaths and (ii) a 10 Hz signal to track the within-breath changes. Various Zrs measures obtained in healthy children (n=75) and those with acute wheeze (n=31) were investigated with receiver operator characteristic (ROC) analysis. The cut-off values obtained for airway obstruction were then tested in children with recurrent wheeze (n=20) before and after administration of salbutamol. RESULTS The largest area under the ROC curve (0.95) was observed for the tidal changes of resistance between the zero-flow values (ΔR). The ΔR cut-off value of 1.42 hPa s/L detected airway obstruction with sensitivity of 92% and specificity of 89% in children with acute wheeze and distinguished children with recurrent wheeze (16/20 above the cut-off value) from healthy children (22/23 below the cut-off value). Furthermore, ΔR significantly decreased after salbutamol in wheezy children but remained unchanged in healthy children. CONCLUSIONS New lung function measure ΔR is able to detect airway obstruction with high sensitivity and specificity and is suitable for use in lung function testing in young children.
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Affiliation(s)
- Dorottya Czövek
- Children's Lung, Environment and Asthma Research Team, University of Queensland, Brisbane, Queensland, Australia Child Health Research Centre, University of Queensland, Brisbane, Queensland, Australia
| | - Claire Shackleton
- Children's Lung, Environment and Asthma Research Team, University of Queensland, Brisbane, Queensland, Australia Child Health Research Centre, University of Queensland, Brisbane, Queensland, Australia
| | - Zoltán Hantos
- Children's Lung, Environment and Asthma Research Team, University of Queensland, Brisbane, Queensland, Australia Child Health Research Centre, University of Queensland, Brisbane, Queensland, Australia Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary Department of Pulmonology, University of Szeged, Szeged, Hungary
| | - Kate Taylor
- Children's Lung, Environment and Asthma Research Team, University of Queensland, Brisbane, Queensland, Australia
| | - Anushma Kumar
- Children's Lung, Environment and Asthma Research Team, University of Queensland, Brisbane, Queensland, Australia
| | - Archana Chacko
- Children's Lung, Environment and Asthma Research Team, University of Queensland, Brisbane, Queensland, Australia
| | - Robert S Ware
- Child Health Research Centre, University of Queensland, Brisbane, Queensland, Australia
| | - Gergely Makan
- Department of Technical Informatics, University of Szeged, Szeged, Hungary
| | - Bence Radics
- Department of Pulmonology, University of Szeged, Szeged, Hungary
| | - Zoltán Gingl
- Department of Technical Informatics, University of Szeged, Szeged, Hungary
| | - Peter D Sly
- Children's Lung, Environment and Asthma Research Team, University of Queensland, Brisbane, Queensland, Australia Child Health Research Centre, University of Queensland, Brisbane, Queensland, Australia
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Kitaguchi Y, Yasuo M, Hanaoka M. Comparison of pulmonary function in patients with COPD, asthma-COPD overlap syndrome, and asthma with airflow limitation. Int J Chron Obstruct Pulmon Dis 2016; 11:991-7. [PMID: 27274220 PMCID: PMC4869610 DOI: 10.2147/copd.s105988] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND This study was conducted in order to investigate the differences in the respiratory physiology of patients with chronic obstructive pulmonary disease (COPD), asthma-COPD overlap syndrome (ACOS), and asthma with airflow limitation (asthma FL(+)). METHODS The medical records for a series of all stable patients with persistent airflow limitation due to COPD, ACOS, or asthma were retrospectively reviewed and divided into the COPD group (n=118), the ACOS group (n=32), and the asthma FL(+) group (n=27). All the patients underwent chest high-resolution computed tomography (HRCT) and pulmonary function tests, including respiratory impedance. RESULTS The low attenuation area score on chest HRCT was significantly higher in the COPD group than in the ACOS group (9.52±0.76 vs 5.09±1.16, P<0.01). The prevalence of bronchial wall thickening on chest HRCT was significantly higher in the asthma FL(+) group than in the COPD group (55.6% vs 25.0%, P<0.01). In pulmonary function, forced expiratory volume in 1 second (FEV1) and peak expiratory flow rate were significantly higher in the asthma FL(+) group than in the ACOS group (76.28%±2.54% predicted vs 63.43%±3.22% predicted, P<0.05 and 74.40%±3.16% predicted vs 61.08%±3.54% predicted, P<0.05, respectively). Although residual volume was significantly lower in the asthma FL(+) group than in the COPD group (112.05%±4.34% predicted vs 137.38%±3.43% predicted, P<0.01) and the ACOS group (112.05%±4.34% predicted vs148.46%±6.25% predicted, P<0.01), there were no significant differences in functional residual capacity or total lung capacity. The increase in FEV1 in response to short-acting β2-agonists was significantly greater in the ACOS group than in the COPD group (229±29 mL vs 72±10 mL, P<0.01) and the asthma FL(+) group (229±29 mL vs 153±21 mL, P<0.05). Regarding respiratory impedance, resistance at 5 Hz and resistance at 20 Hz, which are oscillatory parameters of respiratory resistance, were significantly higher in the asthma FL(+) group than in the COPD group at the whole-breath (4.29±0.30 cmH2O/L/s vs 3.41±0.14 cmH2O/L/s, P<0.01 and 3.50±0.24 cmH2O/L/s vs 2.68±0.10 cmH2O/L/s, P<0.01, respectively), expiratory, and inspiratory phases. CONCLUSION Although persistent airflow limitation occurs in patients with COPD, ACOS, and asthma FL(+), they may have distinct characteristics of the respiratory physiology and different responsiveness to bronchodilators.
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Affiliation(s)
- Yoshiaki Kitaguchi
- First Department of Internal Medicine, Shinshu University School of Medicine, Matsumoto, Japan
| | - Masanori Yasuo
- First Department of Internal Medicine, Shinshu University School of Medicine, Matsumoto, Japan
| | - Masayuki Hanaoka
- First Department of Internal Medicine, Shinshu University School of Medicine, Matsumoto, Japan
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Sokai R, Ito S, Iwano S, Uchida A, Aso H, Kondo M, Ishiguro N, Kojima T, Hasegawa Y. Respiratory mechanics measured by forced oscillation technique in rheumatoid arthritis-related pulmonary abnormalities: frequency-dependence, heterogeneity and effects of smoking. SPRINGERPLUS 2016; 5:335. [PMID: 27064652 PMCID: PMC4792822 DOI: 10.1186/s40064-016-1952-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Accepted: 02/29/2016] [Indexed: 11/10/2022]
Abstract
Rheumatoid arthritis (RA)-related pulmonary disorders specifically airway abnormalities and interstitial pneumonia (IP) are important extra-articular manifestations. The forced oscillation technique (FOT) is a useful method to assess respiratory impedance, respiratory resistance (Rrs) and reactance (Xrs), at different oscillatory frequencies during tidal breathing. The aim of this study was to characterize the respiratory mechanics of patients with RA and to relate them to parameters of the pulmonary function test and findings of chest CT images. Respiratory impedance of RA patients (n = 69) was measured as a function of frequency from 4 to 36 Hz using the FOT device and compared with that of healthy subjects (n = 10). Data were retrospectively reviewed. Patients were female-dominant (60.9 %) and 95.7 % had abnormal CT findings including airway and parenchymal abnormalities. Thirty-seven of 69 patients (53.6 %) were smokers. Rrs was significantly frequency-dependent in RA patients but not in the healthy subjects. Xrs were significantly frequency-dependent in both RA and healthy groups. Rrs was significantly higher during an expiratory phase in both RA and healthy groups. Xrs was significantly lower (more negative) during an expiratory phase than that during an inspiratory phase in RA patients but not in healthy subjects. Xrs of the RA group was significantly more negative than that of the normal control. There was no difference in impedance parameters between the airway lesion dominant (n = 27) and IP dominant groups (n = 23) in the RA group. The impedance parameters of the RA group significantly correlated with most parameters of the pulmonary function test. In pulmonary function test results, % of the predicted value for forced expiratory flow from 25 to 75 % of forced vital capacity was significantly lower and % of the predicted value for diffusing capacity of the lung for carbon monoxide was higher in the airway lesion dominant group than those in the IP dominant group. Krebs von den Lungen-6, a serum indicator of IP, was significantly higher in the IP group than that in the airway lesion dominant group. Taken together, the impedance results reflect abnormalities in pulmonary functions and structures in patients with RA.
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Affiliation(s)
- Risa Sokai
- Department of Respiratory Medicine, Nagoya University School of Medicine, Nagoya, 466-8550 Japan
| | - Satoru Ito
- Department of Respiratory Medicine, Nagoya University School of Medicine, Nagoya, 466-8550 Japan
| | - Shingo Iwano
- Department of Radiology, Nagoya University School of Medicine, Nagoya, 466-8550 Japan
| | - Akemi Uchida
- Department of Clinical Laboratory, Nagoya University School of Medicine, Nagoya, 466-8550 Japan
| | - Hiromichi Aso
- Department of Respiratory Medicine, Nagoya University School of Medicine, Nagoya, 466-8550 Japan
| | - Masashi Kondo
- Department of Respiratory Medicine, Nagoya University School of Medicine, Nagoya, 466-8550 Japan
| | - Naoki Ishiguro
- Department of Orthopedic Surgery and Rheumatology, Nagoya University School of Medicine, Nagoya, 466-8550 Japan
| | - Toshihisa Kojima
- Department of Orthopedic Surgery and Rheumatology, Nagoya University School of Medicine, Nagoya, 466-8550 Japan
| | - Yoshinori Hasegawa
- Department of Respiratory Medicine, Nagoya University School of Medicine, Nagoya, 466-8550 Japan
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Ghafarian P, Jamaati H, Hashemian SM. A Review on Human Respiratory Modeling. TANAFFOS 2016; 15:61-69. [PMID: 27904536 PMCID: PMC5127616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Input impedance of the respiratory system is measured by forced oscillation technique (FOT). Multiple prior studies have attempted to match the electromechanical models of the respiratory system to impedance data. Since the mechanical behavior of airways and the respiratory system as a whole are similar to an electrical circuit in a combination of series and parallel formats some theories were introduced according to this issue. It should be noted that, the number of elements used in these models might be less than those required due to the complexity of the pulmonary-chest wall anatomy. Various respiratory models have been proposed based on this idea in order to demonstrate and assess the different parts of respiratory system related to children and adults data. With regard to our knowledge, some of famous respiratory models in related to obstructive, restrictive diseases and also Acute Respiratory Distress Syndrome (ARDS) are reviewed in this article.
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Affiliation(s)
- Pardis Ghafarian
- Chronic Respiratory Diseases Research Center, National Research Institute of Tuberculosis and Lung Diseases (NRITLD), Shahid Beheshti University of Medical Sciences, Tehran, Iran,, PET/CT and Cyclotron Center, NRITLD, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Hamidreza Jamaati
- Tobacco Prevention and Control Research Center, NRITLD, Shahid Beheshti University of Medical Sciences, Tehran, Iran,Correspondence to: Jamaati HR, Address: Chronic Respiratory Diseases Research Center, National Research Institute of Tuberculosis and Lung Diseases (NRITLD), ShahidBeheshti University of Medical Sciences, Tehran, Iran, Email address:
| | - Seyed Mohammadreza Hashemian
- Chronic Respiratory Diseases Research Center, National Research Institute of Tuberculosis and Lung Diseases (NRITLD), Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Abstract
The forced oscillation technique (FOT) is a noninvasive method with which to measure respiratory system resistance and reactance during tidal breathing. Recently, its clinical application has spread worldwide with the expansion of commercially available broadband frequency FOT devices, including MostGraph and Impulse Oscillometry. An increasing number of reports have supported the usefulness of the FOT in the management of asthma and chronic obstructive pulmonary disease (COPD). However, the FOT is not a surrogate test for spirometry, but should be used complementarily. Furthermore, reference values are not necessarily available and the interpretation of some measured data is controversial. There is a need to update the international statement for not only technical aspects but also the clinical use of the FOT. In this review, we summarize the previously published studies and discuss how to use the FOT in a clinical setting.
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Affiliation(s)
- Toshihiro Shirai
- Department of Respiratory Medicine, Shizuoka General Hospital, Japan
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43
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Aberrant small airways function relates to asthma severity in young children. Respir Med 2015; 111:16-20. [PMID: 26733229 DOI: 10.1016/j.rmed.2015.12.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Revised: 12/11/2015] [Accepted: 12/17/2015] [Indexed: 11/20/2022]
Abstract
BACKGROUND Frequency dependence of resistance (R5-20) assessed by impulse oscillometry (IOS) is suggested to be a measure of small airways. Small airways involvement during induced bronchoconstriction has been shown to reflect severity of asthma in adults. OBJECTIVE Our aim was to evaluate if methacholine (Mch) induced changes in R5-20 are associated with the severity of exercise induced bronchoconstriction (EIB) in young children. METHODS A total of 109 children aged 3-8 years were studied, 95 with obstructive symptoms and 14 in good health, to assess small airways function during a Mch challenge. R5-20 and other IOS resistance and reactance parameters were measured at baseline and after the Mch challenge. In a standardized exercise test, the children were grouped according to the severity of EIB expressed as the percentage increase in resistance at 5 Hz (ΔR5) after exercise, indicating either no EIB (ΔR5 < 40%, n = 84), moderate EIB (ΔR5 40-80%, n = 13) and severe EIB (ΔR5 > 80%, n = 12). RESULTS The baseline R5-20 was not associated with the severity of EIB, but during Mch induced bronchoconstriction the change in R5-20 was significantly higher in children with severe EIB (2.61 fold increase) than in children with moderate EIB (1.48) or no EIB (1.74, p = 0.036). No significant associations were found in changes of other IOS parameters. The children with severe EIB also used more short-acting beta-agonists during the past two months than the other two groups (p < 0.001). CONCLUSION Frequency dependence of resistance (R5-20) measured by IOS during the Mch induced bronchoconstriction and more frequent use of beta-agonists are associated with severe EIB in young children.
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Albanese A, Cheng L, Ursino M, Chbat NW. An integrated mathematical model of the human cardiopulmonary system: model development. Am J Physiol Heart Circ Physiol 2015; 310:H899-921. [PMID: 26683899 DOI: 10.1152/ajpheart.00230.2014] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Accepted: 12/03/2015] [Indexed: 11/22/2022]
Abstract
Several cardiovascular and pulmonary models have been proposed in the last few decades. However, very few have addressed the interactions between these two systems. Our group has developed an integrated cardiopulmonary model (CP Model) that mathematically describes the interactions between the cardiovascular and respiratory systems, along with their main short-term control mechanisms. The model has been compared with human and animal data taken from published literature. Due to the volume of the work, the paper is divided in two parts. The present paper is on model development and normophysiology, whereas the second is on the model's validation on hypoxic and hypercapnic conditions. The CP Model incorporates cardiovascular circulation, respiratory mechanics, tissue and alveolar gas exchange, as well as short-term neural control mechanisms acting on both the cardiovascular and the respiratory functions. The model is able to simulate physiological variables typically observed in adult humans under normal and pathological conditions and to explain the underlying mechanisms and dynamics.
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Affiliation(s)
| | - Limei Cheng
- Philips Research North America, Briarcliff Manor, New York
| | - Mauro Ursino
- Department of Electrical, Electronic, and Information Engineering, University of Bologna, Bologna, Italy; and
| | - Nicolas W Chbat
- Philips Research North America, Briarcliff Manor, New York; Departments of Biomedical Engineering and Mechanical Engineering, Columbia University, New York, New York
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45
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Bhatawadekar SA, Leary D, Maksym GN. Modelling resistance and reactance with heterogeneous airway narrowing in mild to severe asthma. Can J Physiol Pharmacol 2015; 93:207-14. [PMID: 25730711 DOI: 10.1139/cjpp-2014-0436] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Ventilation heterogeneity is an important marker of small airway dysfunction in asthma. The frequency dependence of respiratory system resistance (Rrs) from oscillometry is used as a measure of this heterogeneity. However, this has not been quantitatively assessed or compared with other outcomes from oscillometry, including respiratory system reactance (Xrs) and the associated elastance (Ers). Here, we used a multibranch model of the human lung, including an upper airway shunt, to match previously reported respiratory mechanics in mild to severe asthma. We imposed heterogeneity by narrowing a proportion of the peripheral airways to account for patient Ers at 5 Hz, and then narrowed central airways to account for the remaining Rrs at 18 Hz. The model required >75% of the small airways to be occluded to reproduce severe asthma. While the model produced frequency dependence in Rrs, it was upward-shifted below 5 Hz compared with in-vivo results, indicating that other factors, including more distributed airway narrowing or central airway wall compliance, are required. However, Ers quantitatively reflected the imposed heterogeneity better than the frequency dependence of Rrs, independent of the frequency range for the estimation, and thus was a more robust measure of small-airway function. Thus, Ers appears to have greater potential as a clinical measure of early small-airway disease in asthma.
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Affiliation(s)
- Swati A Bhatawadekar
- School of Biomedical Engineering, Dalhousie University, 5981 University Avenue, Halifax, NS B3H 4R2, Canada
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Abstract
COPD is characterized by airflow limitation that is not fully reversible. The morphological basis for airflow obstruction results from a varying combination of obstructive changes in peripheral conducting airways and destructive changes in respiratory bronchioles, alveolar ducts, and alveoli. A reduction of vascularity within the alveolar septa has been reported in emphysema. Typical physiological changes reflect these structural abnormalities. Spirometry documents airflow obstruction when the FEV1/FVC ratio is reduced below the lower limit of normality, although in early disease stages FEV1 and airway conductance are not affected. Current guidelines recommend testing for bronchoreversibility at least once and the postbronchodilator FEV1/FVC be used for COPD diagnosis; the nature of bronchodilator response remains controversial, however. One major functional consequence of altered lung mechanics is lung hyperinflation. FRC may increase as a result of static or dynamic mechanisms, or both. The link between dynamic lung hyperinflation and expiratory flow limitation during tidal breathing has been demonstrated. Hyperinflation may increase the load on inspiratory muscles, with resulting length adaptation of diaphragm. Reduction of exercise tolerance is frequently noted, with compelling evidence that breathlessness and altered lung mechanics play a major role. Lung function measurements have been traditionally used as prognostic indices and to monitor disease progression; FEV1 has been most widely used. An increase in FVC is also considered as proof of bronchodilatation. Decades of work has provided insight into the histological, functional, and biological features of COPD. This has provided a clearer understanding of important pathobiological processes and has provided additional therapeutic options.
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McNulty W, Usmani OS. Techniques of assessing small airways dysfunction. Eur Clin Respir J 2014; 1:25898. [PMID: 26557240 PMCID: PMC4629724 DOI: 10.3402/ecrj.v1.25898] [Citation(s) in RCA: 159] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Accepted: 09/11/2014] [Indexed: 11/17/2022] Open
Abstract
The small airways are defined as those less than 2 mm in diameter. They are a major site of pathology in many lung diseases, not least chronic obstructive pulmonary disease (COPD) and asthma. The small airways are frequently involved early in the course of these diseases, with significant pathology demonstrable often before the onset of symptoms or changes in spirometry and imaging. Despite their importance, they have proven relatively difficult to study. This is in part due to their relative inaccessibility to biopsy and their small size which makes their imaging difficult. Traditional lung function tests may only become abnormal once there is a significant burden of disease within them. This has led to the term 'the quiet zone' of the lung. In recent years, more specialised tests have been developed which may detect these changes earlier, perhaps offering the possibility of earlier diagnosis and intervention. These tests are now moving from the realms of clinical research laboratories into routine clinical practice and are increasingly useful in the diagnosis and monitoring of respiratory diseases. This article gives an overview of small airways physiology and some of the routine and more advanced tests of airway function.
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Affiliation(s)
- William McNulty
- National Heart and lung Institute, Imperial College London and Royal Brompton Hospital, London, UK
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48
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Brusasco V, Barisione G, Crimi E. Pulmonary physiology: Future directions for lung function testing in COPD. Respirology 2014; 20:209-18. [DOI: 10.1111/resp.12388] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2014] [Accepted: 07/31/2014] [Indexed: 11/29/2022]
Affiliation(s)
- Vito Brusasco
- Department of Internal Medicine and Medical Specialities (DiMI); Genova University and San Martino University Hospital; Genova Italy
| | - Giovanni Barisione
- Department of Internal Medicine and Medical Specialities (DiMI); Genova University and San Martino University Hospital; Genova Italy
| | - Emanuele Crimi
- Department of Internal Medicine and Medical Specialities (DiMI); Genova University and San Martino University Hospital; Genova Italy
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Alzahrany M, Banerjee A, Salzman G. The role of coupled resistance-compliance in upper tracheobronchial airways under high frequency oscillatory ventilation. Med Eng Phys 2014; 36:1593-604. [PMID: 25248986 DOI: 10.1016/j.medengphy.2014.08.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Revised: 08/11/2014] [Accepted: 08/25/2014] [Indexed: 11/25/2022]
Abstract
A large eddy simulation (LES) based computational fluid dynamics (CFD) study was conducted to investigate lung lobar ventilation and gas exchange under high frequency oscillatory ventilation conditions. Time-dependent pressure coupled with the airways resistance and compliance (R&C) were imposed as boundary conditions (BCs) in the upper tracheobronchial tree of patient-specific lung geometry. The flow distribution in the left and right lungs demonstrated significant variations compared to the case in which traditional BCs based on mass flow rate fractions was used and is in agreement with the in vivo data available in the literature. The gas transport due to the pendelluft mechanism was captured in the different lung lobes and units. The computed pendelluft elapsed time was consistent with available physiological data. In contrast to in vivo studies, our simulations were able to predict the volume associated with the pendelluft elapsed time at different frequencies. Significant differences in coaxial counter flow and flow structures were observed between different BCs. The consistency of the results with the physiological in vivo data indicates that computations with coupled R&C BCs provide a suitable alternative tool for understanding the gas transport, diagnosing lung pathway disease severity, and optimizing ventilation management techniques.
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Affiliation(s)
- Mohammed Alzahrany
- Department of Mechanical Engineering and Mechanics, Lehigh University, Bethlehem, PA 18015, United States
| | - Arindam Banerjee
- Department of Mechanical Engineering and Mechanics, Lehigh University, Bethlehem, PA 18015, United States.
| | - Gary Salzman
- Respiratory and Critical Care Medicine, University of Missouri-Kansas City School of Medicine, Kansas City, MO 64108, United States
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Tse HN, Tseng CZS. Update on the pathological processes, molecular biology, and clinical utility of N-acetylcysteine in chronic obstructive pulmonary disease. Int J Chron Obstruct Pulmon Dis 2014; 9:825-36. [PMID: 25125976 PMCID: PMC4130719 DOI: 10.2147/copd.s51057] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Chronic obstructive pulmonary disease (COPD) is a common and morbid disease characterized by high oxidative stress. Its pathogenesis is complex, and involves excessive oxidative stress (redox imbalance), protease/antiprotease imbalance, inflammation, apoptosis, and autoimmunity. Among these, oxidative stress has a pivotal role in the pathogenesis of COPD by initiating and mediating various redox-sensitive signal transduction pathways and gene expression. The protective physiological mechanisms of the redox balance in the human body, their role in the pathogenesis of COPD, and the clinical correlation between oxidative stress and COPD are reviewed in this paper. N-acetylcysteine (NAC) is a mucolytic agent with both antioxidant and anti-inflammatory properties. This paper also reviews the use of NAC in patients with COPD, especially the dose-dependent properties of NAC, eg, its effects on lung function and the exacerbation rate in patients with the disease. Earlier data from BRONCUS (the Bronchitis Randomized on NAC Cost-Utility Study) did not suggest that NAC was beneficial in patients with COPD, only indicating that it reduced exacerbation in an “inhaled steroid-naïve” subgroup. With regard to the dose-dependent properties of NAC, two recent randomized controlled Chinese trials suggested that high-dose NAC (1,200 mg daily) can reduce exacerbations in patients with COPD, especially in those with an earlier (moderately severe) stage of disease, and also in those who are at high risk of exacerbations. However, there was no significant effect on symptoms or quality of life in patients receiving NAC. Further studies are warranted to investigate the effect of NAC at higher doses in non-Chinese patients with COPD.
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Affiliation(s)
- Hoi Nam Tse
- Medical and Geriatric Department, Kwong Wah Hospital, Hong Kong Special Administrative Region
| | - Cee Zhung Steven Tseng
- Medical and Geriatric Department, Kwong Wah Hospital, Hong Kong Special Administrative Region
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