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Zhao D, Mou X, Li Y, Yao Y, Du L, Li Z, Wang P, Li X, Chen X, Li X, Li Y, Fang Z, Xia J. The application of impulse oscillometry system based on machine learning algorithm in the diagnosis of chronic obstructive pulmonary disease. Physiol Meas 2024; 45:055022. [PMID: 38599216 DOI: 10.1088/1361-6579/ad3d24] [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: 08/16/2023] [Accepted: 04/10/2024] [Indexed: 04/12/2024]
Abstract
Objective. Diagnosing chronic obstructive pulmonary disease (COPD) using impulse oscillometry (IOS) is challenging due to the high level of clinical expertise it demands from doctors, which limits the clinical application of IOS in screening. The primary aim of this study is to develop a COPD diagnostic model based on machine learning algorithms using IOS test results.Approach. Feature selection was conducted to identify the optimal subset of features from the original feature set, which significantly enhanced the classifier's performance. Additionally, secondary features area of reactance (AX) were derived from the original features based on clinical theory, further enhancing the performance of the classifier. The performance of the model was analyzed and validated using various classifiers and hyperparameter settings to identify the optimal classifier. We collected 528 clinical data examples from the China-Japan Friendship Hospital for training and validating the model.Main results. The proposed model achieved reasonably accurate diagnostic results in the clinical data (accuracy = 0.920, specificity = 0.941, precision = 0.875, recall = 0.875).Significance. The results of this study demonstrate that the proposed classifier model, feature selection method, and derived secondary feature AX provide significant auxiliary support in reducing the requirement for clinical experience in COPD diagnosis using IOS.
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Affiliation(s)
- Dongfang Zhao
- Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100094, People's Republic of China
- School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing 100094, People's Republic of China
| | - Xiuying Mou
- Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100094, People's Republic of China
- School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing 100094, People's Republic of China
| | - Yueqi Li
- Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100094, People's Republic of China
- School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing 100094, People's Republic of China
| | - Yicheng Yao
- Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100094, People's Republic of China
- School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing 100094, People's Republic of China
| | - Lidong Du
- Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100094, People's Republic of China
- School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing 100094, People's Republic of China
| | - Zhenfeng Li
- Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100094, People's Republic of China
| | - Peng Wang
- Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100094, People's Republic of China
| | - Xiaoran Li
- Beijing Friendship Hospital, Capital Medical University, Beijing, People's Republic of China
| | - Xianxiang Chen
- Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100094, People's Republic of China
- School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing 100094, People's Republic of China
| | - Xiaopan Li
- National Center for Respiratory Medicine, State Key Laboratory of Respiratory Health and Multimorbidity, National Clinical Research Center for Respiratory Diseases, Institute of Respiratory Medicine, Chinese Academy of Medical Sciences, Department of Pulmonary and Critical Care Medicine, Center of Respiratory Medicine, China-Japan Friendship Hospital, Beijing, People's Republic of China
| | - Yong Li
- National Center for Respiratory Medicine, State Key Laboratory of Respiratory Health and Multimorbidity, National Clinical Research Center for Respiratory Diseases, Institute of Respiratory Medicine, Chinese Academy of Medical Sciences, Department of Pulmonary and Critical Care Medicine, Center of Respiratory Medicine, China-Japan Friendship Hospital, Beijing, People's Republic of China
| | - Zhen Fang
- Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100094, People's Republic of China
- School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing 100094, People's Republic of China
- Research Unit of Personalized Management of Chronic Respiratory Disease, Chinese Academy of Medical Sciences, People's Republic of China
| | - Jingen Xia
- National Center for Respiratory Medicine, State Key Laboratory of Respiratory Health and Multimorbidity, National Clinical Research Center for Respiratory Diseases, Institute of Respiratory Medicine, Chinese Academy of Medical Sciences, Department of Pulmonary and Critical Care Medicine, Center of Respiratory Medicine, China-Japan Friendship Hospital, Beijing, People's Republic of China
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Liu CY, Wu JH, Chen ZY, Zhang Y, Huang CL, Lin AM, Xu XT, Gao XH. Effect of Doxofylline on Reducing the Inflammatory Response in Mechanically Ventilated Rats with Chronic Obstructive Pulmonary Disease. Int J Chron Obstruct Pulmon Dis 2021; 16:2375-2383. [PMID: 34429595 PMCID: PMC8378927 DOI: 10.2147/copd.s315639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 08/02/2021] [Indexed: 12/03/2022] Open
Abstract
Objective To evaluate the effect of doxofylline on reducing the inflammatory response in mechanically ventilated rats with chronic obstructive pulmonary disease (COPD). Methods A total of 40 eight-week-old male Sprague Dawley rats were randomly divided into four groups of 10 rats each: a control group (group C), a model group (group M), a model + natural saline group (group N), and a doxofylline group (group D). Then mechanical ventilation, drug intervention, and the extraction of the experimental material were performed in each group. Pulmonary tissue samples were taken after 120 minutes of mechanical ventilation and the pulmonary histopathological changes and the wet/dry (W/D) weight ratio of the pulmonary tissue were identified. The levels of tumor necrosis factor α (TNF-α) and interleukin 10 (IL-10) were detected using an enzyme-linked immunosorbent assay, and the expression levels of c-Jun-N-terminal kinase (JNK) and phosphorylated c-Jun N-terminal kinase (p-JNK) were detected using immunohistochemistry. Results Compared with group C, the pulmonary histopathology in groups M, N, and D showed typical changes associated with COPD. Furthermore, the W/D weight ratio and levels of TNF-α, JNK, and p-JNK in the pulmonary tissue increased in groups M, N, and D (P < 0.05), while the levels of IL-10 decreased (P < 0.05). Compared with group M, no statistically significant changes in the above indicators were detected in the pulmonary tissue of group N (P > 0.05). Compared with group N, the W/D weight ratio and levels of TNF-α, JNK, and p-JNK in the pulmonary tissue decreased in group D (P < 0.05), while the levels of IL-10 increased (P < 0.05). Conclusion Doxofylline might attenuate pulmonary inflammatory responses in mechanically ventilated rats with COPD, and the JNK/stress-activated protein kinase signaling pathway is involved in doxofylline’s inhibition of inflammatory responses in the pulmonary tissue of rats with COPD.
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Affiliation(s)
- Chu-Yun Liu
- Department of Anesthesiology, The Second Affiliated Hospital of Fujian Medical University, Quanzhou, 362000, People's Republic of China
| | - Jian-Hua Wu
- Department of Anesthesiology, The Second Affiliated Hospital of Fujian Medical University, Quanzhou, 362000, People's Republic of China
| | - Zhi-Yuan Chen
- Department of Anesthesiology, The Second Affiliated Hospital of Fujian Medical University, Quanzhou, 362000, People's Republic of China
| | - Yi Zhang
- Department of Anesthesiology, The Second Affiliated Hospital of Fujian Medical University, Quanzhou, 362000, People's Republic of China
| | - Chun-Ling Huang
- Department of Laboratory, The Second Affiliated Hospital of Fujian Medical University, Quanzhou, 362000, People's Republic of China
| | - Ai-Mei Lin
- Department of Anesthesiology, The Second Affiliated Hospital of Fujian Medical University, Quanzhou, 362000, People's Republic of China
| | - Xiao-Ting Xu
- Department of Anesthesiology, The Second Affiliated Hospital of Fujian Medical University, Quanzhou, 362000, People's Republic of China
| | - Xiao-Hua Gao
- Department of Anesthesiology, The Second Affiliated Hospital of Fujian Medical University, Quanzhou, 362000, People's Republic of China
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Sheen YH, Jee HM, Ha EK, Jang HM, Lee SJ, Lee S, Lee KS, Jung YH, Choi SH, Sohn MH, Han MY. Impulse oscillometry and spirometry exhibit different features of lung function in bronchodilation. J Asthma 2018; 55:1343-1351. [PMID: 29300537 DOI: 10.1080/02770903.2017.1418884] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
OBJECTIVE Bronchodilator responses (BDRs) from impulse oscillometry (IOS) are not interchangeable with those from spirometry. We aimed to identify the characteristics of children with small airway hyperresponsiveness and to determine whether BDR from IOS provides an important supplement to BDR from spirometry. METHODS The records of 592 children with asthma or suspected asthma who underwent spirometric and oscillometric BDRs were retrospectively reviewed. Oscillometric BDR was defined as positive when relative or absolute changes of Rrs5 or Xrs5 were beyond two standard deviations and spirometric BDR as positive when absolute change of forced expiratory volume in one second (FEV1) was ≥12%. Subjects were classified as positive for spirometric BDR only, positive for oscillometric BDR only, positive for both BDRs, or negative for both BDRs. RESULTS The results indicated that 101 (17.6%) subjects were positive for spirometric BDR only, 49 (8.5%) positive for oscillometric BDR only, 48 (8.3%) positive for both BDRs, and 377 (65.6%) negative for both BDRs. The agreement between spirometric and oscillometric BDRs was poor. Baseline FEV1, Rrs5, and Xrs5 values strongly influenced the BDRs. Subjects positive for oscillometric BDR only were found to be younger than those positive for spirometric BDR only (P < 0.001). Subjects positive for both BDRs were more likely to have asthma, atopic dermatitis, wheezing apart from cold, or decreased baseline lung function relative to those positive in either test (P < 0.001). CONCLUSIONS There was a low concordance between spirometric and oscillometric BDRs. Use of IOS to detect small airway hyperresponsiveness may add more information about a clinical profile of subjects with asthma.
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Affiliation(s)
- Youn Ho Sheen
- a Department of Pediatrics, CHA Gangnam Medical Center , CHA University , Seoul , South Korea
| | - Hye Mi Jee
- b Department of Pediatrics, CHA Bundang Medical Center , CHA University , Seongnam , South Korea.,c Department of Pediatrics, Graduate School , Yonsei University College of Medicine , Seoul , South Korea
| | - Eun Kyo Ha
- b Department of Pediatrics, CHA Bundang Medical Center , CHA University , Seongnam , South Korea
| | - Ho Min Jang
- b Department of Pediatrics, CHA Bundang Medical Center , CHA University , Seongnam , South Korea
| | - Seung Jin Lee
- b Department of Pediatrics, CHA Bundang Medical Center , CHA University , Seongnam , South Korea
| | - Shinhae Lee
- b Department of Pediatrics, CHA Bundang Medical Center , CHA University , Seongnam , South Korea
| | - Kyung Suk Lee
- b Department of Pediatrics, CHA Bundang Medical Center , CHA University , Seongnam , South Korea
| | - Young-Ho Jung
- b Department of Pediatrics, CHA Bundang Medical Center , CHA University , Seongnam , South Korea
| | - Sun Hee Choi
- d Department of Pediatrics , Kyung Hee University College of Medicine , Seoul , South Korea
| | - Myung Hyun Sohn
- e Department of Pediatrics , Yonsei University College of Medicine , Seoul , South Korea
| | - Man Yong Han
- b Department of Pediatrics, CHA Bundang Medical Center , CHA University , Seongnam , South Korea
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Molino A, Simioli F, Stanziola AA, Mormile M, Martino M, D'Amato M. Effects of combination therapy indacaterol/glycopyrronium versus tiotropium on moderate to severe COPD: evaluation of impulse oscillometry and exacerbation rate. Multidiscip Respir Med 2017; 12:25. [PMID: 28959443 PMCID: PMC5615797 DOI: 10.1186/s40248-017-0105-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Accepted: 08/31/2017] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Small airways are considered the major site of airflow limitation in COPD. Impulse oscillometry (IOS) is a forced oscillation technique, which provides passive measurement of lung mechanics. It can differentiate small airway from large airway obstruction and is more sensitive than spirometry for peripheral airway disease. In this study the efficacy of the combination of Indacaterol/Glycopirronium (IND/GLY) versus Tiotropium on airway resistance (R5, R20, R5-20), lung reactance (X) and resonant frequency in moderate to severe COPD patients has been evaluated. We also evaluated inspiratory capacity (IC), forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), exacerbation rate and quality of life. METHODS Forty patients were monitored with forced oscillation technique and spirometry. Patients were randomized in 2 groups: 20 received fixed dose once daily Indacaterol/Glycopyrronium (Group A) and 20 received single Tiotropium (Group B). The oscillometry parameters were the measure of resistance in the airways at 5 Hz (R5), at 20 Hz (R20) and the lung reactance (X). RESULTS There was a statistically significant difference between pre-dosing at V1 and at follow up visits in R5, R20 and X values in patients receiving dual bronchodilation but not in control group. Pre-dosing IC value at follow up visits in patients receiving dual bronchodilation had a statistical significant variation. CONCLUSIONS The "new" bronchodilator combination LABA/LAMA significantly reduces bronchial obstruction in small airways too. The oscillometry demonstrated greater sensitivity compared with spirometry for monitoring outcome measures of airway obstruction and the effect of long-term therapy.
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Affiliation(s)
- Antonio Molino
- Respiratory Department Federico II University- A.O. "Dei Colli", Via D Fontana, 134, 80128 Naples, Italy
| | - Francesca Simioli
- Respiratory Department Federico II University- A.O. "Dei Colli", Via D Fontana, 134, 80128 Naples, Italy
| | - Anna Agnese Stanziola
- Respiratory Department Federico II University- A.O. "Dei Colli", Via D Fontana, 134, 80128 Naples, Italy
| | - Mauro Mormile
- Respiratory Department Federico II University- A.O. "Dei Colli", Via D Fontana, 134, 80128 Naples, Italy
| | - Maria Martino
- Respiratory Department Federico II University- A.O. "Dei Colli", Via D Fontana, 134, 80128 Naples, Italy
| | - Maria D'Amato
- Respiratory Department Federico II University- A.O. "Dei Colli", Via D Fontana, 134, 80128 Naples, Italy
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Naji N, Keung E, Kane J, Watson RM, Killian KJ, Gauvreau GM. Comparison of changes in lung function measured by plethymography and IOS after bronchoprovocation. Respir Med 2013; 107:503-10. [PMID: 23352224 DOI: 10.1016/j.rmed.2012.12.022] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Revised: 12/19/2012] [Accepted: 12/31/2012] [Indexed: 10/27/2022]
Abstract
AIM Lung function tests are essential for the diagnosis and management of bronchial asthma. Impulse oscillation (IOS) system is an alternative way to measure lung mechanics for some patients. We investigated the relative sensitivities of IOS, body plethysmography and spirometry in detecting allergen- and methacholine-induced bronchoconstriction. METHOD Twenty-two subjects had single allergen inhalation and 8 subjects had 3 methacholine challenges. The tests were stopped when FEV1 fell by 20%. Lung function was measured using IOS (R5, R20, R5-R20, X5, AX, fres), plethysmography (sRaw, sGaw, FRC, lung volumes) and spirometry (FEV1, FVC, PEF, FEF50%) during inhalation challenges, and expressed as percent change from pre-challenge baseline. RESULTS All subjects were non-smoking adults with mild allergic asthma. Following allergen challenges, the most sensitive IOS index was R5-R20 and the most sensitive plethysmography and spirometry measurements were sRaw, sGaw and FEF50%. Following methacholine challenge the most sensitive IOS index was AX, the most sensitive plethysmography measurement was sRaw. Overall, IOS (R5-R20, AX, X5Hz) proved to be more sensitive than plethysmography and spirometry measurements following allergen-induced and methacholine-induced bronchoconstriction. CONCLUSION Our result shows that IOS is more sensitive than other lung function tests following allergen and methacholine challenge. In addition, IOS can act as an alternative measurement technique of airway resistance and obstruction in patients where manoeuvres involved in plethysmography and spirometry prove difficult to perform.
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Affiliation(s)
- Nizar Naji
- Cardiorespiratory Research Laboratory, Department of Medicine, McMaster University, 1200 Main St West, Hamilton, ON L8N 3Z5, Canada
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Nair A, Ward J, Lipworth BJ. Comparison of bronchodilator response in patients with asthma and healthy subjects using spirometry and oscillometry. Ann Allergy Asthma Immunol 2011; 107:317-22. [PMID: 21962091 DOI: 10.1016/j.anai.2011.07.011] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2011] [Revised: 07/14/2011] [Accepted: 07/20/2011] [Indexed: 11/28/2022]
Abstract
BACKGROUND Impulse oscillometry (IOS) is an effort-independent and patient-friendly pulmonary function technique, but limited data are available that correlate the bronchodilator response using spirometry and IOS in adult asthmatic and healthy subjects. OBJECTIVE To compare spirometry and IOS in ongoing bronchodilator response. METHODS The study was a prospective evaluation of patients with asthma and healthy subjects attending screening at a research unit in a university teaching hospital. Reversibility testing was carried out using standardized American Thoracic Society/European Respiratory Society (ATS/ERS) criteria after administering 400 μg salbutamol by AccuhalerTM. Impulse oscillometry measurements (resistance at 5 Hz [R5], resistance at 20 Hz [R20], reactance at 5 Hz [X5]) and spirometry (forced expiratory volume in 1 second [FEV(1)], forced vital capacity [FVC], forced expiratory flow from 25% to 75% of vital capacity [FEF(25-75)]) were recorded pre and postbronchodilator. RESULTS Ninety-five asthmatic and 61 healthy subjects underwent screening. Mean percent (standard error of the mean [SEM]) baseline prebronchodilator FEV(1) was 83.99 (2.23) for patients with asthma, and 99.25 (1.72) for healthy subjects. Baseline percent predicted IOS indices in the group with asthma were 162.22 (7.5) for R5; 154.73 (4.71) for R20; and 441.72 (173.86) for X5. In healthy volunteers, corresponding values were 111.01 (3.96), 127.75 (4.12), and -229.80 (125.75). R5 was the only IOS measure that showed correlation with spirometry (FEV(1)) in both groups. The mean percent (SEM) predicted postbronchodilator change in FEV(1) and R5 in patients with asthma was 6.35 (0.65) and -33.78 (4.43); correspondingly in healthy subjects it was 2.24 (0.32) and -14.91 (2.48). A negative correlation was demonstrated (r = -0.40, P < .001 between the 2 indices in patients with asthma. Linear regression modeling demonstrated that 1 unit change in %FEV(1) corresponds to a 2.5% change in %R5. CONCLUSIONS Low-frequency IOS as R5 and spirometry as FEV(1) correlate in patients with asthma and healthy subjects, with changes that can be predicted by linear regression.
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Affiliation(s)
- Arun Nair
- Asthma & Allergy Research Unit, Centre for Cardiovascular & Lung Biology, Ninewells Hospital & Medical School, University of Dundee, Scotland, UK
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Houghton CM, Woodcock AA, Singh D. A comparison of plethysmography, spirometry and oscillometry for assessing the pulmonary effects of inhaled ipratropium bromide in healthy subjects and patients with asthma. Br J Clin Pharmacol 2005; 59:152-9. [PMID: 15676036 PMCID: PMC1884751 DOI: 10.1111/j.1365-2125.2004.2262.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
AIMS We have compared the ability of plethysmography (sGaw), impulse oscillometry (IOS) and spirometry (FEV(1), MMEF) to detect bronchodilation in response to an anticholinergic. METHODS IOS (R5, R20, X5, RF), sGaw and spirometry were measured in 12 healthy subjects and 12 asthmatics. Variability was assessed by performing two measurements, 30 min apart and the effect of increasing the number of readings for each sGaw measurement was also studied. Ipratropium bromide (IB) 10, 20, 100 and 200 microg was administered and the sensitivity of the methods compared by determining the lowest dose that caused changes greater than variability. RESULTS In healthy subjects significant changes (P < or = 0.05) occurred at 10 microg for FEV(1) (mean [95% CI]; 1.3%[0.3-2.3]), R5 (mean [95% CI]; -7.9%, [-13.2-2.6]) and R20 (mean [95% CI], -6.4%, [-11.4-1.4]). No significant change was detected when the mean of 3 sGaw readings was used, but with 10 readings significant change was observed at 20 microg; (mean increase [95% CI] 15.2%[8.3-22.1]). In asthmatics significant changes (P < or = 0.05) occurred with IB 10 microg for sGaw (mean [95% CI] 25.6%[11.1-40.1]), R5 (mean [95% CI]-11.3%, [-15.5-7.2]), RF (mean [95% CI] 11.7%[6.1-16.3]), FEV(1) (mean [95% CI] 5.1%[2.6-7.7]) and MMEF (mean [95% CI] 12.3%[2.3-22.2]). CONCLUSION IOS and spirometry are more sensitive than sGaw in healthy subjects, but the sensitivity of sGaw improved when the number of readings was increased. The most sensitive method for assessing bronchodilation in asthmatics was sGaw.
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Affiliation(s)
- C M Houghton
- Medicines Evaluation Unit, North-west Lung Research Centre, Wythenshawe Hospital, Manchester, UK.
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Houghton CM, Woodcock AA, Singh D. A comparison of lung function methods for assessing dose-response effects of salbutamol. Br J Clin Pharmacol 2004; 58:134-41. [PMID: 15255795 PMCID: PMC1884595 DOI: 10.1111/j.1365-2125.2004.02105.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Pulmonary function methods which are able to detect small pharmacological effects may be useful for assessing the full dose-response curve of bronchodilatators. We compared the ability of impulse oscillometry (R5, R20, X5, RF), plethysmography (sGaw) and spirometry [forced expiratory volume in 1 s (FEV(1)), maximal mid expiratory flow rate (MMEF)] to measure the dose-response effects of salbutamol in 12 healthy subjects, 12 mild asthmatics (mean FEV(1) 96% predicted) and 12 moderate asthmatics (mean FEV(1) 63% predicted). The techniques were performed twice to assess variability. Then salbutamol 10, 20, 100, 200 and 800 microg was administered. The sensitivity of the methods were compared by determining the lowest dose that caused changes greater than variability. In healthy subjects significant changes (p < or = 0.05) were observed only in FEV(1) (4.1%) and MMEF (14.6%) at 100 microg and sGaw (25.6%) and R20 (8.3%) at 200 microg. In mild asthmatics significant changes were observed in sGaw (15.9%) at 10 microg, X5 (23%), RF (20.3%) and MMEF (15.7%) at 20 microg, R5 (13.9%) and R20 (9.4%) at 100 microg and FEV(1) (7.1%) at 200 microg. All measurements except R20 demonstrated significant changes at 10 micro g in moderate asthmatics. The most sensitive test for assessing bronchodilatation is different in healthy subjects and asthmatics, and varies with severity of airflow obstruction.
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Affiliation(s)
- Catherine M Houghton
- Medicines Evaluation Unit, North West Lung Research Centre, Wythenshawe Hospital, Manchester, UK.
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