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Miyamoto M, Yoshihara S, Shioya H, Tadaki H, Imamura T, Enseki M, Koike H, Furuya H, Mochizuki H. Lung sound analysis in infants with risk factors for asthma development. Health Sci Rep 2021; 4:e379. [PMID: 34557596 PMCID: PMC8448393 DOI: 10.1002/hsr2.379] [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: 04/12/2021] [Revised: 04/23/2021] [Accepted: 08/24/2021] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND AND OBJECTIVES Using a lung sound analysis, the prognosis of asthma was investigated in infants with risk factors for asthma development by a long-term observation. METHODS A total of 268 infants were included (median age: 8 months old). The lung sound parameters (the ratio of the third and fourth area to the total area under the curve [A3/AT and B4/AT], and the ratio of power and frequency at 50% and 75% of the highest frequency [RPF50 and RPF75]) were evaluated at the first visit. At 3 years old, using a questionnaire, we examined the relationship between the lung sound parameters and risk factors of asthma development. RESULTS Among the 268 infants, 175 infants were in good health and 93 had a history of acute respiratory infection (ARI) within 7 days at the first visit. Among the 3- to 12-month-old infants with an ARI, the A3/AT, B4/AT values in those with a history of asthma/asthmatic bronchitis, atopic dermatitis, and atopy were smaller than in the infants without such histories. Among the 13- to 24-month-old infants with an ARI, the A3/AT and B4/AT values in those with a wheezing history were larger than in the infants without such a history. CONCLUSIONS The characteristics of the lung sounds in infants with risk factors for asthma development were demonstrated over long-term follow-up. Lung sound analyses may be useful for assessing the airway condition of infants.
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Affiliation(s)
| | | | - Hiromi Shioya
- Division of PediatricsNational Hospital Organization Yokohama Medical CenterYokohamaJapan
| | - Hiromi Tadaki
- Division of PediatricsNational Hospital Organization Yokohama Medical CenterYokohamaJapan
| | - Tomohiko Imamura
- Department of PediatricsTokai University School of MedicineIseharaJapan
| | - Mayumi Enseki
- Department of PediatricsTokai University School of MedicineIseharaJapan
| | - Hideki Koike
- Department of PediatricsTokai University School of MedicineIseharaJapan
| | - Hiroyuki Furuya
- Department of Basic Clinical Science and Public HealthTokai University School of MedicineIseharaJapan
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Shimoda T, Obase Y, Nagasaka Y, Kishikawa R, Asai S. Lung Sound Analysis Provides A Useful Index For Both Airway Narrowing And Airway Inflammation In Patients With Bronchial Asthma. J Asthma Allergy 2019; 12:323-329. [PMID: 31632092 PMCID: PMC6781844 DOI: 10.2147/jaa.s216877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 09/18/2019] [Indexed: 11/23/2022] Open
Abstract
Background The expiration-to-inspiration sound power ratio in a midfrequency range (E/I MF), a parameter of lung sound analysis (LSA), has been reported to be useful as an index of airway inflammation in patients with bronchial asthma. However, the E/I MF reflects airway narrowing caused by airway inflammation, and there is thus concern that it may not be an index of airway eosinophilic inflammation itself. Methods A total of 131 patients with bronchial asthma were classified into four groups according to the presence or absence of airway narrowing and airway inflammation to examine whether the E/I MF could serve as an index of airway inflammation. Results The E/I MF was significantly higher in patients with a normal forced expiratory volume in one second (FEV1) and high fractional exhaled nitric oxide (FeNO), those with a low FEV1 and normal FeNO, and those with a low FEV1 and high FeNO than in those with a normal FEV1 and normal FeNO (p < 0.05–0.01). In particular, the E/I MF was high even in the patients who had no airway narrowing but had airway inflammation (p < 0.01). The results of multivariate analysis of factors involved in FeNO in patients with a normal FEV1 revealed that the E/I MF was an independent factor (p = 0.0281). Conclusion The E/I MF is a useful index of airway inflammation in the treatment of asthma, regardless of the presence or absence of airway narrowing.
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Affiliation(s)
- Terufumi Shimoda
- Department of Allergy, San Remo Rehabilitation Hospital, Sasebo, Japan.,Department of Allergy, Clinical Research Center, Fukuoka National Hospital, Fukuoka, Japan
| | - Yasushi Obase
- Department of Respiratory Medicine, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Yukio Nagasaka
- Department of Respiratory Medicine, Kyoto Respiratory Center, Otowa Hospital, Kyoto, Japan
| | - Reiko Kishikawa
- Department of Allergy, Clinical Research Center, Fukuoka National Hospital, Fukuoka, Japan
| | - Sadahiro Asai
- Department of Allergy, San Remo Rehabilitation Hospital, Sasebo, Japan
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Characteristics of breath sound in infants with risk factors for asthma development. Allergol Int 2019; 68:90-95. [PMID: 30213444 DOI: 10.1016/j.alit.2018.07.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2018] [Revised: 07/21/2018] [Accepted: 07/24/2018] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND Breath sound parameters have been suggested as biomarkers of the airway narrowing in children. Using a commercially available breath sound analyzer, the characteristics of the airway condition were investigated in infants with the risk factors for asthma development. METHODS A total of 443 infants (mean age, 9.9 months; range, 3-24 months) were included in the present study. The breath sound parameters of the frequency limiting 99% of the power spectrum (F99), the roll-off from 600 to 1200 Hz (Slope) and spectrum curve indices, the total area under the curve of the dBm data (A3/AT) and the ratio of power and frequency at 50% and 75% of the highest frequency of the power spectrum (RPF75 and RPF50), were evaluated. Using an ATS-DLD based original Japanese questionnaire, we examined the characteristics of airway condition of infants. RESULTS Finally, 283 infants in good health were included in the present study. The RPF75, RPF50, Slope and F99 in infants with positive results of allergy and atopic dermatitis were significantly increased more than those in the infants with negative result. CONCLUSIONS Our data highlight the characteristics of breath sounds in infants with risk factors for asthma. The breath sound analysis may be useful for assessing the airways of infants for asthma development.
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Nukaga M, Tabata H, Enseki M, Hirai K, Furuya H, Kato M, Mochizuki H. Changes in the breath sound spectrum with bronchodilation in children with asthma. Respir Investig 2018; 56:392-398. [PMID: 29909073 DOI: 10.1016/j.resinv.2018.05.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 04/04/2018] [Accepted: 05/18/2018] [Indexed: 10/14/2022]
Abstract
BACKGROUND Breath sound parameters have been suggested to be new biomarkers of airway function in patients with asthma. METHODS We investigated the effect of bronchodilation on breath sound parameters in sixty-four children (mean age, 8.9 years; range, 6-16 years) using a breath sound analyzer. The breath sound parameters included frequency limiting 50% and 99% of the power spectrum (F50 and F99), roll-off from 600-1200 Hz (slope), and spectrum curve indices such as the ratios of the third and fourth power area to the total area of the power spectrum (P3/PT and P4/PT), total area under the curve (A3/AT and B4/AT), and the ratio of power and frequency at 50% and 75% of the highest frequency of the power spectrum (RPF75 and RPF50). Lung function was assessed using spirometry and the forced oscillation technique (FOT). All variables were assessed before and after inhalation of a β2-agonist. RESULTS The spectrum curve indices, A3/AT, B4/AT, RPF75, and RPF50, showed statistically significant increase following β2-agonist inhalation. The increase in RPF50 was correlated with the decrease in the difference between resistance at 5 Hz and 20 Hz, R5-R20, measured by FOT. In the multiple regression analysis adjusted for the effect of ΔRPF75, the changes in A3/AT and B4/AT were positively correlated with that in the forced expiratory volume in one second. CONCLUSIONS The spectrum curve indices indicated bronchodilation, and may be useful for the assessment of bronchial reversibility in children with asthma.
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Affiliation(s)
- Mariko Nukaga
- Department of Pediatrics, Tokai University School of Medicine, Japan
| | - Hideyuki Tabata
- Department of Pediatrics, Tokai University School of Medicine, Japan
| | - Mayumi Enseki
- Department of Pediatrics, Tokai University School of Medicine, Japan
| | - Kota Hirai
- Department of Pediatrics, Tokai University School of Medicine, Japan
| | - Hiroyuki Furuya
- Department of Basic Clinical Science and Public Health, Tokai University School of Medicine, Japan
| | - Masahiko Kato
- Department of Pediatrics, Tokai University School of Medicine, Japan
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Pasterkamp H. The highs and lows of wheezing: A review of the most popular adventitious lung sound. Pediatr Pulmonol 2018; 53:243-254. [PMID: 29266880 DOI: 10.1002/ppul.23930] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Accepted: 11/26/2017] [Indexed: 12/22/2022]
Abstract
Wheezing is the most widely reported adventitious lung sound in the English language. It is recognized by health professionals as well as by lay people, although often with a different meaning. Wheezing is an indicator of airway obstruction and therefore of interest particularly for the assessment of young children and in other situations where objective documentation of lung function is not generally available. This review summarizes our current understanding of mechanisms producing wheeze, its subjective perception and description, its objective measurement, and visualization, and its relevance in clinical practice.
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Oliveira A, Lage S, Rodrigues J, Marques A. Reliability, validity and minimal detectable change of computerized respiratory sounds in patients with chronic obstructive pulmonary disease. CLINICAL RESPIRATORY JOURNAL 2017; 12:1838-1848. [PMID: 29148182 DOI: 10.1111/crj.12745] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Revised: 10/17/2017] [Accepted: 11/14/2017] [Indexed: 01/12/2023]
Abstract
INTRODUCTION Computerized respiratory sounds (CRS) are closely related to the movement of air within the tracheobronchial tree and are promising outcome measures in patients with chronic obstructive pulmonary disease (COPD). However, CRS measurement properties have been poorly tested. OBJECTIVE The aim of this study was to assess the reliability, validity and the minimal detectable changes (MDC) of CRS in patients with stable COPD. METHODS Fifty patients (36♂, 67.26 ± 9.31y, FEV1 49.52 ± 19.67%predicted) were enrolled. CRS were recorded simultaneously at seven anatomic locations (trachea; right and left anterior, lateral and posterior chest). The number of crackles, wheeze occupation rate, median frequency (F50) and maximum intensity (Imax) were processed using validated algorithms. Within-day and between-days reliability, criterion and construct validity, validity to predict exacerbations and MDC were established. RESULTS CRS presented moderate-to-excellent within-day reliability (ICC1,3 ≥ 0.51; P < .05) and moderate-to-good between-days reliability (ICC1,2 ≥ 0.47; P < .05) for most locations. Negligible-to-moderate correlations with FEV1 %predicted were found (-0.53 < rs < -0.28; P < .05), and the inspiratory number of crackles were the best discriminator between mild-to-moderate and severe-to-very severe airflow limitations (area under the curve >0.78). CRS correlated poorly with patient-reported outcomes (rs < 0.48; P < .05) and did not predict exacerbations. Inspiratory number of crackles at posterior right chest, inspiratory F50 at trachea and anterior left chest and expiratory Imax at anterior right chest were simultaneously reliable and valid, and their MDC were 2.41, 55.27, 29.55 and 3.98, respectively. CONCLUSION CRS are reliable and valid. Their use, integrated with other clinical and patient-reported measures, may fill the gap of assessing small airways and contribute toward a patient's comprehensive evaluation.
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Affiliation(s)
- Ana Oliveira
- Faculty of Sports, University of Porto, Porto, Portugal.,Lab 3R-Respiratory Research and Rehabilitation Laboratory, School of Health Sciences, University of Aveiro (ESSUA), Aveiro, Portugal.,Institute for Research in Biomedicine (iBiMED), University of Aveiro, Aveiro, Portugal
| | - Susan Lage
- Rehabilitation Sciences Program, School of Physical Education, Physiotherapy and Occupational Therapy (EEFFTO), Federal University of Minas Gerais (UFMG), Belo Horizonte, Minas Gerais, Brazil
| | - João Rodrigues
- Institute of Electronics and Informatics Engineering of Aveiro (IEETA), University of Aveiro, 3810-193 Aveiro, Portugal
| | - Alda Marques
- Lab 3R-Respiratory Research and Rehabilitation Laboratory, School of Health Sciences, University of Aveiro (ESSUA), Aveiro, Portugal.,Institute for Research in Biomedicine (iBiMED), University of Aveiro, Aveiro, Portugal
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Tabata H, Enseki M, Nukaga M, Hirai K, Matsuda S, Furuya H, Kato M, Mochizuki H. Changes in the breath sound spectrum during methacholine inhalation in children with asthma. Respirology 2017; 23:168-175. [PMID: 28960780 DOI: 10.1111/resp.13177] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 07/05/2017] [Accepted: 07/11/2017] [Indexed: 01/24/2023]
Abstract
BACKGROUND AND OBJECTIVE An effort-independent breath sound analysis is expected to be a safe and simple method for clinical assessment of changes in airway function. The effects of bronchoconstriction and bronchodilation on novel breath sound parameters in asthmatic children were investigated. METHODS The study population included 49 children with atopic asthma (male = 33; mean age: 10.2 years). We evaluated breath sound parameters of the highest frequency of the power spectrum (HFp), frequency limiting 50% and 99% of the power spectrum (F50 and F99 ) and roll-off from 600 Hz to the HFp (Slope). We also assessed new parameters obtained using the ratios of sound spectrum parameters (spectrum curve indices), such as the ratio of the third and fourth power area to the total power area (P3 /PT and P4 /PT ), the ratio of the third and fourth areas to the total area under the curve (A3 /AT and B4 /AT ) and the ratio of power and frequency at 75% of HFp and 50% of HFp (RPF75 and RPF50 ). This was measured before and after methacholine inhalation challenge and after β2 agonist inhalation. RESULTS The parameters, F50 and F99 , showed no changes after methacholine inhalation. Conversely, the A3 /AT (12.5-10.0%, P < 0.001), B4 /AT (7.6-5.5%, P < 0.001), RPF75 (6.7-4.0 dBm/Hz, P < 0.001) and RPF50 (5.8-4.3 dBm/Hz, P < 0.001) were significantly decreased. These values returned to the original level after β2 agonist inhalation. CONCLUSION Spectrum curve indices indicate bronchoconstriction and bronchodilation. These parameters may play a role in the assessment of airway narrowing in asthmatic children.
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Affiliation(s)
- Hideyuki Tabata
- Department of Pediatrics, Tokai University School of Medicine, Isehara, Japan
| | - Mayumi Enseki
- Department of Pediatrics, Tokai University School of Medicine, Isehara, Japan
| | - Mariko Nukaga
- Department of Pediatrics, Tokai University School of Medicine, Isehara, Japan
| | - Kota Hirai
- Department of Pediatrics, Tokai University School of Medicine, Isehara, Japan
| | - Shinichi Matsuda
- Department of Pediatrics, Tokai University School of Medicine, Isehara, Japan
| | - Hiroyuki Furuya
- Department of Basic Clinical Science and Public Health, Tokai University School of Medicine, Isehara, Japan
| | - Masahiko Kato
- Department of Pediatrics, Tokai University School of Medicine, Isehara, Japan
| | - Hiroyuki Mochizuki
- Department of Pediatrics, Tokai University School of Medicine, Isehara, Japan
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Shimoda T, Obase Y, Nagasaka Y, Nakano H, Ishimatsu A, Kishikawa R, Iwanaga T. Lung sound analysis helps localize airway inflammation in patients with bronchial asthma. J Asthma Allergy 2017; 10:99-108. [PMID: 28392708 PMCID: PMC5376185 DOI: 10.2147/jaa.s125938] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Purpose Airway inflammation can be detected by lung sound analysis (LSA) at a single point in the posterior lower lung field. We performed LSA at 7 points to examine whether the technique could identify the location of airway inflammation in patients with asthma. Patients and methods Breath sounds were recorded at 7 points on the body surface of 22 asthmatic subjects. Inspiration sound pressure level (ISPL), expiration sound pressure level (ESPL), and the expiration-to-inspiration sound pressure ratio (E/I) were calculated in 6 frequency bands. The data were analyzed for potential correlation with spirometry, airway hyperresponsiveness (PC20), and fractional exhaled nitric oxide (FeNO). Results The E/I data in the frequency range of 100–400 Hz (E/I low frequency [LF], E/I mid frequency [MF]) were better correlated with the spirometry, PC20, and FeNO values than were the ISPL or ESPL data. The left anterior chest and left posterior lower recording positions were associated with the best correlations (forced expiratory volume in 1 second/forced vital capacity: r=−0.55 and r=−0.58; logPC20: r=−0.46 and r=−0.45; and FeNO: r=0.42 and r=0.46, respectively). The majority of asthmatic subjects with FeNO ≥70 ppb exhibited high E/I MF levels in all lung fields (excluding the trachea) and V50%pred <80%, suggesting inflammation throughout the airway. Asthmatic subjects with FeNO <70 ppb showed high or low E/I MF levels depending on the recording position, indicating uneven airway inflammation. Conclusion E/I LF and E/I MF are more useful LSA parameters for evaluating airway inflammation in bronchial asthma; 7-point lung sound recordings could be used to identify sites of local airway inflammation.
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Affiliation(s)
| | - Yasushi Obase
- Second Department of Internal Medicine, School of Medicine, Nagasaki University, Nagasaki
| | | | - Hiroshi Nakano
- Clinical Research Center, Fukuoka National Hospital, Fukuoka
| | - Akiko Ishimatsu
- Clinical Research Center, Fukuoka National Hospital, Fukuoka
| | - Reiko Kishikawa
- Clinical Research Center, Fukuoka National Hospital, Fukuoka
| | - Tomoaki Iwanaga
- Clinical Research Center, Fukuoka National Hospital, Fukuoka
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Li SH, Lin BS, Tsai CH, Yang CT, Lin BS. Design of Wearable Breathing Sound Monitoring System for Real-Time Wheeze Detection. SENSORS 2017; 17:s17010171. [PMID: 28106747 PMCID: PMC5298744 DOI: 10.3390/s17010171] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/13/2016] [Revised: 12/27/2016] [Accepted: 01/13/2017] [Indexed: 11/16/2022]
Abstract
In the clinic, the wheezing sound is usually considered as an indicator symptom to reflect the degree of airway obstruction. The auscultation approach is the most common way to diagnose wheezing sounds, but it subjectively depends on the experience of the physician. Several previous studies attempted to extract the features of breathing sounds to detect wheezing sounds automatically. However, there is still a lack of suitable monitoring systems for real-time wheeze detection in daily life. In this study, a wearable and wireless breathing sound monitoring system for real-time wheeze detection was proposed. Moreover, a breathing sounds analysis algorithm was designed to continuously extract and analyze the features of breathing sounds to provide the objectively quantitative information of breathing sounds to professional physicians. Here, normalized spectral integration (NSI) was also designed and applied in wheeze detection. The proposed algorithm required only short-term data of breathing sounds and lower computational complexity to perform real-time wheeze detection, and is suitable to be implemented in a commercial portable device, which contains relatively low computing power and memory. From the experimental results, the proposed system could provide good performance on wheeze detection exactly and might be a useful assisting tool for analysis of breathing sounds in clinical diagnosis.
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Affiliation(s)
- Shih-Hong Li
- Department of Thoracic Medicine, Chang Gung Memorial Hospital at Linkou, Taoyuan 33305, Taiwan.
- Department of Respiratory Therapy, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan.
| | - Bor-Shing Lin
- Department of Computer Science and Information Engineering, National Taipei University, New Taipei City 23741, Taiwan.
| | - Chen-Han Tsai
- Institute of Imaging and Biomedical Photonics, National Chiao Tung University, Tainan 71150, Taiwan.
| | - Cheng-Ta Yang
- Department of Thoracic Medicine, Chang Gung Memorial Hospital at Taoyuan, Taoyuan 33378, Taiwan.
- Department of Respiratory Therapy, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan.
| | - Bor-Shyh Lin
- Institute of Imaging and Biomedical Photonics, National Chiao Tung University, Tainan 71150, Taiwan.
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Enseki M, Nukaga M, Tabata H, Hirai K, Matsuda S, Mochizuki H. A clinical method for detecting bronchial reversibility using a breath sound spectrum analysis in infants. Respir Investig 2017; 55:219-228. [PMID: 28427749 DOI: 10.1016/j.resinv.2016.11.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 11/02/2016] [Accepted: 11/18/2016] [Indexed: 12/18/2022]
Abstract
BACKGROUND Using a breath sound analyzer, we investigated clinical parameters for detecting bronchial reversibility in infants. METHODS A total of 59 infants (4-39 months, mean age 7.8 months) were included. In Study 1, the intra- and inter-observer variability was measured in 23 of 59 infants. Breath sound parameters, the frequency at 99% of the maximum frequency (F99), frequency at 25%, 50%, and 75% of the power spectrum (Q25, Q50, and Q75), and highest frequency of inspiratory breath sounds (HFI), and parameters obtained using the ratio of parameters, i.e. spectrum curve indices, the ratio of the third and fourth area to total area (A3/AT and B4/AT, respectively) and ratio of power and frequency at F75 and F50 (RPF75 and RPF50), were calculated. In Study 2, the relationship between parameters of breath sounds and age and stature were studied. In Study 3, breath sounds were studied before and after β2 agonist inhalation. RESULTS In Study 1, the data showed statistical intra- and inter-observer reliability in A3/AT (p=0.042 and 0.034, respectively) and RPF50 (p=0.001 and 0.001, respectively). In Study 2, there were no significant relationships between age, height, weight, and BMI. In Study 3, A3/AT and RPF50 significantly changed after β2 agonist inhalation (p=0.001 and p<0.001, respectively). CONCLUSIONS Breath sound analysis can be performed in infants, as in older children, and the spectrum curve indices are not significantly affected by age-related factors. These sound parameters may play a role in the assessment of bronchial reversibility in infants.
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Affiliation(s)
- Mayumi Enseki
- Department of Pediatrics, Tokai University School of Medicine, Shimokasuya 143, Isehara, Kanagawa 259-1193, Japan.
| | - Mariko Nukaga
- Department of Pediatrics, Tokai University School of Medicine, Shimokasuya 143, Isehara, Kanagawa 259-1193, Japan.
| | - Hideyuki Tabata
- Department of Pediatrics, Tokai University School of Medicine, Shimokasuya 143, Isehara, Kanagawa 259-1193, Japan.
| | - Kota Hirai
- Department of Pediatrics, Tokai University School of Medicine, Shimokasuya 143, Isehara, Kanagawa 259-1193, Japan.
| | - Shinichi Matsuda
- Department of Pediatrics, Tokai University School of Medicine, Shimokasuya 143, Isehara, Kanagawa 259-1193, Japan.
| | - Hiroyuki Mochizuki
- Department of Pediatrics, Tokai University School of Medicine, Shimokasuya 143, Isehara, Kanagawa 259-1193, Japan.
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Tabata H, Hirayama M, Enseki M, Nukaga M, Hirai K, Furuya H, Mochizuki H. A novel method for detecting airway narrowing using breath sound spectrum analysis in children. Respir Investig 2015; 54:20-8. [PMID: 26718141 DOI: 10.1016/j.resinv.2015.07.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Revised: 07/22/2015] [Accepted: 07/24/2015] [Indexed: 10/23/2022]
Abstract
BACKGROUND Using a breath sound analyzer, we investigated new clinical parameters that are rarely affected by airflow in young children. METHODS A total of 65 children with asthma participated in this study (mean age 9.6 years). In Study 1, the intra- and inter-observer variability was measured. Common breath sound parameters, frequency at 99%, 75%, and 50% of the maximum frequency (F99, F75, and F50) and the highest frequency of inspiratory breath sounds were calculated. In addition, new parameters obtained using the ratio of sound spectra parameters, i.e., the spectrum curve indexes including the ratio of the third and fourth area to the total area and the ratio of power and frequency at F75 and F50, were calculated. In Study 2, 51 children underwent breath sound analyses. In Study 3, breath sounds were studied before and after methacholine inhalation. RESULTS In Study 1, the data showed good inter- and intra-observer reliability. In Study 2, there were significant relationships between the airflow rate, age, height, and spirometric and common breath sound parameters. However, there were no significant relationships between the airflow rate and the spectrum curve indexes. Moreover, the spectrum curve indexes showed no relationships with age, height, or spirometric parameters. In Study 3, all parameters significantly changed after methacholine inhalation. CONCLUSIONS Some spectrum curve indexes are not significantly affected by the airflow rate at the mouth, although they successfully indicate airway narrowing. These parameters may play a role in the assessment of bronchoconstriction in children.
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Affiliation(s)
- Hideyuki Tabata
- Department of Pediatrics, Tokai University School of Medicine, Shimokasuya 143, Isehara, Kanagawa 259-1193, Japan.
| | - Mariko Hirayama
- Department of Pediatrics, Tokai University School of Medicine, Shimokasuya 143, Isehara, Kanagawa 259-1193, Japan.
| | - Mayumi Enseki
- Department of Pediatrics, Tokai University School of Medicine, Shimokasuya 143, Isehara, Kanagawa 259-1193, Japan.
| | - Mariko Nukaga
- Department of Pediatrics, Tokai University School of Medicine, Shimokasuya 143, Isehara, Kanagawa 259-1193, Japan.
| | - Kota Hirai
- Department of Pediatrics, Tokai University School of Medicine, Shimokasuya 143, Isehara, Kanagawa 259-1193, Japan.
| | - Hiroyuki Furuya
- Department of Basic Clinical Science and Public Health, Tokai University School of Medicine, Shimokasuya 143, Isehara, Kanagawa 259-1193, Japan.
| | - Hiroyuki Mochizuki
- Department of Pediatrics, Tokai University School of Medicine, Shimokasuya 143, Isehara, Kanagawa 259-1193, Japan.
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Data reduction for cough studies using distribution of audio frequency content. COUGH 2012; 8:12. [PMID: 23231789 PMCID: PMC3546839 DOI: 10.1186/1745-9974-8-12] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Accepted: 10/29/2012] [Indexed: 11/10/2022]
Abstract
Background Recent studies suggest that objectively quantifying coughing in audio recordings offers a novel means to understand coughing and assess treatments. Currently, manual cough counting is the most accurate method for quantifying coughing. However, the demand of manually counting cough records is substantial, demonstrating a need to reduce record lengths prior to counting whilst preserving the coughs within them. This study tested the performance of an algorithm developed for this purpose. Methods 20 subjects were recruited (5 healthy smokers and non-smokers, 5 chronic cough, 5 chronic obstructive pulmonary disease and 5 asthma), fitted with an ambulatory recording system and recorded for 24 hours. The recordings produced were divided into 15 min segments and counted. Periods of inactive audio in each segment were removed using the median frequency and power of the audio signal and the resulting files re-counted. Results The median resultant segment length was 13.9 s (IQR 56.4 s) and median 24 hr recording length 62.4 min (IQR 100.4). A median of 0.0 coughs/h (IQR 0.0-0.2) were erroneously removed and the variability in the resultant cough counts was comparable to that between manual cough counts. The largest error was seen in asthmatic patients, but still only 1.0% coughs/h were missed. Conclusions These data show that a system which measures signal activity using the median audio frequency can substantially reduce record lengths without significantly compromising the coughs contained within them.
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14
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Abstract
Modern understanding of lung sounds started with a historical article by Forgacs. Since then, many studies have clarified the changes of lung sounds due to airway narrowing as well as the mechanism of genesis for these sounds. Studies using bronchoprovocation have shown that an increase of the frequency and/or intensity of lung sounds was a common finding of airway narrowing and correlated well with lung function. Bronchoprovocation studies have also disclosed that wheezing may not be as sensitive as changes in basic lung sounds in acute airway narrowing. A forced expiratory wheeze (FEW) may be an early sign of airway obstruction in patients with bronchial asthma. Studies of FEW showed that airway wall oscillation and vortex shedding in central airways are the most likely mechanisms of the generation of expiratory wheezes. Studies on the genesis of wheezes have disclosed that inspiratory and expiratory wheezes may have the same mechanism of generation as a flutter/flow limitation mechanism, either localized or generalized. In lung sound analysis, the narrower the airways are, the higher the frequency of breathing sounds is, and, if a patient has higher than normal breathing sounds, i.e., bronchial sounds, he or she may have airway narrowing or airway inflammation. It is sometimes difficult to detect subtle changes in lung sounds; therefore, we anticipate that automated analysis of lung sounds will be used to overcome these difficulties in the near future.
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Affiliation(s)
- Yukio Nagasaka
- Department of Medicine, Kinki University Sakai Hospital, Osaka, Japan.
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15
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Dellinger RP, Parrillo JE, Kushnir A, Rossi M, Kushnir I. Dynamic visualization of lung sounds with a vibration response device: a case series. Respiration 2007; 75:60-72. [PMID: 17551264 DOI: 10.1159/000103558] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2006] [Accepted: 03/06/2007] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The field of computer-assisted mapping of lung sounds is constantly evolving and several devices have been developed in this field. OBJECTIVES Our objective was to evaluate a new computer-assisted lung sound imaging system, 'vibration response imaging' (VRI), that records and creates a dynamic image of breath sounds. We postulated that the VRI display format would qualitatively and quantitatively reveal breath sound distribution throughout the breathing cycle. METHODS Lung sounds were recorded from 5 healthy adults and 14 patients with various respiratory illnesses using VRI. The lung sounds were processed by the VRI software, which incorporates an algorithm to convert breath sounds in the frequency range of 150-250 Hz to a dynamic image and quantitative assessment of breath sound distribution. RESULTS Images and quantifications from recordings of the healthy adults showed distinct patterns for inspiration and expiration. Images and quantifications from the subjects with respiratory illness differed substantially from the images of the healthy subjects. Both healthy and pathological subjects presented some expected characteristics of breath sound distribution. CONCLUSIONS The VRI device may provide a new perspective in acoustic imaging and quantification of breath sounds by adding aspects of time analysis and quantification of distribution to existing methods. Further studies will be required in order to establish reliability of repeated recordings and to validate the sensitivity of the system in detecting various lung pathologies.
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Affiliation(s)
- R Phillip Dellinger
- Division of Cardiovascular Disease and Critical Care Medicine, UMDNJ - Robert Wood Johnson Medical School at Camden, Cooper University Hospital, Camden, NJ, USA
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16
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Güler I, Polat H, Ergün U. Combining neural network and genetic algorithm for prediction of lung sounds. J Med Syst 2005; 29:217-31. [PMID: 16050077 DOI: 10.1007/s10916-005-5182-9] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Recognition of lung sounds is an important goal in pulmonary medicine. In this work, we present a study for neural networks-genetic algorithm approach intended to aid in lung sound classification. Lung sound was captured from the chest wall of The subjects with different pulmonary diseases and also from the healthy subjects. Sound intervals with duration of 15-20 s were sampled from subjects. From each interval, full breath cycles were selected. Of each selected breath cycle, a 256-point Fourier Power Spectrum Density (PSD) was calculated. Total of 129 data values calculated by the spectral analysis are selected by genetic algorithm and applied to neural network. Multilayer perceptron (MLP) neural network employing backpropagation training algorithm was used to predict the presence or absence of adventitious sounds (wheeze and crackle). We used genetic algorithms to search for optimal structure and training parameters of neural network for a better predicting of lung sounds. This application resulted in designing of optimum network structure and, hence reducing the processing load and time.
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Affiliation(s)
- Inan Güler
- Department of Electronic and Computer Education, Faculty of Technical Education, Gazi University, 06500 Teknikokullar, Ankara, Turkey.
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17
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Sánchez I, Vizcaya C, García D, Campos E. Response to bronchodilator in infants with bronchiolitis can be predicted from wheeze characteristics. Respirology 2005; 10:603-8. [PMID: 16268913 DOI: 10.1111/j.1440-1843.2005.00756.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVE Lung sounds analysis has been used for clinical care. Our objectives were to characterize the spectral pattern of lung sounds and their relation to bronchodilator effects in acute bronchiolitis (AB). We hypothesized that patients with sinusoidal wheezes (SW) would show a more significant bronchodilator response. METHODOLOGY We studied 22 asleep hospitalized infants (14 boys, eight girls), aged 5.2 +/- 1 months, 16 with a positive respiratory syncytial virus test, during their first 3 days after admission. Patients breathed spontaneously through a face mask connected to a pneumotachograph during normal breathing, and only target flows of 0.1 +/- 0.02 L/s were analyzed. Sounds were obtained using two contact sensors attached over both posterior lower lobes. For inspiratory and expiratory sounds, we determined the frequencies below which 25% (F25), 50% (F50), 75% (F75) and 99% (SEF99) of the spectral power between 100 and 1000 Hz was contained. We repeated the measurements 20 min after bronchodilator therapy in all patients. RESULTS We found classic SW in 11 patients, while the other 11 had complex wheezes (CW). There were positive bronchodilator responses in 9/11 with SW and 3/11 with CW (P < 0.01). Patients who responded to salbutamol showed an increase in power at low frequencies after medication (P < 0.01), and a positive correlation between wheezing and the increase in the power spectra measured by F50 and SEF99 (P < 0.001). CONCLUSIONS We conclude that sinusoidal and complex wheezes occur in patients with AB, that a positive response to bronchodilator is significantly more common in those with classic SW and that lung sounds analysis is a reproducible, safe and non-invasive method for assessing wheeze in infants.
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Affiliation(s)
- Ignacio Sánchez
- Section of Pediatric Respirology, Department of Pediatrics, Catholic University of Chile, Santiago, Chile.
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18
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Leuppi JD, Dieterle T, Wildeisen I, Martina B, Tamm M, Koch G, Perruchoud AP, Leimenstoll BM. Can airway obstruction be estimated by lung auscultation in an emergency room setting? Respir Med 2005; 100:279-85. [PMID: 15964751 DOI: 10.1016/j.rmed.2005.05.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2004] [Accepted: 05/01/2005] [Indexed: 11/12/2022]
Abstract
OBJECTIVE Lung auscultation is a central part of the physical examination at hospital admission. In this study, the physicians' estimation of airway obstruction by auscultation was determined and compared with the degree of airway obstruction as measured by FEV(1)/FVC values. METHODS Two hundred and thirty-three patients consecutively admitted to the medical emergency room with chest problems were included. After taking their history, patients were auscultated by an Internal Medicine registrar. The degree of airway obstruction had to be estimated (0=no, 1=mild, 2=moderate and 3=severe obstructed) and then spirometry was performed. Airway obstruction was defined as a ratio of FEV(1)/FVC <70%. The degree of airway obstruction was defined on FEV(1)/FVC as mild (FEV(1)/FVC <70% and >50%), moderate (FEV(1)/FVC <50% >30%) and severe (FEV(1)/FVC <30%). RESULTS One hundred and thirty-five patients (57.9%) had no sign of airway obstruction (FEV(1)/FVC >70%). Spirometry showed a mild obstruction in 51 patients (21.9%), a moderate obstruction in 27 patients (11.6%) and a severe obstruction in 20 patients (8.6%). There was a weak but significant correlation between FEV(1)/FVC and the auscultation-based estimation of airway obstruction in Internal Medicine Registrars (Spearman's rho=0.328; P<0.001). The sensitivity to detect airway obstruction by lung auscultation was 72.6% and the specificity only 46.3%. Thus, the negative predictive value was 68% and the positive predictive value 51%. In 27 patients (9.7%), airway obstruction was missed by lung auscultation. In these 27 cases, the severity of airway obstruction was mild in 20 patients, moderate in 5 patients and severe in 2 patients. In 82 patients (29.4%) with no sign of airway obstruction (FEV(1)/FVC >70%), airway obstruction was wrongly estimated as mild in 42 patients, as moderate in 34 patients and as severe in 6 patients, respectively. By performing multiple logistic regression, normal lung auscultation was a significant and independent predictor for not having an airway obstruction (OR 2.48 (1.43-4.28); P=0.001). CONCLUSION Under emergency room conditions, physicians can quite accurately exclude airway obstruction by auscultation. Normal lung auscultation is an independent predictor for not having an airway obstruction. However, airway obstruction is often overestimated by auscultation; thus, spirometry should be performed.
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Affiliation(s)
- Jörg D Leuppi
- Pneumology, Department of Internal Medicine, University Hospital Basel, Switzerland.
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19
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Abstract
The sounds generated by breathing in asthma are widely accepted as an indicator of disease activity. We have investigated the use of a mobile phone and electronic signal transfer by e-mail and voice mail to study tracheal breath sounds in individuals with normal lung function and patients with chronic or exercise-induced asthma. Spectrograms from patients with active asthma and impaired lung function were significantly different from people without asthma (p<0.0001). Our results suggest that mobile phone recordings clearly discriminate tracheal breath sounds in asthma and could be a non-invasive method of monitoring airway diseases.
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20
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Jones AY, Jones RD, Kwong K, Burns Y. The influence of "sputum-like gel" viscosity on crackle characteristics in a mechanically ventilated porcine lung model. Anaesth Intensive Care 2000; 28:669-75. [PMID: 11153295 DOI: 10.1177/0310057x0002800611] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
This study investigated the influence of airway secretion viscosity on the characteristics of crackle sounds produced using a mechanically ventilated porcine lung model. Aqueous ultrasonic methylene blue stained gel solutions of viscosity 100, 150 and 200 P were prepared and instilled into 15 isolated, mechanically ventilated, porcine lungs immersed in water. Sound signals recorded by a hydrophone before and after instillation of gel were subjected to both fast Fourier transform and wave-form analysis. At the completion of sound recording, the main bronchi were dissected and the location of the stained gel was photographically recorded. Wave-form analysis demonstrated that expiratory phase crackle incidence and amplitude were both significantly higher than inspiratory phase data. This study demonstrates that crackle duration and amplitude are inversely related to gel viscosity and that electronic lung sound analysis can provide indirect evidence of sputum viscosity.
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Affiliation(s)
- A Y Jones
- Department of Rehabilitation Sciences, Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
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21
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Oud M, Dooijes EH, van der Zee JS. Asthmatic airways obstruction assessment based on detailed analysis of respiratory sound spectra. IEEE Trans Biomed Eng 2000; 47:1450-5. [PMID: 11077738 DOI: 10.1109/10.880096] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
This paper concerns the analysis of adventitious sounds produced by individual asthmatic patients, and relates the sounds to the degree of airways obstruction at the moment of sound recording. In this study, airways obstruction is represented by a parameter commonly used in clinical tests, the forced expiratory volume in one second. A nonrestrictive approach using spectral information in detail is followed, resulting in a fairly high resolution of respiration sounds with respect to airways obstruction. The beneficial effect of a power raising transformation is presented, together with an illumination of the background of this effect.
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Affiliation(s)
- M Oud
- Department of Computer Science, Universiteit van Amsterdam, The Netherlands.
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22
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Whittaker AR, Lucas M, Carter R, Anderson K. Limitations in the use of median frequency for lung sound analysis. Proc Inst Mech Eng H 2000; 214:265-75. [PMID: 10902441 DOI: 10.1243/0954411001535769] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The aim of this paper is to investigate methods of standardizing lung sound analysis, with a view to supplementing traditional spirometric air flow measurements to help in the diagnosis of asthma and to provide a measure of the effectiveness of treatment. Lung sounds were measured in nine patients with asthma and five control subjects, alongside air flow measurements of forced expiratory volume (FEV1) and forced vital capacity (FVC). The patients were administered the bronchodilator, salbutamol, to assess how effective these measurement techniques were for quantifying its effect. The results agree with previous studies, that analysis of lung sounds is a potentially useful tool for indicating air flow changes. The results, however, also demonstrate that the emerging standard of 'F50' or 'median frequency' should be treated with great caution because of its high sensitivity to the measurement frequency range. F50 is very unlikely to provide a reliable single indicator of lung condition.
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Affiliation(s)
- A R Whittaker
- Department of Mechanical Engineering, University of Glasgow, Scotland, UK
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23
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Manecke GR, Dilger JP, Kutner LJ, Poppers PJ. Auscultation revisited: the waveform and spectral characteristics of breath sounds during general anesthesia. INTERNATIONAL JOURNAL OF CLINICAL MONITORING AND COMPUTING 1997; 14:231-40. [PMID: 9451573 DOI: 10.1007/bf03356568] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Although auscultation is commonly used as a continuous monitoring tool during anesthesia, the breath sounds of anesthetized patients have never been systematically studied. In this investigation we used digital audio technology to record and analyze the breath sounds of 14 healthy adult patients receiving general anesthesia with positive pressure ventilation. Sounds recorded from inside the esophagus were compared to those recorded from the surface of the chest, and corresponding airflow was measured with a pneumotachograph. The sound samples associated with inspiratory and expiratory phases were analyzed in the time domain (RMS amplitude) and frequency domain (peak frequency, spectral edge, and power ratios). There was a positive linear correlation (R2 > 0.9) between inspiratory flow and sound amplitude in the precordial and esophageal samples of all patients. The RMS amplitude of the inspiratory and expiratory sounds was approximately 13 times greater when recorded from inside the esophagus than from the surface of the chest in all patients at all flows (p < 0.001). The peak frequency (Hz) was significantly higher in the esophageal recordings than the precordial samples (298 +/- 9 vs 181 +/- 10, P < 0.0001), as was the 97% spectral edge (Hz) (740 +/- 7 vs 348 +/- 16, P < 0.0001). In the adult population esophageal stethoscopes yield higher frequencies and greater amplitude than precordial stethoscopes. Quantification of lung sounds may provide for improved monitoring and diagnostic capability during anesthesia and surgery.
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Affiliation(s)
- G R Manecke
- Department of Anesthesiology, University Medical Center, State University of New York at Stony Brook, N.Y. 11794, USA
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24
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Pasterkamp H, Kraman SS, Wodicka GR. Respiratory sounds. Advances beyond the stethoscope. Am J Respir Crit Care Med 1997; 156:974-87. [PMID: 9310022 DOI: 10.1164/ajrccm.156.3.9701115] [Citation(s) in RCA: 281] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Affiliation(s)
- H Pasterkamp
- Department of Pediatrics and Child Health, University of Manitoba, Winnipeg, Canada
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25
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Abstract
Wheeze as an indicator of airway obstruction during bronchoprovocation lacks sensitivity. We therefore studied whether induced airway narrowing is revealed by changes in normal (vesicular) lung sounds. Fifteen subjects with asthma and nine healthy controls, aged 8-16 years, performed a standardized methacholine challenge. Respiratory sounds were recorded with eight contact sensors, placed posteriorly over the right and left superior and basal lower lobes, and anteriorly over both upper lobes, the right middle lobe, and the trachea. Average spectra of normal inspiratory and expiratory sounds, excluding wheeze, were characterized in 12 asthmatics and 9 controls at flows of 1 +/- 0.2 L/sec. Airway narrowing was accompanied by significant changes in lung sounds, but not in tracheal sounds. Lung sounds showed a decrease in power at low frequencies during inspiration and an increase in power at high frequencies during expiration. These changes already occurred at a decrease in forced expiratory volume in 1 sec of less than 10% from baseline and were fully reversed after inhalation of salbutamol. Thus, lung sounds were sensitive to changes in airway caliber, but were not specific indicators of bronchial hyperresponsiveness.
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Affiliation(s)
- H Pasterkamp
- Department of Pediatrics and Child Health, University of Manitoba, Winnipeg, Canada
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26
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Sovijärvi AR, Malmberg LP, Paajanen E, Piirilä P, Kallio K, Katila T. Averaged and time-gated spectral analysis of respiratory sounds. Repeatability of spectral parameters in healthy men and in patients with fibrosing alveolitis. Chest 1996; 109:1283-90. [PMID: 8625681 DOI: 10.1378/chest.109.5.1283] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
STUDY OBJECTIVE To obtain a basis for assessment of changes in breath sound spectra in patients with pulmonary diseases, short-term and day-to-day repeatability of spectral parameters was studied. DESIGN Breath sounds were recorded simultaneously from the trachea and from the chest twice at an interval of 15 min (short-term repeatability) and of 1 to 3 days (day-to-day repeatability). During recordings, air flow at the mouth was controlled, the target inspiratory and expiratory peak flow being 1.25 L/s. Inspiratory and expiratory breath sound spectra were averaged over 7 to 10 successive respiratory cycles. The repeatability of sound intensity (RMS), frequency of maximum intensity (Fmax), and median frequency (F50) was analyzed with analysis of variance. PARTICIPANTS Short-term repeatability was studied in 10 healthy nonsmoking men (age 25 to 44 years), and day-to-day repeatability was studied in 10 healthy nonsmoking men (age 23 to 41 years) and in 12 patients with clinically stable fibrosing alveolitis (age 35 to 82 years). RESULTS Short-term coefficient of variation (CoV) of Fmax and F50 was 2.6 to 6.7% when recorded from the chest, and 6.2 to 8.7% when recorded from the trachea. Day-to-day CoV of Fmax and F50 in healthy subjects was 4.7 to 8.5% and 5.0 to 8.7% recorded from the chest or from the trachea, respectively. Inspiratory day-to-day variation in those parameters was higher in patients with fibrosing alveolitis. CoV of RMS was high, ranging from 18 to 47% in different subject groups and sampling situations. CONCLUSIONS Repeatability of F50 of averaged flow-controlled lung sound spectra is good both in healthy subjects and in patients with fibrosing alveolitis. Thus, F50 of respiratory sound spectra may be useful in monitoring of changes induced by respiratory diseases and interventions. These results emphasize the importance of standardization of recording conditions and of analyzing techniques.
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Affiliation(s)
- A R Sovijärvi
- Department of Medicine, Helsinki University Central Hospital, Finland
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27
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Malmberg LP, Kallio K, Haltsonen S, Katila T, Sovijärvi AR. Classification of lung sounds in patients with asthma, emphysema, fibrosing alveolitis and healthy lungs by using self-organizing maps. CLINICAL PHYSIOLOGY (OXFORD, ENGLAND) 1996; 16:115-29. [PMID: 8964130 DOI: 10.1111/j.1475-097x.1996.tb00562.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The performance of the self-organizing map (SOM), an artificial neural network, was evaluated in the classification of lung sounds. Patients with asthma (n = 8), emphysema (n = 8) and fibrosing alveolitis (n = 8), and patients with healthy lungs (n = 8) were selected for the study. Fast Fourier transform (FFT) spectra from midinspiratory breath sounds recorded at the right lower lobe area were used to construct feature vectors in the learning and classification process of SOM. The sound segments did not contain wheezing sounds. The lung sounds of 25/32 (78%) patients were classified correctly, with an overall kappa (kappa) value of 0.71. The agreement between the clinical and proposed diagnoses based on classification of lung sounds was good among patients with emphysema (kappa = 0.92) and those with healthy lungs (kappa = 0.83), but only moderate among patients with asthma (kappa = 0.52) and fibrosing alveolitis (kappa = 0.54). This is due to the limitations in distinguishing breath sounds of asthmatics without wheezing sounds from those with crackles in fibrosing alveolitis by the spectral pattern alone. The results indicate that SOM based on FFT spectra is potentially useful in the classification of lung sounds, e.g. in health screening or in differential diagnosis of pulmonary disorders. To enhance the performance of SOM, other features of lung sounds should be combined with FFT spectra.
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Affiliation(s)
- L P Malmberg
- Department of Medicine, Helsinki University Central Hospital, Finland
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28
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Bueso A, Irigaray R, Romero PV. [A phonogramic study of expiratory wheezing in the asthmatic patient]. Arch Bronconeumol 1995; 31:501-6. [PMID: 8542181 DOI: 10.1016/s0300-2896(15)30846-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
UNLABELLED The quantitative analysis of expiratory wheezing may offer a new approach for study respiratory function in asthmatics. METHOD The sound spectrum during expiration was analyzed in 9 asthmatics with wheezing and 5 normal subjects. Phonographic parameters were then correlated with spirometric results for baseline respiration and deep breathing. RESULTS a) Expiratory wheezing is heard in a band of 210 to 280 Hz during deep breathing, and b) the volume in this band correlates positively with mean expiratory flow (VT/TE) and negatively with the slope of the volume/flow curve between 50 and 25% of FVC. CONCLUSIONS The degree of air flow limitation in the peripheral airways correlates with the volume of pulmonary sound.
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Affiliation(s)
- A Bueso
- Sección de Fisiopatología Respiratoria, Hospital Prínceps d'Espanya, Ciudad Sanitaria y Universitaria de Bellvitge, L'Hospitalet de Llobregat, Barcelona
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29
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Malmberg LP, Pesu L, Sovijärvi AR. Significant differences in flow standardised breath sound spectra in patients with chronic obstructive pulmonary disease, stable asthma, and healthy lungs. Thorax 1995; 50:1285-91. [PMID: 8553303 PMCID: PMC1021353 DOI: 10.1136/thx.50.12.1285] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND Spectral characteristics of breath sounds in asthma and chronic obstructive pulmonary disease (COPD) have not previously been compared, although the structural differences in these disorders might be reflected in breath sounds. METHODS Flow standardised inspiratory breath sounds in patients with COPD (n = 17) and stable asthma (n = 10) with significant airways obstruction and in control patients without any respiratory disorders (n = 11) were compared in terms of estimates of the power spectrum. Breath sounds were recorded simultaneously at the chest and at the trachea. RESULTS The median frequency (F50) of the mean (SD) breath sound spectra recorded at the chest was higher in asthmatics (239 (19) Hz) than in both the control patients (206 (14) Hz) and the patients with COPD (201 (21) Hz). The total spectral power of breath sounds recorded at the chest in terms of root mean square (RMS) was higher in asthmatics than in patients with COPD. In patients with COPD the spectral parameters were not statistically different from those of control patients. The F50 recorded at the trachea in the asthmatics was significantly related to forced expiratory volume in one second (FEV1) (r = -0.77), but this was not seen in the other groups. CONCLUSIONS The observed differences in frequency content of breath sounds in patients with asthma and COPD may reflect altered sound generation or transmission due to structural changes of the bronchi and the surrounding lung tissue in these diseases. Spectral analysis of breath sounds may provide a new non-invasive method for differential diagnosis of obstructive pulmonary diseases.
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Affiliation(s)
- L P Malmberg
- Department of Medicine, Helsinki University Central Hospital, Finland
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30
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Gavriely N, Nissan M, Rubin AH, Cugell DW. Spectral characteristics of chest wall breath sounds in normal subjects. Thorax 1995; 50:1292-300. [PMID: 8553304 PMCID: PMC1021354 DOI: 10.1136/thx.50.12.1292] [Citation(s) in RCA: 103] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND This study was carried out to establish a reliable bank of information on the spectral characteristics of chest wall breath sounds from healthy men and women, both non-smokers and smokers. METHODS Chest wall breath sounds from 272 men and 81 women were measured using contact acoustic sensors, amplifiers, and fast Fourier transform (FFT) based spectral analysis software. Inspiratory and expiratory sounds were picked up at three standard locations on the chest wall during breathing at flows of 1-2 l/s and analysed breath by breath in real time. RESULTS The amplitude spectrum of normal chest wall breath sounds has two linear parts in the log-log plane--low and high frequency segments--that are best characterised by their corresponding regression lines. Four parameters are needed and are sufficient for complete quantitative representation of each of the spectra: the slopes of the two regression lines plus the amplitude and frequency coordinates of their intersection. The range of slopes of the high frequency lines was -12.7 to -15.2 dB/oct during inspiration and -13.4 to -20.3 dB/oct during expiration. The frequency at which this line crossed the zero dB level--that is, the amplitude resolution threshold of the system--was designated as the maximal frequency (Fmax) which varied from 736 to 999 Hz during inspiration and from 426 to 796 Hz during expiration with higher values in women than in men. The mean (SD) regression coefficient of the high frequency line was 0.89 (0.05). CONCLUSIONS These data define the boundaries of normal chest wall breath sounds and may be used as reference for comparison with abnormal sounds.
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Affiliation(s)
- N Gavriely
- Department of Physiology and Biophysics, Bruce Rappaport Faculty of Medicine, Rappaport Family Institute for Research in the Medical Sciences, Haifa, Israel
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31
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Bohadana AB, Peslin R, Uffholtz H, Pauli G. Potential for lung sound monitoring during bronchial provocation testing. Thorax 1995; 50:955-61. [PMID: 8539675 PMCID: PMC1021308 DOI: 10.1136/thx.50.9.955] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND The use of lung sound monitoring during bronchial provocation testing has not been clearly demonstrated. The appearance of wheeze and changes in inspiratory breath sound intensity have been analysed and related to changes in spirometric parameters and to airways hyperresponsiveness. METHODS Lung sounds were recorded in 38 patients undergoing a routine carbachol airway challenge (CAC) test. Spirometric testing was performed before and after the inhalation of each of five cumulative doses of 320 micrograms carbachol; a fall in forced expiratory volume in one second (FEV1) by 20% or more was considered as significant. Lung sound analysis was carried out using a computerised system. RESULTS The CAC test was positive (CAC+) in 21 patients and negative (CAC-) in 17. At the final stage of the challenge, wheeze was identified in 10 positive patients (48%) and in one negative patient (6%); in non-wheezers the inspiratory breath sound intensity decreased significantly from baseline in 11 CAC+ patients (mean (SD) change -35 (24%)) but not in 16 CAC- patients (mean (SD) change 5 (24%)). In all non-wheezers a linear relationship was found between breath sound intensity and the squared inspiratory airflow (r = 0.53-0.92) which became looser after the inhalation of carbachol. CONCLUSION When unertaking bronchial provocation testing the accurate identification of wheeze may prove useful in avoiding or shortening the test because of the presumed relationship between wheeze and airways hyperresponsiveness. Changes in breath sound intensity may also be useful, but further studies are required to define the threshold for significant changes in this index.
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Affiliation(s)
- A B Bohadana
- Institut National de Rescherche et de Securité (INRS), Nancy, France
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32
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Fiz Fernández J. Sonidos respiratorios. Arch Bronconeumol 1995. [DOI: 10.1016/s0300-2896(15)30938-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Rietveld S, Dooijes EH, Rijssenbeek-Nouwens LH, Smit F, Prins PJ, Kolk AM, Everaerd WA. Characteristics of wheeze during histamine-induced airways obstruction in children with asthma. Thorax 1995; 50:143-8. [PMID: 7701452 PMCID: PMC473903 DOI: 10.1136/thx.50.2.143] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
BACKGROUND An automated system has been developed for the detection of sound patterns suggestive of airways obstruction in long term recordings. The first step, presented here, was tracheal sound recording during histamine-induced airways obstruction. METHODS The tracheal sounds of 29 children aged 8-19 years with asthma were recorded during airways obstruction caused by histamine inhalation using a system for continuous respiratory telemetry and computer analysis. Sound patterns were analysed, classified, and related to airways obstruction measured by lung function tests based on the forced expiratory volume in one second (FEV1). RESULTS Five sound patterns were identified, one dominant sensitive and four specific to a fall in FEV1 of > 20%. The presence of at least one of three specific sound patterns during unforced respiration predicted a fall in FEV1 of > 20% in 87.5% of the subjects. The inspiratory and expiratory sound patterns were almost equally informative of airways obstruction. CONCLUSIONS Wheezes can be differentiated with more precision than is currently accepted. Tracheal sound patterns are sensitive and specific predictors of histamine-induced airways obstruction. These patterns are neither invariably nor proportionally related to the results of lung function testing. However, they can be used for detection of airways obstruction on the basis of their presence or absence.
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Affiliation(s)
- S Rietveld
- Department of Clinical Psychology, Faculty of Psychology, The Netherlands
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Wodicka GR, Kraman SS, Zenk GM, Pasterkamp H. Measurement of respiratory acoustic signals. Effect of microphone air cavity depth. Chest 1994; 106:1140-4. [PMID: 7924486 DOI: 10.1378/chest.106.4.1140] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The use of electret microphones to measure lung sounds is widespread because of their small size, high fidelity, and low cost. Typically, an air cavity is placed between the skin surface and the microphone to convert the chest wall vibrations into a measurable sound pressure. The importance of air cavity depth on this transduction process was investigated in this study. An acoustic model of chest wall--air cavity--microphone interface was developed and the predicted effects of depth were compared with measurements performed using an artificial chest wall and lung sounds from a healthy subject. Model predictions are in general agreement with both in vitro and in situ measurements and indicate that the overall high-frequency response of the transduction diminishes with increasing cavity depth. This finding suggests that smaller cavity depths are more appropriate for detection of lung sounds over a wide band width and stresses the importance of coupler size on microphone measurements.
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Affiliation(s)
- G R Wodicka
- School of Electrical Engineering, Purdue University, West Lafayette, IN 47907-1285
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35
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Malmberg LP, Sorva R, Sovijärvi AR. Frequency distribution of breath sounds as an indicator of bronchoconstriction during histamine challenge test in asthmatic children. Pediatr Pulmonol 1994; 18:170-7. [PMID: 7800434 DOI: 10.1002/ppul.1950180309] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
In order to study changes in respiratory sounds associated with acute bronchoconstriction and -dilatation, breath sounds of 11 children with asthma (age range, 10-14 years) were recorded at the chest and at the trachea during histamine challenge test and after subsequent bronchodilatation. The changes in frequency spectra of breath sounds were compared with simultaneous changes in forced expiratory volume in 1 second (FEV1). In seven children who responded to histamine with a decrease in FEV1 of more than 15%, there was a significant relationship between percentage change in FEV1 (delta FEV1) and percentage change in median frequency (delta F50) of expiratory breath sounds recorded at the chest (r = 0.865; beta = -0.706, P = 0.0001) and at the trachea (r = 0.888; beta = -1.12, P = 0.0001). The association between breath sound intensity and FEV1 was weaker. Based on ANOVA, the increase of F50 during the challenge test was significantly larger in children who responded to histamine than in those who were non-responsive (P = 0.0016). At the chest, a decrease of 15% in FEV1 corresponded to an increase of 8% in expiratory F50. The provocative dose of histamine inducing a decrease of 15% in FEV1 (PD15FEV1) and the provocative dose causing an increase of 8% in F50 (PD8F50) were significantly related (r = 0.927, P = 0.003). We conclude that spectral analysis of breath sounds can be used to indicate airway obstruction during bronchial challenge tests in children, and may be adapted for tests in pre-school children. The results suggest that the same mechanisms that induce airflow limitation due to inhaled histamine may generate an increase in frequency content of breath sounds in children with asthma.
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Affiliation(s)
- L P Malmberg
- Department of Pulmonary Medicine, Helsinki University Central Hospital, Finland
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Malmberg LP, Sovijärvi AR, Paajanen E, Piirilä P, Haahtela T, Katila T. Changes in frequency spectra of breath sounds during histamine challenge test in adult asthmatics and healthy control subjects. Chest 1994; 105:122-31. [PMID: 8275721 DOI: 10.1378/chest.105.1.122] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Air-flow standardized breath sounds were recorded at the chest and at the trachea during histamine challenge test and after subsequent bronchodilation in 12 asthmatics and 6 healthy controls for spectral analysis, to be compared with simultaneous changes in spirometric variables. Of all the lung sound variables measured, the changes in median frequency of the power spectrum (F50) of tracheal expiratory sounds were found to correlate best (r = 0.853, p < 0.0001) with changes in FEV1. The increase of F50 during histamine challenge was significantly larger in asthmatics than in healthy control subjects (p < 0.005). The provocative dose of histamine inducing a decrease of 15 percent in FEV1 (PD15FEV1) and the provocative dose causing an increase of 30 percent in tracheal expiratory F50 (PD30F50) were significantly related (r = 0.754, p = 0.012). In asthmatics, the breath sound frequency distribution in terms of median frequency reflected acute changes in airways obstruction with high sensitivity and specificity. The present method for breath sound analysis can be applied for patients with limited cooperation during bronchial challenge tests.
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Affiliation(s)
- L P Malmberg
- Department of Pulmonary Diseases, Helsinki University Central Hospital, Finland
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Anderson PJ, Dolovich MB. Aerosols as diagnostic tools. JOURNAL OF AEROSOL MEDICINE : THE OFFICIAL JOURNAL OF THE INTERNATIONAL SOCIETY FOR AEROSOLS IN MEDICINE 1993; 7:77-88. [PMID: 10147059 DOI: 10.1089/jam.1994.7.77] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- P J Anderson
- Division of Pulmonary and Critical Care Medicine, University of Arkansas for Medical Sciences, Little Rock 72205
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Pasterkamp H, Kraman SS, DeFrain PD, Wodicka GR. Measurement of respiratory acoustical signals. Comparison of sensors. Chest 1993; 104:1518-25. [PMID: 8222817 DOI: 10.1378/chest.104.5.1518] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
We assessed the performance of three air-coupled and four contact sensors under standardized conditions of lung sound recording. Recordings were obtained from three of the investigators at the best site on the posterior lower chest as determined by auscultation. Lung sounds were band-pass filtered between 100 and 2,000 Hz and sampled simultaneously with calibrated airflow at a rate of 10 kHz. Fourier techniques were used for power spectral analysis. Average spectra for inspiratory sounds at flows of 2 +/- 0.5 L/s were referenced against background noise at zero flow. Air-coupled and contact sensors had comparable maximum signal-to-noise ratios and gave similar values for most spectral parameters. Unexpectedly, less sensitivity (lower signal-to-noise ratio) at high frequencies was observed in the air-coupled devices. Sensor performance needs to be characterized in studies of lung sounds. We suggest that lung sound spectra should be averaged at known airflows over several breaths and that all measurements should be reported relative to sounds recorded at zero flow.
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Affiliation(s)
- H Pasterkamp
- Department of Pediatrics, University of Manitoba, Winnipeg, Canada
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Sanchez I, Powell RE, Pasterkamp H. Wheezing and airflow obstruction during methacholine challenge in children with cystic fibrosis and in normal children. THE AMERICAN REVIEW OF RESPIRATORY DISEASE 1993; 147:705-9. [PMID: 8442608 DOI: 10.1164/ajrccm/147.3.705] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
To study wheeze as an indicator of bronchial responses during standardized methacholine challenge (MCH), we used computerized analysis of respiratory sounds in children with cystic fibrosis (CF) and in healthy control subjects. We recorded tracheal and lung sounds from 10 young CF = yCF patients, mean age 5.7 yr (range 4 to 7 yr), 13 older CF = oCF, age 10.5 yr (8 to 18 yr), 7 young normal subjects = yNO, age 5.3 yr (4 to 7 yr), and 11 older normal subjects = oNO, age 11 yr (8 to 16 yr). Spirometry was obtained after each doubling concentration of methacholine until the concentration provoking a > or = 20% fall in FEV1 (PC20) or the end point (8 mg/ml) was reached. Sound and calibrated flow signals were recorded on tape and later analyzed by respirosonography. The concentration of methacholine associated with wheeze (PCw) was noted. Wheezing was quantified by its duration during inspiration (Tw/TI) and expiration (TW/TE). We found a positive response to MCH in 11 of 13 oCF (PC20 0.75 mg/ml, range 0.08 to 3.0) and in 3 of 11 oNO (PC20 4.2 mg/ml, range 2.5 to 6.5). Wheezing occurred in 6 oCF (PC20 < 8 mg/ml). In 7 yCF PC20 or PCW developed (1.51 mg/ml, range 0.125 to 4.0) versus 4 yNO (4.0 mg/ml, range 2.0 to 8.0). In 10 oCF subjects who performed MCH on three occasions within a 2-wk period, both positive and negative wheeze responses were reproducible. Patients who wheezed had a lower FRC compared with patients who did not (109 versus 147% of predicted, p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- I Sanchez
- Department of Pediatrics, University of Manitoba, Winnipeg, Canada
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Sanchez I, Avital A, Wong I, Tal A, Pasterkamp H. Acoustic vs. spirometric assessment of bronchial responsiveness to methacholine in children. Pediatr Pulmonol 1993; 15:28-35. [PMID: 8419895 DOI: 10.1002/ppul.1950150105] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
To study wheezing as an indicator of bronchial responsiveness during methacholine challenge (MC) in children, we used computer analysis of respiratory sounds and compared wheeze measurements to routine spirometry. MC was performed in 30 symptomatic subjects (sympt), age 11 +/- 3.1 years (mean +/- SD), with suspected asthma and in 12 controls (contr), age 10 +/- 3.4 years. Respiratory rate (RR), spirometry, arterial oxygen saturation (SaO2), and cough were registered until the concentration provoking a > or = 20% fall in forced expiratory flow in 1 second (FEV1;PC20), or the end point (8 mg/mL) was reached. For 1 min after each inhalation, sounds over the trachea and posterior right lower lobe were recorded together with calibrated airflow. Computer analysis of respiratory sounds was used for objective wheeze quantification. Wheezing was measured as its duration relative to inspiration (Tw/Ti) and expiration (Tw/Te). Seventeen of the sympt group developed wheezing (sympt/W) with > or = 5% Tw/Ti or > or = 5% Tw/Te. Thirteen of the sympt did not wheeze (sympt/no W). Three contr developed wheeze (contr/W) while 9 did not (contr/no W). In sympt/W, RR increased from 20 +/- 6.2 per min at baseline to 25 +/- 9.2 (P < 0.05) at the MC concentration provoking wheeze (PCw), and SaO2 decreased from 97.4 +/- 1.2% to 95.3 +/- 2.4 (P < 0.05). In contr/W, RR did not change, but SaO2 decreased from 97.3 +/- 1.5% to 95.7% +/- 1.2% (P < 0.05). Wheezing occurred at both recording sites and was as common during inspiration as during expiration.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- I Sanchez
- Department of Pediatrics and Child Health, University of Manitoba, Winnipeg, Canada
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Spence DP, Bentley S, Evans DH, Morgan MD. Effect of methacholine induced bronchoconstriction on the spectral characteristics of breath sounds in asthma. Thorax 1992; 47:680-3. [PMID: 1440460 PMCID: PMC474798 DOI: 10.1136/thx.47.9.680] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
BACKGROUND Analysis of breath sounds by digital techniques offers an attractive non-invasive method of monitoring changes in airway calibre. Asthmatic breath sounds have been analysed and related to changes in forced expiratory volume in one second (FEV1). METHODS Bronchoconstriction was induced with methacholine in six asthmatic subjects on two occasions and changes in FEV1 and breath sound spectra were measured. RESULTS Audible wheeze appeared after a mean (SE) fall in FEV1 of 35% (6.3%) but the level was not reproducible within patients. The mean and median frequency of the spectra of breath sounds correlated with the percentage of predicted FEV1 (r = -0.5 and -0.6 respectively; p < 0.001). Inclusion of the quartile frequencies in a stepwise multiple regression reduced the residual variance by a further 9%. CONCLUSION Detecting changes in airway calibre by this method of sound analysis so far produces qualitative data only and will not yield quantitative data in individual patients.
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Affiliation(s)
- D P Spence
- Department of Respiratory Medicine, Glenfield General Hospital, Leicester
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