Abnormal Lung Sounds in Patients With Asthma During Episodes With Normal Lung Function

Schreur, Henk J. W.; Vanderschoot, J.; Zwinderman, Aeilko H.; Dijkman, J. H.; Sterk, Peter J.

doi:10.1378/chest.106.1.91

Cited by 50 publications

(48 citation statements)

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“…Nine atopic men with mild asthma (mean age 25 yrs; range 19-28 yrs) and eight healthy male controls (mean age 22 yrs; range 19-24 yrs), of whom baseline characteristics have been reported previously [3], volunteered to participate in this study (table 1). All subjects were lifelong nonsmokers, and there was no history of respiratory tract infection within 4 weeks before the study.…”

Section: Subjectsmentioning

confidence: 99%

“…Phonopneumography included simultaneous registrations of lung sounds in a soundproof room, and measurements of airflow and lung volume changes at the mouth by spirometry (Spiroflow; Morgan, Rainham, Gillingham, UK) according to a previously validated method [3]. The lung sound recordings were made during flow-and lung volume-standardized quiet breathing with flow rates up to 1.5 l·s -1 , and lung volumes between TLC -0.4 × VC +/-1 l for 30 s (TLC: total lung capacity, VC: vital capacity), and during maximum forced flow-volume manoeuvres for 15 s. The subjects were seated in an upright position with their nose clipped.…”

Section: Measurementsmentioning

confidence: 99%

“…These inflammatory changes are present even in clinically stable asthmatics without any current symptoms and with lung function within the normal range [2]. Using computerized phonopneumography, we have previously observed that lung sound intensity is lower and pitch is higher in symptom-free, mildly asthmatic subjects with lung function within the normal range as compared with healthy controls [3]. This suggests that the generation and/or transmission of lung sounds is altered as a result of the morphological changes of the airways in asthma, even when there are no discernable symptoms or spirometric changes.…”

mentioning

confidence: 93%

“…Normal lung sounds appear to be primarily generated by the complex turbulence within the large and medium sized airways [4,6]. The differences in intensity and pitch of lung sounds at baseline between asthmatic and normal subjects could be due to swelling of the airway wall in patients with asthma [3], which may lead to localized reduction of the airway lumen. Any resulting increase in local airflow velocity (m·s -1 ) at given flows at the mouth (l·s -1 ) will enhance turbulence, thus increasing the intensity and frequency content of the sounds generated [4].…”

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confidence: 99%

“…Flutter theory predicts that wheezing during expiratory flow-limitation will occur at lower airflow velocities when airway diameter is decreased [4,5]. At baseline, the airways are probably too wide to show differences in the extent of wheezing between asthmatic and normal subjects [3]. However, during bronchoconstriction intraluminal airflow velocity at given flows at the mouth will be higher, so that critical velocity will be reached at relatively low airflows.…”

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confidence: 99%

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The effect of methacholine-induced acute airway narrowing on lung sounds in normal and asthmatic subjects

Schreur

Vanderschoot²,

Zwinderman³

et al. 1995

Eur Respir J

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T Th he e e ef ff fe ec ct t o of f m me et th ha ac ch ho ol li in ne e--i in nd du uc ce ed d a ac cu ut te e a ai ir rw wa ay y n na ar rr ro ow wi in ng g o on n l lu un ng g s so ou un nd ds s i in n n no or rm ma al l a an nd d a as st th hm ma at ti ic c s su ub bj je ec ct ts s ABSTRACT: The association between lung sound alterations and airways obstruction has long been recognized in clinical practice, but the precise pathophysiological mechanisms of this relationship have not been determined. Therefore, we examined the changes in lung sounds at well-defined levels of methacholine-induced airway narrowing in eight normal and nine asthmatic subjects with normal baseline lung function. All subjects underwent phonopneumography at baseline condition and at ≥20% fall in forced expiratory volume in one second (FEV 1 ), and in asthmatic subjects also at ≥40% fall in FEV 1 . Lung sounds were recorded at three locations on the chest wall during standardized quiet breathing, and during maximal forced breathing. Airflow-dependent power spectra were computed using fast Fourier transform. For each spectrum, we determined the intensity and frequency content of lung sounds, together with the extent of wheezing. The results were analysed using analysis of variance (ANOVA).During acute airway narrowing, the intensity and frequency content of the recorded sounds, as well as the extent of wheezing, were higher than at baseline in both groups of subjects. At similar levels of obstruction, both the pitch and the change in sound intensity with airflow were higher in asthmatics than in normal subjects. Wheezing, being nondiscriminative between the subject groups at baseline, was more prominent in asthmatics than in normal subjects at 20% fall in FEV 1 .We conclude that, at given levels of acute airway narrowing, lung sounds differ between asthmatics and normal subjects. This suggests that airflow-standardized phonopneumography is a sensitive method for detecting abnormalities in airway dynamics in asthma. Our results favour the use of quiet, well-controlled breathing during auscultation.

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Section: Subjectsmentioning

confidence: 99%

Section: Measurementsmentioning

confidence: 99%

mentioning

confidence: 93%

mentioning

confidence: 99%

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confidence: 99%

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