Abnormal lung sounds in patients with asthma during episodes with normal lung function.

Even in patients with clinically stable asthma with normal lung function, the airways are characterized by inflammatory changes, including mucosal swelling. In order to investigate whether lung sounds can distinguish these subjects from normal subjects, we compared lung sound characteristics between eight normal and nine symptom-free subjects with mild asthma. All subjects underwent simultaneous recordings of airflow, lung volume changes, and lung sounds during standardized quiet breathing, and during forced maneuvers. Flow-dependent power spectra were computed using fast Fourier transform. For each spectrum we determined lung sound intensity (LSI), frequencies (Q25%, Q50%, Q75%) wheezing (W), and W%. The results were analyzed by ANOVA. During expiration, LSI was lower in patients with asthma than in healthy controls, in particular at relatively low airflow values. During quiet expiration, Q25% to Q75% were higher in asthmatics than in healthy controls, while the change of Q25% to Q75% with flow was greater in asthmatic than in normal subjects. The W and W% were not different between the subject groups. The results indicate that at given airflows, lung sounds are lower in intensity and higher in pitch in asthmatics as compared with controls. This suggests that the generation and/or transmission of lung sounds in symptom-free patients with stable asthma differ from that in normal subjects, even when lung function is within the normal range. Therefore, airflow standardized phonopneumography might reflect morphologic changes in airways of patients with asthma.

[1]  R. Djukanović,et al.  Mucosal inflammation in asthma. , 1990, The American review of respiratory disease.

[2]  S. Kraman,et al.  Effects of lung volume and airflow on the frequency spectrum of vesicular lung sounds. , 1986, Respiration physiology.

[3]  J Vanderschoot,et al.  Lung sound intensity in patients with emphysema and in normal subjects at standardised airflows. , 1992, Thorax.

[4]  J. Mead.  Expiratory flow limitation: a physiologist's point of view. , 1980, Federation proceedings.

[5]  S. Kraman,et al.  The forced expiratory wheeze. Its site of origin and possible association with lung compliance. , 1983, Respiration; international review of thoracic diseases.

[6]  S. Holgate,et al.  Cellular events in the bronchi in mild asthma and after bronchial provocation. , 1989, The American review of respiratory disease.

[7]  G. Charbonneau,et al.  Forced expirations in normal subjects. Is the shape of the flow rate curve related to existence of a wheeze? , 1987, Chest.

[8]  S. Anderson,et al.  Airway responsiveness : standardized challenge testing with pharmacological, physical and sensitizing stimuli in adults , 1993 .

[9]  Jeffrey R. Hammersley,et al.  Mechanisms of Lung Sound Generation , 1985 .

[10]  D H Evans,et al.  Effect of methacholine induced bronchoconstriction on the spectral characteristics of breath sounds in asthma. , 1992, Thorax.

[11]  Z. Tomori,et al.  Comparison of inspiratory effort in sniff-like aspiration reflex, gasping and normal breathing in cats. , 1993, The European respiratory journal.

[12]  Chaeles S. Lessard,et al.  Correlation of Constant Flow Rate with Frequency Spectrum of Respiratory Sounds When Measured at the Trachea , 1986, IEEE Transactions on Biomedical Engineering.

[13]  R. Lambert,et al.  Role of bronchial basement membrane in airway collapse. , 1991, Journal of applied physiology.

[14]  J B Grotberg,et al.  Forced expiratory wheezes are a manifestation of airway flow limitation. , 1987, Journal of applied physiology.

[15]  Hans Pasterkamp,et al.  Automated Spectral Characterization of Wheezing in Asthmatic Children , 1985, IEEE Transactions on Biomedical Engineering.

[16]  R. Baughman,et al.  Stridor: differentiation from asthma or upper airway noise. , 1989, The American review of respiratory disease.

[17]  N Gavriely,et al.  The reproducibility of forced expiratory wheezes. , 1990, The American review of respiratory disease.

[18]  R. Beckerman,et al.  Continuous Adventitious Lung Sounds: Site and Method of Production and Significance , 1985 .

[19]  H S Hira,et al.  LUNG SOUNDS , 1978, The Journal of the Association of Physicians of India.

[20]  D. Shannon,et al.  Phase delay of pulmonary acoustic transmission from trachea to chest wall , 1992, IEEE Transactions on Biomedical Engineering.

[21]  J. Fish,et al.  Regulation of bronchomotor tone by lung inflation in asthmatic and nonasthmatic subjects. , 1981, Journal of applied physiology: respiratory, environmental and exercise physiology.

[22]  D. Rice,et al.  Transmission of Lung Sounds , 1985 .

[23]  S. Kraman,et al.  Airflow-generated sound in a hollow canine airway cast. , 1990, Chest.

[24]  Y Ploysongsang,et al.  Airflow and normal lung sounds. , 1988, The American review of respiratory disease.

[25]  J E Cotes,et al.  Lung volumes and forced ventilatory flows , 1993, European Respiratory Journal.

[26]  A. James,et al.  The structure of large and small airways in nonfatal and fatal asthma. , 1993, The American review of respiratory disease.

[27]  J B Grotberg,et al.  Flutter in collapsible tubes: a theoretical model of wheezes. , 1989, Journal of applied physiology.

[28]  Steve S. Kraman,et al.  The Forced Expiratory Wheeze , 1983 .