Effect of Deep Inspiration on Flow-Standardized Inspiratory Lung Sounds
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Accession number;03A0567696
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| Title;Effect of Deep Inspiration on Flow-Standardized Inspiratory Lung Sounds |
| Author;
KIYOKAWA HIROSHI
(Social Insurance, Kamata General Hospital, JPN)
GNITECKI J
(Univ. Manitoba, Winnipeg, Can)
PASTERKAMP H
(Univ. Manitoba, Winnipeg, Can)
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Journal Title;Clinical Pharmacology and Therapy
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Journal Code:L1701A
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ISSN:0917-3994
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VOL.13;NO.4;PAGE.325-332(2003)
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| Figure&Table&Reference;FIG.5, TBL.1, REF.5 |
| Pub. Country;Japan |
| Language;Japanese |
| Abstract;Bronchoconstriction and -dilation change the relation of airflow and lung sounds. We have previously shown that bronchial narrowing by methacholine inhalation reversibly decreases the intensity of basic breath sounds at frequencies below 300Hz. We have also shown that the flow required to generate inspiratory lung sounds increases during airway narrowing and decreases after bronchodilation. We assume that the tension of airway smooth muscle may have an effect on sound transmission. Since deep inspiration affects smooth muscle tone and causes bronchodilation in normals we postulated that flow-standardized lung sounds would show increased intensity after a deep inspiration. We studied five healthy non-smokers (three males), ages 29-51y. Flow was measured at the mouth. Lung sounds were detected at the anterior right upper (RU) and posterior right lower lung (RL) using contact sensors. The sound signals were band-pass filtered, digitized and sampled as previously described. The subjects followed a series of breath maneuvers as indicated on a PC screen. These consisted of 1.) slow vital capacity, 2.) shallow breathing (<0.5L/s for 120s), 3.) breath hold (5s), 4.) seven breaths at target flows (1.0-1.4L/s), 5.) inspiration to total lung capacity, 6.) breath hold (5s), then back to resting end-expiratory level, 7.) seven breaths at target flow, and 8.) breath hold (5s). Average spectra of inspiratory sounds obtained from steps 4 and 7 were compared, using background noise information from steps 3 and 8, respectively. After subtracting background noise sound intensity was expressed in dB. We found increased breath sound intensity after deep inspiration in all recording categories and statistical significance was found in RU 300-600Hz.... (author abst.) |
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