Abstract
Though lung sounds auscultation is important for the diagnosis and monitoring of lung diseases, the spectral characteristics of lung sounds have not been fully understood. This study compared the spectral characteristics of lung sounds between the right and left lungs and between healthy male and female subjects using a dual-channel auscultation system. Forty-two subjects aged 18–22 years without smoking habits and any known pulmonary diseases participated in this study. The lung sounds were recorded from seven pairs of auscultation sites on the chest wall simultaneously. We found that in four out of seven auscultation pairs, the lung sounds from the left lung had a higher total power (PT) than those from the right lung. The PT of male subjects was higher than that of female ones in most auscultation pairs. The ratio of inspiration power to expiration power (RI/E) of lung sounds from the right lung was greater than that from the left lung at auscultation pairs on the anterior chest wall, while this phenomenon was reversed at auscultation pairs on the posterior chest wall in combined subjects, and similarly in both male and female subjects. Though the frequency corresponding to maximum power density of lung sounds (FMPD) from the left and right lungs was not significantly different, the frequency that equally divided the power spectrum of lung sounds (F50) from the left lung was significantly smaller than that from the right lung at auscultation site on the anterior and lateral chest walls, while it was significantly larger than that of from the right lung at auscultation site on the posterior chest walls. In conclusion, significant differences in the PT, FMPD, F50, and RI/E between the left and right lungs at some auscultation pairs were observed by using a dual-channel auscultation system in this study. Structural differences between the left and the right lungs, between the female and male subjects, and between anterior and posterior lungs might account for the observed differences in the spectral characteristics of lung sounds. The dual-channel auscultation system might be useful for future development of digital stethoscopes and power spectral analysis of lung sounds in patients with various kinds of cardiopulmonary diseases.
Highlights
Respiration rate is one of the vital signs used daily in clinical settings including anesthesiology and critical care medicine, in addition to body temperature, pulse rate, and blood pressure
There was no significant difference in the PT of lung sounds between left and right lungs at all auscultation pairs in female subjects, except at Auscultation Pair 5 where the PT of lung
The ratio of inspiration power to expiration power (RI/E) of lung sounds from the right lung was greater than that from the left lung at Auscultation
Summary
Respiration rate is one of the vital signs used daily in clinical settings including anesthesiology and critical care medicine, in addition to body temperature, pulse rate, and blood pressure. The auscultation of lung sounds is one of the clinical practices of physicians in the diagnosis and treatment of asthma, chronic bronchitis, chronic obstructive pulmonary disease (COPD), bronchiectasis, pulmonary edema, acute respiratory distress syndrome (ARDS), etc. The rhonchi, rale, wheezing, and stridor heard during auscultation are important clues for the diagnosis of secretion accumulation in the lung, pulmonary edema, asthma, upper airway obstruction, etc. The stethoscope has been one of the most frequently used medical diagnostic tools in clinical settings. Simple structure, portability, safety, noninvasiveness, and quick diagnosis have enabled it to survive for more than a century as a medical device. It has become an icon of physicians. The processing of acquired signals and the way of auscultation has become versatile
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