POSTURAL CHANGES AND LATERALITY OF LUNG SOUND INTENSITY IN HEALTHY SUBJECTS

Background and Aims: We analyzed lung sounds intensity (LSI) of the patients with interstitial pneumonia (IP) and reported that the LSI was greater on the left lung base than the right. On the other hand, postural change of LSI was greater on the right lung base than on the left. The purpose of this study is to evaluate the postural difference and laterality of LSI in healthy subjects and compare them with those of IP patients. Methods: We evaluated LSI of five healthy volunteers. Lung sounds were recorded from bilateral low posterior chest wall in sitting, supine, prone and each lateral decubitus positions. LSI was analyzed by a sound spectrometer with lung sound analyzer LSA2018 (KenzMedico, Japan) as shown in sound-spectrogram (Fig. 1). Results: Postural difference of LSI was not significant among sitting, supine and prone positions, while LSI was greater on the left than the right in sitting and prone positions. As for lateral decubitus positions, LSI was greater on the dependent lung, i.e. greater on the left lung in the left lateral decubitus position and vice versa. (Fig. 2) The difference between left and right was significant only in the left lateral decubitus position. Postural difference was significant on the right lung but not on the left lung. These results showed that LSI was greater on the left than the right and postural change was greater on the right than the left lung. These results were almost identical to those observed in patients with IP. Conclusions: Postural changes and laterality of LSI in healthy subjects were almost the same as those of IP patients, i.e., LSI was greater on the left than the right and postural change was greater on the right than the left lung.