![]() ![]() Furthermore, we analyzed the influence of emphysematous lesions on the lung sound distribution in COPD patients.įorty-seven clinically stable male COPD patients, each with a smoking history of more than 20 pack-years, were recruited. In this study, we investigated the association of lung sound distribution with pulmonary function in COPD patients and healthy subjects, with the goal of acquiring basic knowledge regarding the association of lung sound distribution with pulmonary function. The distribution of emphysematous lesions and the bronchial reactivity appeared to influence regional lung ventilation and the distribution of lung sounds after bronchodilator use.Īlthough the distribution of emphysematous lesions was thought to influence the lung sound distribution, the assessment of regional lung sound might be applicable as a non-invasive tool for evaluating the regional physiological characteristics of COPD patients. However, we also found that the bronchodilator-induced relative increase in the lower lung sound intensity was not observed in one patient with heterogeneous emphysema or in one non-emphysematous patient. We hypothesized that this result was caused by an increase in lower lung airflow, which might reflect an improvement in diaphragm movement. In seven patients with homogeneous emphysema, the relative regional lung sound intensity decreased in the upper-lung field and increased in the lower-lung field after bronchodilator inhalation. In a previous study, we observed changes in the lung sound distribution that was accompanied by pulmonary function improvements in COPD patients after inhalation of a short-acting bronchodilator. Recently, improvements in computer technology have provided new insights into acoustic analysis and have been introduced in clinical studies as a surrogate marker of regional ventilation –. Therapeutic interventions that improve hyperinflation in COPD are thought to modulate regional airflow in the lung, which is reflected by the changes in regional lung sound distribution. ![]() In these circumstances, it seems that regional ventilation may shift from the lower- to upper-lung field, according to the degree of hyperinflation. In severe COPD patients, the movements of the diaphragm are restricted, and accessory respiratory muscles, such as sternocleidomastoid and scalene muscles, are recruited during tidal breathing. Regional lung ventilation in COPD patients seems to be influenced by altered ribcage and diaphragm configurations and movement due to hyperinflation. Although lung sounds are reported to be generated primarily within the lobar to segmental airways, Ploysongsang compared Xenon ventilation scans with the distribution of lung sound intensities and reported that regional lung sound intensity could be used to quantify regional ventilation in subjects with emphysema in whom the physiological deficits are mainly caused by small airway obstruction. ![]() A correlation between the perceived lung sound intensity and the percent-predicted forced expiratory volume over one second (FEV 1) has been reported. Because airflow in the lung produces sound, a generalized reduction in apparent lung sound is one of the indicators of COPD. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Ĭompeting interests: The authors have declared that no competing interests exist.Ĭhronic obstructive pulmonary disease (COPD) is characterized by progressive airflow limitation. All relevant data are within the paper and its Supporting Information files.įunding: This work was supported by the Japan Society for the Promotion of Science Grant-in-Aid for Scientific Research (C) Grant number (24591143). This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.ĭata Availability: The authors confirm that all data underlying the findings are fully available without restriction. Received: Accepted: AugPublished: September 22, 2014Ĭopyright: © 2014 Mineshita et al. ![]() PLoS ONE 9(9):Įditor: Marco Gemma, Scientific Inst. (2014) The Correlation between Lung Sound Distribution and Pulmonary Function in COPD Patients. Citation: Mineshita M, Kida H, Handa H, Nishine H, Furuya N, Nobuyama S, et al. ![]()
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