title: Breath Sound Intensity during Tidal Breathing in COPD Patients.
abstract: OBJECTIVE
  There is a discrepancy in the intensity of breath sounds in chronic obstructive pulmonary disease (COPD) patients between subjective studies, which have reported a diminished intensity, and objective studies using airflow-standardized measurements, which have not demonstrated a diminished intensity. We herein evaluated the breath sound intensity in COPD patients during tidal breathing in order to obtain clinically relevant results.
  
  
  METHODS
  The subjects included 20 stable COPD patients and 20 normal controls. Microphones were attached to six sites on the chest wall, and breath sounds at the chest wall and airflow in the mouth were measured during resting tidal and deep tidal breathing. The octave-band power values of the breath sounds were subsequently calculated.
  
  
  RESULTS
  1. During resting breathing, the intensity of breath sounds during both inspiration and expiration was significantly greater in the COPD group than in the control group; the difference was prominent at higher frequency bands (>400 Hz). In addition, the power of the high frequency bands tended to be positively correlated with the CT visual emphysema scores but not the forced expiratory volume in one second, The airflow during resting breathing did not differ between the two groups. 2. During deep breathing, the intensity of inspiratory breath sounds at the dominant frequency band (200-400 Hz) was diminished over the upper and middle lung fields in the COPD group compared to that observed in the control group, while the intensity during expiration was not. The airflow during deep breathing was lower in the COPD group than in the control group.
  
  
  CONCLUSIONS
  In the present study, the breath sound intensity in the COPD patients was diminished during deep inspiration due to a reduced airflow and increased during both resting inspiration and expiration.
authors.affiliation: Department of Pulmonology, Fukuoka National Hospital, Japan.
authors.forename: Akiko
authors.initials: A
authors.lastname: Ishimatsu
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Nakano
authors.forename: Hiroko
authors.initials: H
authors.lastname: Nogami
authors.forename: Makoto
authors.initials: M
authors.lastname: Yoshida
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Iwanaga
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Hoshino
mesh_terms: D000368:Aged; D045853:Exhalation; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D001239:Inhalation; D008297:Male; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000000981:diagnostic imaging / Q000503:physiopathology*; D011859:Radiography; D012129:Respiratory Function Tests; D012135:Respiratory Sounds / Q000503:physiopathology*; D012720:Severity of Illness Index