title: Analysis of tracheal sounds during forced exhalation in asthma patients and normal subjects: bronchodilator response effect.
abstract: OBJECTIVE
  During the past 10 years, the acoustic analysis of breath sounds has been used as a diagnostic tool in patients suffering from obstructive respiratory diseases. Acoustic analysis might be able to monitor the response to bronchodilator therapy in a clinical setting. So far, few studies have been carried out in asthmatic patients. To assess the responses of a sampling of asthma patients to an inhaled bronchodilator (terbutaline) by means of spectral analysis of the tracheal sound performed during forced expiratory maneuvers.
  
  
  METHODS
  Seventeen nonsmoking asthma patients (9 were male, 8 were female) who had been suffering from the disease for > or = 15 years were included in the study, as were 15 normal subjects (7 were male, 8 were female). The average age (+/- SD) was 56.5 +/- 15.2 years (FVC, 2.7 +/- 0.9 L [63.4%]; FEV1, 1.5 +/- 0.6 L [53.0%]). The tracheal sounds were collected during three forced expiratory maneuvers with a sampling frequency of 5,000 Hz and were analyzed by applying a 16-parameter autoregressive model.
  
  
  RESULTS
  The centroid frequency decreased after the bronchodilator was given at different flow segments between 1.2 and 0.4 L/s, with significant changes between 0.6 and 0.4 L/s.
  
  
  CONCLUSIONS
  Patients with asthma showed changes in the spectral acoustic analysis frequencies after the administration of a bronchodilator drug (terbutaline) during forced expiratory maneuvers.
authors.affiliation: Pneumology Department, Germans Trias i Pujol University Hospital, Badalona, Spain. jafiz@ns.hugtip.scs.es
authors.forename: J A
authors.initials: JA
authors.lastname: Fiz
authors.forename: R
authors.initials: R
authors.lastname: Jané
authors.forename: D
authors.initials: D
authors.lastname: Salvatella
authors.forename: J
authors.initials: J
authors.lastname: Izquierdo
authors.forename: L
authors.initials: L
authors.lastname: Lores
authors.forename: P
authors.initials: P
authors.lastname: Caminal
authors.forename: J
authors.initials: J
authors.lastname: Morera
mesh_terms: D000293:Adolescent; D000328:Adult; D001249:Asthma / Q000188:drug therapy* / Q000503:physiopathology; D001993:Bronchodilator Agents / Q000494:pharmacology* / Q000627:therapeutic use; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008297:Male; D008875:Middle Aged; D012135:Respiratory Sounds / Q000187:drug effects*; D013018:Sound Spectrography; D013147:Spirometry; D013726:Terbutaline / Q000494:pharmacology* / Q000627:therapeutic use; D014132:Trachea / Q000503:physiopathology*; D014797:Vital Capacity
chemical_list: D001993:Bronchodilator Agents; D013726:Terbutaline