title: Lung sound analysis in the diagnosis of obstructive airway disease.
abstract: BACKGROUND
  Dyspnea is prevalent and has a broad differential diagnosis. Difficulty in determining the correct etiology can delay proper treatment. Non-invasively obtained acoustic signals may offer benefit in identifying patients with dyspnea due to obstructive airway disease (OAD).
  
  
  OBJECTIVE
  The aim of this pilot study was to determine whether patients with acute dyspnea due to OAD had distinguishing features when studied with a computerized acoustic-based imaging technique.
  
  
  METHODS
  Respiratory sounds from patients with dyspnea due to OAD (n = 32) and those with dyspnea not due to OAD (n = 39) were studied and compared with normal controls (n = 16).
  
  
  RESULTS
  In patients without OAD and in controls, the ratios of peak inspiratory to peak expiratory vibration energy values (peak I/E vibration ratio) were remarkably similar, 6.3 +/- 5.1 and 5.6 +/- 4, respectively. For the OAD patients, the peak I/E vibration ratio was significantly lower at 1.3 +/- 0.04 (p < 0.01). In the patients without OAD and the controls, the ratios of inspiratory time to expiratory time (I/E time ratio) were again similar, 1.0 +/- 0.1 and 0.99 +/- 0.11, respectively. For the OAD patients, the I/E time ratio was significantly lower at 0.72 +/- 0.19 (p < 0.01).
  
  
  CONCLUSIONS
  This modality was useful in identifying patients whose dyspnea was due to OAD. The ability to objectively and non-invasively measure these differences may prove clinically useful in distinguishing the operant physiology in patients presenting with acute dyspnea.
authors.affiliation: Division of Critical Care Medicine, Robert Wood Johnson School of Medicine, University of Medicine and Dentistry of New Jersey, Cooper University Hospital, Camden, NJ 08103, USA. wangzhen1369@hotmail.com
authors.forename: Zhen
authors.initials: Z
authors.lastname: Wang
authors.forename: Smith
authors.initials: S
authors.lastname: Jean
authors.forename: Thaddeus
authors.initials: T
authors.lastname: Bartter
mesh_terms: D000328:Adult; D000368:Aged; D001314:Auscultation / Q000295:instrumentation*; D003952:Diagnostic Imaging; D004417:Dyspnea / Q000175:diagnosis*; D005260:Female; D006801:Humans; D008173:Lung Diseases, Obstructive / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D013018:Sound Spectrography; D014732:Vibration