SEPARATION OF PULMONARY DISORDERS WITH 2-DIMENSIONAL DISCRIMINANT-ANALYSIS OF CRACKLES

Previous studies have indicated that disorders producing crackling lun g sounds may be different in terms of the waveform of the crackles or their timing in a respiratory cycle. In this study, we evaluated wheth er two-dimensional discriminant analysis of crackles has a better abil ity to separate pulmonary disorders than does a single-dimensional ana lysis. Crackling sounds of patients with cryptogenic fibrosing alveoli tis (n=10), bronchiectasis (n=10), COPD (n=10), heart failure (n=10) a nd acute pneumonia (n=11) and of those recovering from pneumonia (n=9) have been studied. Variables indicating the timing of crackles during inspiration (beginning and endpoint of crackling) and their waveform (initial deflection width (IDW), two cycle duration (2CD) and largest deflection width (LDW)), were used for the analysis. The discriminatio n properties of one- and two-dimensional analyses with these variables were compared. The two-dimensional distances between the patient grou ps were the largest by combining IDW and the end-point of crackling. C ryptogenic fibrosing alveolitis was distinguished from bronchiectasis, COPD, heart failure and acute pneumonia without overlap. The differen ces between the diseases were illustrated two-dimensionally with ellip ses. The two-dimensional analysis resulted in better separation betwee n the groups than the use of single characteristics alone, This type o f analysis can enhance the diagnostic power of acoustic pulmonary stud ies. It is also an informative visual way to find differences among pu lmonary disorders.