PT  - JOURNAL ARTICLE
AU  - P Piirila
AU  - AR Sovijarvi
TI  - Crackles: recording, analysis and clinical significance
AID  - 10.1183/09031936.95.08122139
DP  - 1995 Dec 01
TA  - European Respiratory Journal
PG  - 2139--2148
VI  - 8
IP  - 12
4099  - http://erj.ersjournals.com/content/8/12/2139.short
4100  - http://erj.ersjournals.com/content/8/12/2139.full
SO  - Eur Respir J1995 Dec 01; 8
AB  - Crackles are short interrupted breath sounds usually associated with pulmonary disorders. According to present opinion, a crackle is generated when an abnormally closed airway opens during inspiration or closes at the end of expiration. The timing of crackles in breathing cycles can be assessed with phonopneumography, their duration with time-expanded waveform analysis, and their pitch with analysis of frequency spectra. The timing, pitch and waveform of crackles are different in pulmonary disorders reflecting different pulmonary pathophysiology. This review deals with the genesis, auscultation, recording and analysis of crackles, with an emphasis on modern signal-processing methods.