We modeled discrete emission of sound from lung parenchyma as a point source in an ideal medium. The point source, a quadrupole, represents the stress anomaly in lung parenchyma in the neighborhood of a collapsed airway, and its time course when the airway opens. The dynamics of the airway opening event are characterized by a single time constant. The ideal medium, lung parenchyma, was modeled as a homogeneous linearly elastic lossless nondispersive continuum of infinite extent undergoing infinitesimal strains. Depsite its simplicity, this elementary model leads to predictions of crackle waveforms, spectral densities, and spatial intensity distributions which are consistent with observations. In particular, the model predicts changes of waveform shape and polarity with observation position relative to the source, dramatic influences of transduction processes, and successive increases in zero crossing time intervals.
Skip Nav Destination
Article navigation
March 1983
March 01 1983
Discrete lung sounds: Crackles (rales) as stress–relaxation quadrupoles
Jeffrey J. Fredberg;
Jeffrey J. Fredberg
Cambridge Collaborative Research Foundation, P.O. Box 74, 169 Bent Street, Cambridge, Massachusetts 02142
Search for other works by this author on:
Stephen K. Holford
Stephen K. Holford
Massachusetts Institute of Technology, Department of Electrical Engineering, Cambridge, Massachusetts 02139
Search for other works by this author on:
J. Acoust. Soc. Am. 73, 1036–1046 (1983)
Article history
Received:
July 06 1982
Accepted:
November 16 1982
Citation
Jeffrey J. Fredberg, Stephen K. Holford; Discrete lung sounds: Crackles (rales) as stress–relaxation quadrupoles. J. Acoust. Soc. Am. 1 March 1983; 73 (3): 1036–1046. https://doi.org/10.1121/1.389151
Download citation file:
Sign in
Don't already have an account? Register
Sign In
You could not be signed in. Please check your credentials and make sure you have an active account and try again.
Sign in via your Institution
Sign in via your InstitutionPay-Per-View Access
$40.00