A phonopneumographical study on the direction of the initial deflection of the waveforms of pleural friction rubs
Matsuzaki, M.; Ogasawara, H.; Minami, M.M.; Homma, Y.; Murao, M.
Nihon Kyobu Shikkan Gakkai Zasshi 20(10): 1056-1062
1982
ISSN/ISBN: 0301-1542 PMID: 7182619 Document Number: 192548
Seven patients with pleural friction rubs (PFR) were studied for the direction of the initial deflection (DID) of the waveforms by a phonopneumograph. In 4 cases, in which PFR were heard both on inspiration and on expiration, predominant DID was upward on inspiration and downward on expiration in 2; DID was downward in inspiration and upward in expiration in the other 2. In 3 cases, in which PFR were present only in inspiration, recording was done from 5 points. DID was upward at 4 points and downward at 1. Most of the waveforms on expiration were the reverse versions of the inspiratory ones. Shift of recording locations resulted in a remarkable change in DID distribution. Since DID distribution of clinical PFR is consistent with that of simulated PFR, a model of DID distribution of PFR can be made. Evidently DID can be a useful objective indicator for categorizing discontinuous adventitious lung sounds, coarse crackles, fine crackles and PFR.