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Discontinuous lung sounds and hysteresis in control and Tween 20-rinsed excised rat lungs.

Authors
Cheng-W; DeLong-DS; Franz-GN; Petsonk-EL; Frazer-DG
Source
Respir Physiol 1999 Sep; 117(2/3):131-140
NIOSHTIC No.
20000900
Abstract
In the past, the relationship between pulmonary hysteresis and a model of the recruitment-derecruitment of lung units has been explored (Cheng, W., DeLong, D.S., Franz, G.N., Petsonk, E.L., Frazer, D.G., 1995, Resp. Physiol. 102, 205-215). The recruitment process is characterized by a sequence of events which represents discrete configurational changes in lung structure. It is assumed that energy released during the opening of lung units is associated with the formation of discontinuous lung sounds. The goal of this study was to record tracheal sounds for lungs inflated from different end-expiratory pressures and to relate the sound power to the normalized hysteresis of individual pressure-volume (PL-VL) loops. PL-VL curves and lung sounds were recorded for control lungs and lungs rinsed with Tween 20 in order to estimate the role of alveolar surfactant on the recruitment-derecruitment process. Results indicate that there may be two populations of lung units, one which is altered by Tween 20 and another which is not. The population not affected by Tween 20 appears to be responsible for producing discrete lung sounds and may represent the opening of larger conducting airways. The second population, possibly within the respiratory zone, is affected by alterations in surface tension and contributes to pulmonary hysteresis, but, apparently, does not contribute significantly to lung sound power measured at the trachea.
Keywords
Lung; Lung-function; Pressure-testing; Pressure-gradients; Sound-analyzers; Author Keywords: Airways; closure; Lung; sounds; Mammals; rat; Mechanics of breathing; lung sounds; Recruitment; lung units; sound
CODEN
RSPYAK
Publication Date
19990915
Document Type
Journal Article
Fiscal Year
1999
NTIS Accession No.
NTIS Price
Issue of Publication
2/3
ISSN
0034-5687
NIOSH Division
HELD; DRDS
Priority Area
Other Occupational Concerns
Source Name
Respiration Physiology
State
WV
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