Document Detail

Active inspiratory impedance in halothane-anesthetized humans.
MedLine Citation:
PMID:  6874469     Owner:  NLM     Status:  MEDLINE    
We have used the method of Siafakas et al. (J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 51: 109-121, 1981) to determine active elastance (E'rs) and flow resistance (R'rs) of the respiratory system in eight spontaneously breathing humans anesthetized with halothane. From measurements of flow (V) and volume (V) during unoccluded inspirations and of tracheal pressure (P0tr) during subsequent inspirations with the airways occluded at end expiration, we were able to compute E'rs and R'rs as slopes and intercepts of the following function: -P0tr/V = R'rs + E'rsV/V. These measurements were repeated during inspirations loaded with a series of linear flow resistances (delta R). Neither E'rs nor R'rs was significantly affected by delta R. On the average E'rs and R'rs were, respectively, 34.4 and 16.7% higher than the corresponding passive elastance and flow resistance of the respiratory system, indicating that during active breathing the internal impedance of the respiratory system increases. This provides an internal mechanism by which passive loads are compensated.
P K Behrakis; B D Higgs; A Baydur; W A Zin; J Milic-Emili
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Journal of applied physiology: respiratory, environmental and exercise physiology     Volume:  54     ISSN:  0161-7567     ISO Abbreviation:  J Appl Physiol Respir Environ Exerc Physiol     Publication Date:  1983 Jun 
Date Detail:
Created Date:  1983-09-20     Completed Date:  1983-09-20     Revised Date:  2013-09-26    
Medline Journal Info:
Nlm Unique ID:  7801242     Medline TA:  J Appl Physiol Respir Environ Exerc Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1477-81     Citation Subset:  IM    
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MeSH Terms
Anesthesia, General*
Halothane / pharmacology*
Lung Compliance / drug effects*
Middle Aged
Pulmonary Ventilation / drug effects*
Trachea / physiology
Grant Support
Reg. No./Substance:

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