Document Detail

Effect of volume history on successive partial expiratory flow-volume maneuvers.
MedLine Citation:
PMID:  956096     Owner:  NLM     Status:  MEDLINE    
In normal subjects, the second of two successive partial expiratory flow-volume (PEFV 2) curves often had higher isovolume maximal expiratory flow rates (Vmax) than the first (PEFV 1) (mean increase 30.2 +/- 13%). The higher Vmax on PEFV 2 was present only when there was a greater lung elastic recoil pressure (Pst(L)). In eight subjects the Pst(L) derived from sequential partial quasi-static pressure-volume curves, from interruption of the flow-volume maneuvers and at the start of the PEFV curves showed that isovolume upstream resistance increased although Vmax also increased after going to residual volume (RV). In four subjects the RV volume history did not change the pressure flow relationship across the upstream airways. If airways dimensions were the sole determinant of Vmax, then Vmax on PEFV 2 would be the same or smaller than on PEFV 1. That the opposite was observed in our study indicates that the increase in Pst(L), which results from parenchymal hysteresis, offsets any dimensional decrease in upstream airways due to airways hysteresis.
J J Wellman; R Brown; R H Ingram; J Mead; E R McFadden
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Journal of applied physiology     Volume:  41     ISSN:  0021-8987     ISO Abbreviation:  J Appl Physiol     Publication Date:  1976 Aug 
Date Detail:
Created Date:  1976-11-01     Completed Date:  1976-11-01     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0376576     Medline TA:  J Appl Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  153-8     Citation Subset:  IM    
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MeSH Terms
Forced Expiratory Flow Rates*
Functional Residual Capacity
Lung / physiology*
Maximal Expiratory Flow Rate
Maximal Expiratory Flow-Volume Curves*
Middle Aged
Plethysmography, Whole Body
Tidal Volume
Time Factors

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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