Document Detail

Effects of respiratory variables on regional gas transport during high-frequency ventilation.
MedLine Citation:
PMID:  3391909     Owner:  NLM     Status:  MEDLINE    
The regional effects of tidal volume (VT), respiratory frequency, and expiratory-to-inspiratory time ratio (TE/TI) during high-frequency ventilation (HFV) were studied in anesthetized and paralyzed dogs. Regional ventilation per unit of lung volume (spVr) was assessed with a positron camera during the washout of the tracer isotope 13NN from the lungs of 12 supine dogs. From the washout data, functional images of the mean residence time (MRT) of 13NN were produced and spVr was estimated as the inverse of the regional MRT. We found that at a constant VT X f product (where f represents frequency), increasing VT resulted in higher overall lung spV through the local enhancement of the basal spVr and with little effect in the apical spVr. In contrast, increasing VT X f at constant VT increased overall ventilation without significantly affecting the distribution of spVr values. TE/TI had no substantial effect in regional spVr distribution. These findings suggest that the dependency of gas transport during HFV of the form VT2 X f is the result of a progressive regional transition in gas transport mechanism. It appears, therefore, that as VT increases, the gas transport mechanism changes from a relative inefficient dispersive mechanism, dependent on VT X f, to the more efficient mechanism of direct fresh gas convection to alveoli with high regional tidal volume-to-dead-space ratio. A mathematical model of gas transport in a nonhomogeneous lung that exhibits such behavior is presented.
J G Venegas; Y Yamada; J Custer; C A Hales
Related Documents :
8904569 - Effects of n2o narcosis on breathing and effort sensations during exercise and inspirat...
22010599 - A long-term care facility pandemic influenza preparedness planning assessment tool.
9801479 - Interpretation of capnography.
9517599 - Low load inspiratory muscle training increases diaphragmatic fiber dimensions in rats.
2010409 - Respiratory adaptations to dead space loading during maximal incremental exercise.
948739 - Ventilatory and heart rate adjustments during submaximal and maximal exercise in patien...
1555619 - Exercise echocardiography versus thallium-201 spect for assessing patients before and a...
18089939 - Food-dependent exercise-induced anaphylaxis induced by low dose aspirin therapy.
8439259 - Influence of cryotherapy on spasticity at the human ankle.
Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  64     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  1988 May 
Date Detail:
Created Date:  1988-08-17     Completed Date:  1988-08-17     Revised Date:  2013-09-26    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol (1985)     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  2108-18     Citation Subset:  IM; S    
Department of Biomedical Engineering, Massachusetts General Hospital, Boston 02114.
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
High-Frequency Ventilation*
Pulmonary Gas Exchange*
Tidal Volume
Grant Support

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

Previous Document:  Role of transferrin and ceruloplasmin in antioxidant activity of lung epithelial lining fluid.
Next Document:  Nocturnal shifts in thermal and metabolic responses of the immature rat.