Document Detail


Variations in flow and intraalveolar pressure during jet ventilation: theoretical and experimental analysis.
MedLine Citation:
PMID:  2711054     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Alteration in flow and pressure in a chest-lung model during jet ventilation was studied from a theoretical and experimental standpoint. The model consisted of a stiff box, with an inserted cast of the bronchial tree, simulating either normal or low compliance of the human chest-lung. Airway resistances in the model could be altered. A constant driving flow (Vd) was applied through the opening of the trachea at various rates. The driving flow drew in a constant flow (entrained flow = Ve) and increased the box pressure (PA), which in turn induced an increasing back flow (Vr). Vd, Ve-Vr and PA were measured. Theoretical analysis of time variation in box pressure showed a monoexponential pattern which was confirmed experimentally. Tr, the time at which back flow and entrained flow become equal could be predicted taking the physical characteristics of the experimental set-up and the values of Vd and Ve into account. Tr values depended mainly on the compliance of the experimental set-up. Increasing the resistances was found to reduce Ve. In practice, the efficiency of jet ventilation for gas exchange at a frequency below 4 Hz is known to be mainly related to the volume of gas flowing in the trachea towards the alveoli. This efficiency generally depends on the values of Tr and the inspiratory period (TI). A value of TI less than or equal to Tr will thus improve the jet ventilation efficiency.
Authors:
H Guenard; A M Cros; C Boudey
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Respiration physiology     Volume:  75     ISSN:  0034-5687     ISO Abbreviation:  Respir Physiol     Publication Date:  1989 Feb 
Date Detail:
Created Date:  1989-05-26     Completed Date:  1989-05-26     Revised Date:  2009-11-11    
Medline Journal Info:
Nlm Unique ID:  0047142     Medline TA:  Respir Physiol     Country:  NETHERLANDS    
Other Details:
Languages:  eng     Pagination:  235-45     Citation Subset:  IM    
Affiliation:
Laboratoire de Physiologie, Université de Bordeaux-II, France.
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MeSH Terms
Descriptor/Qualifier:
Adult
High-Frequency Jet Ventilation*
Humans
Lung Compliance
Models, Structural
Pressure
Pulmonary Alveoli / physiology*
Respiration*

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