Document Detail

Inspiratory work of breathing on flow-by and demand-flow continuous positive airway pressure.
MedLine Citation:
PMID:  2676347     Owner:  NLM     Status:  MEDLINE    
Continuous positive airway pressure (CPAP) breathing can be delivered using the demand-flow (DF) or continuous-flow (CF) system. A modified CF system, the flow-by (FB) system, operates with preset base-flow (BF) values between 5 and 20 L/min. The DF depends on changes in pressure for opening the pneumatic valve of the system (pressure sensitivity). In contrast, the FB depends on changes in flow (flow sensitivity). In six healthy male subjects, we determined the mechanical inspiratory work of breathing (WI, J/L) and the inspiratory work rate (J/min) on the DF and the FB systems at a BF of 5 and 20 L/min, at CPAP levels of 0, 5, and 10 cm H2O. In comparison to DF, on the FB system both WI and inspiratory work rate were significantly less at a CPAP of 10 cm H2O (p less than .01). This was most likely due to the smaller drop in airway pressure at the onset of inspiration with the FB system. Varying the BF values in the FB system had no effect on WI or inspiratory work rate.
C S Sassoon; A E Giron; E A Ely; R W Light
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.    
Journal Detail:
Title:  Critical care medicine     Volume:  17     ISSN:  0090-3493     ISO Abbreviation:  Crit. Care Med.     Publication Date:  1989 Nov 
Date Detail:
Created Date:  1989-11-22     Completed Date:  1989-11-22     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0355501     Medline TA:  Crit Care Med     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1108-14     Citation Subset:  AIM; IM    
Department of Medicine, Veterans Administration Medical Center, Long Beach, CA 90822.
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MeSH Terms
Positive-Pressure Respiration / methods*
Work of Breathing*

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

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