Document Detail


Maximum intra-thoracic pressure with anti-G straining maneuvers and positive pressure breathing during +Gz.
MedLine Citation:
PMID:  1510639     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Positive pressure breathing during +Gz (PBG) and anti-G straining maneuvers (AGSM) each improve +Gz tolerance by increasing blood pressure through increases in intra-thoracic pressure, but the maximal intra-thoracic pressure from their combined effect is not known. Six subjects performed the following: 1) maximal AGSM at +1 Gz; 2) assisted PBG (constant 60 mm Hg) at +Gz; 3) submaximal AGSM at +Gz (enough to maintain peripheral vision); 4) maximal AGSM at +Gz; and 5) combined PBG and maximal AGSM at +Gz. They wore TLSS mask/helmet ensemble, CSU-15/P G-suit, and TLSS-style jerkin. Intra-thoracic pressure was measured with a catheter-tip pressure transducer in the esophagus (Pes). The change in gastric pressure was also measured (delta Pga). For both Pes and delta Pga, there were no significant differences among experimental conditions (1), (4) and (5), as above. Group mean Pes and delta Pga in these three conditions were 139 and 197 mm Hg, respectively. The similar results between maximal AGSM, and maximal AGSM and PBG are explained by limited support from the thoracic counter-pressure garment, and the characteristics of the respiratory system.
Authors:
F Buick; J Hartley; M Pecaric
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Aviation, space, and environmental medicine     Volume:  63     ISSN:  0095-6562     ISO Abbreviation:  Aviat Space Environ Med     Publication Date:  1992 Aug 
Date Detail:
Created Date:  1992-09-21     Completed Date:  1992-09-21     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  7501714     Medline TA:  Aviat Space Environ Med     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  670-7     Citation Subset:  IM; S    
Affiliation:
Defence and Civil Institute of Environmental Medicine, Aerospace Physiology Section, North York, Ont., Canada.
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MeSH Terms
Descriptor/Qualifier:
Blood Pressure / physiology*
Breathing Exercises*
Gravitation*
Gravity Suits
Humans
Positive-Pressure Respiration*
Respiratory Physiological Phenomena

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


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