Document Detail


The impact of moderate-altitude staging on pulmonary arterial hemodynamics after ascent to high altitude.
MedLine Citation:
PMID:  20586598     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Staged ascent (SA), temporary residence at moderate altitude en route to high altitude, reduces the incidence and severity of noncardiopulmonary altitude illness such as acute mountain sickness. To date, the impact of SA on pulmonary arterial pressure (PAP) is unknown. We tested the hypothesis that SA would attenuate the PAP increase that occurs during rapid, direct ascent (DA). Transthoracic echocardiography was used to estimate mean PAP in 10 healthy males at sea level (SL, P(B) approximately 760 torr), after DA to simulated high altitude (hypobaric chamber, P(B) approximately 460 torr), and at 2 times points (90 min and 4 days) during exposure to terrestrial high altitude (P(B) approximately 460 torr) after SA (7 days, moderate altitude, P(B) approximately 548 torr). Alveolar oxygen pressure (Pao(2)) and arterial oxygenation saturation (Sao(2)) were measured at each time point. Compared to mean PAP at SL (mean +/- SD, 14 +/- 3 mmHg), mean PAP increased after DA to 37 +/- 8 mmHg (Delta = 24 +/- 10 mmHg, p < 0.001) and was negatively correlated with both Pao(2) (r(2) = 0.57, p = 0.011) and Sao(2) (r(2) = 0.64, p = 0.005). In comparison, estimated mean PAP after SA increased to only 25 +/- 4 mmHg (Delta = 11 +/- 6 mmHg, p < 0.001), remained unchanged after 4 days of high altitude residence (24 +/- 5 mmHg, p = not significant, or NS), and did not correlate with either parameter of oxygenation. SA significantly attenuated the PAP increase associated with continuous direct ascent to high altitude and appeared to uncouple PAP from both alveolar hypoxia and arterial hypoxemia.
Authors:
Aaron L Baggish; Charles S Fulco; Stephen Muza; Paul B Rock; Beth Beidleman; Allen Cymerman; Kibar Yared; Peter Fagenholz; David Systrom; Malissa J Wood; Arthur E Weyman; Michael H Picard; N Stuart Harris
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.    
Journal Detail:
Title:  High altitude medicine & biology     Volume:  11     ISSN:  1557-8682     ISO Abbreviation:  High Alt. Med. Biol.     Publication Date:  2010  
Date Detail:
Created Date:  2010-06-30     Completed Date:  2010-10-21     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100901183     Medline TA:  High Alt Med Biol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  139-45     Citation Subset:  IM; S    
Affiliation:
Massachusetts General Hospital, Boston, 02114, USA. abaggish@partners.org <abaggish@partners.org>
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MeSH Terms
Descriptor/Qualifier:
Adaptation, Physiological / physiology*
Adult
Altitude Sickness / blood,  physiopathology*
Environment, Controlled
Hemodynamics / physiology
Humans
Male
Mountaineering / physiology*
Nontherapeutic Human Experimentation
Oxygen Consumption / physiology*
Pulmonary Alveoli / physiology
Pulmonary Artery / physiology*
Pulmonary Gas Exchange / physiology
Reference Values
Young Adult

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


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