Document Detail

Chronic mountain sickness: recent studies of the relationship between hemoglobin concentration and oxygen transport.
MedLine Citation:
PMID:  15265336     Owner:  NLM     Status:  MEDLINE    
Although an increase in hemoglobin concentration [Hb] in high altitude residents assists oxygen transport, excessive polycythemia ([Hb] > or = 21 g/100 mL) may cause the syndrome of chronic mountain sickness (CMS). A recent theoretical analysis has suggested that increasing [Hb] above 18 g/100 mL provides no further benefit in oxygen transport at rest. To test this hypothesis, we examined oxygen transport at rest for given arterial oxygen saturations (Sa(O2), in classes at intervals of 5%) as reported in 206 residents of various altitudes. For Sa(O2) of 97% versus 87%, [Hb] and a-v oxygen content difference increased (respectively, 14.5 to 17.5 g/100 mL and 4.11 to 5.03 volume %). As Sa(O2) fell further to 66%, a-v progressively decreased to 3.77 volume %, despite an increase in [Hb] to 24.2 g/100 mL. Over the Sa(O2) range of 97% to 66%, the a-v difference changed little (-8%) compared to other subjects made acutely hypoxic (-33%), for Sa(O2) change from 97% to 75%. The results suggest that increasing [Hb] allows greater oxygen extraction (a cardiac output sparing effect), which is maximal at Sa(O2) of 87% and a [Hb] of 17.5 g/100 mL. For more severe hypoxemia, even to Sa(O2) of 66%, both increasing [Hb] and increasing output are utilized for oxygen transport.
John T Reeves; Fabiola Leon-Velarde
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, U.S. Gov't, P.H.S.; Review    
Journal Detail:
Title:  High altitude medicine & biology     Volume:  5     ISSN:  1527-0297     ISO Abbreviation:  High Alt. Med. Biol.     Publication Date:  2004  
Date Detail:
Created Date:  2004-07-21     Completed Date:  2004-10-05     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  100901183     Medline TA:  High Alt Med Biol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  147-55     Citation Subset:  IM; S    
University of Colorado Health Sciences Center, Denver, 80262, USA.
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MeSH Terms
Altitude Sickness / blood*
Anoxia / metabolism
Cardiac Output / physiology
Chronic Disease
Hemoglobins / metabolism*
Oxygen / blood*
Oxygen Consumption / physiology
Reference Values
Grant Support
Reg. No./Substance:
0/Hemoglobins; 7782-44-7/Oxygen

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

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