Document Detail


Concise Clinical Review: High Altitude Medicine.
MedLine Citation:
PMID:  23103737     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
Abstract Medical problems occur at high altitude because of the low inspired PO2 which in turn is caused by the reduced barometric pressure. The classical physiological responses to high altitude include hyperventilation, polycythemia, hypoxic pulmonary vasoconstriction increased intracellular oxidative enzymes, and increased capillary density in muscle. However with the discovery of Hypoxia Inducible Factors (HIFs) it is now apparent that there is a multitude of other responses to cellular hypoxia. HIFs constitute a master switch determining the general response of the body to oxygen deprivation. The recent discovery of genetic changes in Tibetans has opened up an exciting area of research. Remarkably the two major human populations that have adapted well to high altitude, the Tibetans and Andeans, have strikingly different phenotypes. Diseases of lowlanders going to high altitude include Acute Mountain Sickness, High Altitude Pulmonary Edema and High Altitude Cerebral Edema. Diseases affecting permanent residents or highlanders include Chronic Mountain Sickness and High Altitude Pulmonary Hypertension. Important recent advances have been made on mitigation of the effects of the hypoxic environment. Oxygen enrichment of room air is very powerful. Every 1% increase in oxygen concentration reduces the equivalent altitude by about 300 m. This procedure is now used in numerous facilities at high altitude and in a Chinese train to Lhasa. An alternative strategy is to increase the barometric pressure as in aircraft cabins. A hybrid approach combining both strategies shows promise but has never been used. Mines that are being developed at increasingly high altitudes pose great medical problems.
Authors:
John B West
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-10-26
Journal Detail:
Title:  American journal of respiratory and critical care medicine     Volume:  -     ISSN:  1535-4970     ISO Abbreviation:  Am. J. Respir. Crit. Care Med.     Publication Date:  2012 Oct 
Date Detail:
Created Date:  2012-10-29     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9421642     Medline TA:  Am J Respir Crit Care Med     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Affiliation:
Dept. of Medicine 0623A, University of California San Diego, La Jolla, California, United States.
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