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The effect of head-down tilt and water immersion on intracranial pressure in nonhuman primatesIntracranial pressure (ICP) is investigated in primates during and after -6-deg head-down tilt (HDT) and immersion in water to examine the effects of the headward fluid shift related to spaceflight. Following the HDT the primates are subjected to head-out thermoneutral water immersion, and the ICP is subsequently measured. ICP is found to increase from 3.8 +/- 1.1 to 5.3 +/- 1.3 mm Hg during the horizontal control period. ICP stabilizes at -6.3 +/- 1.3 mm Hg and then increases to -2.2 +/- 1.9 mm Hg during partial immersion, and ICP subsequently returns to preimmersion levels after immersion. These data indicate that exposure to HDT or water immersion lead to an early sharp increase in ICP, and water immersion alone leads to higher ICP levels. A significant conclusion of the work is that the ICP did not approach pathological levels, and this finding is relevant to human spaceflight research.
Document ID
Document Type
Reprint (Version printed in journal)
Keil, Lanny C.
(NASA Ames Research Center Moffett Field, CA, United States)
Mckeever, Kenneth H.
(Ohio State University Columbus, United States)
Skidmore, Michael G.
(NASA Ames Research Center Moffett Field, CA, United States)
Hines, John
(NASA Ames Research Center Moffett Field, CA, United States)
Severs, Walter B.
(Pennsylvania State University Hershey, United States)
Date Acquired
August 15, 2013
Publication Date
March 1, 1992
Publication Information
Publication: Aviation, Space, and Environmental Medicine
Volume: 63
ISSN: 0095-6562
Subject Category
Life Sciences (General)
Accession Number
Funding Number(s)
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