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Intracranial and intraocular pressure during various degrees of head-down tilt

Marshall-Goebel, Karina and Mulder, Edwin and Bershad, Eric and Laing, Charles and Eklund, Anders and Malm, Jan and Stern, Claudia and Rittweger, Jörn (2017) Intracranial and intraocular pressure during various degrees of head-down tilt. Aerospace Medicine and Human Performance, 88 (1), pp. 10-16. Aerospace Medical Association. DOI: 10.3357/AMHP.4653.2017 ISSN 2375-6314

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Abstract

BACKGROUND: More than half of astronauts develop ophthalmic changes during long-duration spaceflight consistent with an abnormal intraocular and intracranial pressure (IOP, ICP) difference. The aim of our study was to assess IOP and ICP during head-down tilt (HDT) and the additive or attenuating effects of 1% CO2 and lower body negative pressure (LBNP). METHODS: In Experiment I, IOP and ICP were measured in nine healthy subjects after 3.5 h HDT in five conditions: -6°, -12°, and -18° HDT, -12° with 1% CO2, and -12° with -20 mmHg LBNP. In Experiment II, IOP was measured in 16 healthy subjects after 5 min tilt at +12°, 0°, -6°, -12°, -18°, and -24°, with and without -40 mmHg LBNP. RESULTS: ICP was only found to increase from supine baseline during -18° HDT (9.2 6 0.9 and 14.4 6 1 mmHg, respectively), whereas IOP increased from 15.7 6 0.3 mmHg at 0° to 17.9 6 0.4 mmHg during -12° HDT and from 15.3 6 0.4 mmHg at 0° to 18.7 6 0.4 mmHg during -18° HDT. The addition of -20 mmHg LBNP or 1% CO2 had no further effects on ICP or IOP. However, the use of -40 mmHg LBNP during HDT lowered IOP back to baseline values, except at 224° HDT. DISCUSSION: A small, posterior intraocular-intracranial pressure difference (IOP . ICP) is maintained during HDT, and a sustained or further decreased difference may lead to structural changes in the eye in real and simulated microgravity.

Item URL in elib:https://elib.dlr.de/110463/
Document Type:Article
Title:Intracranial and intraocular pressure during various degrees of head-down tilt
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Marshall-Goebel, Karinainstitute of aerospace medicine, german aerospace center (dlr)UNSPECIFIED
Mulder, Edwingerman aerospace center (dlr), institute of aerospace medicine, space physiology, cologne, germanyUNSPECIFIED
Bershad, Ericdepartment of neurology, baylor college of medicine, houston, texasUNSPECIFIED
Laing, CharlesKing’s College LondonUNSPECIFIED
Eklund, Andersdepartment of radiation sciences, umeå university, umeå, swedenUNSPECIFIED
Malm, Jandepartment of pharmacology and clinical neuroscience, umeåUNSPECIFIED
Stern, Claudiainstitut für luft- und raumfahrtmedizin, operationelle medizinUNSPECIFIED
Rittweger, Jörninstitute of aerospace medicine, deutsches zentrum für luft- und raumfahrt, dlr e.v., cologne, germany and medical faculty, university of cologne, cologne, germany; joern.rittweger (at) dlr.deUNSPECIFIED
Date:January 2017
Journal or Publication Title:Aerospace Medicine and Human Performance
Refereed publication:Yes
Open Access:Yes
Gold Open Access:No
In SCOPUS:Yes
In ISI Web of Science:Yes
Volume:88
DOI :10.3357/AMHP.4653.2017
Page Range:pp. 10-16
Publisher:Aerospace Medical Association
ISSN:2375-6314
Status:Published
Keywords:lower body negative pressure, carbon dioxide, visual impairment, translaminar pressure gradient, posture.
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Space
HGF - Program Themes:Research under Space Conditions
DLR - Research area:Raumfahrt
DLR - Program:R FR - Forschung unter Weltraumbedingungen
DLR - Research theme (Project):R - Vorhaben Integrative Studien (old)
Location: Köln-Porz
Institutes and Institutions:Institute of Aerospace Medicine > Space Physiology
Deposited By: Becker, Christine
Deposited On:11 Jan 2017 10:14
Last Modified:31 Jul 2019 20:07

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