TY - JOUR
T1 - Internal jugular vein volume during head-down tilt and carbon dioxide exposure in the SPACECOT study
AU - The SPACECOT Investigators Group
AU - Marshall-Goebel, Karina
AU - Stevens, Brian
AU - Rao, Chethan Venkatasubba
AU - Suarez, Jose I.
AU - Calvillo, Eusebia
AU - Arbeille, Philippe
AU - Sangi-Haghpeykar, Haleh
AU - Donoviel, Dorit B.
AU - Mulder, Edwin
AU - Bershad, Eric M.
AU - Basner, Mathias
AU - Becker, Christine
AU - Clark, Jonathan
AU - Damani, Rahul
AU - Doering, Wolfgang
AU - Dohmen, Christian
AU - Frings-Meuthen, Petra
AU - Gauger, Peter
AU - Gerlach, Darius
AU - Hand, Olga
AU - Hasan, Khader
AU - Huth, Elfriede
AU - Johannes, Bernd
AU - Kramer, Larry
AU - Kraus, Gabriele
AU - Limper, Ulrich
AU - Mittag, Uwe
AU - Muller, Klaus
AU - Nasrini, Jad
AU - Niederberger, Ben
AU - Poddig, Dirk
AU - Putzke, Matthias
AU - Rittweger, Jörn
AU - Sagner, Martina
AU - Schrage-Knoll, Irmtrud
AU - Sies, Wolfram
AU - Stern, Claudia
AU - Stetefeld, Henning
AU - Strangman, Gary
AU - von Waechter, Annette
AU - Weber, Tobias
AU - Wittkowski, Martin
AU - Gerzer, Rupert
AU - Do, Julie
AU - Sutton, Jeff
N1 - Publisher Copyright:
© by the Aerospace Medical Association, Alexandria, VA.
PY - 2018/4/1
Y1 - 2018/4/1
N2 - BACKGROUND: Cerebral hemodynamics and venous outflow from the brain may be altered during exposure to microgravity or head-down tilt (HDT), an analog of microgravity, as well as by increased ambient CO2 exposure as experienced on the International Space Station. METHODS: Six healthy subjects underwent baseline tilt table testing at 0°, 6°, 12°, 18°, 24°, and 30° HDT. The right internal jugular (IJ) vein cross-sectional area (CSA) was measured at four intervals from the submandibular to the clavicular level and IJ volume was calculated. Further measurements of the IJ vein were made after ~26 h of 12° HDT bed rest with either ambient air or 0.5% CO2 exposure, and plasma and blood volume were assessed after 4 h, 24 h, and 28.5 h HDT. RESULTS: IJ vein CSA and volume increased with progressively steeper HDT angles during baseline tilt table testing, with more prominent filling of the IJ vein at levels closer to the clavicle. Exposure to 26 h of 12° HDT bed rest with or without increased CO2, however, had little additional effect on the IJ vein. Further, bed rest resulted in a decrease in plasma volume and blood volume, although changes did not depend on atmospheric conditioning or correlate directly with changes in IJ vein CSA or volume. DISCUSSION: The hydrostatic effects of HDT can be clearly determined through measurement of the IJ vein CSA and volume; however, IJ vein dimensions may not be a reliable indicator of systemic fluid status during bed rest.
AB - BACKGROUND: Cerebral hemodynamics and venous outflow from the brain may be altered during exposure to microgravity or head-down tilt (HDT), an analog of microgravity, as well as by increased ambient CO2 exposure as experienced on the International Space Station. METHODS: Six healthy subjects underwent baseline tilt table testing at 0°, 6°, 12°, 18°, 24°, and 30° HDT. The right internal jugular (IJ) vein cross-sectional area (CSA) was measured at four intervals from the submandibular to the clavicular level and IJ volume was calculated. Further measurements of the IJ vein were made after ~26 h of 12° HDT bed rest with either ambient air or 0.5% CO2 exposure, and plasma and blood volume were assessed after 4 h, 24 h, and 28.5 h HDT. RESULTS: IJ vein CSA and volume increased with progressively steeper HDT angles during baseline tilt table testing, with more prominent filling of the IJ vein at levels closer to the clavicle. Exposure to 26 h of 12° HDT bed rest with or without increased CO2, however, had little additional effect on the IJ vein. Further, bed rest resulted in a decrease in plasma volume and blood volume, although changes did not depend on atmospheric conditioning or correlate directly with changes in IJ vein CSA or volume. DISCUSSION: The hydrostatic effects of HDT can be clearly determined through measurement of the IJ vein CSA and volume; however, IJ vein dimensions may not be a reliable indicator of systemic fluid status during bed rest.
KW - Analog
KW - Cerebral hemodynamics
KW - Cross sectional area
KW - Plasma volume
KW - Spaceflight
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U2 - 10.3357/AMHP.4934.2018
DO - 10.3357/AMHP.4934.2018
M3 - Article
C2 - 29562964
AN - SCOPUS:85044867950
SN - 2375-6314
VL - 89
SP - 351
EP - 356
JO - Aerospace Medicine and Human Performance
JF - Aerospace Medicine and Human Performance
IS - 4
ER -