Lower body negative pressure reduces jugular and portal vein volumes and counteracts the elevation of middle cerebral vein velocity during long-duration spaceflight
Philippe Arbeille, Kathryn Zuj, Brandon R. Macias, Douglas Ebert, Steven S. Laurie, Ashot E. Sargsyan, David S. Martin, Stuart M. C. Lee, Scott A. Dulchavsky, Michael B. Stenger, Alan R. Hargens
Abstract
Microgravity-induced fluid shifts markedly enlarge jugular and portal veins and increase cerebral vein velocity. These findings demonstrate a marked flow engorgement at neck and splanchnic levels and may suggest compression of the cerebral veins by the brain tissue in space. LBNP (-25 mmHg for 30 min) returns these changes to preflight levels and, thus, reduces the associated flow and tissue disturbances.
Topics & Concepts
Supine positionSpaceflightMedicineWeightlessnessVenous return curveLower bodySpace medicineJugular veinCardiologyInternal medicineAnesthesiaHemodynamicsAviation medicinePathologyAstronomyPhysicsAerospace engineeringEngineeringSpaceflight effects on biologyCardiovascular and Diving-Related ComplicationsHigh Altitude and Hypoxia