Task Impact of +Gz and -Gz induced fluid shifts on ocular and cerebral parameters during simulated Orion re-entry.
Last Published:  03/26/21 03:34:00 PM (Central)
Short Title: Pull-Push Gz Fluid Shifts
Responsible HRP Element: Human Health Countermeasures
Collaborating Org(s):
Funding Status: Terminated - A formerly active task that was stopped before its completion date due to deselection, descoping, reorganization etc.
Procurement Mechanism(s):

Specific Aim 1: To determine the impact of sequential +1 Gz followed by -0.3 Gz stress

on cerebrovascular and ocular structure and function without the orthostatic intolerance

countermeasures normally applied in astronauts returning from space flight.

Hypothesis: Following +1.0 Gz exposure, –Gz exposure will increase jugular vein

distention and pressure, increase intraocular and intracranial pressure, and distend

optic nerve sheath diameter but not change cerebral blood flow velocity.

Specific Aim 2: To determine the effect of anti-orthostatic countermeasures (fluid

loading, gradient compression garments, legs up posture with foot pressure) on the +1

Gz to -0.3 Gz induced fluids shift and subsequent impact on cerebral and ocular

structure and function.

Hypothesis: The addition of the anti-orthostatic countermeasures will exacerbate ocular

and vascular effects induced by the HDT fluid shift and will overcome the ability of

cerebral autoregulation to minimize these changes resulting in clinically significant

elevations in ICP.

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