Development of lower body negative pressure as a countermeasure for orthostatic intolerance.
Exposure to prolonged (1-4 hr) lower body negative pressure (LBNP) is a countermeasure against postflight orthostatic intolerance which is used in the Soviet space program and planned for use in the American space program. LBNP in combination with fluid-loading is believed to act by promoting a transient positive fluid balance resulting in an increase in vascular, as well as extravascular fluid. Inflight LBNP also may provide beneficial orthostatic effects by restoring baroreceptor reflex functions and/or lower body venous compliance. Current research efforts at the Johnson Space Center are directed towards increasing the effectiveness and efficiency of the LBNP and saline countermeasure. A promising avenue may involve combining pharmacologic agents, such as inhaled anti-diuretic hormone, or mineralocorticoids, with mechanical stimuli such as LBNP.
Fortney
S M
SM
Space Biomedical Research Institute, NASA Johnson Space Center, Houston, Texas 77058.
D006801:Humans; D007024:Hypotension, Orthostatic / Q000517:prevention & control*; D008150:Lower Body Negative Pressure; D013026:Space Flight