Validation of a Cephalad Fluid Shift Countermeasure

This project directly addresses Critical Path Roadmap Risks and Questions regarding “Risk of Spaceflight-Induced Intracranial Hypertension/Vision Alterations,” and Integrated Research Plan Gap VIIP13: We need to identify preventative and treatment countermeasures to mitigate changes in ocular structure and function and intracranial pressure during spaceflight. Ophthalmic evaluations of astronauts after their 6-month missions to the International Space Station revealed unexpected vision problems. While there are many possible explanations for these vision problems in astronauts, elevated intracranial pressure due to a headward fluid shift during microgravity is proposed as the leading mechanism for the observed disc edema, globe flattening, choroidal folds, and hyperopic shifts. However, it is unclear if and how lower body fluid sequestration by an advanced thigh cuff device reduces ICP. These experiments will provide critical data required to objectively determine how an optimized thigh cuff could be incorporated into the NASA integrated physiological countermeasure suite. Therefore, the objective of this study is to determine the efficacy of a novel thigh cuff device to mitigate cephalad fluid shifts. In addition, this project will determine tissue pressure distribution applied by thigh cuffs in order to improve comfort, mobility, and efficacy of the countermeasure.