illustration (IMAGE) UT Southwestern Medical Center Caption James Leidner spent three nights in a high-tech sleeping bag that unloads pressure in the brain by suctioning fluids into the lower body. NASA hopes the sack can be used by astronauts in space to alleviate the vision problems they commonly endure during longer missions. Credit UT Southwestern Medical Center Usage Restrictions none License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.