NASA Prebreathe Study

This study will validate the experimental method and chamber facility at the Duke Center for Hyperbaric Medicine \& Environmental Physiology and test team capabilities to support NASA decompression sickness (DCS) studies. This project is related to development of protocols for extravehicular activity (EVA, "spacewalks") to minimize the risk of decompression sickness. Duke will perform four test days, collecting and recording data each day. Each test day will involve 3 volunteer subjects ages 18-50 years, who will breathe 100% oxygen for 6 hours. This will be followed by 6 hours in the hypobaric chamber at 1/3 atmosphere, during which subjects will perform various tasks, including arm and leg exercises, and undergo ultrasound testing to detect vascular bubbles. End-points will include bubble scores, and decompression sickness (DCS). If subjects develop DCS symptoms they will immediately be recompressed to ambient pressure and be assessed and treated.