National Aeronautics and Space Administration (NASA)
The purpose of Lunar OI (Orthostatic Intolerance) is to determine if there are differences between males and females in tolerance to and cardiovascular responses during different angles of head-up tilt simulating gravity levels less than or equal to Earth's gravity. Also, this study will determine if a gradient compression garment affects tolerance to tilting and the cardiovascular stress at different tilt angles. Males and females are being identified by biological sex. This will be a two-phased study design. In Phase I we will determine whether there are differences in the development of signs or symptoms of orthostatic intolerance between males and females when tilted head up on a table to different angles to simulate gravity levels that astronauts may experience when landing on or launching from the surface of the Moon. In Phase II, the tilt tests simulating the same gravity levels from Phase I will be repeated, but a custom-made lower-body compression garment will be worn to see if wearing the garment affects the development of orthostatic intolerance. For both study phases, before tilting, a drug will be administered to reduce the amount fluid in the blood (plasma) to levels similar to that experienced by astronauts during spaceflight.
Phase I, Visit one Alpha (1A); OIG (Orthostatic Intolerance Garment) Measurement: Participants will lie supine while torso and anthropometric measurements are acquired. The investigators will utilize the same procedures developed and adopted by the Orion Program to obtain foot, leg, and torso circumference measurements at pre-determined intervals. This detailed measurement procedure has shown to be effective at providing precise compression levels at pre-determined anatomical locations. The target levels of compression will be verified by the manufacturer, using a Hosiery and Allied Trades R…
Inclusion Criteria: • Pass a test subject screening facility modified Air Force Class III physical Exclusion Criteria: * Known allergy to furosemide or sulfa drugs * Currently taking drugs or medications known to adversely interact with furosemide, including but not limited to aspirin, NSAIDs, antibiotics, or immunosuppressant drugs * Systemic diseases or current medications known to influence the cardiovascular system * Renal disease * Type II Diabetes * Pregnant participants will be excluded (a urine pregnancy screen will be made available).
Participants will be given a potassium supplement that will help prevent low blood potassium levels.
Furosemide (Lasix, 20 mg) will be administered through IV catheter to induce urination. The goal of this procedure is to reduce the volume of plasma in the blood.
From the torso and leg measurements obtained during Visit 1A, a custom-designed compression garment will be constructed.