2002 OPEN FORUM Abstracts
Design of Medical Vacuum System for Use in Space
Jimmy Wu BS, Terrell M. Guess, Victor Hurst IV PhD, George Beck BA, RRT Wyle Laboratories Life Sciences Systems & Services, Houston, TX
Background: The International Space Station (ISS) Medical Operations Requirements Document (JSC SSP 50260) states there must be a means to provide advanced life support (ALS) aboard ISS. Fundamental to ALS is the requirement for medical vacuum capabilities that allow for airway management, cavity drainage, and biohazardous waste management. Most terrestrial medical vacuum systems use gravity to separate air and fluid. This is not an option in space; therefore an alternative method of air-fluid separation must be used. Furthermore, a means to filter the vacuumed air stream must be implemented to remove airborne microorganisms and aerosolized particulates so they do not pose an additional contamination hazard to the ISS environment.
Method: A trade study was conducted to evaluate air-fluid separation technologies used in terrestrial medical vacuum systems. In addition, technologies used on the space shuttle and ISS that perform air-fluid separation (toilet, shower, wet/dry vacuum, condensation collector) were investigated. These technologies were evaluated based on several criteria including performance, mass, volume, power requirement, and cost. Several design concepts were developed that would convert these existing vacuum system technologies into a space medical vacuum system (SMVS). All these concepts involved use of a bacterial/viral air filter and a closed suction catheter. A parallel trade study of these devices was conducted to select the best commercial-off-the-shelf (COTS) filter and catheter.
Results: The ISS wet/dry vacuum (WDV) cleaner assembly met the most requirements but still needed modifications for use in medical contingencies. An adaptation design was selected that required no direct modification to the ISS WDV. Instead, the SMVS consists of attachments that accessorize the ISS WDV enabling medical vacuum use. All biohazardous waste is separated and contained within SMVS, external to the WDV. The COTS bacterial/viral air filter isolates airborne microorganisms and particulates, while the closed suction catheter serves as the patient interface and added protection for the crew care provider.
Conclusion: Deploying a medical vacuum system for use in space will serve to enhance ALS aboard ISS. SMVS represents a combination of COTS and currently flown NASA devices to provide augmented critical care capability in space.
This work was supported under contract to NASA, NAS9-97005.