NASA has long recognized the difficulty in providing emergency medical care to astronauts in space. Many aspects of space travel make medical care inherently difficult, and sufficient storage space for medical equipment severely limits the ability to carry a full complement of diagnostic and therapeutic equipment onboard. The Microgravity Compatible Medical Suction Device (MCMSD) enables aspiration and containment of bodily fluids and vomitus, while preventing the transmission of infectious agents.
Many medical procedures require aspiration to remove saliva and blood during dental procedures; blood and loose tissue during surgery; or vomit, mucus, and saliva during airway management. Aspirated material is trapped in a collection vessel, which prevents exposure of medical personnel and the environment to biological hazards.
Microgravity aspiration poses its own set of challenges. The most serious problem is a means to separate liquids from gases, allowing fluid capture within a collection vessel. Although centripetal forces may be used to separate aspirated liquids and particles from a gas-containing stream, postcollection handling of the biofluids requires a more complex phase separator.
The novel feature of the MCMSD is the ability to capture and retain large volumes of biological fluids from a rapidly flowing air stream in any gravitational environment. The basis of the device was an absorbent material deposited on to an open cell support contained within a collapsible polymer cartridge. The absorbent material captures aqueous liquids while the open cell support and internal baffles produce a tortuous pathway that inhibits transport of solids and viscous fluids in various aspirated substances. A hydrophobic microporous filter membrane mounted to the effluent end of the MCMSD cartridge prevents transfer of liquids and infectious agents into the external vacuum system. The MCMSD cartridges were tested with saline solution, yogurt, cottage cheese, and a 50/50 bovine blood/normal saline mixture.
The ability to aspirate mixed-phase biological materials reliably and permanently retain the solid/liquid components will be crucial for many medical emergencies including surgery, recovery of airway, regurgitation events, and any other situation involving fluid removal/retention.
Commercialization of this technology has many opportunities in the emergency medical response market. The current state-of-the-art portable medical aspirator technology relies on gravity to retain solids and liquids at the bottom of a containment vessel. Any major upset to the vessel that changes its orientation to gravity may cause aspirant to block the pathway to the vacuum source.