Making Medical Grade Saline in Space

Whenever an injured or ill person is admitted into an emergency room, one of the first steps in many treatments is for the patient to receive saline solution intravenously (through a vein). This basic, yet essential, treatment both keeps the patient hydrated and prepares them to receive any other needed drugs intravenously. Severely injured patients, such as burn victims, can require several liters of saline, a mixture of salt and purified water.

When astronauts venture out into space—whether to the International Space Station, the moon, Mars or beyond—they receive specialized first-aid and medical training to ensure they can care for health issues that might confront themselves or other crew members. NASA spacecraft are equipped with medical equipment and supplies, including saline solution. However, saline solution cannot be stored indefinitely, and given that NASA is developing vehicles and planning for exploration missions progressively further away from Earth, a method is needed to create sterile saline solution on spacecraft or the space station.

NASA's Glenn Research Center in Cleveland, Ohio is preparing to launch their IntraVenous Fluid Generation (IVGEN) technology demonstration hardware to the space station on shuttle mission STS-131, currently scheduled for March. IVGEN represents years of dedicated work by Glenn scientists and engineers and their industry partner, ZIN Technologies, Inc. of Middleburg Heights, Ohio. IVGEN will be tested on the space station to validate its performance in microgravity, and could eventually become a key component of the medical equipment carried on long-duration space flights.

Jane Moultrie, M.D. tests the hardware aboard NASA's Reduced Gravity Aircraft C-9 in May 2007. Image Credit: NASA

"IVGEN is important because medical requirements stipulate that exploration missions carry over 100 liters of IV fluid. The vehicle cannot afford the mass and volume necessary to meet that requirement," says DeVon Griffin, the Exploration Medical Capability Project Manager at Glenn and the project manager for IVGEN. "IVGEN technology will consume much less mass and volume, while allowing the crew to generate the needed treatment fluid should that become necessary."

The goal of IVGEN is to generate U.S. Pharmacopeia (USP) grade IV solution using "in situ" resources—to make sterile saline solution using the water that is available on the space station. This solution is normal saline, or a mix of .9% salt and water. The saline must meet strict medical requirements and weigh less and take up less space than pre-prepared solution would (it’s expensive to launch liquid into space because it's heavy.)

DeVon Griffin, his Glenn team and ZIN Technologies have developed, designed and extensively tested their invention. IVGEN has exceeded expectations in its Earth bound trials as well as in reduced gravity flight tests aboard the NASA C-9 aircraft. Now, it is ready to be tested in the long duration microgravity environment on the space station.

To operate, the device is hooked up to the Water Processor Assembly (WPA) on the space station because USP regulations require using potable, or drinkable, water. The water first flows into an accumulator—a plastic bag within a container. Nitrogen from the space station pressurizes the accumulator between the inner wall of the container and the outer wall of the bag, to push the water out of the container and through the first filter. The IVGEN team also developed concepts to provide fluid flow in the event of an emergency where nitrogen is not available.

IVGEN sends water through a variety of filters and mixes it with salt to create a sterile saline solution. Image Credit: NASA

This Glenn-designed filter, called a deionizing filter, is a high-tech version of a water softening filter that is commonly used on Earth. The filter contains beads coated in special chemicals to remove impurities and sterilize the water. The water flows through additional filters to remove air (to prevent bubbles which could lead to embolisms during injection) and any remaining particles.

The water then flows into an IV bag, similar to the kind that are used in hospitals on Earth. This bag, which contains a stir bar and salt, is then pressurized to evenly and thoroughly mix the saline solution. After a final filtration to ensure the solution is completely bacteria-free, the sterile saline solution is complete.

The accumulator transfers water from the Space Station into IVGEN. Image Credit: NASA

During the upcoming testing on the space station, crew members will run the device several times. For the purposes of this flight test, additional computers and sensors have been installed to take on-orbit data of all solution created and measure the equipment performance. Two bags of the sterile saline solution will return to Earth on a shuttle for additional testing.

The ability to manufacture sterile saline solution—of the same high quality that can be made on Earth—has the potential to influence even more than life aboard the space station. It could quite possibly change the way we explore space, helping enable our astronauts to travel farther than ever before.

"IVGEN is currently the number one priority of the Exploration Medical Capabilities Element of the Human Research Program," DeVon Griffin says.

Tori Woods (S.G.T.)
NASA’s Glenn Research Center

For more information visit http://www.nasa.gov/centers/glenn/shuttlestation/station/ivgen.html

---