Rice students offer simple solution to reduce IV infections

David Ruth

Jade Boyd

Rice students offer simple solution to reduce IV infections

Redesigned IV tubing could flush away IV infections in developing world

HOUSTON — (May 2, 2013) — The latest student invention from Rice University’s award-winning engineering design program — a set of intravenous tubing that could slash IV-related infections — looks so simple. But looks can be deceiving.

The four graduating seniors who created the EZ Flush IV tubing set spent hundreds of hours creating an elegant solution to a major health care problem in the developing world: Most hospitals there cannot afford the prefilled saline syringes that nurses in developed countries routinely use to flush IV lines.

Regular flushing prevents infections from forming around the IV catheter, a thin, flexible tube that stays inside the patient’s arm. Infections from catheters can be deadly, and the rate of these infections is much higher in developing countries.

Smooth Saline team members Becky Zaunbrecher, Lindsay Miller, Jessica Williams and Kathleen Wiest are each slated to graduate May 11 with degrees in bioengineering. Prior to teaming up last fall at Rice’s Oshman Engineering Design Kitchen (OEDK), all four had taken courses in global health, and three had spent a summer abroad testing innovative medical designs in the developing world as part of Rice’s award-winning, hands-on engineering education program Beyond Traditional Borders (BTB).

Smooth Saline team member Lindsay Miller explains the EZ Flush design to Rice University Representative Y. Ping Sun at Rice's annual Engineering Design Showcase.

“Ours is pretty unique in terms of a global health project because ours was actually pitched by Becton/Dickenson, a medical device company in the United States,” Wiest said. “BD sells prefilled saline syringes in the United States and around the world, and they asked us to create a new design that would be more affordable for developing countries.”

Smooth Saline’s ingenious solution would allow a nurse in a low-resource hospital to regularly flush IV lines using sterile saline from a patient’s IV bag. All that’s required is a set of IV tubing that contains three tiny clamps, about six inches of extra tubing and a tiny plastic pouch about the size of a ketchup packet. To flush an IV catheter, a nurse simply clamps off the IV line leading to the patient’s arm, redirects a few milliliters of sterile saline from the IV bag into the pouch, opens one clamp, closes another and then squeezes the saline from the pouch through the catheter.

“If we add up the features of our prototype, it costs us about $2.50 to manufacture the whole thing,” Williams said. “But we’re using slightly more expensive parts since we don’t buy them in bundles of 5 million like an IV tubing manufacturer would.”

Smooth Saline team members Becky Zaunbrecher and Jessica Williams test some prototypes to determine if the seals are watertight.

With economies of scale, Smooth Saline estimates the design will add less than $1 to the cost of producing a set of IV tubing. Because each set can be used for about two dozen flushes, the per-flush cost of adding the feature is around 4 cents.

The EZ Flush design earned Smooth Saline the top prize in Rice 360°’s Undergraduate Global Health Technology Design Competition as well as first prize in Rice’s annual Undergraduate Elevator Pitch Competition. The simplicity of the award-winning design is worthy of a team with such terrific chemistry that the members often finish one another’s sentences. But arriving at the design was far from easy.

“It was very iterative,” Miller said. ” We didn’t start out with our end prototype in mind.”

“We didn’t start anywhere near that,” Williams said. “We started with a Windex bottle or maybe like a Nerf-gun type thing.”

“We had a lot of crazy ideas to start with,” Zaunbrecher said.

Some of the crazy ideas had to do with producing saline. The team knew it would be expensive to ship, so they toyed with lots of notions about producing it on site.

Smooth Saline team members (from left) Jessica Williams, Kathleen Wiest, Lindsay Miller and Becky Zaunbrecher.

“At a certain point, we were talking about making giant vats of saline, and we realized it was just NOT feasible to expect doctors or nurses to do that,” Williams said.

Smooth Saline credits their OEDK advisers — bioengineering faculty members Ann Saterbak and Maria Oden — with directing them toward the more practical option of using what was already available.

“They already have IV bags at all hospitals and clinics,” Miller said. “The biggest decision we made was to take advantage of the saline that was already there, and that’s what led us to design this IV tubing set.”

But that too was a challenge. In fact, most of their initial ideas about how to get the saline from the bags were also overly complex.

“As we were drawing out our ideas, we were literally drawing tubing sets without realizing that we were drawing them,” Wiest said. “We were coming up with these ideas of connecting something between an IV bag and a patient, and it didn’t dawn on us until …”

“… after we had designed it, and someone phrased it to us differently,” Zaunbrecher continued. “And we were like, ‘Oh, wow. It really is just an IV tubing set with something added on.’ It was a big breakthrough day because we realized that was how we could market it and sell it, and it would just make it much more accessible and usable by nurses.”

All four members of Smooth Saline credit BTB and Rice’s global health program with permanently changing their lives. Williams is joining the Peace Corps in June, and Wiest decided to become a doctor rather than an engineer and to practice medicine in the developing world.

“I don’t plan on directly pursing global health, but it’s definitely changed my outlook on health technologies,” said Zaunbrecher, who, like Miller, plans to attend graduate school in bioengineering. “It will definitely always stay with me … the importance of keeping health technologies accessible to everyone and just helping the overall health of the planet and not just a small subset of the people who can afford something.”


VIDEO is available at:

The following IMAGE is available in high-resolution.

CAPTION: Smooth Saline team member Lindsay Miller explains the EZ Flush design to Rice University Representative Y. Ping Sun at Rice’s annual Engineering Design Showcase.
CREDIT: Jeff Fitlow/Rice University

More information about Smooth Saline is available at:


About Jade Boyd

Jade Boyd is science editor and associate director of news and media relations in Rice University's Office of Public Affairs.