Applying the right pressure
The leading cause of maternal mortality is entirely preventable. Worldwide, as many as 140,000 women die every year from postpartum hemorrhage, primarily in developing countries. But a life-saving medical device once used to stabilize injured soldiers during the Vietnam War may be poised to cut those numbers dramatically, thanks in part to the work of four Berkeley Engineering undergraduates.
The students were assigned to work with a UCSF team that had done extensive research on the device, known as a non-pneumatic anti-shock garment (NASG). To improve the device’s effectiveness, the team from bioengineering professor Amy Herr’s senior capstone class came up with a reliable pressure gauge.
“The device works by applying pressure to the patient, so it’s vital to know what the pressure actually is,” said Rebecca Farr (B.S.’13 BioE), who now works in the medical device field.
The NASG device had already been shown in clinical trials conducted by the UCSF team to reduce maternal mortality from postpartum hemorrhage by 50 percent or more. The neoprene-and-Velcro garment looks like the lower half of a wetsuit, cut into segments designed to wrap tightly around the legs and waist. When applied, it slows blood loss and helps women recover from shock while awaiting medical treatment. Last October, the World Health Organization, which aims to reduce maternal mortality to 1990 levels by 2015, added the device to its guidelines for treating postpartum hemorrhage.
“We have been able to demonstrate this across a variety of settings, and the trend is almost always a 50 percent reduction in mortality,” said Suellen Miller, who directs the Safe Motherhood Program at UCSF and is principal investigator for its NASG project, called LifeWrap. In some cases the rates have been far higher: In Egypt, Miller saw a 68 percent reduction when a NASG was used, and in Nigeria, 64 percent.
Although these results were exciting, the tests also revealed what remained the device’s biggest shortcoming and source of uncertainty: the lack of a pressure gauge.
“We were still not sure exactly what pressures were being applied, so there were bioengineering questions that could still be answered, and maybe some advances made in the device itself,” says Miller, who served as the Berkeley team’s primary adviser. A fix would make it more reliable and perhaps save thousands more lives.
In Herr’s class, Farr and Sandeep Prabhu, Alisha Manandhar and Atri Choksi (all B.S.’13 BioE) were challenged to engineer and produce a prototype of a device that would provide continuous pressure readings while also being easy to sterilize. They ultimately succeeded—and were so encouraged by feedback from Miller and her UCSF colleagues that three of them continued the project after graduation.
Their initial idea came together quickly: After consulting with Miller about the device’s needs, the students began with a sketch of a circular pressure cuff comprising an air bladder, two clips that attach to the garment, a fist-size air pump and a pressure gauge.
Next, they had to build it. Early prototypes included variations on a standard blood-pressure cuff and a homemade polyvinyl bladder stuck to pieces of tubing with silicone glue. But the final model developed for the capstone class was something of a hybrid: a neoprene bladder attached via spliced tubing to a hand pump and a gauge from a store-bought blood-pressure cuff.
Farr, Prabhu and Manandhar wanted to keep going. “What drove me to continue with the project was that I saw that the product we created could impact thousands of lives,” Manandhar said.
The three recently drafted a long-term plan that includes filing for a patent by the beginning of next year, then securing funding, performing mechanical testing and manufacturing and distributing the instrument for clinical testing. Their goal is worldwide distribution by early 2020.
The team’s latest prototype ran about $10. Expenses will surely come down as production scales up, but they envision keeping the price around $10 and using surplus profits to distribute products for free in places that can’t afford them.
“Our idea is not to sell this for a profit,” Manandhar says. “Our idea is to help people.”