In mid-February, about a month after a massive earthquake leveled much of Port-au-Prince, Haiti, a wound-care team from Brigham and Women’s hospital in Boston traveled to the devastated capital. The team’s task was to help care for scores of patients suffering from the large open wounds that accompany amputations, crushed limbs, and other injuries. Among the team was MIT graduate student Danielle Zurovcik, who arrived ready to test a device she had developed as part of her thesis research–a cheap and portable version of the negative-pressure devices currently used to speed wound healing in hospitals.
Zurovcik and her collaborators hope the device, which costs about $3, will provide a way to improve care for patients after the emergency phase of relief efforts, including life- and limb-saving surgeries, has ended. Even after many of the emergency medical teams leave the disaster zone, the dangers of chronic wounds remain high.
“My experience in Haiti and other major earthquakes is that after the acute medical response, such as amputating limbs and setting fractures, the major disease burden is wounds,” says Robert Riviello, a trauma surgeon at Brigham and Women’s, and Zurovcik’s collaborator. Negative-pressure therapy decreases the need to change wound dressings from one to three times per day to once every few days, a major benefit when medical staff is in short supply.
Negative-pressure devices, which act like a vacuum over the bandaged wound, have become a central part of wound therapy in the United States over the last decade. They speed healing up to threefold, depending on the type of wound, and in some cases eliminate the need for plastic surgery or skin grafts. A number of commercial versions are available in the U.S. and are used to treat burns and chronic wounds such as bed sores or diabetic foot ulcers. While scientists don’t exactly know why this treatment accelerates the healing process, it likely helps by removing some of the fluid and bacteria that accumulates at the injury site and by increasing blood flow to the wound. The pressure itself may also help healing by bringing together the edges of the wound and delivering mechanical pressure, which has been shown to spur cell growth, says Dennis Orgill, a surgeon at Brigham and Women’s who was not involved in the project.
Existing devices are often heavy, about five to 10 pounds, and require an energy source to create the vacuum, making them difficult to apply in disaster settings. Texas-based KCI, the leading maker of negative-pressure machines, has a portable version that’s battery powered, but it costs approximately $100 per day to rent. A number of companies are working on even more portable versions, say Orgill.
But Zurovcik, inspired by a burn surgeon’s plea, went a step further, designing a human-powered device that applies pressure via a simple bellows pump weighing less than half a pound. By improving the seal around the wound dressing to reduce air leaks, Zurovcik cut the pump’s power requirements from about 14 watts to 80 microwatts, which comes from a hand pump.