The Defense Advanced Research Projects Agency (DARPA) is developing a foam that can be injected into the body cavities of battlefield wounded to protect them from internal abdominal bleeding. The agency hopes that when perfected, the foam will help the wounded to survive the critical minutes needed to transport them to proper surgical facilities for treatment.
Developed by Arsenal Medical, Inc. as part of DARPA’s Wound Stasis program, the product is a polyurethane polymer foam designed to control internal hemorrhaging for at least an hour and is designed to be easy for doctors and surgeons to remove.
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The “Golden Hour” is the 60 minutes when initial treatment of battlefield casualties means the probable difference between life and death. Abdominal injuries are particularly dangerous during this time because they can’t be treated with compression pads or tourniquets. This means that internal bleeding is a real threat to survival before proper facilities can be reached.
The polymer foam is intended to be injected into the abdominal cavity by a field medic in two liquid phases – a polyol phase and an isocyanate phase. When the liquids combine, they react and expand to 30 times their original volume – a bit like foam thermal insulation. As the foam expands, it fills the intact abdominal cavity and hardens into a dressing that molds itself to the internal organs and resists blood loss. Removing the foam is also remarkably easy. In tests, it showed little signs of sticking to tissues and surgeons were able to remove it in a solid block in less than a minute.
No human tests have been conducted, but work has been done with test swine injuries. Preclinical data presented by project members at the 2012 Annual Meeting of the American Association for the Surgery of Trauma in Kauai, Hawaii showed that the foam raised survival rates for liver injuries after three hours from 8 to 72 percent, while reducing blood loss six fold.
Arsenal Medical is currently working on Phase II of the project under a US$15.5 million contract from DARPA. Meanwhile, the agency is hoping for clinical trials.
“If testing bears out, the foam technology could affect up to 50 percent of potentially survivable battlefield wounds," says DARPA program manager Brian Holloway. "We look forward to working with the U.S. Food and Drug Administration on future regulatory submission of this device, and with our partners, the Army Institute of Surgical Research and Special Operations Command, on getting this technology to where it’s desperately needed on the front lines.”
The animation below shows the foam in action.