During this "Golden Hour," internal bleeding – particularly in the abdominal cavity - is life-threatening because there is little that can be done to stop the bleeding. Internal wounds can't be compressed like external wounds, nor can they be treated with tourniquets and hemostatic dressings, which require a medic to access to the injury in order to dress it.
DARPA hopes their new foam can help the wounded survive until they get to treatment facilities. Designed by Arsenal Medical as part of DARPA's Wounded Stasis Program, the polyurethane polymer foam can be injected by a field medic in two liquid phases, a polyol phase and an isocyanate phase.
When the liquids mix, they expand to 30 times their original volume.
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As it expands, the foam fills the abdominal cavity and conforms to the surface of the injured tissue and organs. The foam then hardens, providing resistance to intra-abdominal blood loss. DARPA says the foam can even expand through pooled and clotted blood.
During tests, removal of the foam took less than one minute after an incision by a surgeon. Only minimal amounts of the foam remained in the abdominal cavity and no significant amount of tissue stuck to the foam.
No human tests have been conducted yet. However, tests on swine did show that the foam raised survival rates for liver injuries after three hours from eight to 72 percent and reduced blood loss by six fold. DARPA recently awarded Arsenal Medical a $15.5 million contract for Phase II of the project to continue development in hope of future FDA approval of a prototype device.