New Bandage May Buy More Time in Traumas
Despite medical and military advances, blood loss still causes 50% of battlefield deaths in the U.S. armed forces, and the methods for coping with it are still low-tech: Slap on a battle dressing, press down and wait for evacuation.
But that may be changing. Late last year, the Food and Drug Administration cleared a Massachusetts firm to market a “Rapid Deployment Hemostat (RDH)”: a 4-inch-by-4-inch battle dressing impregnated with a marine alga that the company says can stop arterial bleeding within seconds.
If it works as advertised, the bandage could add a critical, and perhaps lifesaving, grace period between casualty and treatment, not only for soldiers but also for victims of such traumas as auto crashes and stabbings.
“The bandage stops bleeding but doesn’t interfere with clot formation,” said biochemist John Vournakis, of Marine Polymer Technologies in Danvers. The phenomenon drops off in a few hours--but by then, the victim can be on the operating table.
Vournakis said the bandage grew from an idea he and two colleagues conceived nearly 10 years ago: that a diatom microalga, plentiful in the ocean, produced “an interesting molecule” that could be cultured to make a polymer--the equivalent of a long sugar molecule.
The polymer had extraordinary hemostatic properties. It was a catalyst; it did not participate in clotting, but it provoked a rapid local reaction in the bloodstream.
“Red blood cells can’t get through [the dressing], so they form a plug,” Vournakis said. “Chemical signals from the blood tell the arteries and veins to reduce their diameter.” This constriction buys time for the “clotting cascade” to begin but doesn’t endanger tissue, a critical drawback of tourniquets.
“We still don’t know the full story” of how it works, Vournakis said. For some reason, the microalga attracts red blood cells and platelets, which would rather stay next to the bandage than bleed away.
Also unique is how quickly the platelets signal the blood vessels to constrict and, in an unrelated process, how quickly vessels release a hormone called endothelin-1, a natural constrictor. “It’s not that the patch is doing anything new,” Vournakis said. “It’s speeding the whole thing up.”
Besides the RDH bandage, funded by the Office of Naval Research, the U.S. Army and the American Red Cross have also designed a new bandage: a Styrofoam-like mesh dressing covered with the clot-forming proteins thrombin and fibrinogen.
As with the RDH bandage, the effect is dramatic, but it will take years before the mesh bandage goes to market. And since it uses human fibrinogen, it will be expensive--”up to $1,000” for each one. Vournakis said Marine Polymer doesn’t yet know how much it will charge for the RDH bandage.
