A new way to heal bullet wounds - with sponges

A new treatment for gunshot wounds could revolutionise military trauma care and greatly reduce deaths from blood loss in the battlefield.

Oregon-based startup RevMedx, which is made up from veterans, scientists and engineers, has created the XStat, a device which could drastically improve wounded soldiers chances of survival in the critical first minutes of injury.

The traditional means of treating gunshot wounds involves packing the wound with gauze to stop the bleeding. It is intensely painful - according to former US Army Special Operations medic John Steinbaugh, who joined RevMedx in 2012 after retiring with a head injury.

"You take the guy's gun away first, it's that painful", says Steinbaugh. "Gauze bandages just don't work for anything serious". A 2011 medical paper describes haemorrhaging from major trauma as "the predominant mechanism of death" in 80 per cent of potentially survivable battlefield injuries.

RevMedx has come up with an alternative. The XStat began life inspired by the expanding foam that is used to repair car tyres. "That's what we pictured as the perfect solution: something you could spray in, it would expand, and bleeding stops".

Early efforts with foam proved futile, however, as it was forced out of the wound by blood pressure. The team turned their attention to sponges and almost by accident went straight to the ideal size - 1cm circles of sponge that expand when wet.

Following successful trials on animal wounds and a $5m grant from the US Army, the XStat was developed. The sponges are made from wood pulp, and coated with chitosan, a blood-clotting antimicrobial substance made from shrimp shells.

A marker visible under X-rays is added to each marker to prevent them being accidentally left behind in the body after treatment. In 15 seconds, the sponges expand to fill the wound and create enough pressure to halt bleeding.

To enable the sponges to be easily packed into deep, narrow wounds, the team decided to package them in wide syringe-like applicators, available in 12mm-wide or 30mm-wide gauges.

Currently, each XStat costs around $100. "I spend the whole war on terror in the Middle East, so I know what a medic needs when someone has been shot," says Steinbaugh. "I've trained lots of guys who would have benefited from this product. That's what drives me."