A pair of French product designers have created an inflatable bandage that snaps around the wrist like a slap bracelet so it can be self-administered with only one hand.

Uflex is an all-in-one self-inflating compress and gauze for an emergency situation in which the user finds themselves injured and alone, and must apply and maintain pressure to the wound while calling for help.

This solution by French duo Inès Le Bihan and Julian Loïs is made from a retractable metal band that snaps around the affected limb and inflatable fabric held in place with Velcro that creates the necessary pressure.

"It is a beautiful solution - inexpensive, efficient and answered all of our constraints," said the designers.

With experience in first aid as a life guard, Loïs saw how hard it was it dress wounds quickly and effectively.

"What if you are alone and injured, suffering from a heavy bleeding? How do you patch yourself up if you are unable to use both of your hands and in state of shock? To my eyes, it appeared to be a real problem for design engineers to answer," he told Dezeen.

Loïs explained this problem to Le Bihan while unlocking his bike. Le Bihan immediately saw a potential solution. "I suggested we use the kind of reflective retractable metal bands that he uses on his bike. It clamps onto your arm in a flash," said Le Bihan. "Uflex was born."

"Very quickly we were able to confirm our hypothesis with a quick and dirty mock-up: the retractable metal bands allowed the compress to lock on to the wound efficiently," he told Dezeen. “This gesture works like the good old slap wrap – it had to be as intuitive as possible considering the stress level of our users."

The compress is made of non-woven swabs to absorb blood without sticking to the wound.

Once it was tested, the designers realised that to stop an artery bleed it would need to be significantly tightened after application.

"We discussed various mechanical solutions including strings, handles and tourniquets, and finally came up with an inflatable fabric held in place with Velcro," they said.

The inflating process is based on polyurethane foaming. The fabric is made of two compartments filled with polyol and isocyanate – types of plastic that expand when mixed together.

Once Uflex is rolled around the wound, the partition between the two compartments breaks and allows the two liquids to mix and inflate.

The Velcro holds the fabric together, so the inflation creates and maintains the pressure on the wound and stops the haemorrhage.

Uflex was shortlisted for this year's James Dyson Award, which rewards products that have a significant and practical purpose, are commercially viable, and are designed with sustainability in mind.