Medics working in war zones may soon have a good way of stopping patients from losing too much blood, according to a recent US study.

The researchers used polymer-based synthetic platelets to reduce the bleeding time of severely wounded people.

The synthetic platelets worked by binding with the natural platelets found in the bodies of the study subjects.

Every single synthetic platelet has its own surrounding water shield, which allows the body to flush out extra ones if the patient receives too many of them.

So far, the platelets have only been tested on rats.

Compared with no treatment at all, the synthetic platelets halved bleeding times in tests on rats.

However, a delay time of 20 seconds caused the clotting rate to drop by three-quarters. The use of donor platelets is the current blood-clotting method. It is a good method, but it involves more complications than the new synthetic method.

Donor platelets only last five days before they need to be thrown out, and may also be rejected by patients.

Synthetic platelets do not need to be thrown out, and have no direct limitations upon their supply.

Lead researcher Erin Lavik said that the new method could complement current therapies.

Lavik said that, while the US military had developed a lot of technology to halt bleeding from external or compressible injuries, many combat injuries were internal blast traumas not amenable to current methods.