Balloon surgery stops fatal bleeding at roadside
17 June 2014 Last updated at 03:00 BST
London's Air Ambulance crew have become the first team in the world to use a balloon device to control catastrophic bleeding at the roadside.
The small balloon can be inflated inside major blood vessels to stop internal blood loss - a common cause of death after severe cycling accidents or falls from a significant height.
Patients involved in these incidents can suffer fatal blood loss before they make it to hospital.
London's Air Ambulance hope that by stopping blood loss at the scene, they will buy valuable time and improve the chances of survival.
Dr Gareth Davies, medical director of London's Air Ambulance and emergency medicine consultant at Barts Health NHS Trust, describes how the procedure is carried out.
Video journalist: Smitha Mundasad