Cornwall's air ambulance medics can now give blood transfusions at the site of an emergency for the first time.
The charity's helicopter has started carrying blood, giving an option to start transfusions "before a patient even reaches hospital", managers said.
A 17-year-old boy was the first recipient when he was treated on a roadside following a serious crash.
Blood from the Royal Cornwall Hospital, Truro, is taken to its Newquay base by riders from Cornwall Blood Bikes.
Paul Maskell, a Cornwall Air Ambulance trainee critical care paramedic, said the partnership meant the charity had "significantly enhanced the level of service we can provide to our patients".
Teenager Zack Hancock was the first patient to benefit after an accident at St Tudy left him with life-threatening internal injuries, along with broken bones in his face, arms and legs.
He received the transfusion on 4 December, within three days of the service launching.
The charity said he was now back home in Bodmin and recovering well from the accident, which left him in a coma for 11 days.
Donna Jewell, Zack's mother, said: "Without this service, I would not have a son. The care he received from everyone has been amazing."
Paul Maskell said: "Zack had lost a lot of blood and was very poorly when we arrived on scene.
"He was the first person to be able to benefit from this lifesaving intervention on the roadside in Cornwall. It's amazing to see the difference it can make."