The concept of medical robots isn't new (TFOT only recently reported the development of a new robotic surgeon). Robotic medevac isn't a new concept as well and DARPA along with other organizations are currently studying the subject. It was proposed that medevac robots could be based on either existing or future models such as the four legged BigDog. After the Second Lebanon war in the summer of 2006, the Israeli army started showing a growing interest in flying medevac robots which can replace manned helicopters which risked the life of Israeli pilots time and time again during the war to evacuate wounded soldiers from the front line.
The Elios RescueBot as it is known is currently just a concept and might stay that way, but medevac robots wheeled, legged or flying will enter service in the next few years and help save soldiers on the front lines.
More images of Elios RescueBot from Marcos Nolan website