I was watching the directors commentary on an episode of Mad Men, one where Roger has a heart attack, in the commentary one of the writer said that Ambulances in the early sixties basically hoped you'd still be alive by the time you got to the hospital. Obviously this changed into the kind of care you get now but when was this change made? What was the main cause for the change and who made it?
Former EMT here - we had a unit at the beginning of our training that covered this and the answer is that it kind of varied depending on where you lived but the on-scene emergency medicine upgrades really started to be implemented in the mid-60s through the early 80s.
There was a massive train wreck in the UK in the mid-50s that killed over 100 people and injured almost 350 more. Many of the injured ended up dying because ambulances didn't have medical equipment to treat them. So that and other similar incidences coupled with new inventions like portable defibrillators and oxygen systems all helped to create the ambulance and emergency medical system you see today.
Edit: spelling
Oddly enough it was spearheaded by the National Highway Traffic Safety Administration:
In 1966, a report entitled "Accidental Death and Disability" was released by the National Academies of Sciences, bringing to light the "neglected epidemic" of accidental injury. This report, along with passage of the 1966 Highway Safety Act, provided impetus for increased national attention on the plight of victims of motor vehicle trauma.
You can read more here: https://www.ems.gov/OEMShistory.html
Early EMS care was very limited due to technology at the time but has evolved much over the years.