Just to add to Charlie's history the real push came in the late 60's with the Highway transportation act that set guidelines for automobiles and for ambulances, ie kkk specifications, EMT education grew from red cross first aid and communication improvements ie HEAR radio. With the standards of CPR being established in the mid 70's space restrictions eliminated the Cadillac /vehicle ambulances. With more space needed for portable and state of the art equipment that also requires advanced training you have today the er room on wheels. Even in our youth we saw the primitive ambulance used in the western movies, Papa Hemingway telling us about WW1 exploits in his book. The American civil war was the start of triage and transportation and even now we regress back to amputation with military type injuries.
I have had the privilege of having a 44 year career in pre hospital care from my first CPR lesson that being of a doctor slamming his fist on a table to 12 leads, hands free defib, IO therapy, the wonder of D50 and Narcan. and Capnography.
I'm walking a line. Visiting houses in motion
I'm walking a line. Just barely enough to be living