Funny story. Back in the day, they did a study of highway deaths. One thing that leapt out was that most people who died in traffic accidents could have been saved if they got to the hospital fast enough. Pretty soon it was legislated that every community had to have an EMS system.

Basic Emergency Medical Technicians and Advance Life Saving EMTs [aka paramedics] provide medical care on scene and stabilize patients for rapid transport.

Most Fire Departments in the USA are currently Fire/Rescue with the ambulances operated by the Fire Department. Almost all firefighters are Certified First Responders, trained in CPR and first aid.

Nurses are trained for skills that paramedics don't need because nurses also do long term care, where EMS is supposed to be off scene as fast as possible.