The Emergency Medical Service system is liable for providing pre-hospital care by paramedics, emergency medical technicians (EMT's), and medical initial responders. The aim of EMS is to provide early action to those in need of urgent medical care, and ultimately rapid shipping to an Emergency department. Stabilizing patients early considerably increases their chances of survival, particularly in the occurrence of a heart attack, diabetic emergency, or severe physical trauma. Many EMT responsibilities also need the EMT to extricate the patient from where they are whether it is in a tight position in a home, or from a vehicle using the Jaws of Life.

EMS providers job under the license and indirect supervision of a medical director or board-certified physician who oversees the policies and protocols of an exacting EMS system or organization. Due to the nature of the location in which EMS personnel must work, equipment and events are necessarily limited; however, prehospital personnel are able to offer a high level of advanced care.

EMS professionals are trained to chase a formal and carefully designed conclusion tree, more commonly referred to as a protocol or regular of care, which has been created and accepted by physicians. The stress in emergency services is on following correct practice quickly and exactly rather than on making in-depth diagnoses that require much specialized training and experience. The use of a conclusion tree allows EMS workers to be trained in a much shorter time than physicians, with EMT-Basic classes, for example, as little as 1-5 months.

National EMS standards for the US are resolute by the U.S. Department of Transportation and adapted by each state's Department of EMS, and further changed by Regional Medical Advisory Committees or by other committees or smooth individual EMS providers. In addition, the National Registry of Emergency Medical Technicians, an autonomous body, was created in 1970 at the proposal of President Lyndon B. Johnson in an effort to provide a nationwide agreement on protocols and a nationally accepted certification. National Registry certification is extensively accepted in some parts of the U.S., while other areas still keep their own, separate protocols and teaching curricula.