Emergency medical service (EMS) is a branch of medicine that is performed in the field (i.e., the streets, peoples' homes, etc.) by paramedics, emergency medical technicians (EMTs), and certified first responders (CRFs).

Although not commonly understood, EMS systems in U.S. provide emergency care that is almost on par with that of an emergency room. Equipment and procedures are obviously limited, due to the nature of the environment that EMS personnel must work in. EMS providers work under the license and indirect supervision of a medical director (a board-certified physician), who oversees the policies and protocols of a particular EMS system or organization.

EMS workers are trained to follow a formal and carefully designed decision tree which has been created and approved by physicians. The emphasis in emergency services is on following correct procedure quickly and accurately rather than on making in-depth diagnosis which requires much professional experience. The use of a decision tree allows EMS workers to be trained in a much shorter time than physicians.

National EMS standards are drawn up by the U.S. Department of Transportation, modified from state to state by the state's Department of EMS (usually under its Department of Health), and further altered by Regional Medical Advisory Comittees (usually in rural areas) or by other comittees or even individual EMS providers. All alterations to U.S. DOT protocols are made by qualified people and conform to all applicable rules and regulations.

Table of contents
1 History
2 Levels of Care
3 "Scoop and run", "stay and play" or "play and run"?
4 References


The origins of EMS date back to the days of Napoleon, when the French army utilized horse drawn "ambulances" to transport the injured soldier from the battlefield. Its more recent incarnation can be traced back to 1869, when Dr. Edward L. Dalton at Bellevue Hospital, then known as the Free Hospital of New York, in New York City started a basic transportation service for the sick and injured. The component of care on scene began in 1928, when Julien Stanley Wise started the Roanoke Life Saving Crew, the first rescue squad in the nation. Over the years EMS continued to evolve into much more than a "ride to the hospital."

In particular in the US state of California and in King County, Washington state, projects began to include paramedics in the EMS responses in the late 1960s. Despite opposition from firefighters and doctors, the program eventually gained acceptance as its effectiveness became obvious. Furthermore, such programs became widely popularized around North America in the 1970s with the television series, Emergency which in part followed the adventures of two Los Angeles County Fire Department paramedics as they responded to various types of medical emergency. The popularity of this series encouraged other communities to establish their own equivalent services.

In a return to the military roots of EMS, the United States Army has developed the combat lifesaver program to instruct soldiers in advanced first aid and limited paramedic skills including intubation. The combat lifesaver is intended to bridge the gap between self-aid / buddy-aid and the platoon medic on the 21st century decentralized battlefield.

Levels of Care

Two levels of care are provided by EMS systems: BLS and ALS (Basic Life Support and Advanced Life Support). BLS providers are CFRs and EMTs and provide all care outlined in the EMS standard of care, except for invasive procedures and (to a certain extent) giving medications. ALS providers are principally paramedics and can perform invasive procedures and give a wide variety of drugs.

In times of economic crisis and in poorer areas, much normal medical care is provided through emergency services to patients who do not have regular physicians or regular medical attention.

"Scoop and run", "stay and play" or "play and run"?

The strategy developped for prehospital care in North America is called scoop and run. It is based on the golden hour concept, i.e. the best chances for the victim in case of a severe trauma is to have surgery within one hour, especially in case of internal bleeding. Thus, the minimal prehospital care are performed (A.B.C., stop the external bleeding, cover the injuries, spine immobilisation, endotracheal intubation) and the victim is transported as fast as possible to the most adapted trauma center.

The stay and play strategy was designed in France with the SMUR (Service mobile d'urgence de réanimation, emergency mobile resuscitation unit) and SAMU (Service d'aide médicale d'urgence, i.e. EMS), as they noted that most of time, the victim died during transportation. They developped a strategy based on maximum cares before transportation, the prehospital cares are made by a MD, a nurse and an ambulance technician, with almost all the equipment and drugs that can be found in an emergency department (there is no paramedic). The priority here is the stabilisation, including intravenous drip to rise the blood pressure (one of the causes of death during transportation is the drop of the pressure perfusion of the brain and heart due to the accelerations, see shock). In case of a severe myocardial infarction (or heart attack), all the cares are performed onsite (including possibly thrombolysis), and the victim is transported only if the heart starts again or is declared dead: the time for a victime to be evacuated is longer than the time for the medical team to come to the victim because of the scoop (the defibrilation is performed by a firefighter rescue team with an automated external defibrillator if it arrives before the medical team).

Both strategies have their advantages and drawbacks. The confrontation of these two opposite experiences led recently to a new concept: the play and run. In this strategy, the time that cannot be reduced (e.g. while freeing a victim trapped in a car) is used to perform cares, and the aim is no longer to recover a "normal" blood pressure, but a minimal blood pressure, using not only intravenous drip but also vasopressing drugs and antishock pants (to compress the legs and push the blood into the rest of the body). The aim is to reduce the risk of death due to transportation trauma and to respect the golden hour.


See also: trauma center, battlefield medicine