Emergency medical system

In developed countries, there is an emergcency medical system (EMS) both outside the hospital and inside it. Most often, it is activated with a telephone call to a local or regional emergency number (e.g., 911 in North America and 112 in Europe. A dispatcher answering the call, who may have varying levels of emergency training, will estimate the severity of problem, the availability or resources, other demands on resources, and then dispatch resources to the person reporting the problem. In some urgent situations where the individual person reporting has no knowlege of what to do, the dispatcher may attempt to give instructions until trained personel arrive.

Dispatches may dispatch fire, police, or other services, singly or together, as required by the incident. If the description from one or more calls indicated that a multiple casualty incident or mass casualty incident may have taken place, the dispatcher may either escalate the report, or, following standard protocols, initiate the Incident Command System. Hospitals also may receive alerts of significant numbers of victims. In some cases, the dispatcher may alert electrical or gas utility companies, or chemical plants and other private facility, that they may need to activate local response.

First responder
A first responder, who has milimal medical training, or may be the first person on the scene with any level of knowledge. Ideally, a first responder has basic first aid training, as a police officer, member of a Scouting organization, a teacher or lifeguard, or similar person. Unless this an immediate threat to life, a first responder should not attempt to move the victim. If the patient is not breathing, a trained first responder, or sometimes one coached over the telephone, can begin rescue breathing. If the patient is pulseless, the first responder may begin cadiopulmonary respiration, and possibly use an automatic external electric defibillator if one is immediately avaiable. Immediate steps to stop direct bleeding are appropriate, principally in applying direct pressure to the bleeding area. These procedures constitute basic life support (BLS).

Emergency medical technician
In the emergency medical system, there are various training levels for Emergency Medical Technicians. They have state and locally defined "scopes of pratice", defining what they may do on their own, when directed by medical control personel (e.g., physicians or emergency nurses, or not at all.) If the Incident Control System is activated, they will take direction from medical operations at the scene.

EMT-B
The first trained rescuers likely to arrive are emergency medical techincians-Basic (EMT-Basic). These may be police officer or firefighters in their regular vehicles, or a BLS-capable ambulance. THe EMT-basic may, depending on local rules, apply the existing measures with more skill, as well as more advanced measures. An EMT-basic, for example, might insert minimal airway devices to protect the airway from vomitus, but not insert a tube into the airway. EMTs might apply tourniquets for traumatic amputations.

In a mass casualty incident, they may perform initial triage, recognizing, according to protocols, victims that are clearly dead, or that are in need of immediate surger.

In many jurisdictions, they also have the mimimal additional training to use an automatic external defibrillator, perhaps one with slight additional capability.

EMT-I
While the training and scope of practice vary with location, EMT-I's, who should take control over EMT-B, possibly simply telling them continue, have additionals that may include establishing intravenous access] and adminstering drugs through it on the orders of medical control; advanced airway management that may involve passing a tube at least partially into the trachea, or to block the esophagus.; or use of the defibrillator for conditions beyond the scope of an automated defibirillto

EMT-P
EMS technicians at the Paramedic (or other variants such as cardiac care), have the authority to initiate, or request authorization from medical control for much more invasive and advanced treatment. This could include combined drug and electrical management of complex cardiac care, administering antidoes for knon posioning or anticonvulsants in convulsive disorders, stabilizing glucose levels in diabetics, etc.

While the popular image is that they do considerable stabilization on the scene, there are conditions, paticularly in major trauma, where the EMT's proper action is "scoop an run", getting the victim to surgery as soon as possible.