Emergency medical services:

Emergency medical services (abbreviated to the initialism "EMS" in some countries) are a branch of Emergency services dedicated to providing out-of-hospital acute medical care and/or transport to definitive care, to patients with illnesses and injuries which the patient, or the First responder, believes constitutes a medical emergency.
Emergency medical services may also be locally known as: First aid squad, Emergency squad, Rescue squad,Ambulance squad, Ambulance service, Ambulance corps or Life squad.
The goal of most emergency medical services is to either provide treatment to those in need of urgent medical care, with the goal of satisfactorily treating the malady, or arranging for timely removal of the patient to the next point of definitive care. This is most likely an emergency department at a hospital or another place where physicians are available. The term Emergency Medical Service evolved to reflect a change from a simple transportation system (ambulance service) to a system in which actual medical care occurred in addition to transportation. In some developing regions, the is not used, or may be used inaccurately, since the service in question does not provide treatment to the patients, but only the provision of transport to the point of care.
In most places in the world, the EMS is summoned by members of the public (or other emergency services, businesses or authority) via an emergency telephone number which puts them in contact with a control facility, which will then dispatch a suitable resource to deal with the situation.
In some parts of the world, the term EMS also encompasses services developed to move patients from one medical facility to an alternative one; inferring transfer a higher level of care. In such services, the EMS is not summoned by members of the public but by clinical professionals (eg. physicians or nurses) in the referring facility. Specialized hospitals that provide higher levels of care may include services such as neonatal intensive care (NICU), pediatric intensive care (PICU), state regional burn centers, specialized care for spinal injury and/or neurosurgery, regional stroke centers, specialized cardiac care (cardiac catherization), and specialized/regional trauma care.
In some jurisdictions, EMS units may handle technical rescue operations such as extrication, water rescue, and search and rescue. Training and qualification levels for members and employees of emergency medical services vary widely throughout the world. In some systems, members may be present who are qualified only to drive the ambulance, with no medical training.[9] In contrast, most systems have personnel who retain at least basic first aid certifications, such as (Basic Life Support (BLS)). Additionally many EMS systems are staffed with Advanced Life Support (ALS) personnel, including paramedics, nurses, or, less commonly, physicians.

The purpose of EMS:

Emergency medical services exists to fulfill the basic principles of first aid, which are to Preserve Life, Prevent Further Injury, and Promote Recovery.
This common theme in medicine is demonstrated by the star of life. The Star of Life shown here, where each of the 'arms' to the star represent one of the 6 points. These 6 points are used to represent the six stages of high quality pre-hospital care, which are:

1. Early Detection - Members of the public, or another agency, find the incident and understand the problem
2. Early Reporting - The first persons on scene make a call to the emergency medical services and provide details to enable a response to be mounted
3. Early Response - The first professional (EMS) rescuers arrive on scene as quickly as possible, enabling care to begin
4. Good On Scene Care - The emergency medical service provides appropriate and timely interventions to treat the patient at the scene of the incident
5. Care in Transit - the emergency medical service load the patient in to suitable transport and continue to provide appropriate medical care throughout the journey
6. Transfer to Definitive Care - the patient is handed over to an appropriate care setting, such as the emergency department at a hospital, in to the care of physicians

Levels of care in EMS

Emergency Medical Service is provided by a variety of individuals, using a variety of methods. To some extent, these will be determined by country and locale, with each individual country having its own 'approach' to how EMS should be provided, and by whom. In some parts of Europe, for example, legislation insists that efforts at providing advanced life support (ALS) services must be physician-led, while other permit some elements of that skill set to specially trained nurses, but have no paramedics. Elsewhere, as in North America, the UK and Australia, ALS services are performed by paramedics, but rarely with the type of direct "hands-on" physician leadership seen in Europe. Increasingly, particularly in the UK and in South Africa, the role is being provided by specially-trained paramedics who are independent practitioners in their own right. Beyond the national model of care, the type Emergency Medical Service will be determined by local jurisdictions and medical authorities, based upon the needs of the community, and the economic resources to support it. A category of emergency medical service which is known as 'medical retrieval' in some countries (Australia, NZ, Britain) refers to critical care transport of patients between hospitals (as opposed to pre-hospital). Such services are a key element in regionalised systems of hospital care where intensive care services are centralised to a few specialist hospitals.
Generally speaking, the levels of service available will fall into one of three categories; Basic Life Support (BLS), Advanced Life Support (ALS), and care by traditional healthcare professionals, meaning nurses and/or physicians working in the pre-hospital setting and even on ambulances. In some jurisdictions, a fourth level, Intermediate Life Support (ILS), which is essentially a BLS provider with a moderately expanded skill set, may be present, but this level rarely functions independently, and where it is present may replace BLS in the emergency part of the service. When this occurs, any remaining staff at the BLS level is usually relegated to the non-emergency transportation function. Job titles typically include Emergency Medical Technician, Ambulance Technician, or Paramedic. While these job titles are protected by legislation in some countries, this protection is by no means universal, and anyone might, for example, call themselves an 'EMT' or a 'paramedic', regardless of their training, or the lack of it. In some jurisdictions, both technicians and paramedics may be further defined by the environment in which they operate, including such designations as 'Wilderness', 'Tactical', and so on.