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 medical practitioner, 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 term 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 to 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. 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.