The essential decision in prehospital care is whether the patient should be immediately taken to the hospital, or advanced care resources are taken to the patient where they lie. The scoop and run approach is exemplified by the MEDEVAC aeromedical evacuation helicopter, whereas the stay and play is exemplified by the French and Belgian SMUR emergency mobile resuscitation unit or the German Notarzt-System (preclinical emergency physician). The use of helicopters was pioneered in the Korean war, when time to reach a medical facility was reduced from 8 hours to 3 hours in World War II, and again to 2 hours by the Vietnam war.

The strategy developed for prehospital trauma care in North America is based on the Golden Hour theory, i.e., that a trauma victims best chance for survival is in an operating room, with the goal of having the patient in surgery within an hour of the traumatic event. This appears to be true in cases of internal bleeding, especially penetrating trauma such as gunshot or stab wounds. Thus, minimal time is spent providing prehospital care (spine immobilization; ABCs, i.e. ensure airway, breathing and circulation; external bleeding control; endotracheal intubation) and the victim is transported as fast as possible to a trauma centre. The aim in Scoop and Run treatment is generally to transport the patient within ten minutes of arrival, hence the birth of the phrase, the platinum ten minutes (in addition to the golden hour), now commonly used in EMT training programs. The Scoop and Run is a method developed to deal with trauma, rather than strictly medical situations (e.g. cardiac or respiratory emergencies), however, this may be changing. Increasingly, research into the management of S-T segment elevation myocardial infarctions (STEMI) occurring outside of the hospital, or even inside community hospitals without their own PCI labs, suggests that time to treatment is a clinically significant factor in heart attacks, and that trauma patients may not be the only patients for whom load and go is clinically appropriate. In such conditions, the gold standard is the door to balloon time. The longer the time interval, the greater the damage to the myocardium, and the poorer the long-term prognosis for the patient. Current research in Canada has suggested that door to balloon times are significantly lower when appropriate patients are identified by paramedics in the field, instead of the emergency room, and then transported directly to a waiting PCI lab.The STEMI program has reduced STEMI deaths in the Ottawa region by 50 per cent.In a related program in Toronto, EMS has begun to use a procedure of rescuing STEMI patients from the Emergency Rooms of hospitals without PCI labs, and transporting them, on an emergency basis, to waiting PCI labs in other hospitals.

Models of care

Although a variety of differing philosophical approaches are used in the provision of EMS care around the world, they can generally be placed into one of two categories; one physician-led and the other led by pre-hospital allied health staff such as emergency medical technicians or paramedics (which may, or may not have accompanying physician oversight). These models are typically identified by their locations of origin. The Franco-German model is physician-led, with doctors responding directly to all major emergencies requiring more than simple first aid. In some cases in this model, such as France, paramedics, as they exist in the Anglo-American model, are not used, although the term paramedic is sometimes used generically, and those with that designation have training that is similar to an U.S. EMT-B.The teams physicians and in some cases, nurses, provide all medical interventions for the patient, and non-medical members of the team simply provide the driving and heavy lifting services. In other applications of this model, as in Germany, a paramedic equivalent does exist, but is sharply restricted in terms of scope of practice; often not permitted to perform Advanced Life Support (ALS) procedures unless the physician is physically present, or in cases of immediate life-threatening conditions. Ambulances in this model tend to be better equipped with more advanced medical devices, in essence, bringing the emergency department to the patient. High-speed transport to hospitals is considered, in most cases, to be unnecessarily unsafe, and the preference is to remain and provide definitive care to the patient until they are medically stable, and then accomplish transport. In this model, the physician and nurse may actually staff an ambulance along with a driver, or may staff a rapid response vehicle instead of an ambulance, providing medical support to multiple ambulances. The second care structure, termed the Anglo-American model, utilizes pre-hospital allied health staff, such as emergency medical technicians and paramedics, to staff ambulances, which may be classified according to the varying skill levels of the crews. In this model it is rare to find a physician actually working routinely in the pre-hospital setting, although they may be utilised on complex or major injuries or illnesses. In this system, a physicians involvement is most likely to be the provision of medical oversight for the work of the ambulance crews, which may be accomplished in terms of off-line medical control, with protocols or standing orders for certain types of medical procedures or care, or on-line medical control, in which the technician must establish contact with the physician, usually at the hospital, and receive direct orders for various types of medical interventions. In some cases, such as in the UK, South Africa and Australia, a paramedic may be an autonomous health care professional, and does not require the permission of a physician to administer interventions or medications from an agreed list, and can perform roles such as suturing or prescribing medication to the patient. In this model, patients may still be treated at the scene up to the skill level of the attending crew, and subsequently transported to definitive care, but in many cases the reduced skill set of the ambulance crew and the needs of the patient indicate a shorter interval for transport of the patient than is the case in the Franco-German model.

Clinical governance

Paramedics in countries that follow the Anglo-American model normally function under the authority (medical direction) of one or more physicians charged with legally establishing the emergency medical directives for a particular region. Paramedics are credentialed and authorized by these physicians to use their own clinical judgment and diagnostic tools to identify medical emergencies and to administer the appropriate treatment, including drugs that would normally require a physician order. Credentialing may occur as the result of a State Medical Board examination (U.S.) or the National Registry of Emergency Medical Technicians (U.S.). In England, and in some parts of Canada, credentialing may occur by means of a College of Paramedicine. In these cases, paramedics are regarded as a self-regulating health profession. The final common method of credentialing is through certification by a Medical Director and permission to practice as an extension of the Medical Directors license to practice some medical acts. The authority to practice in this semi-autonomous manner is granted in the form of standing order protocols (off-line medical control) and in some cases direct physician consultation via phone or radio (on-line medical control). Under this paradigm, paramedics effectively assume the role of out-of-hospital field agents to regional emergency physicians, with clinical decision-making authority using standing orders or protocols. In some parts of the world, those in the paramedical professional role are only permitted to practice many of their advanced skills while assisting a physician who is physically present, or they face cases of immediately life-threatening emergencies. In many other parts in the world, most notably in France, Belgium, Luxembourg, Italy, and Spain, but also in Brazil and Chile. All MICU skills in the pre-hospital setting are performed by physicians and nurses and an On-line Permanent medical supervision is done by the SAMU. In certain other jurisdictions, such as the United Kingdom and South Africa, paramedics may be entirely autonomous practitioners capable of prescribing medications. In other jurisdictions, such as Australia and Canada, this expanded scope of practice is under active consideration and discussion.