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. physician-led ems ambulance in the czech republic physician-led ems is also known as the franco-german model, "stay and play", "stay and stabilize" or "delay and treat". in a physician-led system, doctors respond directly to all major emergencies requiring more than simple first aid. the physicians will attempt to treat casualties at the scene and will only transport them to hospital if it is deemed necessary. if patients are transported to hospital, they are more likely to go straight to a ward rather than to an emergency department. countries that use this model include austria, france, belgium, luxembourg, italy, spain, brazil and chile. in some cases in this model, such as france, there is no direct equivalent to a paramedic. physicians and (in some cases) nurses provide all medical interventions for the patient. other ambulance personnel are not non-medically trained and only provide driving and heavy lifting. in other applications of this model, as in germany, a paramedic equivalent does exist, but is an assistant to the physician with a restricted scope of practice. they are only permitted to perform advanced life support (als) procedures if authorized by the physician, 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. personnel emt staff at an emergency call in new york city a patient arriving at a hospital ambulance personnel are generally professionals and in some countries their use is controlled through training and registration. 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. a unique aspect of ems is that there are two hierarchies of authority, as the chain of command is separate to medical authority. emergency medical dispatcher an emergency medical dispatcher is also called an emd. an increasingly common addition to the ems system is the use of highly trained dispatch personnel who can provide "pre-arrival" instructions to callers reporting medical emergencies. they use carefully structured questioning techniques and provide scripted instructions to allow callers or bystanders to begin definitive care for such critical problems as airway obstructions, bleeding, childbirth, and cardiac arrest. even with a fast response time by a first responder measured in minutes, some medical emergencies evolve in seconds. such a system provides, in essence, a "zero response time," and can have an enormous impact on positive patient outcomes. first responder