Prehospital emergency care

5 Prehospital emergency care P I E R R E A. C A R L I GENEVIEVE BARRIER

The involvement of anaesthetists in prehospital emergency care is very different from one emergency system to another, and depends greatly on the country concerned. This chapter will aim to compare the US emergency system, where the role of the physician is limited, and some European systems such as the French Service d'Aide M6dicale Urgente (SAMU) created and ruled mainly by anaesthetists. In the early 1970s it became obvious in many developed countries that prehospital intervention might result in a decrease in death and disability resulting from medical emergencies. At the same time US military experience had shown that aggressive field resuscitation followed by rapid transportation to specialized medical facilities lowered the battlefield death rate. This was the basis of the development of the US emergency medical service (EMS) system as defined by the Emergency Medical Service Systems Act in 1973. According to this act, funding was provided for up to 5 years for the implementation and planning of an EMS if it met the 15 standard requirements. Consequently many areas of the USA have developed an EMS programme based on the same principles since this time. Meanwhile, in Europe (England, France, Ireland and Germany) some local or regional programmes were started, mainly for the prehospital care of acute coronary emergencies (Pantridge and Geddes, 1967). In France in the 1970s the first SAMU local organizations were informally created by anaesthetists aware of the high mortality of trauma patients before reaching the hospital. The concept of these organizations was opposite to that in the US: the hospital must go to the patient and not the contrary. Consequently medical teams composed mainly of anaesthetists and anaesthetist residents were sent to the field, to manage the most severely injured patients before they reached the hospital. In accordance with this very early involvement of specialized physicians in prehospital care the doctrine was not to run to the hospital, but rather to stabilize and treat (if possible) the patient in the prehospital setting, and then gently transport the patient to the hospital most appropriate to the case. Nevertheless, these two very different EMS systems have some common points: medical control by trained physicians is mandatory for quality assurance and liability. We will now review the different components of these two types of EMS, and the role of the physician and the anaesthesiologist. Baillidre's Clinical Anaesthesiology--

Vol. 6, No. 1, March1992 ISBN0--7020-1616-0

67 Copyright9 1992,byBailli6reTindall Allrightsofreproductionin anyformreserved

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O R G A N I Z A T I O N OF THE EMS The US system

In the US system, the 15 standard components defined almost 20 years ago in the 1973 act continue to serve as the basis of the EMS (American College of Emergency Physicians, 1988). The points, in essence, are as follows: 1. 2. 3.

4. 5. 6. 7. 8. 9. 10. 11. 12. 13.

14. 15.

Manpower and personnel: Adequate number of trained personnel to provide 24 h-a-day care, including first responders, emergency medical technicians (EMTs), paramedics, nurses and medical staff. Training of personnel: Initial and continuing education programmes for EMS health care providers--workshops, 'hands-on', clinical exposure. Communications: Emergency telephone number (911) and a control centre to receive all emergency requests and to direct all responses. Communication with the EMT teams in the field, and interconnections to other services, systems and hospitals. Transportation: Adequate transportation vehicles (air, ground) meeting the federal standards for specification and equipment. Response time of 5 min in 95% of urban calls, and 20 min in rural calls. Categorization of facilities: In each EMS region identification of hospitals' capabilities to manage emergency patients. Categorization of these facilities according to the national standards. Critical care units: For access to designated hospital medical units for admission. Protocols for transportation, transfer and triage. Use of public safety agencies: Interface with standard regional EMS system. Consumer participation: Link to Health Systems Agency. Accessibility of care: No discrimination of care on any basis. Transfer of patients: Protocols to provide for patient transfer to appropriate facility. Record keeping: Standard medical record to be made of the patient care undertaken by the system. Public information and education: System to help citizens to understand and use the EMS. Review and evaluation: Review of the EMS performance, evolution and progress. Clinical evaluation of severe trauma, burn, spinal cord injury, acute coronary insufficiency, poisonings, high risk pregnancy and psychiatric emergencies. Disaster linkage: Organization to face mass casualties or disaster situation linked to regional and state organizations. Mutual aid: Arrangements for border areas to provide continuous coverage.

The EMS system is a comprehensive system that addresses the total care of the victim from beginning to end. Since the 1970s the number and efficiency of these systems has been growing, but many differences exist according to their location. In urban areas the coverage is dense and many hospital

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facilities are available, but in rural areas this is not always the case. The way the EMS works is simple: an E M T ambulance is sent to any medical emergency request. Protocols are established under medical supervision to briefly manage and evaluate the patient at the scene. For critically ill patients a paramedic team is sent (either directly or as a second tier) as a backup for the E M T team. The patient is then transported as fast as possible to the designated emergency facility according to the regional categorization. Scoring and protocols are widely used to avoid any deviation from established standards of care. Medical control is provided by radio with the team in the field, but frequently delegated to specialized nurses or controllers. We will see later more precisely the role of physicians in the US EMS: they are controllers of the system but do not participate in the prehospital management of the patient (Pepe and Stewart, 1986). The French SAMU

The French system as defined by the French law on 'aide m6dicale urgente' (emergency medical assistance) is fundamentally different (Carli et al, 1991). The law gives only the outlines of SAMU implementation and functioning, and variations in local practice occur. However, the basis of the system remains the same all over France: medical involvement in all the phases of prehospital care, and a comprehensive but very flexible response to emergency requests. The following points are common to almost all SAMU organizations as defined by the French law and official recommendations. The SAMU is a regional dispatching and control centre reserved for medical emergencies but connected to all the other public services in the area. This centre is under medical control, and works 24 h a day. The SAMU is a public service that coordinates all public and private emergency medical systems and plans admission of the patient to public or private hospitals. Telephone access to S A M U is free, and the care given by SAMU teams is covered by the national public health insurance system. The SAMU is also in charge of interhospital transportation of critically ill patients, as well as the coordination of all public or private systems related to emergency medical transport. At the S A M U control centre emergency calls come from various different sources (e.g. lay people, police, firemen, general practitioners). This centre is almost always located in a major hospital and is connected (by phone and/or radio) to all the other public and private emergency facilities. The call is first analysed by a specialized switchboard operator who discerns general information: Who is calling? Why? Where precisely is the patient located? This information is needed for establishing a medical file and to decide what the response to the emergency request will be. The details of the situation are then transmitted to a physician, the 'medical dispatcher', who is responsible for all medical actions. He/she decides what to do, gives the orders and checks that every case is correctly managed. There are several possible responses to an emergency call. The most simple is to give only medical advice. The medical dispatcher can also decide

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to send to the patient a basic EMT team, a private ambulance or a general practitioner for a home visit. However, any time he/she suspects a lifethreatening emergency it is mandatory to send a resuscitation ambulance with a medical team, known as the mobile intensive care unit (MICU). This unit is staffed by a specially trained physician. The MICU is related to a hospital-based unit (dependant of the same regional SAMU--2-5 hospitalbased units). The MICU is equipped with all the devices needed to perform advanced life support (ALS) in the field. The team is transported by a fast car, a special ambulance or even a helicopter. However, the duty of the medical dispatcher is not only limited to deciding the response that should be given to the call. When he/she decides to send a MICU he/she has also to choose the most appropriate hospital to subsequently receive the case. For that purpose the SAMU is connected by direct phone lines to the critical care units of the major city hospitals and is kept informed of the up-to-date bed availability situation. As soon as the patient is stabilized and evaluated in the field, the physician of the MICU informs the medical dispatcher of the patient status, the treatment he/she has given and the presumed diagnosis. This information will be the basis for choosing which receiving hospital can provide the required degree of sophistication of care. The hospital chosen is not necessarily the nearest, but rather the most appropriate for the management of the patient and the one equipped with all the facilities needed. In the designated hospital the patient is then directly admitted to a specialized critical care unit without passing through a crowded emergency room. This principle can be described as the '3R' rule: the right patient, in the right hospital, at the right time (Delooz, 1991). Unfortunately some aspects of the SAMU system have not been developed; for example, the hospital categorization and the allocation of funding between the local and national administrations are not clearly defined.

THE LEVEL OF PREHOSPITAL CARE

In the USA the two major standards of the level of care of the EMS are the response time and prehospital ALS. However, paramedic training to the ALS level is difficult, expensive and useful only for a minority of the patients managed by the system (less than 5%). This has led to the development of at least three levels of training for prehospital care: 1. 2.

Basic EMT: Training programme of 90 to 120 h, limited to life saving procedures (basic life support). Paramedics: According to the National Standards curriculum, their training consists of a minimum of an 800-h programme. They also have to complete successfully advanced cardiac life support (ACLS) and/or an advanced trauma life support (ATLS) course (Smith and Bodai, 1985). EMT paramedics act as a physician extender according to preestablished protocols under medical supervision.

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Physicians: Rarely accompany the ambulance, and are not directly trained for field action. Anaesthesiologists are not involved in the EMS system.

The level of care in the SAMU system is different. Like in the USA, the first tier are mainly firemen and they receive a basic training similar to the EMT. Intermediate EMT and paramedic levels do not exist. All care other than basic life support is performed by the SAMU physicians. Initially these physicians were anaesthetists. The standard anaesthesiology training includes prehospital care and surgical critical care. There are still many anaesthetists in the SAMU, but more recently physicians trained in emergency medicine have been added. Their standard training programme is a 2-year course on emergency medicine with hands-on experience, guided by a senior SAMU physician. Complementary training programmes on disaster medicine, aeromedical transport and hyperbaric medicine are also available. In the SAMU system the patient management is not ruled by precise protocols, in contrast to the US EMS. However, many of the guidelines included in the training programme are commonly used (Carli et al, 1991). The aim of prehospital treatment in the SAMU is to stabilize and evaluate the patient before transportation to the hospital. The basis of this treatment is closely related to the advanced critical care performed in hospital. For example, in the case of respiratory distress the trauma patient is rapidly intubated and mechanically ventilated with a high oxygen concentration. Tension pneumothoraces require percutaneous needle thoracostomy, which is more simple to perform than a chest tube insertion on scene. An intravenous line (large bore peripheral catheter) is inserted in all patients and volume loading is mandatory if hypovolaemia is suspected. The intravenous fluids infused are exclusively colloids (gelatins, dextran or starch); blood products and prehospital transfusions are rarely used. Patients with acute hypovolaemia are consequently often haemodiluted when they reach hospital (Carli et al, 1990a). Military anti-shock trousers (MAST) are not routinely used: they are indicated in specific cases such as pelvic fracture with a large retroperitoneal haematoma and shock. The administration of prehospital autotransfusion in cases of uncontrollable haemothorax is limited to teams trained in this procedure, but is available (Barriot et al, 1988). Comatose head trauma patients receive full respiratory and circulatory support. Retrograde intubation is very useful in cases of difficult intubation in the prehospital setting: it is very simple and no specialized equipment is needed (Barriot and Riou, 1988a). Cervical spine stabilization and fracture splinting are also standard procedures: The success rate of these procedures carried out by anaesthesiologists or other trained physicians in the field is very high. Analgesia is frequently administered in the field. Anaesthesia is only performed by trained anaesthesiologists, but some regional blocks are performed by other trained physicians. For example, crurat block with lignocaine (lidocaine USP) is routinely administrated in the case of a fractured femoral shaft (Barriot and Riou, 1988b). Obvious indications for

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general anaesthesia in the field are limited: extrication of a trapped patient, intractable restlessness or severe head trauma with presumed elevated intracranial pressure. Nevertheless, many anaesthesiologists think that anaesthesia is the best way to avoid recall of the trauma and its adverse psychological sequelae. However, prehospital anaesthesia modifies the later hospital management of the patient, as neurological and clinical evaluation is impaired by the loss of consciousness due to anaesthesia and a head computed tomography (CT) scan is then mandatory. For cardiac emergencies the level of care in the SAMU is also very high. ACLS is performed by the SAMU team. As soon as the MICU arrives at the scene the patient is defibrillated, intubated and receives intravenous or intratracheal adrenaline (epinephrine USP).However, it has been demonstrated that increases in survival rates depend on the efficiency of the whole system and not just that of the ACLS. Other factors in the prognosis are: immediate alarm, cardiopulmonary resuscitation by bystanders, early EMT defibrillation (Paris, 1988), and the patient's history and initial rhythm (ventricular fibrillation). This may explain why the survival rate observed in this system is not different from others (Cummins et al, 1991). Prehospital fibrinolysis of acute myocardial infarction has been widely developed in the French and other European systems involving physicians in the field. A precise determination of the diagnosis and the absence of contraindications to fibrinolytic agents, and the recognition and treatment of arrhythmias are the keys of this procedure, and are simple for a trained physician. Prehospital fibrinolysis saves time (Roupie et al, 1989) and may decrease the morbidity of acute myocardial infarction. Large scale randomized studies are still being performed to determine the best and cheapest fibrinolytic agent, but this treatment is already accepted as standard prehospital care in many European countries. The involvement of full trained anaesthetists in the SAMU also provides a very high level of care during interhospital transport. In this setting anaesthetists can take care of a patient under circulatory assistance (aortic balloon pump, cardiopulmonary bypass) or heavy respiratory care (mechanical ventilation with high positive end-expiratory pressure, jet ventilation, etc.). Transmission of information from the sending and the receiving hospital is simple since a physician is continuously in charge of the patient. Close monitoring, even when very sophisticated (e.g. Swan-Ganz catheter capnometry), is available, and the anaesthetist can adapt the treatment and the drugs required by the patient according to his/her own judgement during the journey (Carli et al, 1990b). THE USE OF HELICOPTERS IN PREHOSPITAL CARE

The use of helicopters is frequently considered as a way to improve the efficiency of prehospital care. Historically helicopter medical transport was first used during the Korean War and then extensively during the Vietnam War. Severely injured soldiers were briefly resuscitated in the battlefield and then sent after in-flight evaluation to a mobile army surgical hospital

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(MASH). This mode of transport decreased the time to definitive trauma care, and was one of the factors in the increased survival rates. Since this period, more than 170 helicopter programmes have been implemented in the USA, and all the developed countries now include helicopter use in their prehospital care organization. In the early 1970s in the USA single engine hospital-based helicopters were used only for trauma patients (Gabram and Jacobs, 1990). The programmes were mainly sponsored by one hospital, where the patient was systematically admitted. The helicopter was staffed by a flight nurse or a physician and not integrated in the EMS system. It is only recently that helicopters have been included in the whole EMS system and used for the transport of critically ill patients to any of the designated facilities in the area. Since then helicopters have become one of the most honed tools of prehospital management. The benefit of medical helicopter transport has been illustrated by many studies. Baxt and Moody (1987a,b) observed a decrease in predicted mortality by the TRISS (trauma score and injury security score) methodology (Boyd and Tolson, 1987) in patients transported by helicopters compared with the standard paramedic service. In-flight safety and patient monitoring are two important issues in the use of helicopters. The increasing number of helicopter accidents has led to enforced helicopter regulations for medical transport (Collett, 1988). Twin engine helicopters fitted with specialized equipment are recommended. Monitoring of the patient during the flight needs to be very accurate and sensitive. Equipment for pulse oximetry and capnometry are commonly added to standard equipment. The involvement of critical care nurses and physicians in the team allows the use, in-flight or before boarding, of the most sophisticated medical procedures. The helicopter is used as an extension of the hospital: this is close to the European concept of prehospital care. Efficient use of medical helicopters is based on patient selection and rapid transportation. The decrease in predicted mortality demonstrated in many studies is only observed in critically ill patients. The ability to reduce the transportation time is obvious in rural areas and remote places. In the urban setting, it is limited to appropriate use of the helicopter: if the landing is difficult or the scene near the hospital, little benefit willbe obtained. A precise audit of helicopter use is now a standard evaluation procedure in the USA. In Europe helicopters are also available. In Germany, the whole country is covered by a helicopter network. In France, helicopters suitable for the EMS can be lent by other public services (police, fire brigade) to the SAMU for medical transport. Many regions have private helicopters included in the public service and funded by private organizations or the local administration. The helicopters used are the Aerospatiale single engine Alouette or Ecureil and the twin engine Dauphin. In remote places, and especially in mountain areas, their use for prehospital care is highly developed. All the French seaside beaches in summer are covered by medical helicopters. In large towns such as Paris the use of helicopters is limited for safety reasons. Landing on the scene is difficult (narrow streets) and some old hospitals are not equipped with regular landing pads. Ground transportation remains the basis of prehospital care in the city. Helicopters are reserved for interhospital long distance transport or mass casualties.

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COMMUNICATION IN EMS SYSTEMS In the two types of EMS reviewed, communication plays a vital role. Both the US and the French system will not be effective if communication between the EMS control centre, the field and the hospital is not perfect. Communication is the basis of on-line medical control in the US EMS (Wasserberger et al, 1987). In some areas paramedics are required to contact a physician before administering medications. In other places immediate medical control is impaired by the difficulty of radio contact or physician availability. In the SAMU system, medical control is not the first aim of communication. Direct contact between the physician in the field and the medical dispatcher is mandatory for other reasons: a precise evaluation of the patient is needed to choose the appropriate receiving hospital and to prepare the critical care unit for admission of the patient. The lack of hospital categorization and sometimes the multiple possibilities for patient admission in one area enhances the need for on-line communication between the field and the control centre. Radio is the most common communication system used in the EMS. Two-way street VHF systems are mainly used, but U H F systems are more efficient in large cities. Landline telephone or cellular phone can also be useful, and be used for telemetry (transmission of electrocardiographic recordings). A very important point in the use of radio systems is to ensure patient confidentiality. In France radio procedures avoid giving the patient name and location. The use of codes for the transmission of the diagnosis and patient evaluation improve confidentiality but may also be confusing for the prehospital team.

R E G I S T R A T I O N OF PATIENTS

Patient reports and registration are the key to off-line medical control and quality assurance. A precise transmission of the status of the patient in the field is mandatory for admission into hospital facility. It is the only way to guarantee continuous management from the scene to definitive care. The report may include the patient's history, the mechanism of injury (for trauma) or suspected medical emergency, the status of the patient, vital signs, prehospital treatment and evolution during transport. The analysis of this record permits evaluation of the response time, time spent on scene, epidemiology and therapeutic protocol efficiency. When the patient arrives at the hospital the transmission of this record is sometimes difficult when a paramedic team is confronted with an emergency physician or nurse unaware of prehospital problems. In France, where anaesthetists are in charge of prehospital care and also run many emergency departments, it is easier to find a common language and complementary procedures for prehospital and emergency room management. Involvement of physicians in the field action is the most effective way to link prehospital and inhospital care. If this link is too weak the whole system's efficiency may be compromised.

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QUALITY ASSURANCE Quality assurance in prehospital care has been extensively developed in the US system because non-physicians are involved in medical practice (Holroyd et al, 1986; Polsky and Weigang, 1990). Quality has been assessed by comparing pre-established standards and actual performance. These standards included time criteria, compliance with the protocol, and the skills and knowledge of the EMT. The first point of quality assurance is the direct medical control of the team in the field. This direct communication with the field improves the quality of care and clarifies the thought processes and abilities of the EMT. The second point is the analysis of the E M T findings by the emergency physician receiving the patient. This is a unique opportunity to correct wrong practice or statements and the best way to teach hands-on emergency medicine. The third point is the 'off line' retrospective control, which is the most commonly used. This is based on patient prehospital record analysis. This allows determination of deviation from the protocols and statistical analysis of mortality rates, response times and duration of transport. After complaints or an incident report on a particular case a more complete debriefing can be performed. This is critical in the evaluation of patient management but also a very effective quality assessment. Quality assurance may also be obtained through outcome- or problem-oriented audits. Retrospective data or prospective protocols focused on a precise goal can serve as the basis for new standards of care or organization improvements: the most important consequence of an efficient quality assurance policy is the improvement of the training programme. In systems where physicians are directly in'charge of prehospital care the need for quality assurance was considered to be less important because medical liability is the same as in the hospital. In France, for example, quality assurance in the SAMU system is under the same regulation as any other hospital practice and every physician in the field is liable for his/her own acts.

CONTROVERSIES IN PREHOSPITAL CARE

As we have seen, many differences exist between the structure of the US and the European EMS. The major difference is whether or not the physician is involved in the field treatment of the patient. The two basic principles of the US EMS are the short as possible response and transport times and a standard level of care (the EMT-paramedic). Many studies have demonstrated that improvements in these parameters decrease mortality and morbidity (Trunkey, 1984), but none of these studies has compared the overall efficiency of the US system to that in other countries, especially to the SAMU. Are these two basic principles still valid in a system which includes a physician in the field? Unfortunately it is too late in France to start comparative studies since the SAMU system has been legalized. However, some of the advantages of physician involvement seem

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to be obvious. We will discuss some of these points and give examples in the areas of trauma and cardiology. For trauma patients the comparison of the two systems is commonly limited to the 'scoop and run' versus 'stabilize' controversy. The time used in the field to stabilize the patient is thought to be wasted and to delay definitive care. In a system including a physician the analysis may be different. The time devoted to prehospital care is not lost; rather it decreases the time spent in the emergency room on arrival at hospital. For example, what is the benefit of a very short" transport time to the nearest hospital if when a multiple trauma patient arrives he/she loses 2 h because the surgical team is not ready and the operating room not set up? Additional delay may also occur if the patient is not evaluated and prepared for immediate surgery on arrival. Conversely, the same patient with intractable haemorrhage fully resuscitated and anaesthetized by a prehospital team including an anaesthetist may go directly from the ambulance to the operating room, without losing time in the emergency room, and surgery may be initiated immediately. Emergency diagnosis of the injuries by the anaesthesiologist at the scene of the injury will be quickly confirmed by a previously briefed trauma surgeon as soon as the patient reaches the hospital. In such a case the time spent at the scene has been used to prepare the patient for definitive care and also allows the medical dispatcher of the control centre to find the best available facility ready to receive the patient. Prehospital fibrinolysis is also an obvious example. This sophisticated prehospital treatment can save more than 30 rain to definitive care (coronary reperfusion) compared with standard emergency room management. This procedure decreases patient morbidity but its beneficial effect on mortality remains to be demonstrated (Roupie et al, 1989). On the other hand, a decrease in mortality and morbidity has not clearly been demonstrated when physicians are sent to the scene. A positive effect on prognosis was described by Baxt and Moody (1987a,b) when a medical helicopter was used for the prehospital treatment of severe head trauma, even when the transport time was longer than with field ambulances. In the same way in Belgium it has been observed that well-trained emergency physicians called to the scene of injury as a second tier for selected trauma cases can improve the outcome (Delooz, 1991). With the S A M U system patients with a very high injury severity score have arrived alive at the hospital despite their statistically lethal prognosis. This then increased the inhospital mortality because even when such patients lived to reach the hospital their injuries were too severe to be successfully treated. Positive effect on morbidity is also difficult to demonstrate. For example, prehospital volume loading has been criticized as an ineffective and timeconsuming procedure (Trunkey, 1984). Obviously an infusion of 200 ml of crystalloid solution given to a shocked patient during a transport period of a few minutes will not modify the haemodynamic status. However, 1000 ml or more of a colloid solution over 30 min can significantly improve cardiac output and oxygen transport. Such aggressive fluid management in the field is common in the S A M U system (Carli et al, 1990a). This early treatment of hypovolaemic shock, if it is successful, may decrease the onset of delayed

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multiple organ failure. This hypothesis remains to be confirmed. However, from a practical point of view acute renal failure after hypovolaemic shock has almost disappeared from French trauma critical care units since patients have received mandatory volume loading in the field. INTEGRATION OF PREHOSPITAL AND IN-HOSPITAL CARE A comprehensive EMS system is not only limited to efficient prehospital care and the appropriate choice of the hospital to receive the patient: emergency room management is directly linked to the prehospital phase. A precise integration of these two components is mandatory to guarantee the continuity of the overall patient treatment. A sophisticated prehospital management will obviously have no beneficial effect for the patient if it is not followed by complementary treatment at the hospital. This goal is sometimes difficult to reach. In the US the EMS system prehospital care providers are often not directly affiliated to the hospital. They may be members of the fire brigade and therefore their training does not include the principles of in-hospital care. This explains the need for very detailed prehospital protocols. On the contrary, when specialized nurses or physicians are involved, the link between prehospital and in-hospital care is easier to establish, without the need for rigid protocols. In Europe in some EMS systems it is the same pool of physicians who are in charge of the MICU prehospital team and/or the emergency room. This is the best method to guarantee a permanent link between these two phases of patient management. MEDICAL L E A D E R S H I P

Regardless of the type and structure of the EMS and the degree of physician involvement, the medical leadership is probably the most important specification. An effective medical director with a strong field experience is irreplaceable (Pepe and Stewart, 1986). Medical direction of paramedics in one system, or of trained physicians in the other, is needed for education, field supervision and research. Many large urban EMS systems in the USA, as in other countries, have full-time medical directors who are academically oriented physicians. Under medical director supervision, medical training programmes, including field experience, give the young physicians a unique opportunity to develop their clinical judgement and their understanding of prehospital problems (Stewart et al, 1987). The direct contact with EMTs or prehospital care providers is very valuable for physicians when later in charge of emergency rooms or critical care units. Field supervision, as we have seen, is another positive consequence of medical leadership. It improves the quality of care and is the basis for system evaluation. Without a medical director no effective quality assurance can be performed.

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Research in prehospital emergency medicine is also very dependent on the involvement and leadership of a physician. Implementing scientific research programmes and collecting prehospital data needs strong medical control. Responsible physicians, especially if they are academically oriented, may develop projects directed at developing new resuscitation techniques. The prehospital setting is a wide experimental area for new technologies and new concepts in emergency medicine.

THE PRINCIPLES OF AN IDEAL EMS SYSTEM

None of the EMS systems reviewed above may be considered as a universal standard. They evolve in different ways as a result of many factors such as hospital organization, hospital funding, the health insurance system. However, the strong points of each of these different organizations could be taken to provide the basis of an ideal EMS system. We will briefly review those points that we consider to be the most important. The first point is medical involvement. An ideal system should include a practising physician at the scene of the injury. Intervention by the physician may only be needed in some cases on request, or as a back-up, but the need for a flexible response to any situation is necessary. Integration of prehospital and in-hospital care is the second point. A categorization of all the facilities in the area is needed to ensure that the patient is taken to the hospital most appropriate for that patient's management. C o m m o n protocols for out-of-hospital and in-hospital management are mandatory if the prehospital management of the patient is not limited to the 'scoop and run' practice. The same level of training and/or affiliation to the same department is the safest way to correlate these two phases of the patient's management and to increase the level of prehospital care. Finally an ideal system needs to be evaluated and developed. The definitive aim of such control is not only to ensure quality but also to increase the efficiency of the overall system.

SUMMARY

The involvement of physicians, and especially anaesthetists, in prehospital care is very different from one EMS system to another. In this chapter we mainly compare the US EMS system, where the role of the physician is limited, and the French S A M U system, which was created and is run by anaesthetists. Despite major differences in the bases of these two organizations, there are some c o m m o n points as far as involvement of the physician is concerned: medical control, leadership and education and research need the presence of a trained physician with strong field experience.

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