Feature Reviews

MJM FORUM: SPECIAL FORUM ON TRAUMA CARE SYSTEMS

The History of Trauma Care Systems From Homer to Telemedicine
The Evidence Supporting a Systematic Approach to the Care of the Injured Patient:From Prevention to Rehabilitation

The History of Trauma Care Systems From Homer to Telemedicine

Moishe Liberman, M.D.*†§¥, David S Mulder, M.D.†, John S Sampalis, Ph.D.†§¥
*To whom correspondence should be addressed: Moishe Liberman, McGill University Health Centre, Montreal General Hospital Departments of Surgery and Clinical Epidemiology 1650 Cedar Avenue, L10-520 Montreal, Quebec, Canada H3G 1A4
hone: (514) 934-6116, fax: (514) 934-9913 E-mail: moishe.liberman@mail.mcgill.ca
†Montreal General Hospital - Department of Surgery, McGill University Health Center
§Montreal General Hospital - Department of Clinical Epidemiology, McGill University Health Center
¥ Hôpital Sacre Coeur - Department of Surgery, Université de Montreal, Montreal, Quebec, Canada

ANCIENT SYSTEMS OF TRAUMA CARE
The systematic and organized care of injured patients was born in times of war (1). In one of the earliest human writings, Homer in the Iliad, refers to the treatment of the injured patient during the Trojan war (5th century BC) (2). Homer reports a 77% mortality rate from injury among the 147 wounded soldiers. Surgical care of these injured soldiers was poor compared to the advanced techniques of today. However, the ancient Greeks recognized the importance of systems of trauma care. Injured soldiers were transported to, and treated in, specialized barracks called klisiai or transported to offshore ships for treatment of their wounds.

Hippocrates believed that the care of traumatic injuries during war was the ideal school for surgeons. The earliest documentation of a rudimentary trauma system is the description of medical care for the Roman Legions in approximately 100 AD (3). The Romans had organized on-site first aid, ambulances and surgeons that were on-call 24 hours a day. The trauma care hospitals (valetudinarian) were strategically located near every important encampment and were fairly sophisticated in both design and concept (4).

NAPOLEONIC ERA
Dominique-Jean Larrey (1766-1842), a Frenchman, was probably the pioneer of systematic trauma care. When international war broke out in 1792, he became a field doctor in the Rhine army. While waiting in Strasbourg for action, he organized a military medical association. Once the fighting erupted, it did not take him long to realize that an organized system was needed in order to save more soldiers. He wrote (5):

"I now discovered the trouble it took us to move our bandaging stations - our military hospitals. According to the rules, they were supposed to stay about five kilometres from the army. The wounded were left on the field until the battle was over, or gathered at some convenient spot to which the ambulance rushed. But the roads were so choked with wagons, and such delays arose, that most of the victims died before the ambulance arrived. This gave me the idea of building an ambulance that was adequate to help the wounded during the actual battle."

Following a battle at Limburg in which the conditions were awful and casualties high, Larrey wrote to the General with a proposal; he later wrote of this proposal:

My suggestion was accepted and I received orders to construct a cart which I called the flying ambulance. My first plan was to transport the wounded on a horse-litter, but experience soon made me give it up. The next effort was to make a cart with good suspension, combining speed with safety and comfort."

Previously, wounded soldiers were left on the battlefield until the fighting ended for the day. Larrey's ambulance could evacuate these soldiers soon after injury. The ambulance carried a doctor, quarter-master, non-commissioned officer, twenty-four infantrymen, and a drummer-boy who carried the bandage kit. He replaced the saddles' pistol holders with courier bags full of instruments and bandages. Larrey's "flying ambulance" was a big success. In April of 1973, Larrey was sent back to Paris with orders to arrange flying ambulances for the whole army. For his skill and efforts, Napoleon made him a Baron and the French Army's Surgeon General. Napoleon said of him: "He is the most virtuous man I have ever known."

Military hospitals were designed to concentrate the injured soldiers in one area and operate on them as soon as possible following injury. Larrey realized the importance of the time to definitive care on outcome and arranged to establish his military hospitals as close to the battlefields as possible. Larrey, not only organized to have the wounded evacuated from the battlefield and brought promptly to treatment centers, but was also a pioneer in expanding the role of the military surgeon to encompass all aspects of patient care (6). He was the first to realize the importance of the surgeon in organizing all aspects of the care of the injured patient - the first "trauma system". He worked to improve sanitation, procurement of food and supplies for the sick and wounded, training of medical personnel as well as the rapid evacuation of the wounded from the battlefield.

CIVIL WAR
The American Civil War was another important step in systematic care of the injured patient. The large number of casualties, primarily due to the advances made in firearms, forced the creation of an extensive infrastructure in order to support the surgeons on the battlefield and care for the injured (1). A major advance in the systematic approach to trauma care came after the war, when the Union published 'The Medical and Surgical History of the War of the Rebellion', in a six volume set (7). This national publication reported the epidemiology of injuries and mortalities that occurred during the rebellion. It also explained the techniques and system elements that were employed throughout the war.

During the war, hospitals were strategically located near creeks in order to provide water that was vital to the care of the injured soldiers. When numerous regimental hospitals were involved in a single battle, they banded together to form a single brigade hospital. The next level of treatment centre was the division hospital and the ultimate level was the general hospital (1). The Union soon recognized the deficiencies in their system of care. The small regimental hospitals were inadequate to care for the wounded. When the regiment displaced, these hospitals could not move with the regiment and transfer all the injured soldiers. This forced the establishment of independent hospitals that could receive the injured soldiers after the regiment relocated. These new hospitals were called "general hospitals", were permanent, and were able to accept the injured from the front line hospitals following displacement of the regiment (1).

WORLD WAR I
Mechanical advances were responsible for improvements in trauma care in World War I. These advances allowed for field ambulances to become motor driven, instead of horse-driven, as they had been in previous conflicts. Timely evacuation of wounded soldiers occurred through "echelons of treatment facilities" (8). Echelons, each with a greater treatment capacity, were established as a standard protocol. The first tier was the evacuation of injured soldiers from the frontlines by corpsmen and stretcher-bearers. Initial treatments of the wounded men were administered at battle aid stations near the battlefront. At these stations, the injured were administered narcotics, external hemorrhage was controlled and fractures were splinted. Seriously wounded men were then evacuated to clearing stations where surgeons performed emergency surgery, which consisted mostly of the debridement of wounds. Soldiers that survived were then transported to evacuation hospitals located at safe distances from the battlefields. Definitive care was delivered at these centers and patients convalesced with the ultimate goal of returning them to the front lines. This system of escalating echelons of trauma care became the foundation for modern day civilian trauma systems. Due to the huge numbers of casualties seen in some areas, the concept of triage was born. Injured patients were sorted based both on priority and salvageability.

WORLD WAR II
Emergency medical services in Britain were instituted under the direction of the Minister of Health for both civilian and British Forces in 1940 (9). The British government realised that there would be mass civilian casualties during the war and therefore the War Office and the Minister of Health agreed to pool resources in order to create a system of trauma care that made no distinction between military and civilian casualties. At the outbreak of war it was estimated that approximately 300,000 hospital beds would be needed to treat casualties. Therefore civilian hospitals, civilian physicians and allied health professionals were selected and enrolled into the British Emergency Medical Service. Furthermore, there were specific detailed guidelines established for the organization of trauma centres, their location, corridors for pre-hospital transport and triage, as well as mobile surgical teams which could be deployed close to the areas of casualties. Trauma centres were classified based on resources for the first time in history (Adapted from - Bailey H; Surgery of Modern Warfare, 1942, Vol. II p.917(9)):

Class 1A - Hospitals of over 50 beds in which full surgical facilities are available.
Class 1B - Smaller hospitals in which there are good surgical facilities.
Class 2 - Hospitals suitable for the treatment of convalescent surgical and chronic medical cases. In certain cases some of these hospitals were upgraded.
Class 3 - Infectious Disease hospitals, which were kept available for their peace-time use.
Special Hospitals - Many well-equipped special hospitals were classified between 1 and 2. In some cases they were reserved for peace-time use (e.g.: maternity, children's and mental facilities)

In World War II, the immobile medical units that were used in WWI by the United States could not keep up with the fast pace of troop movement. This need gave birth to the "AUX units" which were composed of special surgical teams that travelled to the front lines in order to treat wounded soldiers. Furthermore, the advent of air travel allowed for the evacuation of wounded patients by plane during the WWII conflict, which had not been previously used in war-time situations.

The passage of patients through the echelons of care established in WWI became quicker and more efficient (8). Time lag to definitive treatment was shown to have a negative impact on survival in thoracic and abdominal wounds, as well as in extremity fractures (10,11). Trueta recognized that and wrote: "Surgical aid to casualties in the frontline is impeded by many factors and has to be adapted to varying conditions, but the main basis of success is to have the wounded patient on the operating table at the earliest possible moment" (11). In WWI, the time from injury to definitive care ranged between 12 and 18 hours. This was decreased by 50% in WWII (1,12). The improvements in time to definitive care as well as the advances in antisepsis, shock resuscitation, transfusion and surgical technique contributed to significantly improved survival rates for injured patients. The many civilian physicians, surgeons and anesthesiologists who were drafted into service in WWII observed the benefits of the systematic approach to trauma care and brought back high expectations to their civilian communities in North America (8).

KOREAN WAR
The AUX units of WWII were the basis for the establishment of the MASH (Mobile Army Surgical Hospital) units utilized in the Korean conflict. The MASH unit was a mobile surgical hospital comprising 60 beds that operated to the rear of the combat area, just out of range of artillery fire. Injured soldiers no longer had to endure multiple transportations before receiving definitive care. Instead they arrived at definitive care centres often within the "golden hour" of trauma care (13). The introduction of air ambulances and helicopters were also a major advance in the timely care of the wounded in Korea. The Korean War was the first time in military history that the helicopter was used extensively to evacuate casualties from the forward battlefields to supporting medical facilities (14). These transport mechanisms reduced the time from injury to definitive care to between 2 and 4 hours and further reduced mortality to only 2.4% (1,4).


Timeline Part 1

Timeline Part 2

VIETNAM
The Vietnam War saw the treatment of 250,000 casualties (15). In Vietnam, due to the mountainous terrain and the consequent difficulty in evacuating injured soldiers, the helicopter was utilized extensively as a part of the pre-hospital arsenal (16,17). The first helicopters used for evacuation of injured soldiers had two pods on the outside of the aircraft on either side for evacuation of injured soldiers from the front lines to the awaiting MASH units. The classic pattern of casualty evacuation from previous conflicts was revised in Vietnam. The battalion and regimental aid stations, which had formerly been the first line of surgical care by a physician, were being systematically overflown by the medical evacuation helicopters in Vietnam that were landing in an area where definitive care could be rendered. This area was either a unit from a medical battalion, a mobile surgical hospital, a field hospital, an evacuation hospital, or a hospital ship waiting offshore. These helicopters further decreased time to definitive surgical care to between one and one and a half hours (16).

Pre-hospital time for patients treated at the U.S. Navy Hospital in Da Nang was reported to be only 80 minutes (18). In WWII, it often took four to six months from the time of injury to get an injured soldier back to the United States by hospital ship. Due to improvements in transportation as well as the newly orchestrated evacuation and treatment system, soldiers injured on the battlefields in Vietnam would often arrive at the Naval Hospital, Great Lakes, Illinois within 72 to 96 hours from the time of injury (19). The significant advances in both the systematic care of the injured patient, as well as the improvements in surgical, transfusion-related, and antimicrobial technology resulted in decreases in mortality for patients reaching medical facilities from 8% in WWI to 4.5% in WWII to 2.5% in Korea and to less than 2% in Vietnam (20,21,22). Average times to definitive care were: 10 hours in WWII, 5 hours in Korea and 1 hour in Vietnam (21).

CIVILIAN TRAUMA CARE SYSTEMS
The civilian interest and the move towards the regionalisation of trauma care in the United States were secondary to the U.S. military experience with organized trauma care (23). The care of the injured patient evolved and improved significantly in World War II and was further developed during the subsequent Korean and Vietnam wars. It was the Korean and Vietnam conflicts that provided the basis for civilian regionalised emergency medical and trauma systems (21). Civilian trauma providers learned about well-trained paramedical personnel providing care in the field, effective pre-hospital, in-hospital and pre- to in-hospital communications, rapid emergency evacuation and transport systems (helicopter evacuations), and specialized "trauma surgeons" working out of specially designed "trauma centers" or MASH units.

In the early 1960s more Americans were killed annually on the nation's highways than were killed during the entire Vietnam conflict (24). In the United States, until the late nineteen-sixties and early nineteen-seventies, trauma care mostly occurred in the city and county hospitals or at the hospital nearest to the scene of the accident (25). The hospitals receiving trauma patients were ill-equipped and ill-staffed to handle injured patients and pre-hospital care consisted of poorly trained personnel with little equipment (26). During peak hours and at night these emergency rooms were often staffed with the most junior or unprepared physicians or poorly trained "moonlighters". In the ambulance, there was often only a driver with little emergency training and the patient would be transferred unattended in the back of the ambulance to the nearest hospital. Radios were rarely available in ambulances, and when present they were mainly used to monitor police transmissions in order to try and pick up accident calls and arrive early on-scene. Rockwood recalls that in some cities throughout the US, animals received better emergency care than citizens. They had radio dispatched vehicles and well-trained personnel available for emergency calls for pets. Trauma mortality was often due to late, inadequate or unrecognized surgical emergencies (27,28,29).

In the early 1960s, a slew of studies were published demonstrating excess mortality following trauma in non-regionalized areas. In 1961, Van Wagoner studied 606 non-combat military deaths and concluded that one sixth (103 cases) of these were secondary to injuries from which recovery could normally be expected and another one sixth from injuries which received inadequate care (96 cases) (30). This was the first published report attempting to assess preventable deaths among injured patients occurring in a non-regionalized system of care. This paper opened the eyes of healthcare providers to the poor and inadequate care that injured patients were receiving and began a movement towards establishing an effective system to prevent these needless deaths.

Following the study by Van Wagoner, Frey showed that out of 159 patients dying as a result of trauma in Michigan, which lacked a regionalized trauma system, 28 received inappropriate care (31). Gertner demonstrated that one third of deaths involving abdominal trauma following motor vehicle collisions in Baltimore, a non-regionalized area, were preventable (32) and Moylan showed that quality of care in hospitals treating trauma patients in five hospitals in Wisconsin was unacceptable in 16% of seriously injured patients (33). These preventable death studies and other reports observing excess mortality in various areas throughout North America have been vital in the move toward regionalization in respective regions (34).

The realization by the US government of the toll that trauma was taking on society, particularly young society, in terms of morbidity and mortality as well as the "ineffective nonsystems"(20) of trauma care led the National Academy of Sciences to dub injury the "neglected disease of modern society" (35) in the sentinel report of 1966 prepared by the Committee on Shock and Trauma of the National Research Council. This report was titled: "Accidental Death and Disability: The Neglected Disease of Modern Society" and nicknamed the "white paper". Many important and revolutionary recommendations were made which shaped trauma systems as we know them today, including: pre-hospital radio communication systems, categorization of hospitals, the development of trauma registries, implementation of hospital trauma committees, calls for research into clinical areas of trauma care and in the areas of shock and resuscitation, and injury prevention strategies. Following this vital paper, many were convinced that injury was indeed a neglected disease and that it would continue to negatively impact on society if change was not brought about. By the early 1970s, many influential members of medical society believed that lessons learned on the battlefields in Korea and Vietnam in terms of triage, rapid transport of trauma patients to definitive care centers, and standardisation of pre-hospital and in-hospital care could be applied effectively to civilian trauma patients (36).

Accidental Death and Disability significantly contributed to what we today consider standard elements of trauma care. It highlighted the importance of standards of care, protocols for pre-hospital care providers, credentialing standards for EMS providers, improvements in accident prevention, emergency first aid and medical care, ambulance services, emergency medical communication, use of air evacuation by helicopter, upgrading emergency departments, improvements and expansion of intensive care units to properly deal with injured patients and specifications for the construction of ambulances. It also called for rapid definitive care of injured patients in the hospital setting and specialized physicians specifically trained and ready at all times to take care of injured patients. This recommendation later was integral in the establishment of a new specialty in medicine - Emergency Medicine. A strong case was made for the development of a system of trauma patient care, as well as a system of subsystem components essential to the success of an overall effective effort (20). The document called for the credentialing of four different levels of hospitals to treat trauma patients and suggested that outside credentialing agencies be designated to assign these categories. One of the most important and revolutionary recommendations made in the report was that hospitals and hospital staff be accountable for the outcomes of patients under their care. The creation of trauma registries and outcome analysis, including autopsy studies were therefore born.

Based on the recommendations of Accidental Death and Disability, United States Congress enacted the National Highway Safety Act of 1966. This legislation mandated the Department of Transport to: decrease motor vehicle accident deaths, conduct research into car safety devices, to coordinate pre-hospital care and establish pre-hospital communication.

In 1971, United States Congress proposed a law consisting of program guidelines and technical assistance measures in order to create a nationally coordinated and comprehensive system of regionalized emergency accessibility and care for all American citizens (23). This led to the Emergency Medical Services Act of 1973 (37). The Act enabled the federal government to designate a lead agency role to the Division of Emergency Medical Services in order to develop regional comprehensive emergency medical service (EMS) systems. It also provided financial aid to states for the coordination of EMS activities (38).

The first civilian trauma units were established in 1966 at Cook County Hospital in Chicago and at San Francisco General Hospital in California (1,39,40,41). The first regionalized trauma system was in established in Illinois in 1971 (20,23,42,43,44,45,46,47). Lowe and Baker highlighted the concept of the "team approach" to trauma care as being of paramount importance in establishing this system of treating injured patients, which encompassed access to the system through rehabilitation (39). Hospital designation, triage and transport guidelines as well as the concept of a "burn center" were put into place. For the first time, a central bed registry and a patient distribution and triage program were established. In Illinois, there was an eight percent decline in highway mortality in the first 6 months of 1972 (following regionalisation) compared to the same six month period in 1971, prior to regionalisation (47). This decrease in injury related mortality was observed in spite of an increase in highway accidents and injuries during that same period. In 1973, R. Adams Cowley expanded the existing Shock-Trauma program at the University of Maryland to encompass the entire state and established the Maryland Institute for Emergency Medical Services (MIEMS) (48,49,50).

By 1974, only 2 states (Maryland and Illinois) had established emergency medical systems with integrated organized trauma services within these systems. However, in 1974, the trauma system concept took off and slowly, many communities started to organize trauma care. There was however, little civilian outcome data demonstrating a positive effect for systematic trauma care at that time.

In 1973, Waters reported a 38% reduction in motor vehicle accident mortality following introduction of a regionalized trauma system in Jacksonville, Florida (51). This was one of the first reports demonstrating a beneficial effect on patient outcome with a systems approach to trauma care. The system included an emphasis on pre-hospital care, well trained pre-hospital crews, rapid response times and improved pre-hospital communication.

In 1976, the American College of Surgeons Committee on Trauma (52) assumed the leadership role in trauma system development with the publication of the first edition of Optimal Hospital Resources for Care of the Seriously Injured (53,54). For the first time in 1977, Detmer et al. defined the four categories of hospitals designated as civilian trauma centres which were to become the basis of today's level I, II, III and IV centers (55). More equipped centers subsequently were shown to have significantly less unacceptable care compared to less equipped, or lower level centers.

WEST AND TRUNKEY REVOLUTIONIZE TRAUMA CARE
The first and landmark study critically evaluating civilian regionalized care for injured patients and comparing a regionalized to a non-regionalized area was published by West, Trunkey and Lim in 1979 (56,57). This remarkable and original study was responsible for a new field of healthcare and health services research. They retrospectively studied one hundred consecutive motor vehicle fatalities in two counties (San Francisco and Orange County) in California between 1974 and 1975. The injured patients in San Francisco County were taken to a single trauma centre and the patients in Orange County were transported to the closest receiving hospital (39 hospitals receiving injured patients). They excluded patients who were transferred from other facilities where they had received care prior to treatment in the study hospitals and patients who died prior to reaching hospital. Deaths were classified as clearly preventable, potentially preventable and not preventable by an expert panel.

Patients in Orange County were significantly younger and had injuries of lower severity than patients in the San Francisco County cohort. Nevertheless, a panel of experts deemed that thirty-seven percent (11/30) of non-CNS related deaths in the Orange County cohort were judged to be clearly preventable compared to none in the San Francisco County cohort. Another 37% (11/30) of deaths in Orange County were judged to be potentially preventable, compared to only one death in San Francisco. This study was the first to begin to shed light on the importance of specialized, early definitive care of trauma patients and the magnitude of bringing injured patients directly to appropriately staffed, experienced and equipped care facilities.

Orange County was regionalized in 1980. Following the study by West, a complementary autopsy study (58,59) was performed on patients injured in motor vehicle collisions in Orange County before and after trauma care regionalisation (60,61,62). Cales retrospectively evaluated the outcomes of patients following implementation of a regionalized trauma system in Orange County by reviewing trauma deaths via an expert panel. This was the first ever before and after study of regionalized trauma care and served as a standard to which numerous subsequent studies would be compared. Fifty-eight deaths occurring prior to regionalisation were compared to 60 deaths occurring following implementation of a trauma system. Potentially preventable death rates dropped from 34% prior to regionalisation to 15% following regionalisation (p<0.02). Fifty-four percent of potentially preventable deaths occurred in patients transported to non-trauma centres, compared to 4% of patients transported to trauma centres. They also found that the death rate from vehicular trauma dropped from 15.7 per 100,000 to 13.9 per 100,000 (p < 0.03) in the first year following regionalisation and from 15.8 per 100,000 to 12.4 per 100,000 after 2 years of regionalisation (p < 0.02). These remarkable and convincing results were strengthened due to the fact that the patients in the post-regionalisation cohort had higher Injury Severity Scores (ISS) and median age compared to those in the pre-regionalisation cohort. The improvement in outcomes was in part attributed to the aggressive approach to the care of the traumatized patient following regionalisation, which was suggested by an increased percentage of patients who received surgical interventions (62). Even though there has been some debate over the statistical methods (i.e. preventable death rate analysis) used to demonstrate efficacy in the early studies of trauma systems (63,64,65,66,67,68,69), these results are not only impressive, they also are responsible for the changes in trauma care occurring over the following 30 years.

The studies out of Orange County disclosed to the public, for the first time, the problem of inadequate trauma patient care due to the absence of a system. Backed by public demand, governments and healthcare authorities were forced to be accountable for trauma outcomes to the public. The scientific evaluation of trauma systems and their impact on society by West and Trunkey from the 1970s are unparalleled in terms of both their originality and impact on trauma care systems. These studies are the basis of modern systematic trauma care as we know and take for granted today.

ADVANCED TRAUMA LIFE SUPPORT
Prior to 1980, there were no standardized protocols or programs to train physicians in the appropriate care of the injured patient. In 1976, an orthopedic surgeon from Nebraska initiated the Advanced Trauma Life Support (ATLS) Course for training physicians in trauma care, after his wife and 3 children were killed when he crashed his plane (70). The care that his injured wife and children received was poor and this motivated the surgeon to create a course in order to train physicians with little chance to practice trauma treatment skills in the acute management of injured patients. This course was revised and adopted by the American college of Surgeons Committee on Trauma in 1979. It has since become an international standardized trauma training program, further contributing to the standardization of trauma care across regions.

MODERN DAY TRAUMA SYSTEMS
In 1985 and 1988, the Committee on Trauma Research of the National Research Council and the Institute of Medicine published "Injury in America, A Continuing Public Health Problem" (71) and "Injury Control, A Review of the Status and Progress of the Injury Control, Program at the Centers for Disease Control" (72). These reports were a follow-up to the white paper and looked at the progress that had been achieved since 1966 in trauma treatment and prevention and made extensive recommendations regarding the future of trauma care and trauma systems. These recommendations were based on the extensive body of scientific evidence that had surfaced since 1966 regarding trauma system effectiveness. The committee stated that trauma was a public health problem whose toll was unacceptable. They called for the nation to address the problem through research and legislation. The challenge proposed in Injury in America was to establish injury prevention and treatment as a recognized interdisciplinary field of scientific evaluation and ongoing research. The 1985 report was again expanded on and reassessed in 1999 in the report put out by the Institute of Medicine; "Reducing the Burden of Injury - Advancing Prevention and Treatment" (73). This report re-emphasized the point that had been highlighted previously in Accidental Death and Disability, Injury in America and Injury Control: investment in injury research in the United States did not balance the magnitude of the problem of injury. It further emphasized the positive impact of systems of trauma care on the outcome of injured patients and called for the development of more trauma systems throughout the country.

Trauma systems and regionalized trauma care has seen multiple changes and improvements over the years. It is the authors' opinion that future challenges for trauma systems include the identification of specific components of trauma systems and their impact on outcome, the creation of effective tailor-made and cost-effective systems created to fit individual community needs, the creation of novel methods to assess population-based outcome following trauma, as well as the extension of the excellent results demonstrated in urban areas to the rural setting. The advent of telemedicine promises to improve trauma care in these rural and often inaccessible areas, however further research in this area is required (74,75,76). Furthermore, aircraft (helicopter and fixed wing) are being used to transfer critically injured patients from rural centres to urban tertiary trauma centres, improving systematic care and outcomes for patients injured at great distances from definitive care facilities.

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Moishe Liberman MD, is a fourth year resident in the Division of General Surgery at McGill University. He is also a research fellow in the Department of Experimental Surgery at McGill. David S. Mulder MD, MSc, FRCSC is the Chairman of the Division of Cardiothoracic Surgery at the McGill University Health Center, Senior Surgeon at the Montreal General Hospital, and Professor of Surgery at McGill University. John S. Sampalis PhD, is the Head of Surgical Epidemiology at McGill University, an Associate Professor in the Departments of Surgery, Epidemiology and Biostatistics, and an Associate Professor in the Department of Social and Preventive Medicine at Université de Montréal and at Université de Laval. He has been a past recipient of the Medical Research of Canada Scientist award and is currently a senior scientist supported by the Fonds de la recherche en sante du Quebec (FRSQ).

The Evidence Supporting a Systematic Approach to the Care of the Injured Patient:From Prevention to Rehabilitation

Moishe Liberman MD†, David S Mulder MD†, John S Sampalis PhD*
*To whom correspondence should be addressed: Moishe Liberman, McGill University Health Centre, Montreal General Hospital Departments of Surgery and Clinical Epidemiology 1650 Cedar Avenue, L10-520 Montreal, Quebec, Canada H3G 1A4
hone: (514) 934-6116, fax: (514) 934-9913 E-mail: moishe.liberman@mail.mcgill.ca
†Montreal General Hospital - Department of Surgery, McGill University Health Center
§Montreal General Hospital - Department of Clinical Epidemiology, McGill University Health Center
¥ Hôpital Sacre Coeur - Department of Surgery, Université de Montreal, Montreal, Quebec, Canada

INTRODUCTION
Trauma is the leading cause of death for individuals under 45 years of age in the Western world and remains the fourth leading cause of death for all ages combined (1,2,3,4). Approximately 0.9 million people worldwide die secondarily to injury (8% of all deaths) (5). It is also a major cause of morbidity in both the short and long-term (6). Furthermore, injury is a leading cause of disability, potential years of life lost and a major contributor to overall health care costs (7,8,9). It is estimated that injury causes 36 life-years lost per death compared to 16 life-years for cancer and 12 years for heart disease and stroke combined (10). In 1994, 8,687 people died following accidents in Canada (1). Approximately four times as many patients suffer severe disability related to accidents each year.

The cost of acute medical care for injured patients is in excess of $16 billion per annum (11). This represents the second largest source of medical expenditures in the United States. In addition to the health dollars spent on the acute care of injured patients, an additional $150 billion US are required to cover the annual cost due to death, disability, and lost wages and taxes (9). From a health-economic perspective, the cost of trauma and its consequences makes the elucidation of evidence-based practices paramount. Trauma care systems have been shown to significantly decrease medical care costs. It is estimated that by extending trauma care systems throughout the entire United States, annual medical care payments could be lowered by $3.2 billion (12). If productivity costs due to premature death are taken into account, the total savings could total $10.3 billion.

TRAUMA SYSTEMS
Trauma care throughout Canada and the rest of North America has seen tremendous changes over the last 30 years. The regionalisation of trauma care, which has occurred in some Canadian and American regions, has shifted the scope of trauma patient management from hospital-based care to a systems approach. A regionalised approach to trauma care (a trauma system) consists of the global care of the injured patient, from the time of injury until the end of rehabilitation (13,14). The system provides a continuum of services encompassing four elements: [1] pre-hospital care, [2] in-hospital care [3] rehabilitation, and [4] research. The ultimate goal of these systems is to get the injured patient to definitive care as soon as possible (15,16).

Trauma systems have been designed to render "optimal care" to injured patients. Eggold defines optimal care as being based on two implied premises (17): One premise is that suboptimal trauma care is possible and demonstrable and the other premise is that optimal care must result in reduced mortality and/or morbidity, "the sine qua non of medical progress". Furthermore, by pooling resources and avoiding duplication through a system of care within a region, cost effectiveness is assured (18).

The care of injured patients is a continuum from the moment of injury, until the return to daily life (19,20). Regionalised trauma care incorporates several different elements, which together make up the trauma "system". These systems have been repeatedly shown to decrease mortality and improve the outcome of injured patients in multiple different regions throughout the Western world.

EPIDEMIOLOGY OF TRAUMA DEATHS
Trauma is a devastating disease. It contributes to approximately 140,000 deaths per year in the United States (21). Unintentional injuries account for 4.6% of deaths and 19.6% of potential years of life lost in patients younger than 65 years of age. (22) Injuries account for 61% of deaths due to trauma in the United States and nearly half of these deaths are due to motor vehicle accidents (7). Falls, occurring mostly in the octogenarian population, account for the second most prevalent portion of unintentional deaths.

Death resulting from trauma follows a trimodal distribution (19,23,24,25,26). These peaks were first alluded to in reports by Beebe and DeBakey in 1952 (27) and by Zollinger in 1955 (28) and later expanded on by Trunkey in 1983 (19). The first peak of death following injury is dubbed the "immediate deaths" and occurs within seconds of injury. It accounts for 50% of trauma-related mortality. These early deaths occur secondary to lacerations to the brain, upper spinal cord, heart, aorta and other major vessels. Virtually all of these patients die and little, if anything, can be done to save them. Cales showed that 44% of trauma deaths occurred at the scene (29). The only way to reduce deaths in the first peak of trauma mortality is through prevention strategies and programs, as well as tougher legislation on firearms and motor vehicle traffic laws (30). Injury prevention and control has been shown to have more immediate health and economic benefits than the prevention and control of chronic diseases (31).

The second peak of mortality, the "early deaths" occurs within minutes to a few hours following injury and contributes to 30% of mortality following trauma. This period has been dubbed the "golden hour" following injury (19). Deaths in this period are secondary to injuries that require urgent and emergent care. These injuries are time-critical and the sooner the patient receives definitive care for these injuries, the better the outcome. Important injuries in this category include: subdural and epidural hematomas, hemopneumothorax, liver lacerations, ruptured spleen, pelvic and long bone fractures causing significant bleeding, as well as injuries to blood vessels contributing to significant blood loss. These injuries require timely definitive care, usually through surgery to repair the source of blood loss and stop the hemorrhage or to evacuate a compressive hematoma (cerebral hemorrhage), or an interventional procedure (tube thoracostomy, pericardiocentesis, angio-embolisation…). If these procedures are not provided promptly and properly by the appropriate personnel in the appropriate setting, mortality occurs.

It is for the patients in the second period of trauma deaths that systematic trauma care attempts to make an impact. These are the time-critical patients, desperately in need of definitive and appropriate care in a timely manner. Patients receiving rapid transport to hospital will not have good outcomes if they are taken to the wrong hospital. Patients taken to the right hospital will also have poor outcomes if there is a delay in getting them there. The second peak is the focus of trauma systems and regionalised care of the injured patient.

The third peak of mortality following trauma, the "late deaths", occurs several days or week following injury. These deaths account for approximately 20% of deaths after injury. Deaths in this period are usually secondary to sepsis and multiple organ system failure. Rapid and appropriate care can reduce these injuries, however most of these deaths will occur regardless of the system of trauma care and the key to reducing them lies in research into systemic mediators of sepsis and multiple organ dysfunction. Time is less of a factor in the outcome of these patients; rather, the quality of medical care and the state of medical knowledge contribute to outcome in these patients.

Recently researchers have identified a fourth peak of trauma deaths, which requires further study. The fourth peak of deaths is that which occurs in the first year following injury (32). The age characteristics of this unique group of patients show that patients over the age of 65 have a 15-fold greater chance of dying in the year following injury.

PROCESS OF REGIONALISATION, BUILDING A "TRAUMA SYSTEM"
The basis for the regionalisation of trauma care or the development of a "trauma system" is the need to link all aspects of care in order to maximize efficiency, pool resources and improve outcomes. A comprehensive trauma system links hospitals, pre-hospital care and other emergency medical services, post hospital care facilities (rehabilitation and long-term care centres), as well as health care and public safety agencies (33). Ideal trauma systems include prevention, access, acute hospital care, rehabilitation, and research activities (34). These systems have been developed in order to direct seriously injured patients to specific facilities on local, regional, and state/province wide bases. The two main goals of regionalised trauma care are to improve the quality of care and to decrease its cost (35).

The American College of Surgeons Committee on Trauma clearly outlines the importance of emphasising the trauma system, rather than the trauma centre as being integral in improving trauma patient outcome (34).

"Care of the injured patient requires a system approach to ensure optimal patient care. A systematic approach is necessary within a facility; however no one trauma centre can do everything alone. Thus, a system approach is necessary within an entire community regardless of its size…If resources for optimal care of the injured patient are to be used wisely, then some concentration of resources should occur. This type of resource allocation should allow patients to move to the highest level of care available and, ideally, should also avoid excessive and inappropriate expenditure in a time of limited medical resources."

Integral to the trauma care system is the designation of definitive trauma care facilities. These facilities provide the full spectrum of trauma care to injured patients in the most efficient and effective manner. The overall goal of the system is patient care and outcome, however efficiency and proper use of resources is emerging as an important aspect of trauma systems. Every trauma system or regionalised trauma area should have a "lead hospital". The lead hospital should be the hospital with the highest level of care (highest designation) in the area.

Trauma centres serve as the hubs of these systems. Trauma centres also exist in areas without formal trauma systems in place. In these areas they are usually not designated as trauma centres, but act as "de facto" or "functional" centres (36). Tertiary trauma centres (level I centres) are responsible for receiving the most seriously injured patients directly from the field (in most cases), as well as accepting and guiding transfer from secondary and primary centres. They also serve the purpose of being leaders in trauma care and prevention programs for the region. They are also responsible for conducting trauma-related research.

West identified eight essential elements that were integral to an inclusive trauma system based on criteria from the American College of Surgeons (37). These criteria were: (a) the presence of a lead agency with legal authority to designate trauma centres; (b) the use of a formal process for trauma centre designation; (c) the use of American College of Surgeons standards for trauma centres; (d) the use of an out-of-area survey team for trauma centre designation; (e) limiting the number of designated trauma centres in a community based on assessment of population need; (f) the application of written triage criteria that form the basis for bypassing non-trauma centre hospitals; (g) the presence of ongoing monitoring systems for trauma centres; and (h) the state-wide availability of trauma centres.

The integral steps in developing a regional trauma system are (37):

1. BASIC DATA
The first step is defining the magnitude of the problem in the area to be regionalised. This can be carried out using autopsy studies (38,39), preventable death studies (40), and/or regional trauma reviews (41). Out-of region experts should be recruited in order to provide objective assessments of the system in place.

2. DEVELOP A COMPREHENSIVE REGIONAL PLAN
The regional plan should deal with patient care from the time of injury until the end of their rehabilitation. It should be based on guidelines from the American College of Surgeons (42,43,44) and have local surgeons heavily involved in planning and development.

The plan should address the following issues:
- Pre-hospital Care
- Air Transport
- Triage
- Trauma Centre Designation
- Quality Assurance
- Specialty Care Programs
- Research
- Rehabilitation
- Prevention and Public Education
- Disaster Planning

3. IDENTIFY BARRIERS TO CHANGE
By identifying barriers to changes prior to attempted implementation, a young system can develop strategies to overcome these changes. The major barriers to change are usually economic.

4. DEVELOP A MANAGEMENT STRUCTURE
A lead agency must be identified and given formal, legal authority for trauma centre designation.

5. HOW TO IMPLEMENT THE PLAN
Once the plan has been developed, all regional hospitals should be encouraged to participate and undergo formal verification.

An "inclusive" approach to trauma system design has been adopted by trauma system planners (45). This approach is designed to improve the quality of care provided to injured patients by developing strategies for overcoming problems of access, cost and variation in the quality of services. Planning and implementing a system of trauma care is a huge undertaking (46). It requires intensive study, coordination and financial commitment. In the United States, the problem of access for patients without health insurance and those in rural areas have become paramount to the "inclusive" system. These problems are constantly being investigated and commitment on the part of systems for the care of these patients are vital to the success of these systems in the future.

THE ELEMENTS OF A TRAUMA SYSTEM
A model trauma care system includes the basic concept of "inclusiveness". An inclusive system encompasses all aspects of trauma from prevention of injury until the patient returns to their pre-injury baseline level of function. The key elements of regionalised trauma systems are: (1) a lead public agency with legal authority to establish and enforce trauma system policy; (2) facility categorization; (3) trauma centre designation; and (4) the implementation of triage and transfer protocols which identify patients in need of transport to definitive care at a designated trauma care centre (47,48,49). Even though these elements are essential and common across all trauma systems, individual variations exist. These variations are present in the methods different communities use to design, implement and run their systems. These differences are profound in the area of the process of trauma centre designation (48). Bazzoli et al identify three key elements integral to trauma care regionalisation: pre-hospital care, organization of hospitals and inter-hospital transfer agreements (50). By assuring appropriate and timely inter-hospital transfers, patients can be appropriately treated in a system encompassing remote and rural areas (51).

The American Trauma Society (ATS) identifies four fundamental components necessary for trauma systems and eight key infrastructure elements that are critical to trauma system success (52):

Fundamental Components
- Injury Prevention
- Pre-hospital Care
- Acute Care Facilities
- Post-hospital Care

Key Infrastructure Elements
- Leadership
- Professional Resources
- Education and Advocacy
- Information Management
- Finances
- Research
- Technology
- Disaster Preparedness and Response - Conventional and Unconventional

Time-distance relationships between injured patients and definitive and appropriate care are vital to any trauma system design (53). Systems need to be created with geographic, time-transportation factors and maximum health delivery capabilities of a region in mind (54).

Another crucial element involved in maintaining an effective regionalised trauma system is quality improvement. Effective and continuous quality improvement programs depend upon concurrent monitoring of the events involved and surrounding the care of the trauma patient (21). The information for quality improvement programs is usually stored in a trauma databank, maintained either at the individual institutions within the system, or in a centralised databank for the entire system, state/province or country. Important elements to be evaluated include: facts related to the patient's injury event, injury severity, process of care and outcome.

Pre-hospital triage algorithms are integral to the optimal care for the injured patient. Injured patients need to be taken to the appropriate level facility that is prepared, properly staffed, and equipped to handle the trauma patient. Various schemes have been proposed for the pre-hospital triage of trauma patients. The most widely used is probably the American College of Surgeons Triage Algorithm (55,34). Triage schemes have been shown to be effective at decreasing trauma mortality (56,57,58). The algorithms outline strategies for transporting the seriously injured patient to an appropriate centre, bypassing lower level centres, which are often closer to the scene of the accident.

Trauma centres remain a key component in the systems approach to the acute care of the severely injured patient (59,60). Designation of these centres is integral to improving outcomes (36,61). By having designated centres committed to the resource allocation and care of injured patients, improvements in both morbidity and mortality have been demonstrated. However, the system encompasses all phases of care, from pre-hospital through acute care and rehabilitation. The creation and running of an effective system requires complete commitment from medical and allied health care professionals, as well as from regional health boards, governmental agencies and communities. Furthermore, even though the designation of trauma centres shifts more severely injured patients to designated hospitals (62), trauma centre care has been shown to significantly reduce length of stay and cost of care compared to injury severity matched patients transferred from a non-trauma facility (63). Patients directly transported to trauma centres also have less missed injuries than transferred patients (64). However, it has also been demonstrated that hospitals in remote areas that do not possess all elements necessary for the designation of trauma centres, can have similar, if not better, outcomes than those meeting criteria (65).

Surgical leadership is vital to maintaining an effective trauma system (66,67,68). The American College of Surgeons Committee on Trauma emphasizes the role of the trauma surgeon in the design, implementation and running of a trauma system and trauma centre (34). The American Association for the Surgery of Trauma (AAST) expands on this and requires that a trauma surgeon be (69):

- Actively involved in the process of prehospital triage and treatment of trauma patients
- Thoroughly knowledgeable of the diagnostic options and treatment available in the emergency department and understands how to use them in the most appropriate and cost-effective manner
- Able to prioritise and coordinate the resuscitation and treatment of multiple serious injuries while coordinating care between multiple services and subspecialties
- Expert in the operative and nonoperative management of life-threatening and limb-threatening injuries
- Responsible for the comprehensive management of the injured patient in the critical care unit, including hemodynamic monitoring, ventilator management, nutrition and posttraumatic complications
- Integrally involved in the rehabilitation of the injured patient.
- Responsible for monitoring outcomes, identifying deficiencies in care when they exist, and correcting any identified deficiencies.
- Actively involved in trauma education, research and injury prevention.
- An advocate for the optimal care of trauma patients in public forums.

Another key element in the overall running of a trauma system is prevention (44). In fact, prevention is probably the single most effective way to decrease mortality and morbidity associated with injury.

Boyd appropriately points out that in order to design and implement an effective regional trauma system, focusing on one component of the subsystem will not be as effective as an overall and comprehensive view of the sequence of events as they affect the course and final outcome (53).

IN-HOSPITAL CARE - CHARACTERISTICS OF TRAUMA TREATMENT CENTRES
The categorisation of hospitals based on their ability to care for injured patients was first suggested by Youmans and Brose in 1970 (70). They conceptualised a classification system for hospitals treating injured patients in order to assure quality of care within a community. The initial classification system comprised: "major emergency facilities", "emergency facilities" and "provisional emergency facilities". These classifications later gave birth to level I, level II and level III trauma treatment centres.

Designated trauma centres have been shown to decrease mortality, complication rates, and length of hospital stay compared to non-trauma centres (71,72,73,74,75). Verification has also been shown to improve the process of care within trauma centres (76,77,78). An overview of a centre's role and requirements as part of a system of trauma care based on the ACS criteria for trauma centre designation is as follows:

Level I
Level I trauma centres are tertiary care facilities that are the focal point of a regionalised trauma system. These centres often, but not always occur in university hospitals. The facility must be capable of providing leadership and total care for every aspect of injury, from prevention to rehabilitation (59).

Level II
Level II trauma centres function in a similar capacity to level I centres, however, they do not have the extensive resources and facilities as level I centres. They are required to provide initial definitive trauma care to injured patients regardless of injury severity.

Level III
Level III centres usually occur in communities that do not have access to level I or II centres. These centres must have the capability to manage the initial care of the majority of injured patients and have transfer agreements and corridors set up for transfer of patients that exceed the hospitals resources and capabilities.

Level IV
Level IV centres are those centres treating and stabilizing injured patients in rural areas without other hospitals. They are the "de facto trauma centres" in these regions due to geographical location (59). They are responsible for providing Advanced Trauma Life Support care (55) in remote areas where no higher level of care is available prior to transfer to an advanced level centre.

The evaluation and management of severely injured patients requires significant institutional commitment and the commitment of skilled personnel (13). Recently, there has been much debate over the American College of Surgeons' requirements for minimal trauma centre volume in order for a centre to receive a designation (34). Numerous studies have been published over the last few years with conflicting results regarding the correlation between volume and outcome. Several studies have shown that volume has a positive correlation with survival (79,80,81,79,82,83,81), however others have demonstrated a lack of association (84,85,65,86,87). Guidelines for level I trauma centre verification require 1,200 admissions per year. Many centres in the US and Canada that cannot meet these requirements do, however, meet all other requirements for level I status.

THE IMPACT OF TRAUMA CARE REGIONALISATION
The initial fervour for trauma system implementation was backed by very few studies and lacked the large amounts of evidence that were to come over the years (88,89). However, since the late 1960s there have been over thirty studies demonstrating a positive impact on survival in regionalised compared to non-regionalised trauma systems (Table 1). Furthermore, the lack of a trauma care system has also been repetitively shown to contribute to substandard care and outcomes (90,91,92,93,94). By centralising the care of severely injured patients in to a few highly specialized centres, as well as creating corridors for direct entry and easy exit from acute care, trauma systems significantly improve the outcome for injured patients (46,95,96,97,98,99,100,101,102,103) and change the pattern of preventable mortality from delays or inadequate interventions to postoperative care errors (104). Aggregated population-based evidence (61,71,72,73,105,106,107,108,109,110,111,112,113,114) has demonstrated a 15 to 20% improved survival rate for seriously injured patients following trauma system implementation (115).

Shackford (116) found that in the first year following establishment of a regionalised trauma system in San Diego County, severely injured patients (TS = 8) had a probability of survival (Ps) of 18% compared to injured patients treated at numerous centres throughout the US and Canada (117), and an actual survival of 29%. Many subsequently used this evidence in order to push healthcare systems and governments to establish organised systems of trauma care. San Diego County instituted a regionalised trauma system in 1984. Guss subsequently performed a before and after preventable death evaluation in the County (118,119) using the validated autopsy review methodology proposed by West (120). Preventable death evaluation involves the calculation of a preventable death rate (PDR), which is the proportion of all deaths judged to have been preventable if optimal care had been delivered (40). Guss found that by expert panel evaluation, 2 out of 211 deaths (1%) were preventable post regionalisation compared to 20 out of 177 (11.4%) pre-regionalisation (p < 0.001). Similar to the Orange County and San Francisco County patients, the decline in mortality post regionalisation was mostly attributed to a decline in mortality from non-central nervous system deaths.

Shackford studied the effect of regionalised trauma care on outcomes of "major trauma victims" in the first 5 months post-regionalisation and compared it to the period immediately prior to the implementation of a system in San Diego County using the medical audit committee technique for assessing optimal or suboptimal care (121). He found suboptimal care was rendered in 32% of cases prior to regionalisation, and that the implementation of a trauma system decreased the proportion to 4.2% (122). Preventable deaths occurred in 13.6% of fatalities prior to implementation, compared to 2.7% following system implementation. Shackford subsequently looked at a subset of severely injured trauma patients (Trauma Score of = 8) in the first year after trauma care regionalisation in San Diego County (121). He compared actual survival to predicted survival based on the Major Trauma Outcome Study (MTOS) (117). Following regionalisation, the probability of survival in blunt trauma patients was 18% compared to the 29% survival observed (p<0.05). In penetrating trauma, the probability and observed survivals were 8% and 20%, respectively (p<0.05).

Mullins evaluated the outcomes of trauma patients before and after institution of a regionalised trauma system. The risk of death in level I trauma centres improved following implementation of a regionalised system in the North Willamette region of Oregon between 1984 and 1991 (odds ratio = 0.65 post regionalisation) (109). The establishment of a regionalised trauma system also shifted the more seriously injured patients to the level I centres (123). Mullins then evaluated the influence of the implementation of a state-wide trauma system in Oregon on the location of hospitalisation and outcome of injured patients before and after regionalisation (110). In Oregon, following state-wide regionalisation, chances for an injured patient being admitted to a level I or II trauma centre increased and the chance of dying decreased.

A further study was done in order to attempt to control for temporal trends in advancements in medical and surgical care of injured patients (111). In this study injured patients in Oregon and Washington were compared before either state had a regionalised trauma system (1985-1988) as well as when only Oregon had a trauma system in place (1990-1993). Following trauma system implementation in Oregon, there was a significant risk reduction for death in patients with Injury Severity Scores > 15 (Odds Ratio = 0.8, CI = 0.70-0.91) compared to Washington. Pediatric mortality was also shown to be positively influenced by system implementation in Oregon, compared to Washington (107). Secular trends in trauma mortality are best adjusted by the types of studies that compare two systems over the same time period (124).

Kane evaluated the survival of seriously injured patients in Los Angeles County prior to (1982) and following (1984) implementation of a regionalised system of trauma care (108). There was an observed significant improvement in the adjusted odds of survival following regionalisation (odds ratio = 1.455, p-value = 0.048) compared to the period prior to the establishment of the system. Cayten reported on mortality following motor vehicle collisions in the Hudson Valley region of New York from 1987 to 1996 (125). There was also a significant decrease in motor vehicle collision mortality that was related and attributed to the establishment of a regionalised trauma system between 1990 and 1995.

Nathens evaluated the effect of trauma systems throughout the United States. He looked at data from states with organized trauma systems in place and compared them to those without regionalised trauma care (126). States that contained regionalised trauma systems (n=22) had a 9% lower crude mortality rate compared to those without regionalised care. After sub-analysis for motor-vehicle collisions, areas with organized trauma systems had a 17% reduction in mortality compared to those without systems.

Nathens also studied the effect of regionalised trauma care on motor vehicle crash mortality throughout the United States between 1979 and 1995 (127). He found that it took approximately 10 years following regionalisation of care to start to see a decline in mortality. By 15 years, mortality from motor vehicle collisions decreased by 8%. The 10-year interval between trauma system implementation and the improvement in outcomes was attributed to the necessary time for trauma system maturation, development of trauma triage protocols, inter-hospital transfer agreements, trauma centre organization, and ongoing quality assurance. These factors, however, were not assessed in this study and remain hypotheses.

Clark critically re-evaluated the aforementioned studies performed by Mullins (109), Cayten (125) and Nathens (127), which used data from the Fatality Analysis Reporting System (FARS), in order to test the accuracy of their results and assess the conclusions that were drawn regarding the effectiveness of trauma systems from these studies (128). He found that the positive impact of trauma system regionalisation was less convincing when all available data was displayed and potential confounding factors were assessed. Mortality following trauma was found to be decreasing throughout the United States and this contributed to the declining rates of mortality following injury. Clark's findings are controversial and have caused much debate (129). However, even if trauma systems do not impact on national mortality as much as some believe, they have and do definitely contribute to superior care for injured patients.

Jurkovich and Mock compared patients with serious injuries in three cities: Seattle (Washington), Monterrey (Mexico) and Kumasi (Ghana) (130,131,132). Seattle is considered to have the most advanced EMS service in the world, Monterrey has a basic EMS service and Kumasi has no EMS system. Major differences also obviously existed in hospital capabilities and socioeconomic factors. Overall survival for seriously injured patients were: Kumasi (36%), Monterrey (45%) and Seattle (65%). The increased survival was primarily attributed to decreased pre-hospital deaths, further highlighting the importance of the "system" in the outcome of seriously injured patients.

In July of 1998, a symposium was organized at the Skamania Lodge in Stevenson, Washington (133). The symposium was titled: "Trauma Systems - Evidence, Research, Action." The symposium was planned in order to assemble health care professionals from various disciplines to critically review the available evidence concerning trauma system effectiveness and was a huge success (134,135). Prior to the symposium, a comprehensive review of the literature was undertaken by the organizing committee and key articles concerning trauma system effectiveness were selected, summarized and sent to participants (136). The articles were then critiqued by the participants at the symposium and summarized in an important paper by Mann et al. in a supplement to the Journal of Trauma (10). Mann concluded that there was evidence supporting the effectiveness of regional trauma care systems in reducing in-hospital mortality. However, further outcome studies were required including studies based on 30-day post discharge mortality and the evaluation of morbidities.

Outcomes have also been shown to improve as time passes following establishment of a trauma system (137,138,139). As the system matures, mortality for severely injured patients declines. O'Keefe was able to show a positive survival advantage for injured patients with ISS = 16 over 10 years at a single level I trauma centre between 1986 and 1995 (140).

The effects of regionalisation in Canada have not been as extensively studied as the systems of trauma care in the United States. However, the impact of regionalisation on the outcome of trauma patients in the province of Quebec has been studied in depth over the last 15 years (58,93,138,141,142). Regionalisation of trauma care has been shown to significantly improve outcome for seriously injured patients in Quebec.

In the early years of trauma care regionalisation, designation of trauma care centres does not lead to increases in patient volume at designated trauma centres. Instead, there is a redistribution of patients, with the more severely injured patients being transported to the higher level centres (29,143). However, once a system becomes established and is running efficiently, outcomes improve (137) and proportions of trauma patients being transported to higher level centres increase (144,145). The increase in patients is usually secondary to the triage and transport of patients with low injury severity injuries. Pre-hospital care workers and dispatchers prefer

to err on the side of over-triage in order not to miss significant occult injuries (146,147). Furthermore, triage algorithms are designed to over-triage less severely injured patients (43,148,149,150). These factors contribute significantly to the high costs of running a level I trauma centre (48).


Table 1: Studies Demonstrating Survival Benefit Following Trauma System Implementation (Part 1). (click for larger image)

Table 1: Studies Demonstrating Survival Benefit Following Trauma System Implementation (Part 2). (click for larger image)

Table 1: Studies Demonstrating Survival Benefit Following Trauma System Implementation (Part 3). (click for larger image)

Table 1: Studies Demonstrating Survival Benefit Following Trauma System Implementation (Part 4). (click for larger image)

CONCLUSION
Regionalisation of trauma care improves outcome for injured patients by utilizing a systematic approach to the care of the injured patient. This approach encompasses all phases of injury from prevention to rehabilitation. A systematic approach to the care of the trauma patient is based on cooperation between pre-hospital emergency medical services, hospitals of all levels, rehabilitation facilities and local, regional, state-wide/provincial and national organizations. By pooling resources and emphasizing teamwork and cooperation, trauma systems have changed the face of trauma patient care, significantly decreased morbidity and mortality secondary to injury and set a benchmark for the regionalised approach to patient management for other areas of healthcare.

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Moishe Liberman MD, is a fourth year resident in the Division of General Surgery at McGill University. He is also a research fellow in the Department of Experimental Surgery at McGill. David S. Mulder MD, MSc, FRCSC is the Chairman of the Division of Cardiothoracic Surgery at the McGill University Health Center, Senior Surgeon at the Montreal General Hospital, and Professor of Surgery at McGill University. John S. Sampalis PhD, is the Head of Surgical Epidemiology at McGill University, an Associate Professor in the Departments of Surgery, Epidemiology and Biostatistics, and an Associate Professor in the Department of Social and Preventive Medicine at Université de Montréal and at Université de Laval. He has been a past recipient of the Medical Research of Canada Scientist award and is currently a senior scientist supported by the Fonds de la recherche en sante du Quebec (FRSQ).