Trauma Systems, Triage, and Transport
DEFINITION OF TRAUMA SYSTEMS
A trauma system is an organized approach to acutely injured patients in a defined geographic area that provides full and optimal care and that is integrated with the local or regional emergency medical service (EMS) system.
A system has to achieve cost efficiency through the integration of resources with local health and EMS system to provide the full range of care (from prehospital to rehabilitation).1–3
Regionalization is an important aspect of trauma as a system because it facilitates the efficient use of health care facilities within a defined geographic area and the rational use of equipment and resources. Trauma care within a trauma system is multidisciplinary and is provided along a continuum that includes all phases of care.2–6
The major goal of a trauma system is to enhance the community health. This can be achieved by identifying risk factors in the community and creating solutions to decrease the incidence of injury, and by providing optimal care during the acute as well as the late phase of injury including rehabilitation, with the objective to decrease overall injury-related morbidity and mortality and years of life lost. Disaster preparedness is also an important function of trauma systems, and using an established trauma system network will facilitate the care of victims of natural disasters or terrorist attacks. The Model Trauma System Planning and Evaluation Standard has recently been completed by the U.S. Department of Health and Human Services.7
THE NEED FOR TRAUMA SYSTEMS—HISTORY
The need for a trauma system seems obvious and intuitive. However, trauma is not yet recognized as a disease process. Many people still think of trauma as an accident. Trauma is an epidemic that affects all age groups with devastating personal, psychological, and economic consequences. Recent calculations have estimated the total cost of injury in the United States to be about $260 billion per year.8
Because of the association of injury and personal behavior, trauma is often predictable and preventable.
The modern approach to trauma care is based on lessons learned during war conflicts. Advances in rapid transport, volume resuscitation, wound care management of complex injuries, surgical critical care, early nutritional management, and deep venous thrombosis prophylaxis were all derived from the military experience.
The American College of Surgeons Committee on Trauma (ACSCOT) was created in 1949 and evolved from the Committee on the Treatment of Fractures that was established in 1922. A specific trauma unit was opened in 1961 at the University of Maryland. In 1966, the National Academy of Sciences and the National Research Council published the important “white” paper entitled Accidental Death and Disability: The Neglected Disease of Modern Society.9 The outgrowth of this document was the development and propagation of systems of trauma care. This publication increased public awareness and led to a federal agenda for trauma system development. Two trauma centers were simultaneously formed in Chicago and San Francisco.
The Maryland Institute of Emergency Medicine became the first completely organized, statewide, regionalized system in 1973. Similar initiatives were taken in 1971 in Illinois,10 where the designation of trauma centers was established by state law, and in Virginia in 1981, where a statewide trauma system based on volunteer participation and compliance with national standards as defined by the ACSCOT was established.
In 1973, the Emergency Medical Services Systems Act became law, providing guidelines and financial assistance for the development of regional EMS systems. In addition, state and local efforts were initiated by using prehospital care systems to deliver patients to major hospitals where appropriate care could be provided. Prehospital provider programs were formalized, and training programs were established for paramedics and emergency medical technicians (EMTs).
At that time, major teaching hospitals in large cities were, by default, recognized as regional trauma centers. With strong academic leadership, these centers were able to develop regionalization of systems of trauma care by setting examples.
ACSCOT developed a task force to publish Optimal Hospital Resources for the Care of the Seriously Injured in 1976, establishing a standard for evaluation of care. This document was the first to set out specific criteria for the categorization of hospitals as trauma centers. This document is periodically revised and is recognized nationally and internationally as the standard for hospitals aspiring to be trauma centers. The current version entitled Resources for Optimal Care of the Injured Patient was published in 2006.4 It establishes criteria for prehospital and trauma care personnel and the importance of ongoing quality assessment. In addition, ACSCOT developed the Advanced Trauma Life Support (ATLS) course in 1980, which has contributed to the uniformity of initial care and the development of a common language for all care providers.
In 1985, the National Research Council and the Institute of Medicine published Injury in America: A Continuing Health Care Problem. This document concluded that despite considerable funding used to develop trauma systems, little progress had been made toward reducing the burden of injury.11 This document also reinforced the necessity of investments in epidemiological research and injury prevention. Following the publication of this document, the Centers for Disease Control and Prevention (CDC) was chosen as the site for an injury research center, to coordinate efforts at the national level in injury control, injury prevention, and all other aspects of trauma care.
In 1987, the ACSCOT instituted the Verification/Consultation Program, which provided further resources and incentive for trauma system development and trauma centers’ designation. More recently, the ACSCOT published a document entitled Consultation for Trauma Systems with the objective of providing guidelines for trauma system evaluation and enhancement.12 In 1987, the American College of Emergency Physicians (ACEP) published Guidelines for Trauma Care Systems.13 This document focused on the continuum of trauma care, and identified essential criteria for trauma care systems.
In 1988, the National Highway Safety Administration (NTHSA) established the Statewide EMS Technical Assessment Program and the Development of Trauma Systems Course, both important tools to assess the effectiveness of trauma system components as well as for system development. NHTSA also developed standards for quality EMS, including trauma care. The standard required that the trauma care system be fully integrated into the state’s EMS system and have specific legislation (Table 4-1). The trauma care component must include designated trauma centers, transfer and triage guidelines, trauma registries, and initiatives in public education and injury prevention.
TABLE 4-1 Criteria for Statewide Trauma Care System
In 1990, the Trauma Systems Planning and Development Act created the Division of Trauma and EMS (DTEMS) within the Health Resources and Services Administration (HRSA) to improve EMS and trauma care. Unfortunately, the program was not funded between 1995 and 2000 in many states that were in the process of developing trauma systems. Two initiatives from this legislation were noteworthy: (1) planning grants for statewide trauma system development were provided to states on a competitive basis and (2) the Model Trauma Care System Plan was published as a consensus document.15 The Model Trauma Care System Plan established an apolitical framework for measuring progress in trauma system development and set the standard for the promulgation of systems of trauma care. The program was again funded in fiscal year 2001 but lost funding in 2006. New legislation is being written to further this effort. The newest document for trauma system planning uses the public health care model of assessment, policy development, and evaluation of the outcome. With appropriate federal funding, this approach will be very successful.7
TRAUMA SYSTEM DEVELOPMENT
The criteria for a statewide EMS and trauma systems have been determined and are identified in Tables 4-1 and 4-2. The first step is to establish legal authority for the development of a system. This usually requires legislation at a state or local level that provides public agency authority. The next step in the development of a trauma system is to determine the need of such a system. In general, this has been done in communities by reviewing the outcome of trauma cases in the region. Traditionally, such reviews have focused on preventable deaths. The surgeon’s role is critical in both leadership and commitment to establish a better standard of care.
TABLE 4-2 Emergency Medical Service System Components
The designated agency in combination with local trauma surgeons and other medical personnel develops criteria for the trauma system, determines which facilities will be designated trauma centers, and establishes a trauma registry, a fundamental component of a quality assurance program4,14–17 (Fig. 4-1).
FIGURE 4-1 Regional trauma system development must progress in a sequential fashion; a comprehensive needs assessment is a pivotal early step. (Reproduced with permission from Moore EE. Trauma systems, trauma centers, and trauma surgeons: opportunity in managed competition. J Trauma. 1995;39:1.)
TRAUMA SYSTEM COMPONENTS
The most significant improvement in the care of injured patients in the United States has occurred through the development of trauma systems. However, recent data show that only 60% of states in the United States have statewide trauma systems, and about 20% have no trauma system at all. The necessary elements of a trauma system are: access to care, prehospital care, hospital care, and rehabilitation, in addition to prevention, disaster medical planning, patient education, research, and rational financial planning. Prehospital communications, transport system, trained personnel, and qualified trauma care personnel for all phases of care are of utmost importance for a system’s success (Fig. 4-1).
External peer review generally is used to verify specific hospital’s capabilities and its ability to deliver the appropriate level of care. The verification process can be accomplished through the ACSCOT or by inviting experts in the field of trauma as outside reviewers. Finally, quality assessment and quality improvement is a vital component of the system, as it provides directions for improvement as well as constant evaluation of the system’s performance and needs.
The Model Trauma Care System Plan introduced the concept of the “inclusive system”15 (Fig. 4-2). Based on this model, trauma centers were identified by their ability to provide definitive care to the most critically injured. Approximately 15% of all trauma patients will benefit from the resources of a Level I or II trauma center. Therefore, it is appropriately expected in an inclusive system to encourage participation and to enhance capabilities of the smaller hospitals.
FIGURE 4-2 Diagram showing the growth of the trauma care system to become inclusive. Note that the number of injured patients is inversely proportional to the severity of their injuries.
Surgical leadership is of fundamental importance in the development of trauma systems. Trauma systems cannot develop without the commitment of the surgeons of a hospital or community.
PUBLIC INFORMATION, EDUCATION, AND INJURY PREVENTION
Death following trauma occurs in a trimodel distribution. Effective trauma programs must also focus on injury prevention, since more than half of the deaths occur within minutes of injury, and will never be addressed by acute care.
Because trauma is not considered an important public health problem by the general population, efforts to increase awareness of the public as well as to instruct the public about how the system operates and how to access the system are important and mandatory. A recent Harris Poll conducted by the Anemia Trauma Society showed that most citizens value the importance of a trauma system with the same importance as fire and police services. Trauma system must also focus on injury prevention based on data relevant to injuries and what interventions will likely reduce their occurrence. Identification of risk factors and high-risk groups, development of strategies to alter personal behavior through education or legislation, and other preventive measures have the greatest impact on trauma in the community, and, over time, will have the greatest effect on nonfatalities.18–20
HUMAN RESOURCES
Because the system cannot function optimally without qualified personnel, a quality system provides quality education to its providers. This includes all personnel along the trauma care continuum: physicians, nurses, EMTs, and others who impact the patient and/or the patient’s family.
PREHOSPITAL
Trauma care prior to hospital arrival has a direct effect on survival. The system must ensure prompt access and dispatch of qualified personnel, appropriate care at the scene, and safe and rapid transport of the patient to the closest, most appropriate facility.
The primary focus is on education of paramedical personnel to provide initial resuscitation, triage, and treatment of trauma patients. Effective prehospital care requires coordination between various public safety agencies and hospitals to maximize efficiency, minimize duplication of services, and provide care at a reasonable cost.
COMMUNICATIONS SYSTEM
A reliable communications system is essential for providing optimal trauma care. Although many urban centers have used modern electronic technology to establish emergency systems, most rural communities have not. A communications system must include universal access to emergency telephone numbers (e.g., 911), trained dispatch personnel who can efficiently match EMS expertise with the patient’s needs, and the capability of EMS personnel at the trauma incident to communicate with prehospital dispatch, the trauma hospital, and other units.
Access also requires that all users know how to enter the system. This can be achieved through public safety and information and school educational programs designed to educate health care providers and the public about emergency medical access.
MEDICAL DIRECTION
Medical direction provides the operational matrix for care provided in the field. It grants freedom of action and limitations to EMTs who must rescue injured patients. The medical director is responsible for the design and implementation of field treatment guidelines, their timely revision, and their quality control. Medical direction can be “off-line” in the form of protocols for training, triage, treatment, transport, and technical skill operations or “online,” given directly to the field provider.
TRIAGE AND TRANSPORT
The word triage derives from the French word meaning “to sort.” When applied in a medical context, triage involves the initial evaluation of a casualty and the determination of the priority and level of medical care necessary for the victim. The purpose of triage is to be selective, so that limited medical resources are allocated to patients who will receive the most benefit. Proper triage should ensure that the seriously injured patient be taken to a facility capable of treating these types of injuries—a trauma center. Patients with lesser severity of injuries may be transported to other appropriate medical facilities for care.
Each medical facility has its own unique set of medical resources. As such, triage principles may vary from one locale to another depending on the resource availability. Likewise, established triage principles may be modified to handle multiple casualty incident or mass casualties. Then, a different set of triage criteria may be employed that will attempt to provide medical care to the greatest number of patients. In this scenario, some critically injured patients may not receive definitive care as this may consume an “unfair share” of resources. The goal of triage and acute medical care is to provide the greatest good to the greatest numbers.
From a historical perspective, war has been the catalyst for developing and refining the concept of medical triage. Dominique Jean Larrey, Napoleon’s chief surgeon, was one of the first to prioritize the needs of the wounded on a mass scale. He believed “… it is necessary to always begin with the most dangerously injured, without regard to rank or distinction.” He evacuated both friend and foe on the battlefield and rendered medical care to both. He refined his techniques for evacuation and determining medical priorities for injured patients over the 18 years and 60 battles while being a member of the French army.
During World War I, the English developed the “casualty clearing station,” where the injured were separated based on the extent of their injuries. Those with relatively minor injuries received first aid, while those with more serious injuries underwent initial resuscitative measures prior to definitive care. As medical and surgical care of battlefield injuries expanded, a system of triage and tiered levels (echelons) of medical care was designed. Echelons of medical care and triage of single, multiple, and mass casualties remain the paradigm for military combat medical care.
There are five echelons (or levels) of care in the present military medicine. The first line of medical care is that which is provided by fellow soldiers. Principles of airway management, cessation of bleeding, and basic support are offered by fellow soldiers. Organized medical care begins with a medic or corpsman who participates in echelon 1 care. They are assigned to functional military units and serve as the initial medical evaluation and care of the injured patient. Echelon 2 is a battalion aid station or a surgical company. Resuscitation and basic lifesaving surgical procedures may be performed at these stations. Echelon 3 is a Mobile Army Surgical Hospital (MASH) or Fleet Surgical Hospital. Advanced surgical and medical diagnostic and therapeutic capabilities are available at these facilities. An Echelon 4 facility is larger and has enhanced medical capacity. Examples include a hospital ship (USNS Mercy or Comfort) or an out-of-country medical facility (Landstuhl Region Medical Center [Army], Germany). An Echelon 5 facility is a large tertiary and rehabilitative medical facility and is located within the home country (Naval Medical Center San Diego). Each increasing echelon has a more comprehensive medical and surgical capacity. As patients are identified on the battlefield, they are triaged and transferred to the next higher echelon for care. During the Vietnam War, air medical transport enabled the triage of a seriously injured soldier from the battlefield directly to an MASH unit. The time to definitive surgical care was less than 2 hours compared to 6 hours during World War II.
The lessons learned from the triage and treatment of combat casualties were slow to translate into civilian use. Injured patients, regardless of the severity of injury, were simply taken to the nearest hospital for treatment. Neither a triage system nor an organized approach to injury existed. The ATLS course was created in the late 1970s and with it the concept of requisite skills and facilities to treat injured patients emerged.
PURPOSE AND CHALLENGES OF TRIAGE
The purpose of triage is to match the patient with the optimal resources necessary to adequately and efficiently manage his or her injuries. It is a dynamic process of patient evaluation and reevaluation until the patient receives definitive care. The challenge of a triage system lies in correctly identifying which patient has injuries in need of a designated trauma center. Studies have demonstrated better outcomes in major trauma victims who have been treated at hospitals that have a commitment for this specialized care.16 Of all trauma patients, only 7–15% have injuries that require the facilities of a dedicated trauma center.
The ideal triage system would direct patients with serious injuries to the most appropriately staffed hospital while transporting those with less serious injuries to all other hospitals within the geographic area. Due to the complexities of patient evaluation and injury determination, “the perfect triage system” is yet to be developed.
The primary goal of an effective triage system is to identify which casualties are seriously injured and in need of immediate surgical or medical care. This requires a rapid evaluation of the patient and a decision about the level of emergency care that will be needed for the patient. Once this is determined, they are matched and transported to the appropriate medical facility. The triage physician often has limited resources, information, and time to make this important decision. While many triage methods can be used, they often rely on physiologic, anatomic, and mechanism of injury information to assist in the triage decision. Once the patient has been routed to a treatment facility, information concerning the patient’s injuries and physiologic state should be transmitted to the receiving facility if possible. This will give the receiving physician an opportunity to gather the appropriate personnel and equipment to treat the incoming casualty. A concise prehospital radio report will enable the receiving medical personnel to anticipate emergent equipment and personnel needs. In some instances, a direct operative resuscitation may be indicated to stabilize the patient.21 In other cases, emergent airway control may be the primary concern. The few minutes of preparation, prior to the patient’s arrival, may be the difference in patient survival.
The other goal is to define the “major trauma victim.” While this term may be easy to conceptualize, it is very difficult to quantify. A precise definition is important so that triage, treatment, and outcomes can be compared. Prompt recognition of those patients who are in immediate risk of life (e.g., loss of airway or hemorrhagic shock) or loss of a limb (ischemia) or will need immediate operative or lifesaving interventions is paramount. These patients are in need of definitive care in an expedient fashion where delays in care may result in excess morbidity or mortality.
The Injury Severity Score (ISS) provides the means for a trauma system to retrospectively identify major trauma victims with an ISS of greater than 15 being a commonly accepted level.22 Another definition of major trauma is provided by the Major Trauma Outcome Study (MTOS), which defines the trauma patient as all patients who died due to their injuries or were admitted to the hospital.23 The threshold that defines the major trauma victim within a trauma system is based not only on the resources of a particular trauma center but also on the inability of the nondesignated hospitals to consistently provide appropriate care for an injury exceeding the threshold. This may vary from system to system.
After a traumatic event, the effectiveness of a triage system should be analyzed based on expected performance standards. Data monitoring and quality assessment tools should be applied after a disaster or after any one patient who has been treated so that system or operator errors can be identified and corrected. Each multiple casualty event presents unique problems to a triage system. Constant reevaluation and refinement are cornerstones for improved performance.
One of the accepted performance markers to an effective triage system is found in the determination of the undertriage and overtriage rates. Undertriage is defined as a triage decision that classifies a patient as not needing a higher level of care (e.g., trauma center), when in fact they do. This is false-negative triage classification.44 Undertriage is a medical problem that may result in an adverse patient outcome. The receiving medical facility may not be adequate to diagnose and treat the trauma victim.
Defining an acceptable level of undertriage is dependent on how one defines the patient requiring trauma center care. One method is to identify all the potentially preventable causes. Using this method, a target undertriage rate would be 1% or less. Using a broader definition, undertriage would also result in patients being sent to institutions without the capability to render appropriate care. In this instance, an undertriage rate of 5–10% is accepted.
Another method is to determine how many major trauma patients were incorrectly transported to a nontrauma center. If an ISS of greater than 16 or more is used to define the major trauma patient, undertriaged patients would be those patients (ISS >16) who were taken to a nontrauma center hospital. Using this method, an acceptable undertriage rate can be as high as 5%.
Overtriage is a decision that incorrectly classifies a patient as needing a trauma center, although retrospective analysis suggests that such care was not justified. It has been said to result in overutilization of finite material, that is, financial and human resources.24
COMPONENTS OF TRIAGE TOOLS AND DECISION MAKING
Trauma triage decisions are usually made within a limited time frame and are based on information that can be difficult to obtain. These decisions are based on evidence gathered in the field that estimates the potential for severe injury. Physiologic and anatomic criteria, mechanism of injury, and comorbid factors are used in the triage decision-making process. Unfortunately, all these criteria have limitations that affect their validity in certain situations. The judgment of experienced EMS personnel is also a key factor in triage.
PHYSIOLOGIC CRITERIA
Physiologic data are felt to represent a snapshot into the well-being of an injured patient. Physiologic criteria include measurements of basic life-sustaining functions such as heart rate, blood pressure, respiratory rate and effort, level of consciousness, and temperature. The advantage of physiologic data is that they are readily assessable in the field with a simple physical examination. These data can be ranked into a numerical format, which allows them to be quantified, and used in various trauma scoring systems such as the Revised Trauma Score (RTS). The larger the deviation from normal, the more likely there is a severe injury. In this way, physiologic data may correlate to severity of injury and may predict serious injury or death. Patients who have sustained a mortal injury tend to have the greatest deviation in their vital signs.25 The problem is that their ability to detect physiologic derangement is time dependent. A single set of physiologic signs is only a snapshot to the patient’s state. Patients who have sustained significant injury may not manifest physiologic changes immediately after the event and, as a result, are at risk for undertriage. A significant injury may take some time to manifest life-threatening hemorrhage or tension pneumothorax. This is especially true of young, otherwise healthy adults who have significant physiologic compensation mechanisms that may mask the true extent of the injury.
ANATOMIC CRITERIA
The anatomic location and external appearance of the injury aid in the immediate field triage decisions. This visual picture of the injured patient may be sufficient for an experienced triage officer to make a disposition decision without further evaluation. In a mass casualty event, rapid triage may be performed with a quick visual exam of the patient. Anatomic criteria that suggest triage to a trauma center may include, but are not limited to: penetrating injury to the head, neck, torso, or proximal extremity; two or more proximal long-bone fractures; pelvic fracture; flail chest; amputation proximal to the wrist or ankle; limb paralysis; or greater than 10% total body surface area burn or inhalation injury. Each regionalized trauma system must decide what constitutes significant anatomic injury as a triage criterion.
Anatomic injury may be challenging to predict reliably based on physical examination in the field. Fracture of long bones, amputations, and skin and soft tissue injuries may appear devastating in the field but are rarely life threatening and may distract the field examiner as well as the patient from more subtle and serious injuries.
Significant blunt chest and abdominal injuries can have little external evidence of internal injury and initial physical examination lacks diagnostic accuracy.26,27 Other significant injuries missed on initial examination include spine28 and certain types of pelvic injuries. A pelvic bony injury can be diagnosed on physical examination in the awake, cooperative patient; however, a significant number of trauma victims have altered mental status due to head injury or ingestion of drugs or alcohol.
The distinction between blunt and penetrating injury is an important triage distinction. Oftentimes there may be little external trauma to the patient. However, recognition of the penetrating wounds correlated with the likelihood of internal injury is needed to effectively triage these patients. Penetrating injuries to trunk and proximal extremities are of concern because of their proximity to vital structures; however, it is nearly impossible to know the direction or depth of penetration while in the field. Finally, the triage officer must expeditiously evaluate patients and not perform time-consuming physical examinations in the field that only slow down the triage process. Complex patients may be better served by urgent transport to a trauma center.
MECHANISM OF INJURY
Evaluation is more than the simple determination of how a trauma injury occurred. To the trained eye, it can give information on the type, amount, and direction of force or energy applied to the body. Prehospital personnel, who view the effects of the forces that were applied during the injurious event, can estimate the amount of energy involved. This, in turn, helps predict the likelihood of injury. Mechanisms of injury felt to have a high potential for major trauma include falls of more than 15 ft; motor vehicle accidents with a fatality at the scene, passenger ejection, prolonged extrication (>20 minutes), or major intrusion of the passenger compartment; pedestrians struck by a motor vehicle; motorcycle accidents of more than 20 mph; or any penetrating injuries to the head, neck, torso, or proximal extremities. When used as a triage criterion by itself, mechanism of injury results in the high overtriage rate. However, when combined with other triage components, such as physiologic indices and anatomic injury, mechanism of injury improves the sensitivity and specificity of the triage process.29,30
AGE, COMORBID DISEASE, AND ENVIRONMENTAL CONCERNS
Age has been shown to impact the outcome of trauma victims and should be taken into consideration when triaging a patient. Elderly trauma victims, using a variety of definitions (i.e., >55 years old, >65 years old, etc.), have been shown to have increased morbidity and mortality compared to younger trauma victims. When compared to young patients, the elderly are at risk for undertriage, because a similar amount of force may cause a greater magnitude of injury.31
The effect of age on morbidity and mortality is not as clear in the pediatric population.32 There are significant differences in physiology and anatomy in the pediatric population that require specialized equipment, facilities, and personnel. Certainly, the optimal treatment involves identifying the unique resources needed to care for the injured child and having those available when needed. These differences are significant enough that specialized triage criteria have been developed for the pediatric population.33
Chronic diseases have also been shown to have a significant impact on morbidity and mortality in the trauma victim independent of age and injury severity.34 Acute conditions such as ethanol or cocaine intoxication or systemic anticoagulation may also impact morbidity and mortality. Comorbidities such as cardiopulmonary, hepatic, renal disease, diabetes mellitus, malignancy, or neurologic disorders have been found to have increased mortality rates compared to their disease-free counterparts. The problem is that many times the associated medical condition of the patient cannot be ascertained in the prehospital arena unless the patient has identification such as a medical alert bracelet or a relative who can provide the necessary history to the field personnel.
Environmental extremes can have serious consequences for the trauma patient. Hypothermia is known to have adverse physiologic effects, prolongs blood coagulation time, and contributes to mortality.35 Prolonged heat exposure may lead to dehydration. Burn injuries require accurate assessment for resuscitation and wound care, as well as evaluation for potential inhalation injury. When combined with associated trauma, patient management can be complex36 (Table 4-3).
TABLE 4-3 Commonly Used Trauma Triage Criteria
PARAMEDIC JUDGMENT
A working familiarity of clear, concise, and reliable triage guidelines is essential for effective triage. Experience and judgment of EMS personnel are crucial to this mission. EMS personnel are in a unique position to directly assess the trauma scene, ascertain the mechanism of injury, determine the extent of the patient’s injuries, and estimate the patient’s physiologic response. For example, a patient with a fractured femur due to a frontal, high-speed motor vehicle collision will be evaluated and triaged differently than will a patient with a femur fracture due to a low-speed collision. Paramedic triage is outlined in the prehospital trauma life support manual.
Several studies have shown that prehospital field personnel judgment can be as good or better than the available triage scoring methods commonly in use37 and, when combined with other triage criteria, improves on the identification of major trauma victims. In a systematic review of Mulholland et al. there was no conclusive evidence for or against paramedic judgment in the field.38 The one constant theme in triage at all levels of medical personnel was the level of clinical experience. Pointer et al.39 studied the compliance of paramedics to established triage rules. Paramedic triage was best when evaluating triaging based on a patient’s injury patterns. Compliance was intermediate when based on mechanism of injury and the lowest for patients evaluated for physiologic triage criteria. They demonstrated a paramedic undertriage rate of 9.6%, which is relatively close to the acceptable 5% or less undertriage rate.
CURRENT FIELD METHODS FOR FIELD TRIAGE SCORING
In order for a triage scoring method to be acceptable for use in the field, it must meet certain criteria. The components of the scoring scheme must be credible, meaning that they have some correlating relationship with the injuries being described. Because there is no “gold standard” to test the accuracy of the scoring scheme, the results of the scoring scheme must be in general agreement with other, currently accepted scoring methods.40
The triage scoring method must correlate with outcome. The scores that indicate more severe injury should identify the patients with worse outcomes. The better the correlation with outcome, the lower the undertriage and overtriage rates within a trauma care system. Outcomes for major trauma victims are usually classified as death, need for urgent/emergent surgical intervention, length of intensive care unit (ICU) and/or hospital stay, and major single-system or multisystem organ injuries.
The scoring scheme must also have interobserver and intraobserver reliability, that is, it should be able to be consistently applied between observers and by the same observer at another point in time with the same results. Finally, the scoring scheme must be practical and easily applied to trauma victims for a variety of mechanisms, by a variety of personnel without the need of specialized training or equipment.
SPECIFIC TRIAGE METHODS—DEFINITIONS
Trauma Index
The Trauma Index was one of the earliest triage scoring methods, first reported in 1971 by Kirkpatrick and Youmans.41 It included measures of five variables: blood pressure, respiratory status, central nervous system (CNS) status, anatomic region, and type of injury. One study showed some correlation with injury severity42; however, the Trauma Index never saw widespread use. A revision of the Trauma Index in 1990 reported undertriage and overtriage rates comparable to those of the Trauma Score (TS); circulation, respiration, abdominal/thoracic, motor, and speech (CRAMS); Prehospital Index (PHI); and mechanism of injury scales and correlated to the final ISS.43
Glasgow Coma Scale
When Teasdale and Jennett first introduced the Glasgow Coma Scale (GCS),44 it was intended as a description of the functional status of the CNS, regardless of the type of insult to the brain, and was never intended to be used as a prehospital assessment tool. The three components of the score reflect different levels of brain function with eye opening corresponding to the brainstem, motor response corresponding to CNS function, and verbal response corresponding to CNS integration.
Because the degree of injury to the CNS is considered to be a major determinant of outcome in trauma victims, many of the field triage tools measure CNS function, including the TS,45 the RTS,46 the CRAMS scale,47 and the Trauma Triage Rule (TTR).48 Interpretation of GCS in the presence of an intubated patient diminishes the ability to use the GCS as a prehospital evaluation tool. A more recent study found that the motor component of the GCS is almost as good as the TS and better than the ISS in predicting mortality. This suggests that the motor component score could be used to identify patients who are likely to require urgent trauma center care.
Triage Index, Trauma Score, Revised Trauma Score
The Triage Index (TI) was described in 1981, and analyzed physiologic parameters of an injured patient. These variables were examined alone and in combination in an effort to make the TI more precise. One year later, Champion et al. modified the TI by adding systolic blood pressure and respiratory effort in an effort to be more discriminatory in patient severity identification. The resulting TS was designed to look at those physiologic parameters known to be associated with higher severity of injury if found to be abnormal.45 Central to this idea was the fact that the known leading causes of traumatic death were related to dysfunction of the cardiovascular, respiratory, and CNS. The authors recommended trauma center care for trauma victims with a TS of 12 or less. The TS was revised in 1989 because of concerns about accurate assessment of capillary refill and respiratory effort at night as well as potential underestimation of CNS injury.46 These components were deleted and the RTS consists of three parameters: GCS, systolic blood pressure, and respiratory rate.
CRAMS Scale
CRAMS was first proposed as a simplified method of field triage.47 These parameters are individually assessed and assigned a value corresponding to normal, mildly abnormal, or markedly abnormal. With a range of 0–10, a score of 8 or less signifies major trauma, indicating that the patient should be taken to a designated trauma center. Both retrospective and prospective studies have shown that the CRAMS method of triage is accurate in identifying major trauma victims with relatively high specificity and sensitivity and is easy to use.49
Prehospital Index
The PHI consists of field measurements of blood pressure, pulse, respiratory status, and level of consciousness, which were determined to have the best correlation with mortality or the need for surgery. A subsequent prospective multicenter validation study by the same authors showed that the PHI is accurate in predicting the need for lifesaving surgery within 4 hours and death within 72 hours following injury.50 Furthermore, the attachment of non-time-dependent variables such as age, body region injured, and mechanism of injury to the PHI improved the predictive power to select those patients who were likely to need intensive care or a surgical procedure.
Trauma Triage Rule
The TTR proposed by Baxt et al. consists of measurements of blood pressure, the GCS motor response, and the anatomic region and type of injury.48 Rather than comparing the scoring method to traditional outcome measures to determine the factors that constitute a major trauma victim, major trauma was defined a priori as a systolic blood pressure of less than 85 mm Hg; a GCS motor component score of 5 or less; or penetrating trauma to the head, neck, or trunk. Retrospective review revealed major trauma victim identification with a sensitivity and specificity of 92%. The TTR was concluded to potentially reduce overtriage while maintaining an acceptable undertriage rate. However, it has not been adapted widely.
Disaster Triage: Simple Triage and Rapid Treatment (START)
In the event of a mass casualty or disaster, EMS personnel may utilize the START triage system initially developed to be used in earthquakes in California. The object of this system is to triage large numbers of patients rapidly. It is relatively simple and can be used with limited training.51 The focus of START is to evaluate four physiologic variables: the patient’s ability to ambulate, respiratory function, systemic perfusion, and level of consciousness. It can be performed by lay and emergency personnel. Victims are usually divided into one of the four groups with color codes according to the timing of care delivery based on the clinical evaluation as follows: (a) green—minor injuries (walking wounded); (b) red—immediate; (c) yellow—delayed; and (d) black—unsalvageable or deceased.
If the patient is able to walk, he or she is classified as a delayed transport, but if not, ventilation is assessed. If the respiratory rate is >30, the patient is an immediate transport. If the respiratory rate is <30, perfusion is assessed. A capillary refill of >2 seconds will mandate an immediate transport. If the capillary refill is <2 seconds, the patient’s level of consciousness is assessed. If the patient cannot follow commands, he or she is immediately transported; otherwise he or she is a delayed transport. The Fire Department of New York used this system during the World Trade Center disaster. Unfortunately, due to the collapse of the buildings and concern for the safety of the rescue workers, the START system came to a complete halt.52 It resumed only when it was declared safe to approach ground zero.
In some systems the START system is coupled with severity scores: in the immediate category the TS varies from 3 to 10, in the urgent category the TS varies from 10 to 11, and in the delayed (nonurgent) group the TS is 12.
The triage principles are the same for children and adults. However, due to differences in physiology, response to insults, ability to talk and walk, and anatomic differences, disaster triage in the pediatric age group is not straightforward. Assessment tools have been proposed to increase the accuracy of the process but were found to have major limitations.
The START system is important in the triage of severely injured trauma patients because those requiring surgical care are transported by air or ground ambulances to trauma centers distant enough from the incident where the number of victims is lower and the resources are still available to provide optimal care.
Combination Methods
While most of the field triage criteria are based on physiologic criteria, there are other methods for assessing the severity of the potential injury to a trauma victim. As shown earlier in the chapter, mechanism of injury, anatomic region and type of injury, preexisting illnesses, and paramedic judgment are important considerations in providing additional information in the field to help determine whether a patient requires transport to a designated trauma center. Combination field triage methods make use of this additional information by including it in the initial evaluation of the trauma victim.
American College of Surgeons Field Triage System
The ACS Field Triage System is a more complete, advanced triage scoring scheme that is described in the Resources for Optimal Care of the Injured Patient
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