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Address correspondence and reprint requests to E. Brooke Lerner, PhD, Department of Emergency Medicine, Medical College of Wisconsin, 9200 W Wisconsin Ave, Milwaukee, WI 53226 (e-mail: eblerner{at}mcw.edu).
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Key Words: triage trauma and injury emergency medical services
The original concept and advancement of mass casualty triage has largely resulted from the need of militaries to efficiently and effectively treat multiple battle casualties.1,2 Many of the strategies used to triage and treat wounded soldiers have been advocated for the civilian setting, and the ability of civilian emergency medical services (EMS) providers to prioritize patients for treatment and transport during a mass casualty incident is viewed as an essential skill. However, within the United States, the specific system of mass casualty triage that a prehospital care provider learns to use has been dependent largely on local or regional protocols, with little consistency or interoperability between jurisdictions. Large scale disasters require cross-jurisdictional cooperation and highlight the need for a national, standardized approach to mass casualty triage.
Triage occurs at different times, performed by different types of health care providers for a variety of reasons during the provision of emergency care. Examples range from emergency medical technicians determining whether an injured patient needs to be transported to a trauma center, to emergency department nurses determining which patient needs to be placed in a treatment room first. These decisions incorporate much of the same information as is used for mass casualty triage and are made by most emergency providers every day. However, during mass casualty triage the decisions must be made more rapidly, leaving providers with less time to gather the information upon which to base their decisions. Furthermore, in the mass casualty situation, the emphasis shifts from ensuring the best possible outcome for each individual patient to ensuring the best possible outcome for the greatest number of patients. In the United States, outside of drills or other artificial training scenarios, EMS providers rarely have the opportunity to make mass casualty triage decisions.
The new emphasis on community preparedness in the United States has led to greater efforts to improve and develop local EMS providers' skills in mass casualty triage, including tremendous investments of time and money. Unfortunately, many communities have had little assistance in appraising the myriad triage systems that are available on the market. Many of these systems use only slightly modified criteria for assigning triage priorities and are based on proprietary tagging systems. Selecting the proper triage instrument is not an inconsequential decision. In a synthesis of available evidence, Frykberg3 found that during a mass casualty incident there is a nearly linear relation between overtriage and poor patient outcome.
This project enlisted a multidisciplinary committee (see Appendix) to review the available triage systems and evaluate the scientific evidence available for each system. The committee was then charged with determining whether a national guideline could be developed for mass casualty triage that would allow interoperability between jurisdictions and systems. In general, the committee worked to identify a standardized set of triage priority categories and color designations, as well as a suggested methodology for assigning primary triage categories to patients during a mass casualty incident.
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View this table: [in a new window] View this table (figure): as a PowerPoint Slide |
TABLE 1 Comparison of Existing Mass Triage Systems
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View this table: [in a new window] View this table (figure): as a PowerPoint Slide |
TABLE 1 Comparison of Existing Mass Triage Systems
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Several secondary triage tools, such as Secondary Assessment of Victim Endpoint triage and System of Risk Triage, also were identified but not evaluated because this project focused on primary triage only. Although it was recognized that primary triage constitutes only the initial part of the triage process during a mass casualty incident, the committee was charged with being focused in its review.
The Move, Assess, Sort, Send (MASS) Triage system as presented in the National Disaster Life Support suite of courses was also examined.13 This triage system allows the use of any triage categorization system, but provides guidance on the process of evaluating patients at the scene. The MASS system recognizes the need for an initial global sorting of patients before individual assessment. This is done in the move stage by asking ambulatory patients to go to a specific location and then asking those who cannot move to wave their hands. The rescuer then goes first to those patients who are not moving or waving to conduct an individual assessment. This individual assessment is then used to categorize patients into 1 of 4 categories: immediate, delayed, minimal, or expectant, or they are identified as deceased. Patients are then sorted into their respective categories to stage for transport. Once this is complete, patients have been prioritized for transport and should be sent to an appropriate receiving facility.
The French red and white plans also were reviewed, and it was determined that these plans were global response plans. However, they do provide some insight into the French approach to the primary triage of patients.14 The French approach involves bringing patients from the scene to a field triage unit for evaluation, and then moving patients to a hospital based on the assessment that takes place in the field unit. This assessment places patients in 1 of 3 categories: absolute emergency, relative emergency, and involved. The committee determined that this was different from the process in the United States, where primary priority decisions are made by the providers at the scene. Furthermore, the French system requires providers with different skill sets (eg, physicians staff the field hospital) than are currently used in the field in the United States.
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Predictive Ability of Physiological Criteria
Conducting clinical research on the optimal response to a disaster prospectively is difficult, if not impossible. Having sufficient data to evaluate disaster responses retrospectively also can be challenging due to the limited frequency of events and the poor quality of the records that are maintained. A potential surrogate is to study the characteristics of trauma patients who sustain injuries from mechanisms that are not the result of a mass casualty incident. This information is not ideal but can be informative in considering methods for triaging mass casualties.
In particular, the usefulness of certain physiological measurements in predicting which patients need immediate assistance has been considered. A recent Centers for Disease Control and Prevention (CDC)–sponsored review of the trauma triage guidelines used by EMS providers to determine which patients require a trauma center found that the physiological criteria of the Field Triage Decision Scheme were well supported.22,23 This includes a Glasgow coma score of less than 14, a systolic blood pressure less than 90 mmHg, and a respiratory rate less than 10 or greater than 29 breaths per minute. These parameters are used, in some form, in most existing mass casualty triage systems.
Blood pressure is typically not a part of mass casualty triage systems because it would be difficult and time consuming to measure during an incident with a large number of patients. Instead, a palpable radial pulse or capillary refill of less than 2 seconds has typically been used as a surrogate measure to assess perfusion. It is important to recognize that some systems have moved away from using capillary refill time because it is impossible to measure in the dark and it can be inaccurate when the victim is cold or has been in contact with vasoconstricting or vasodilating agents (eg, during an incident in which a chemical agent is released). At least 1 study also has suggested that capillary refill is not an accurate predictor of hypovolemia.24
The Glasgow coma score is cumbersome for most providers to calculate in the field, particularly during the stress and time constraints of a major incident, and there is some literature to indicate that EMS providers may not accurately calculate the score for their individual patients.11,25 However, it has been suggested that the motor component of the Glasgow coma score, or more simply the ability to follow commands, is sufficient for identifying patients in need of immediate aid and/or rapid transport to a medical facility. This was shown by both Garner et al9 and Meredith et al26 using large numbers of trauma patients as the study sample.
Validation of Specific Triage Systems
The work group identified a limited number of publications that attempted to validate specific triage systems. There were few studies, but they are an important initial step in evaluating the existing systems.
The Simple Triage and Rapid Treatment (START) triage system was used during a 2002 train crash in the United States. Kahn et al27 retrospectively compared 132 patients' assigned triage codes to their ultimate outcome and found that 64 patients (48%) were triaged correctly, 65 were overtriaged (49%), and 3 were undertriaged (2%). Two studies of START triage used written tests to evaluate whether provider triage skills improved with education. Risavi et al28 evaluated 109 providers and found the average pre-education test score was 55%, and after a 2-hour education session the average score increased to 75%. Baez et al29 evaluated 55 Latin-American EMS providers using a Web-based education module and found that before the module 5 participants correctly triaged 4 or more of the 5 simulated patients, and after the education module 49 participants correctly triaged 4 or more of the patients.
JumpSTART, a variant of START for pediatric patients, also was evaluated using paper-based patient simulations in a study of 32 providers (emergency medical technicians and registered nurses) before and after receiving educational materials. The study found that of a possible 11 points on the paper-based scenarios, participants initially scored an average of 6.22 points. After the JumpSTART education was provided, the group scored an average of 8.25 points, and 3 months after the education they scored an average of 8.41 points.30 It is not known how well performance on a paper test predicts performance in the field.
For most (existing) systems only minor changes would be needed to make them compatible with this proposed national guideline . . .
A study of police officers using paper-based scenarios found that when given written educational materials on Triage Sieve and the Pediatric Triage Tape, the officers did significantly better at triaging patients with the educational materials than without.31 They correctly triaged 80% of the patient scenarios with the materials and only 60% without. The Pediatric Triage Tape also was evaluated by applying it to 3461 children who presented to a South African trauma unit to determine whether it accurately identified patients with an Injury Severity Score >15.32 They found that the tape had a sensitivity of 38% and specificity of 99%. If it had been used, 39% of children would have been overtriaged and 4% would have been undertriaged.
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The creators of the Sacco Triage Method used simulation to compare their method to START triage using a test dataset of patients with blunt trauma from the Pennsylvania Trauma Systems Foundation and outcomes determined by 6 trauma care experts who came to consensus using the Delphi technique.33 They found that the assessment of each patient with START took about 30 seconds, whereas the Sacco method took 45 seconds. They concluded that the Sacco method had greater expected survivorship compared with START. They had similar conclusions when using similar methods to compare the 2 triage systems for patients with penetrating trauma.34 Although these results are promising, it must be noted that the same committee was used to develop the rule as was used to validate the rule, and both were based on a trauma registry of patients who sustained injuries that did not result from mass casualty events. Furthermore, the consensus committee's assessment of survival time and treatment need was based solely on a secondary database review.
Triage systems for pediatric patients were compared in a study by Wallis and Carley,35 which evaluated 3461 patients presenting to an emergency department in South Africa. They prospectively scored each injured patient using the Pediatric Triage Tape, CareFlite, START (for patients older than 8 years), and JumpSTART (for patients younger than 8 years old), then followed the patients to determine the actual severity of their injuries. Using an Injury Severity Score >15 as the outcome, CareFlite had the greatest sensitivity at 48.4% compared with the Pediatric Triage Tape (37.8%), START (31.3%), and JumpSTART (3.2%). CareFlite also had the greatest specificity at 98.8% compared with the Pediatric Triage Tape (98.6%), START (77.9%), and JumpSTART (97.8%). These measurements were made by the same providers over the course of several months. Therefore, they had more experience than the average provider. Furthermore, they were made in the relatively less stressful and less austere emergency department environment, rather than at the scene of a major incident.
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![]() View larger version (16K): [in a new window] View this table (figure): as a PowerPoint Slide |
FIGURE 1 Proposed national triage guideline: SALT mass casualty triage.
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Global Sorting
Most systems begin the triage process by identifying those who are able to walk. In most cases, these patients are triaged as minimally injured. This decision is based on the fact that a patient who can follow the command to walk illustrates that they have sufficient cerebral perfusion, and are likely to have a palpable radial pulse or a fast capillary refill, and they are demonstrating the ability to follow commands.
Many critics have noted that this group may still have injuries that need immediate or delayed treatment. Furthermore, it is widely believed and anecdotally reported that many casualties will leave the scene and take themselves to a health care facility during a mass casualty incident, causing the closest facilities to the incident to be overwhelmed with these patients before the more severely injured patients arrive.36–38 To address these issues, a global sorting of patients was included in SALT Triage, similar to what is recommended in the move stage of the MASS Triage system. Simple voice commands are used to prioritize patients for individual assessment and to give those who can walk clear instructions regarding where to go for help. These instructions may keep casualties from self-triaging to the closest hospital by giving them a specific place to go for additional assistance.
The committee determined that those who could walk should be prioritized as last for individual assessment, and not simply assigned to a minimally injured category without further evaluation. The wave command used in MASS casualty triage also was adopted to further prioritize those patients who remain at the site. Incorporating a wave command into the global sorting process allows the provider to distinguish those patients who are not able to follow a command from those who are not physically able to walk but can still follow a command. By assessing those patients who are not waving or making purposeful movements first (ie, those not able to follow commands), the provider is likely to approach those patients who may require lifesaving interventions first. We recognize that certain patients (people with impaired hearing, very young people, and individuals with mental disabilities) may be inappropriately prioritized first for individual assessment using the walk and wave commands, but this would be acceptable and would likely not involve excessive numbers of patients.
The guideline suggests that those who can wave or are making purposeful movements should be individually assessed second. However, because a patient with uncontrolled hemorrhage who can follow commands may be prioritized second and exsanguinate while awaiting attention, the committee included those with obvious uncontrolled hemorrhage in the group that should be assessed first. This ensures that these patients receive timely hemorrhage control.
This proposed national guideline includes what is believed to be the best components of the existing triage systems.
Lifesaving Interventions
All of the analyzed triage systems allow for providing lifesaving interventions during the initial triage process. Specifically, all of the systems included opening the airway using basic interventions before assigning the patient to the "dead" category. In the SALT Triage guideline, providing lifesaving interventions is a formal process that is completed before assigning a triage category. Lifesaving interventions should be provided quickly and only if needed supplies are readily available and the provider is trained in their use. The committee agreed that lifesaving interventions should include control of major hemorrhage, opening the airway, provision of 2 rescue breaths for child casualties, decompression of tension pneumothorax, and use of autoinjector antidotes. These interventions were selected because they can be applied rapidly and can have a profound impact on survival, although data regarding actual application in mass casualty settings are lacking. JumpSTART recommends that 5 rescue breaths be given to children. The committee reduced this to 2 to be consistent with the American Heart Association cardiopulmonary resuscitation guidelines, allowing easier recall and taking less time to perform.
Assigning Triage Categories
As shown in Figure 1 and Table 1, the SALT Triage guideline for assigning specific triage categories largely parallels the process established by the existing triage systems. The major difference is that this process includes an expectant category, and we recommend the category be represented using the color gray. The expectant category is intended to be resource based and the definition could and should change depending on the magnitude of the incident, available resources, and the provider's level of training and comfort with using the category. The expectant category will be needed only if there are not enough resources available in the field to meet demand. This methodology allows providers to focus resources on potentially salvageable patients rather than applying resuscitation resources to those who are unlikely to survive.
The expectant category also is intended to be flexible and dynamic to ensure that should additional resources become available, it will be easy to find dying patients so that they can receive resuscitation or comfort care. Patients categorized as expectant should be readily identified, reevaluated frequently as resources become available, and have their triage categorization changed as appropriate.
Unlike the other triage categories (ie, immediate = red, delayed = yellow, minimal = green, and dead = black), the color designation for expectant patients is not common among the existing mass casualty triage systems. Some systems use the color blue; however, that may potentially lead to confusion because blue also has been used to designate patients who need decontamination. In an effort to reflect the fluid nature of this category and to have a distinct color associated with it, the committee selected gray.
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Some may feel that this process simply creates a new triage system that, like the others, is not validated. However, this proposed national guideline includes what is believed to be the best components of the existing triage systems. It was developed after critical evaluation of the existing literature by a multidisciplinary panel. A standardized guideline was created that is based on existing mass casualty triage systems, incorporating available scientific data, and when there is insufficient data, incorporating the panel's opinion. The committee recognizes the paucity of scientific evidence with regard to mass casualty field triage and recognizes the need for further research in disaster field triage, the validation of the proposed SALT Triage guideline, and adjustment of this proposed national guideline as more scientific data becomes available. This will require the development of a sustainable mechanism for this process, including the identification of a body that will be responsible for periodically reviewing new and available literature, advocating for further research, and incorporating new findings and updates into the SALT Triage guidelines. At this juncture, this process has not yet been established.
Training systems need to be created for SALT Triage, but it is the committee's expectation that responders of all levels could be trained to use the SALT Triage guideline; the individual patient assessment is designed to be used by people with any level of training. Furthermore, because there is an emphasis on continual reevaluation, as additional responders arrive on scene they will be able to re-sort and refine the triage decisions that initial providers have made.
Limitations and Future Directions
There is no existing measure against which to judge the accuracy or appropriateness of mass casualty triage decisions in either the trauma or disaster literature. This lack of a universally accepted measure of triage accuracy makes it difficult to evaluate triage systems. The medical and scientific communities must develop a consensus position on how to determine whether triage decisions are "correct." Once a consensus is reached, mass casualty triage systems will be able to achieve a broader and more reliable scientific base and true advancements will be possible in mass casualty triage.
Triage decisions cannot be made in isolation and must be made considering the availability of resources. Responding to 30 victims with 4 ambulances is different from responding with 16 ambulances and numerous responders. Furthermore, there is no differentiation of patients in most primary triage systems once they are placed in large categories (ie, immediate, delayed, minimal, and expectant). Clearly, within those categories some patients will need treatment sooner than others. As stated in the introduction, SALT Triage only addresses primary triage, the initial sorting of patients into relatively large categories that allow responders to organize their initial response to a mass casualty incident. The decision of whom to treat and/or transport first and how best to use the resources on hand requires additional discussion and evaluation. Triage methods that take into account resource availability may also be important, particularly because alternate transport vehicles, such as buses, or transport of minor or delayed patients with immediate patients can be important yet complicated parts of the process of evacuating casualties from a scene. More work is needed in this area before any recommendation can be made and incorporated into the SALT Triage guideline.
Using limited resources to treat casualties with little chance of survival may negatively affect the outcome of patients with time-dependent injuries who are forced to wait for additional resources. This is a difficult part of mass casualty triage, especially because during normal conditions the goal of all EMS providers is to do everything to achieve the best possible outcome for each patient. Given the resource constraints of a mass casualty triage situation, the goal must change to do the most good for the greatest number of people. The committee felt that to achieve this change in standards, an expectant category had to be included in the SALT Triage guideline. The expectant category is intended to be resource-based and the definition will change depending on the situation and the available resources. It is only needed if there are not enough resources at the scene to meet demand and it requires the provider to consider the probable prognosis of the patient. This may be difficult for the first responder, in which case the category can be withheld and those patients would be tagged as immediate until a more advanced level provider is available to reevaluate the patient. This does add a level of complexity, but the expectant category allows providers to focus resources on potentially salvageable patients rather than applying resuscitation resources to those who are unlikely to survive.
A patient's condition may deteriorate or improve over time. Therefore, the triage finding at 1 point in time may not be accurate at a later time. Triage should be conducted as a dynamic process and prioritization should be altered by changing patient conditions, resources, and scene safety.
Training in and maintenance of mass casualty triage skills is a final area that still requires a great deal of consideration and development. Providers are infrequently able to use mass casualty triage protocols and thus may not be as proficient in this skill as they are with other skills that they use regularly. This committee did not attempt to address this issue other than to make the SALT Triage guideline as simple as possible and applicable to all patients in all situations, including small events (eg, multiple-patient car crashes).
Finally, although this system is intended for all-hazard responses, it will work only when there is a common scene where all casualties are present at a single point in time. It will not work for a large-scale biological incident in which patients will present during different periods of time and in numerous locations.
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Additional participants who attended the work group meetings:
Drs Lerner and Liu are with the Department of Emergency Medicine, Medical College of Wisconsin; Drs Schwartz and Coule are with the Department of Emergency Medicine, Medical College of Georgia; Drs Weinstein and Cone are with the Department of Surgery, Section of Emergency Medicine, Yale University School of Medicine; Drs Hunt and Sasser are with the Division of Injury Response, National Center for Injury Control and Prevention, CDC; Mr Nudell is with the Idaho EMS Bureau, Boise, ID; Dr Wedmore is with the Department of Emergency Medicine, Madigan Army Medical Center; Dr Hammond is with the Robert Wood Johnson Medical School; Dr Bulger is with the Department of Surgery, University of Washington; Dr Salomone is with the Division of Trauma/Surgical Critical Care, Department of Surgery, Emory University School of Medicine; Ms Sanddal is with the Critical Illness & Trauma Foundation; Mr Lord is with the Homeland Security Policy Institute, The George Washington University; Dr Markenson is with the Center for Disaster Medicine, New York Medical College; and Dr O'Connor is with the Department of Emergency Medicine, University of Virginia Health System.
Received for publication March 11, 2008; accepted June 4, 2008.
Authors' Disclosures
The authors report no conflicts of interest.
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