Abstract
This chapter focuses on triage management in both national and international mass casualty incidents. They be a sudden-onset natural disaster, a public health emergency of international concern, or a war or armed conflict resulting in the deployment of field level hospitals that are focused on civilians, the military, or both, and are capable of rapid deployment and expansion or contraction to meet immediate emergency requirements for a specified period of time. The goal of triage is to treat as many victims as possible who have an opportunity for survival. Triage does not exist in isolation, but represents a complex process that balances clinical requirements with resource allocation and system management where the decision operatives are the likelihood of medical success and the conservation of scare resources.
Introduction
A mass-casualty incident (MCI) is an “event which generates more patients at one time than locally available resources can manage using routine procedures requiring exceptional emergency arrangements and additional or extraordinary assistance[1].” Direct MCI mortality and morbidity arise from natural disasters, human system failures, and war and armed conflict-based crises[2]. Additional indirect mortality and morbidity will occur from each of these crises when the public health system’s essential infrastructure (water, sanitation, shelter, food, medical access and availability, and energy) are absent, destroyed, overwhelmed, not recovered or maintained, or selectively denied to populations[3].
Historically, both national and international MCIs have frequently resulted in the deployment of field level hospitals that are focused on civilians, the military, or both, and defined as a “mobile, self-contained, self-sufficient health-care facility capable of rapid deployment and expansion or contraction to meet immediate emergency requirements for a specified period of time [4].” These hospitals have served as the major frontline response capacity to MCIs for many decades and share the following characteristics:
have capacity and capability to bring lifesaving care as close to the frontline of war or armed conflict, natural disaster, public health emergencies of international concern, or other humanitarian crises as possible
operationally, are considered resource constrained facilities
triage management will be practiced at every level of care on a daily basis
standards of care impacting the triage process may vary depending on resources
The World Health Organization (WHO) Emergency Medical Team (EMT) System
In 2013, WHO published Classification and Minimum Standards for Foreign Medical Teams in Sudden Onset Disasters, with a trauma and surgical focus[5]. In 2014, over 40 organizations – including international NGOs, military, faith-based organizations, and governments – deployed FMTs throughout the Ebola response. Recognizing the important lessons gained from these events led to formalizing a global health workforce designed to improve coordination, quality, and predictability of clinical response teams deploying with surge capacity now referred to as EMTs. These teams, both I-EMTs and N-EMTs “serve as a deployment and coordination mechanism for all partners who aim to provide clinical care in emergencies such as tsunami, earthquake, flood, and more recently, in large outbreaks, such as the West Africa Ebola outbreak, which require a surge in clinical care capacity. It allows a country affected by a disaster or other emergency to call on teams that have been preregistered and quality assured[6].”
Under this system, EMT type 1 facilities pertain to initial outpatient emergency care of injuries and other significant health-care needs. Traditional EMTs (field-level hospitals) fall under type 2 inpatient surgical emergency care facilities, which provide inpatient acute care and general and obstetric surgery for trauma and other major conditions, and type 3 inpatient referral care facilities, which provide complex inpatient surgical care, including intensive care capacity. Additional specialized care teams and specialized care cells will be placed within type 2, 3, or a local hospital. WHO serves as the deployment and coordination mechanism for all partners prepared to provide clinical care in emergencies. Through a global registration system, WHO provides preregistered, quality assured, verified, and classified EMTs, which meet minimum standards for deployment as a time-limited surge clinical capacity to affected populations[6].
Triage Guidance Under the WHO Classification and Minimum Standards for FMTs
The WHO publication Classification and Minimum Standards for Foreign Medical Teams in Sudden Onset Disasters provides guidelines starting with “initial and field level triage, assessment and first aid” at type 1 EMTs, stating that “staff should be experienced in those elements of initial trauma care that relate to triage on a mass scale, wound and basic fracture management, basic emergency care of pediatric, obstetric, mental health, and medical presentations.” Surgical triage and assessment at type 2 levels calls for “ability to receive, screen, and triage new and referred patients, with ability to perform at least 7 major or 15 minor operations daily with at least 20 inpatient beds per one operating table and be able to perform 24 hours per day, seven days per week for at least 3 weeks but ideally longer.” Type 3 EMTs are required to provide “complex referral triage[5].”
The WHO publication further recognizes eight different EMT classification systems worldwide, which have in common the three levels of EMT response teams with “escalating complexity and capacity for each level.” It emphasizes that no one model is applicable to all EMTs functioning internationally. For example, the European Union European Civil Protection Modules call for triage of “at least 20 patients per hour stabilizing 50 patients in 24 hours, with supplies to treat 100 patients with minor injuries per 24 hours” at the equivalent of a type 1 EMT, and an “advanced medical Post with surgery providing similar triage numbers per hour” plus “surgical team capability of damage control surgery for 12 patients per 24 hours, working in 2 shifts, and supplies to treat 100 patients with minor injuries per 24 hours.” Their EMT level equivalent calls for both initial and/or follow-up trauma and medical care with “10 beds for heavy trauma patients with possible capacity to expand with medical teams” for “triage, intensive care, surgery, serious but not life-threatening injuries, evacuation, specialist support personnel and at least covering the following: generalist, emergency physicians, orthopedist, pediatrician, anesthetist, obstetrician, health director, lab technician, X-ray technician[5].”
Mass-Casualty Incident Triage Management Requirements
Operational Levels of Triage
In MCIs, the practice of triage must occur to both sort and prioritize patients to meet unexpected circumstances traditionally using immediate, delayed, minimal, or expectant categories within minutes of arrival. Prehospital primary triage is practiced for all MCIs, at which point victims are assigned an acuity-level based on injury severity. The decision-making processes involved in primary triage and patient hospital distribution are influenced by both reactive (ad hoc) and proactive (based on situational awareness) factors[7]. The most commonly adopted triage systems used are sort, assess, lifesaving interventions, treatment/triage (SALT): a nonproprietary free system developed from available research, with widely accepted best practices of existing mass triage systems and consensus opinion, the simple triage and rapid treatment (START), which substitutes radial pulse for capillary refill[8], and coupled with a system of secondary triage termed “secondary assessment of victim endpoint (SAVE).”
The SAVE triage was developed to direct limited resources to the subgroup of patients expected to benefit most from their use. The START and SAVE triage techniques are used in situations in which triage is dynamic, occurs over many hours to days, and only limited, austere, field, advanced life-support equipment is readily available[9].
Secondary triage, or a reevaluation of the victim’s condition after initial medical care, may also occur at the scene of the MCI following emergency medical services’ (EMS) interventions or during transport to an emergency department or secondary collection station[7]. In EMTs, secondary triage is an ongoing process, which continues after the initial triage decisions are made, which move the first stage of victims to the operating rooms and others for delayed treatment or as stable candidates initially triaged for evacuation, as the patient’s condition may change for the better or for the worse.
Many of the crises responded to by EMTs realistically exist where little or no effective prehospital care or triage occurs before victim arrival. This chapter restricts itself to advanced triage where some victims are triaged based on inclusion criteria but others – those severely injured or ill who are triaged based on resource-poor or constrained settings (exclusion criteria) – may not receive the resources normally expected.
Minimal Qualifications for Survival
Based on collective knowledge of existing resource constraints, EMTs are held responsible to develop predetermined agreed-on criteria referred to as “minimal qualifications for survival” (MQS), which define what cases will not receive curative care but will receive pain relief, emotional care, and, if available, spiritual support[10]. MQS define who is triaged in the “expectant” category, which normally includes those moribund with multiple major wounds whose management would be considered wasteful of scarce resources including operating time and blood transfusions, those without vital signs regardless of injury or illness, transcranial ballistic wounds, multiple-organ failure from severe trauma, severe third-degree burns without reasonable chance of survival, open pelvic injuries with uncontrolled class IV shock, advanced respiratory failure, and dosimetry-confirmed lethal radiation doses[11].
Every disaster has its own contributing factors for MQS requirements, but the conditions influencing the MQS are not always immediately known and become more clarified as the nature of the crisis and state of the victims are better understood[12]. For example, in the 2010 Haiti earthquake, a significant number of neglected casualties presented with serious wounds and advanced infections, which progressed to multiple-organ failure resulting in higher-than-normal expectant triage category designations[13,14]. Triage officers (TOs) may seek reassessments of the triage protocols to ensure they remain appropriate to the MQS. For example, the traditional disaster medical assistance team (DMAT) triage system collapsed when it became evident on the first day of hurricane Katrina that thousands of evacuated seriously ill critical care patients with nontraumatic illness were being triaged using inappropriate DMAT trauma-related protocols[15,16].
Potential Injury/Illness Creating Event
Koenig and colleagues have developed a potential injury/illness creating event (PICE) nomenclature, which provides a method and framework for consistency in “crisis classification” based on the likelihood that outside medical assistance will be needed. Stage 0 means little or no chance, stage I means there is a small chance, stage II means there is a moderate chance, and stage III means local medical resources are clearly overwhelmed. As such, EMTs, both international and national, are deployed as assets for PICE stage III events[17].
Legal and Ethical Issues of Triage
Society recognizes that legal, ethical, and moral expectations and obligations exist during crises and that triage plans exist to treat as many victims as possible who have an opportunity for survival. When triage is performed in accordance with accepted medical practice, it is both sanctioned and recognized by law in most countries[18,19]. In fact, medical providers are held legally accountable for the triage process, but the process itself cannot ensure either treatment or survival[11,20]. Because unrealistic triage results in unacceptable death rates among those who should survive, triage plans must be well thought out and designed. The WMA asserts that “The physician must act according to the needs of patients and the resources available. He/she should attempt to set an order of priorities for treatment that will save the greatest number of lives and restrict morbidity to a minimum[21].”
Under- and Overtriage
The primary goal of triage is to identify the majority of field trauma victims at risk for life-threatening injuries. The accuracy of triage is the degree of match between the severity of injury and the level of care. Sensitivity and specificity of screening tests are useful indicators of accuracy[22]. In reality, casualty differences, occult injuries, and the complexities of assessment preclude perfect accuracy in triage decisions suggesting that, in practice, a “perfect” triage system is not possible[10,18,21].
Most triage protocols are based on physiological criteria and subject to under- and overtriage. Overtriage occurs when a casualty receives a high acuity triage assignment, is transported to the EMT, and unnecessarily consumes scarce resources. Undertriage occurs when a casualty receives a low acuity triage assignment and does not receive the specialized trauma treatment needed, resulting in inappropriate admission or death. Based on disaster experience, studies have sought a balance between over- and undertriage for a given set of triage criteria[23,24].
Designing a triage system that maximizes specificity (undertriage) to avoid delaying care for sick people, while maximizing sensitivity (overtriage) to avoid wasting resources, is a challenge for any EMT. Once this balance has been defined, triage guidelines can be modified to meet unique triage objectives. Standards set by the American College of Surgeons Committee on Trauma aim for overtriage rates less than 50% (i.e., a specificity of greater than 50%), considered acceptable to minimize patients who are undertriaged, and undertriage rates of less than 5–10% (i.e., a sensitivity of greater than 95%) considered acceptable for trauma patients[25]. A multisite assessment of the American College of Surgeons Committee on Trauma offers a field triage decision scheme for identifying seriously injured children and adults. Anything higher may lead to unnecessary morbidity and mortality in severely injured, but potentially salvageable, patients[26,27,28].
Studies suggest that triage can conflict with human rights legislation and even with humanitarian laws, but “accountability for reasonableness” can temper the disagreements on the setting of priorities[29]. After a comprehensive evaluation of the actions taken under the extraordinary circumstances during the Haitian relief experience, it was determined that the concept and triage policy used allowed the best chance of survival for the largest possible number of victims. At EMT levels of care, the triage systems must be flexible and reevaluated daily with “extensive adaptation to local condition[13].” For example, significant improvement of over- and undertriage rates and casualty severity predictability were accomplished across triage levels when the South African Triage Score (SATS) four-level system made modifications to make it more clinically and culturally sensitive[30,31]. Similarly, the chosen triage protocol (START) used in the Haiti earthquake was tailored to the local situation for surge capacity either by increasing resource availability or by reducing inpatient use. The process not only differentiated patients according to the severity of their injuries but also by the resources required and expected outcomes. The triage system must be flexible, reevaluated daily, and “requires extensive adaptation to local condition[13].”
Altered Standards of Care
The term “altered standards of care” generally means a shift in the provision of care and the allocation of equipment, supplies, and personnel in a way to ensure the greatest good for the greatest number. The majority of studies on altered standards of care pertain to emergency services triage management in developed countries. EMTs function daily in resource-poor or constrained settings where shortfalls are anticipated and standards of care maintenance strategies are best when planned for, ongoing, and steady, with the least observed consequences to avoid untoward, abrupt, or unethical consequences.
In EMTs, triage protocols need to be flexible enough to change as the size and speed of the crisis grows. Any change in triage decision tools must be understood by the entire medical staff. TOs first consider “reactive and proactive alterations” of the triage protocol process, but much can be done before alteration becomes an operational reality. Hick and colleagues list six key strategies: prepare with optimal stockpiling, conserve use of certain therapies, substitute equivalent medications, adapt existing devices for purposes they were not intended, reuse material resources, and as a last resort, the reallocation of resources to those most likely to benefit[32,33].
Triage decisions will affect the allocation of resources across all triage categories and the entire EMT. For example, the triage area may be reserved for immediate casualties only, intensive care areas may become surgical suites, and regular wards become isolation or other specialized units. Recovering casualties may be evacuated/transferred earlier than anticipated, nurses function as physicians and physicians function outside their specialties, disposable supplies reused, treatment decisions based on clinical judgment from physical exams without additional laboratory testing and X-ray resources, single person isolation units become group isolation units, and identifying safe alternate care sites from facilities not previously designed to provide medical care[32,33].
Reverse Triage
Geneva Convention (GC) medical protocols and ethicists are opposed to any system of triage prioritization other than medical need. The GC explicitly states “only urgent medical reasons will authorize priority in order of treatment to be administered [34].” However, under extreme battle conditions when the combat situation demands that soldiers be returned to combat as rapidly as possible, NATO may contradict this position, using “reverse triage”, resulting in military personnel with minimal injuries treated first and returned to duty before more seriously injured casualties are managed[35]. The legal argument supporting reverse triage is that military physicians do not enter into a physician–patient relationship with the casualties. Therefore, this difference warrants that triage reversal should occur if the chain of command requires it.
Triage Officers
The placement of experienced civilian and military TOs at the EMT level is crucial to success. Burkle described the desirable characteristics of TOs as “surgically experienced, easily recognized, and respected, demonstrating good judgment and leadership, decisive, knowledgeable, familiar with resources, staff skills, and limitations, equipment and evacuation potential” and who “maintain control of the often unpredictable triage situation[36].” Others assert that few cases are sorted improperly where trained TOs exist, adding that while the “full extent of the disaster may not be fully known for several hours, the parameters of casualty flow, patient care, and rapid recognition of priorities require the continued attention of the TO.
International Committee of the Red Cross (ICRC) guidelines recommend that only one TO is required, a physician or nurse, with experience and understanding of war wounds, with an overview of all aspects of the functioning of the EMT and its resources, and the ability to make clear decisions under stress. The decisions made by the TO must be respected[37]. The TO decides when triage is implemented and ensures that all departments are informed. The clinical assessment and allocation of a triage category must be supervised or performed by the TO, who must see all the patients. The triage process is implemented and defined with specific roles of each member of the EMT and of each department as an extension of the normal hospital routines. The situation needs constant reassessment to determine the need for additional staff, supplies, and ward areas. The ICRC cautions that, while a surgeon can make an accurate surgical assessment of each patient, they might give preference to those cases corresponding to his or her own specialty. An anesthesiologist may be able to leave the operating theater to help the TO with clinical assessment. The TO has the responsibility to ensure that the EMT is “a safe place” by being aware of outside events, any security situation, and maintaining control of the number of people entering the EMT[37].
Baker, with extensive experience in war surgery, maintains that the ideal triage officer needs “exceptional leadership skills, strong clinical expertise, and good communication abilities that requires constant situational awareness, tactical understanding, adaptability, and decisiveness.” Additional expectations are that the TO prevents confusion, fear, competition among staff members, prevents bottlenecks at critical locations, and ensures that critical casualties are not passed unnoticed and a contaminated casualty is prevented from entering the wrong staging area[38,39].
Triage Teams
TOs are dependent on clinically strong, knowledgeable, and trusted team members who, at a minimum, have triage experience (nurse or medic/corpsman) and with immediate access to other triage team members from logistics and communications. The triage team for a public-health emergency requires multidisciplinary expertise emphasizing public health skills, infectious disease, field epidemiology, and cultural anthropology, which was especially relevant during the Ebola epidemic in West Africa when the native population resisted treatment out of fear of the motives of foreign aid workers[40].
Triage Tagging
Tagging is important to continuity of care and often serves as the only ongoing medical record of the casualty. The purposes of tags are to (1) identify the victim, (2) identify to which triage category the victim belongs, and (3) provide some space to document details about the victim and their management[41]. Among the numerous varieties available, the most useful are those easy to read and interpret, having space for instructions and vital signs. Colored tapes and more permanent plastic tags are also available. Tags are usually attached to the large toe or wrist. If the casualty is retriaged to another level, the new tag is attached over the original tag, providing evidence of a change in clinical status[36].
Tags may be unavailable or destroyed. A system using “Xs” marked on the forehead with indelible pens is acceptable. X indicates minor injury, XX indicates serious injury but some delay in treatment possible, and XXX indicates serious injury requiring immediate attention.
There is no published evidence that indicates triage tags improve management of incidents involving more than 24 people[41]. Alternative systems demand adherence to the “daily routine doctrine,” an expansion of normal services to accommodate the new patient load, and emphasizes that “geographical triage” of victim separation on urgency pertains only to the pre-EMT incident scene[42,43]. This outcome may be helpful in that all “immediate” category victims will arrive together at the EMT. It is dependent on a well-organized pre-EMT system, a state that is not normally available for most EMT situations[43].
The Triage Process
The first round of decisions in the triage area is often where the most decisive, collective, efficient, and agreed-on stage of the triage process occurs in directly moving casualties to the operating rooms[44]. The initial triage exam, and those that follow, should focus equally on physiological and anatomical parameters. Physiologic parameters, with a prehospital triage sensitivity of 0.7, provide only a brief “snapshot” of the physiologic stability at the time of the triage exam and may initially lead to undertriage. Anatomical criteria alone have a prehospital sensitivity of 0.5 and a 20%–30% yield for identifying major trauma victims. When both parameters are combined, the triage sensitivity becomes 0.8[45]. This information, along with attention to mechanism of injury of the chest, head, upper abdomen, face, and amputations, represents for the first triage performed at the EMT, the combination of information that best determines casualties triaged as “immediate” for emergency lifesaving surgery. Additionally, focused exams and tests performed in the triage area better clarify the extent of organ injuries, including occult fractures.
The second round of triage for remaining casualties begins automatically and is often more challenging, complex, and unpredictable, especially when an unexpected influx of new casualties occurs. During the Vietnam War, this stage of triage was referred to as “the triage dance.” The singular actions of the TO become more demanding as each casualty is reassessed by the triage team process, which is constantly updated and performed in an orderly and consistent manner. The TO monitors and supervises the physiological information provided by trusted team members, which depict an increasingly accurate picture of how casualties are maintaining their stability[46]. Additional focused exams and tests performed in the triage area better clarify the extent of organ injuries including occult fractures. This continuous triage flow of information and decision-making confirms that basic and advanced procedures are being carried out despite the continuous decision challenges.
Knowledge of the larger system of resources and security beyond the EMT is required, including trusted relationships with outside resources and authorities. The TO needs to know and be updated on the status of crucial resources in medical logistics, blood products, staffing, evacuation potential, expected time to an open operating room, and additional security risks for the wounded and EMT staff, while preparing for the arrival of additional casualties, to name but a few. Scarce items that impacted ongoing triage decisions during the 100-hour 1991 Persian Gulf War were blood products, surgical sutures, lap pads, stretcher straps, blankets, and surgical gloves: any one of these had the potential to disrupt the entire triage process and the functional capacity of the EMT[47,48,49].
These second-stage decisions directly impact the priority list for surgery and may prompt the triage team to consider other options, including immediate evacuation if such a calculated decision provides an opportunity for survival without additional risks that compromise safety or vital resources. These decisions are often difficult to make, always debated, second-guessed, and learned from when discussed during the post-event evaluation.
Decoding Vital Signs
Over the generations, there have been multiple attempts to improve triage scoring systems and correlation with outcomes. Unfortunately, they are a poor substitute for good clinical judgment and experience. Vital signs are routinely monitored and reported as numbers either electronically or by medical professionals other than physicians or experienced nurses. The number values alone of vital signs provided verbally to the triage officer, triage team, or written on a triage tag fail to provide the needed sensitivity and specificity desired for expeditious decisions required in triage. The numbers alone may or may not properly alert the triage officer and team to pending physiologic failure. Properly “decoding the vital signs” and attention to their physiologic meaning can discover subtle worsening of the physiologic state by incorporating visual alerts such as subtle mental status changes, especially in an otherwise quiet but increasingly anxious or apprehensive casualty, and delayed capillary refill, first on the distal extremities and moving up to the core of the body, which reveals physiologic attempts to maintain the central blood flow[46,50].
Parameters for Decoding Vital Signs
mental status: anxious, apprehensive
resting tachycardia
pulse: soft, nonexpansive, nonvibratory
systolic BP < 100 mm Hg
pulse pressure < 30 mm Hg
narrowing pulse pressure: absent or faint diastolic
resting tachypnea or bradypnea
regions: head, chest, upper abdomen, amputation, face
Triage Protocols in Deployed EMTs
A large number of triage protocol systems are available to prehospital emergency medical systems in the developed world. Few are relevant to EMT resource-poor or constrained settings where triaged victims include those unlikely to survive. Despite all the current technological advances, the basic skill of disaster triage of large numbers of injured to optimize available resources remains a vital tool.
This section describes advanced triage protocols currently in use for:
sudden-onset disasters
complex humanitarian emergencies
public health emergencies of international concern
war and conflict
Sudden Onset Disasters (SODs)
Weather-related disasters increased by 50% between 2005 and 2014, along with a dramatic intensification of natural disasters from earthquakes, typhoons, cyclones, wild fires, and floods, which are often exacerbated by climate change, severe droughts, rapid unsustainable urbanization, biodiversity crises, and national scarcities of food, water, and energy. Over 20 million refugees have been displaced by these disasters[51].
Related posts:
Chapter 6 – Training and Accreditation
Chapter 3 – Definitions, Needs, Scenarios, Functional Concept, and Modes of Deployment
Chapter 7 – Personnel
Chapter 15 – Pediatrics in a Field Hospital
Chapter 18 – Orthopedics in a Field Hospital
Chapter 25 – Infectious Diseases and Public Health in a Field Hospital
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