Triage is the process of determining the priority of patients' treatments based on the severity of their condition. This rations patient treatment efficiently when resources are insufficient for all to be treated immediately; influencing the order and priority of emergency treatment, emergency transport, or transport destination for the patient.
This article covers the various types of triage systems as it occurs in medical emergencies, including the prehospital setting, disasters, and emergency department treatment, along with their limitations and ethical considerations.
Modern medical triage was invented by Dominique Jean Larrey, a surgeon during the Napoleonic Wars, who "treat[ed] the wounded according to the observed gravity of their injuries and the urgency for medical care, regardless of their rank or nationality", though the general concept of prioritizing by prognosis is foreshadowed in a 17th-century BCE Egyptian document. Triage was used further during World War I by French doctors treating the battlefield wounded at the aid stations behind the front. Those responsible for the removal of the wounded from a battlefield or their care afterwards would divide the victims into three categories:
For many emergency medical services (EMS) systems, a similar model may sometimes still be applied. In the earliest stages of an incident, such as when one or two paramedics exist to twenty or more patients, practicality demands that the above, more "primitive" model will be used. However, once a full response has occurred and many hands are available, paramedics will usually use the model included in their service policy and standing orders.
As medical technology has advanced, so have modern approaches to triage, which are increasingly based on scientific models. The categorizations of the victims are frequently the result of triage scores based on specific physiological assessment findings. Some models, such as the START model may be algorithm-based. As triage concepts become more sophisticated, triage guidance is also evolving into both software and hardware decision support products for use by caregivers in both hospitals and the field.
This section is for concepts in triage. See other sections for specific triage tools, methods, and systems
Simple triage is usually used in a scene of an accident or "mass-casualty incident" (MCI), in order to sort patients into those who need critical attention and immediate transport to the hospital and those with less serious injuries. This step can be started before transportation becomes available.
Upon completion of the initial assessment by physicians, nurses or paramedical personnel, each patient may be labelled which may identify the patient, display assessment findings, and identify the priority of the patient's need for medical treatment and transport from the emergency scene. At its most primitive, patients may be simply marked with coloured flagging tape or with marker pens. Pre-printed cards for this purpose are known as a triage tags.
A triage tag is a prefabricated label placed on each patient that serves to accomplish several objectives:
Triage tags may take a variety of forms. Some countries use a nationally standardized triage tag, while in other countries commercially available triage tags are used, and these will vary by jurisdictional choice. The most commonly used commercial systems include the METTAG, the SMARTTAG, E/T LIGHT tm and the CRUCIFORM systems. More advanced tagging systems incorporate special markers to indicate whether or not patients have been contaminated by hazardous materials, and also tear off strips for tracking the movement of patients through the process. Some of these tracking systems are beginning to incorporate the use of handheld computers, and in some cases, bar code scanners.
For classifications, see the specific section for that topic.
In advanced triage, specially trained doctors, nurses and paramedics may decide that some seriously injured people should not receive advanced care because they are unlikely to survive. It is used to divert scarce resources away from patients with little chance of survival in order to increase the chances for others with higher likelihoods.
The use of advanced triage may become necessary when medical professionals decide that the medical resources available are not sufficient to treat all the people who need help. The treatment being prioritized can include the time spent on medical care, or drugs or other limited resources. This has happened in disasters such as terrorist attacks, mass shootings, volcanic eruptions, earthquakes, tornadoes, thunderstorms, and rail accidents. In these cases some percentage of patients will die regardless of medical care because of the severity of their injuries. Others would live if given immediate medical care, but would die without it.
In these extreme situations, any medical care given to people who will die anyway can be considered to be care withdrawn from others who might have survived (or perhaps suffered less severe disability from their injuries) had they been treated instead. It becomes the task of the disaster medical authorities to set aside some victims as hopeless, to avoid trying to save one life at the expense of several others.
If immediate treatment is successful, the patient may improve (although this may be temporary) and this improvement may allow the patient to be categorized to a lower priority in the short term. Triage should be a continuous process and categories should be checked regularly to ensure that the priority remains correct given the patient's condition. A trauma score is invariably taken when the victim first comes into hospital and subsequent trauma scores are taken to account for any changes in the victim's physiological parameters. If a record is maintained, the receiving hospital doctor can see a trauma score time series from the start of the incident, which may allow definitive treatment earlier.
Usually, triage refers to prioritizing admission. A similar process can be applied to discharging patients early when the medical system is stressed. This process has been called "reverse triage". When a major wave of patients arrive to a hospital, such as immediately after a natural disaster, many hospital beds will be already occupied by regular non-critical patients. To accommodate a greater number of the new critical patients, the existing patients may be triaged, and those who will not need immediate care can be discharged until the surge has dissipated, for example through the establishment of temporary medical facilities in the region.
Undertriage is underestimating the severity of an illness or injury. An example of this would be categorizing a Priority 1 (Immediate) patient as a Priority 2 (Delayed) or Priority 3 (Minimal). Historically, acceptable undertriage rates have been deemed 5% or less.
Overtriage is the overestimating of the severity of an illness or injury. An example of this would be categorizing a Priority 3 (Minimal) patient as a Priority 2 (Delayed) or Priority 1 (Immediate). Acceptable overtriage rates have been typically up to 50% in an effort to avoid undertriage. Some studies suggest that overtriage is less likely to occur when triaging is performed by hospital medical teams, rather than paramedics or EMTs.
In telephone triage, decision makers over the phone must effectively assess the patient's symptoms and provide directives based on the urgency. This should be done in a timely fashion while meeting standard guidelines in order to prevent symptoms from worsening.
This section is for general concepts in triage-based treatment options and outcomes. For specific triage systems and methods see the sections dedicated to that topic.
Alternative care facilities are places that are set up for the care of large numbers of patients, or are places that could be so set up. Examples include schools, sports stadiums, and large camps that can be prepared and used for the care, feeding, and holding of large numbers of victims of a mass casualty or other type of event. Such improvised facilities are generally developed in cooperation with the local hospital, which sees them as a strategy for creating surge capacity. While hospitals remain the preferred destination for all patients, during a mass casualty event such improvised facilities may be required in order to divert low-acuity patients away from hospitals in order to prevent the hospitals becoming overwhelmed.
In advanced triage systems, secondary triage is typically implemented by emergency nurses, skilled paramedics, or battlefield medical personnel within the emergency departments of hospitals during disasters, injured people are sorted into five categories.
Some crippling injuries, even if not life-threatening, may be elevated in priority based on the available capabilities. During peacetime, most amputation injuries may be triaged "Red" because surgical reattachment must take place within minutes, even though in all probability the person will not die without a thumb or hand.
This section is for examples of specific triage systems and methods. For general triage concepts, see the sections for types of triage, treatment options, and outcomes.
During the early stages of an incident, first responders may be overwhelmed by the scope of patients and injuries. One valuable technique is the Patient Assist Method (PAM). The responders quickly establish a casualty collection point (CCP) and advise, either by yelling, or over a loudspeaker, that "anyone requiring assistance should move to the selected area (CCP)". This does several things at once, it identifies patients that are not so severely injured, that they need immediate help, it physically clears the scene, and provides possible assistants to the responders. As those who can move, do so, the responders then ask, "anyone who still needs assistance, yell out or raise your hands"; this further identifies patients who are responsive, yet maybe unable to move. Now the responders can rapidly assess the remaining patients who are either expectant, or are in need of immediate aid. From that point the first responder is quickly able to identify those in need of immediate attention, while not being distracted or overwhelmed by the magnitude of the situation. Using this method assumes the ability to hear. Deaf, partially deaf, or victims of a large blast injury may not be able to hear these instructions.
Examples of scoring systems used:
S.T.A.R.T. (Simple Triage and Rapid Treatment) is a simple triage system that can be performed by lightly trained lay and emergency personnel in emergencies. It is not intended to supersede or instruct medical personnel or techniques. It has been taught to California emergency workers for use in earthquakes. It was developed at Hoag Hospital in Newport Beach, California for use by emergency services. It has been field-proven in mass casualty incidents such as train wrecks and bus accidents. Though it was developed by community emergency response teams (CERTs) and firefighters after earthquakes.
Triage separates the injured into four groups:
Triage also sets priorities for evacuation and transport as follows:
The JumpSTART pediatric triage MCI triage tool is a variation of the S.T.A.R.T. model. Both systems are used to sort patients into categories at mass casualty incidents (MCIs). However, JumpSTART was designed specifically for triaging children in disaster settings. Though JumpSTART was developed for use in children from infancy to age 8, where age is not immediately obvious, it is used in any patient who appears to be a child (patients who appear to be young adults are triaged using START).
Within the hospital system, the first stage on arrival at the emergency department is assessment by the hospital triage nurse. This nurse will evaluate the patient's condition, as well as any changes, and will determine their priority for admission to the emergency department and also for treatment. Once emergency assessment and treatment are complete, the patient may need to be referred to the hospital's internal triage system.
For a typical inpatient hospital triage system, a triage nurse or physician will either field requests for admission from the ER physician on patients needing admission or from physicians taking care of patients from other floors who can be transferred because they no longer need that level of care (i.e. intensive care unit patient is stable for the medical floor). This helps patient flow more efficient in the hospital.
This triage position is often done by a hospitalist. A major factor contributing to the triage decision is available hospital bed space. The triage hospitalist must determine, in conjunction with a hospital's "bed control" and admitting team, what beds are available for optimal utilization of resources in order to provide safe care to all patients. A typical surgical team will have their own system of triage for trauma and general surgery patients. This is also true for neurology and neurosurgical services. The overall goal of triage, in this system, is to both determine if a patient is appropriate for a given level of care and to ensure that hospital resources are utilized effectively.
In an advanced triage process injured people are sorted into categories. Conventionally there are five classifications with corresponding colors and numbers although this may vary by region.
The Australasian Triage Scale (abbreviated ATS and formally known as the National Triage Scale) is a triage system that is implemented in both Australia and New Zealand. The scale has been in use since 1994. The scale consists of 5 levels, with 1 being the most critical (resuscitation), and 5 being the least critical (nonurgent).
|Level||Description||Should be seen by provider within|
In the mid-1980s, The Victoria General Hospital, in Halifax, Nova Scotia, Canada, introduced paramedic triage in its Emergency Department. Unlike all other centres in North America that employ physician and primarily nurse triage models, this hospital began the practice of employing Primary Care level paramedics to perform triage upon entry to the Emergency Department. In 1997, following the amalgamation of two of the city's largest hospitals, the Emergency Department at the Victoria General closed. The paramedic triage system was moved to the city's only remaining adult emergency department, located at the New Halifax Infirmary. In 2006, a triage protocol on whom to exclude from treatment during a flu pandemic was written by a team of critical-care doctors at the behest of the Ontario government.
For routine emergencies, many locales in Canada now employ the Canadian Triage and Acuity Scale (CTAS) for all incoming patients. The system categorizes patients by both injury and physiological findings, and ranks them by severity from 1-5 (1 being highest). The model is used by both paramedics and E/R nurses, and also for pre-arrival notifications in some cases. The model provides a common frame of reference for both nurses and paramedics, although the two groups do not always agree on scoring. It also provides a method, in some communities, for benchmarking the accuracy of pre-triage of calls using AMPDS (What percentage of emergency calls have return priorities of CTAS 1,2,3, etc.) and these findings are reported as part of a municipal performance benchmarking initiative in Ontario. Curiously enough the model is not currently used for mass casualty triage, and is replaced by the START protocol and METTAG triage tags.
|Level||Description||Should be seen by provider within|
|4||Less Urgent||60 minutes|
|5||Non Urgent||120 minutes|
In France, the Prehospital triage in case of a disaster uses a four-level scale:
This triage is performed by a physician called médecin trieur (sorting medic). This triage is usually performed at the field hospital (PMA-poste médical avancé, i.e. forward medical post). The absolute urgencies are usually treated onsite (the PMA has an operating room) or evacuated to a hospital. The relative urgencies are just placed under watch, waiting for an evacuation. The involved are addressed to another structure called the CUMP-Cellule d'urgence médico-psychologique (medical-psychological urgency cell); this is a resting zone, with food and possibly temporary lodging, and a psychologist to take care of the brief reactive psychosis and avoid post-traumatic stress disorder.
In the emergency department of a hospital, the triage is performed by a physician called MAO-médecin d'accueil et d'orientation (reception and orientation physician), and a nurse called IOA- infirmière d'organisation et d'accueil (organisation and reception nurse). Some hospitals and SAMU organisations now use the "Cruciform" card referred to elsewhere.
France has also a Phone Triage system for Medical Emergencies Phone Demands in its Samu Medical Regulation Centers through the 15 medical free national hot line. "Medical Doctor Regulator" decides what is to be the most efficient solution = Emergency Telemedecine or dispatch of an Ambulance, a General Practitioner or a Physician+ Nurse + Ambulance Man, Hospital based MICU (Mobile Intensive Care Unit).
Preliminary assessment of injuries is usually done by the first ambulance crew on scene, with this role being assumed by the first doctor arriving at the scene. As a rule, there will be no cardiopulmonary resuscitation, so patients who do not breathe on their own or develop circulation after their airways are cleared will be tagged "deceased". Also, not every major injury automatically qualifies for a red tag. A patient with a traumatic amputation of the forearm might just be tagged yellow, have the bleeding stopped, and then be sent to a hospital when possible. After the preliminary assessment, a more specific and definite triage will follow, as soon as patients are brought to a field treatment facility. There, they will be disrobed and fully examined by an emergency physician. This will take approximately 90 seconds per patient.
The German triage system also uses four, sometimes five colour codes to denote the urgency of treatment. Typically, every ambulance is equipped with a folder or bag with coloured ribbons or triage tags. The urgency is denoted as follows:
|T1 (I)||Acute danger for life||Immediate treatment, transport as soon as possible||Arterial lesions, internal haemorrhage, major amputations|
|T2 (II)||Severe injury||Constant observation and rapid treatment, transport as soon as practical||Minor amputations, flesh wounds, fractures and dislocations|
|T3 (III)||Minor injury or no injury||Treatment when practical, transport and/or discharge when possible||Minor lacerations, sprains, abrasions|
|T4 (IV)||No or small chance of survival||Observation and if possible administration of analgesics||Severe injuries, uncompensated blood loss, negative neurological assessment|
|Deceased||Collection and guarding of bodies, identification when possible||Injuries not compatible with life, no spontaneous breathing after clearing of airway, downgraded from T1-4|
In Hong Kong, triage in Accident & Emergency Departments is performed by experienced registered nurses, patients are divided into five triage categories: Critical, Emergency, Urgent, Semi-urgent and Non-urgent.
In Japan, the triage system is mainly used by health professionals. The categories of triage, in corresponding color codes, are:
All public hospitals in Singapore use the Patient Acuity Category Scale (PACS) to triage patient in Emergency Departement. PACS is a symptom-based differential diagnosis approach that triages patients according to their presenting complaints and objective assessments such as vital signs and Glasgow Coma Scale, allowing acute patients to be identified quickly for treatment. PACS classifies patients into four main categories: P1, P2, P3, and P4.
|Category (Priority Level)||Category Name||Description||Example|
|P1||Critically ill and requires resuscitation||State of cardiovascular collapse or in imminent danger of collapse and require immediate medical attention.||Multiple major trauma, head injury with loss of consciousness, shortness of breath, unconsciousness from any cause|
|P2||Major emergency||unable to walk and are in some form of distress, appear stable on initial examination, and are not in imminent danger of collapse, requires very early attention||Chest pain, major limb fractures, major joint dislocations, spinal cord injury, trunk injury with stable vital signs|
|P3||Minor emergency||able to walk, have mild to moderate symptoms and require early treatment||All sprains, mild constant abdominal pain, fever with cough for several days, insect stings or animal bites (not in severe distress), superficial injuries with or without mild bleeding, minor head injury (alert, no vomiting), foreign object in ear, nose, or throat, urinary tract infections, headaches.|
|P4||Nonemergency||Old injury or condition that has been present for a long time.||Chronic lower back pain, high cholesterol, acne.|
In Spain, there are 2 models which are the most common found in hospitals around the country:
In the UK, the commonly used triage system is the Smart Incident Command System, taught on the MIMMS (Major Incident Medical Management (and) Support) training program. The UK Armed Forces use this system on operations. This grades casualties from Priority 1 (needs immediate treatment) to Priority 3 (can wait for delayed treatment). There is an additional Priority 4 (expectant, likely to die even with treatment) but the use of this category requires senior medical authority.
In the UK and Europe, the triage process used is sometimes similar to that of the United States (see below), but the categories are different:
Triage in a multi-scale destruction, disaster, catastrophic, casualty event, such as following a tornado or an explosion in a populated area, first responders follow a similar triage category scale as the US military. The civilian medical industry uses a similar system for triage. Normally medical personnel aren't immediately available on scene. First responders are usually the first to arrive on scene. They could be police, fire rescue, paramedics, or community individuals with disaster training (CERT certified). They are trained to perform first aid, basic life saving and rescue techniques while performing the greatest good, for the greatest number of people. They will rapidly classify victims and sort them into 4 categories, treating quickly as they go. This system is intended to rapidly identify and classify victims for arriving transport or advanced care medical personnel such as doctors and nurses. The local National Guard and other military units responding would be using the military system of triage rather than civilian. The triage categories are general and the names may vary by region of the nation:
A battlefield situation, however, requires medics and corpsmen to rank casualties for precedence in MEDEVAC or CASEVAC. The casualties are then transported to a higher level of care, either a Forward Surgical Team or Combat Support Hospital and re-triaged by a nurse or doctor. In a combat situation, the triage system is based solely on resources and ability to save the maximum number of lives within the means of the hospital supplies and personnel.
The triage categories (with corresponding color codes), in precedence, are:
Afterwards, casualties are given an evacuation priority based on need:
In a "naval combat situation", the triage officer must weigh the tactical situation with supplies on hand and the realistic capacity of the medical personnel. This process can be ever-changing, dependent upon the situation and must attempt to do the maximum good for the maximum number of casualties.
Field assessments are made by two methods: primary survey (used to detect & treat life-threatening injuries) and secondary survey (used to treat non-life-threatening injuries) with the following categories:
Notions of mass casualty triage as an efficient rationing process of determining priority based upon injury severity are not supported by research, evaluation and testing of current triage practices, which lack scientific and methodological bases. START and START-like (START) triage that use color-coded categories to prioritize provide poor assessments of injury severity and then leave it to providers to subjectively order and allocate resources within flawed categories. Some of these limitations include:
Research indicates there are wide ranges and overlaps of survival probabilities of the Immediate and Delayed categories, and other START limitations. The same physiologic measures can have markedly different survival probabilities for blunt and penetrating injuries. For example, a START Delayed (second priority) can have a survival probability of 63% for blunt trauma and a survival probability of 32% for penetrating trauma with the same physiological measures - both with expected rapid deterioration, while a START Immediate (first priority) can have survival probabilities that extend to above 95% with expected slow deterioration. Age categories exacerbate this. For example, a geriatric patient with a penetrating injury in the Delayed category can have an 8% survival probability, and a pediatric patient in the Immediate category can have a 98% survival probability. Issues with the other START categories have also been noted. In this context, color-coded tagging accuracy metrics are not scientifically meaningful.
Poor assessments, invalid categories, no objective methodology and tools for prioritizing casualties and allocating resources, and a protocol of worst first triage provide some challenges for emergency and disaster preparedness and response. These are clear obstacles for efficient triage and resource rationing, for maximizing savings of lives, for best practices and National Incident Management System (NIMS) compatibilities, and for effective response planning and training.
Inefficient triage also provides challenges in containing health care costs and waste. Field triage is based upon the notion of up to 50% overtriage as being acceptable. There have been no cost-benefit analyses of the costs and mitigation of triage inefficiencies embedded in the healthcare system. Such analyses are often required for healthcare grants funded by taxpayers, and represent normal engineering and management science practice. These inefficiencies relate to the following cost areas:
Because treatment is intentionally delayed or withheld from patients, triage has ethical implications that complicates the decision-making process.
Since ethical implications vary between different settings and the type of triage system employed, there is often no single gold-standard approach to triage. Once triage decisions have been made, it may be difficult to evaluate afterwards whether the decisions were ethically justified and the appropriate course of action. This can be especially stressful for triage responders who lack experience or support from peers.
It is advised for emergency departments to preemptively plan strategies in attempts to mitigate the emotional burden on these triage responders. While doing so, standards of care must be maintained to preserve the safety of both patients and providers.
Under the utilitarian model, triage decisions are aimed to maximize the most benefits to the most people possible.
During disaster scenarios, this approach is further complicated and may not be entirely possible. Using this approach implies that some individuals may likely suffer or perish in order for the majority to survive. Triage officers must allocate limited resources and weigh an individual's needs with the population as a whole.
There is wide discussion regarding how VIPs and celebrities should be cared for in the emergency department. It is generally argued that giving special considerations or deviating from the standard medical protocol for VIPs or celebrities is unethical due to the cost of others. However, others argue that it may be morally justifiable as long as their treatment does not hinder the needs of others after assessing overall fairness, quality of care, privacy, and other ethical implications.