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. The term comes from the French verb trier, meaning to separate, sift or select. Triage may result in determining the order and priority of emergency treatment, the order and priority of emergency transport, or the transport destination for the patient.
Triage may also be used for patients arriving at the emergency department, or telephoning medical advice systems, among others. This article deals with the concept of triage as it occurs in medical emergencies, including the prehospital setting, disasters, and emergency room treatment.
The term triage may have originated during the Napoleonic Wars from the work ofDominique Jean Larrey. The term was used further during World War I by Frenchdoctors 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:
• Those who are likely to live, regardless of what care they receive;
• Those who are likely to die, regardless of what care they receive;
• Those for whom immediate care might make a positive difference in outcome.
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 has 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 physiologicalassessment 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.
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 medical 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 tag.
Many triage systems use triage tags with specific formats
Emergency Triage (E/T) Lights – particularly useful at night or under adverse conditions
A triage tag is a prefabricated label placed on each patient that serves to accomplish several objectives:
• identify the patient.
• bear record of assessment findings.
• identify the priority of the patient’s need for medical treatment and transport from the emergency scene.
• track the patients’ progress through the triage process.
• identify additional hazards such as contamination.
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, doctors and specially trained nurses 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 of survival of others who are more likely to survive.
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 volcanic eruptions, mass shootings, earthquakes, 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. A trauma score is invariably taken when the victim first comes into hospital and subsequent trauma scores taken to see 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.
Continuous integrated triage
Continuous integrated triage is an approach to triage in mass casualty situations which is both efficient and sensitive topsychosocial and disaster behavioral health issues that affect the number of patients seeking care (surge), the manner in which a hospital or healthcare facility deals with that surge (surge capacity) and the overarching medical needs of the event.
Continuous integrated triage combines three forms of triage with progressive specificity to most rapidly identify those patients in greatest need of care while balancing the needs of the individual patients against the available resources and the needs of other patients. Continuous integrated triage employs:
• Group (Global) Triage (i.e., M.A.S.S. triage)
• Physiologic (Individual) Triage (i.e., S.T.A.R.T.)
• Hospital Triage (i.e., E.S.I. or Emergency Severity Index)
However any Group, Individual and/or Hospital Triage system can be used at the appropriate level of evaluation.
In addition to the standard practices of triage as mentioned above, there are conditions where sometimes the less wounded are treated in preference to the more severely wounded. This may arise in a situation such as war where the military setting may require soldiers be returned to combat as quickly as possible, or disaster situations where medical resources are limited in order to conserve resources for those likely to survive but requiring advanced medical care. Other possible scenarios where this could arise include situations where significant numbers of medical personnel are among the affected patients where it may be advantageous to ensure that they survive to continue providing care in the coming days especially if medical resources are already stretched. In cold water drowning incidents, it is common to use reverse triage because drowning victims in cold water can survive longer than in warm water if given immediate basic life support and often those who are rescued and able to breathe on their own will improve with minimal or no help.
Undertriage and overtriage
Undertriage is the 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.
For those patients that have a poor prognosis and are expected to die regardless of the medical treatment available,palliative care such as painkillers may be given to ease suffering before they die.
In the field, triage sets priorities for evacuation or relocation to other care facilities.
Alternative care facilities
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.
Secondary (in-hospital) triage
In advanced triage systems, secondary triage is typically implemented by emergency nurses, skilled paramedics, orbattlefield 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 amputations 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.
A triage sign at a Mexican emergency room indicating the waiting time for patients based on the severity of their condition
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.
Practical applied triage
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:
• In Western Europe the Triage Revised Trauma Score (TRTS) is sometimes used and integrated into triage cards.
• The Injury Severity Score (ISS) is another example of a trauma scoring system. This assigns a score from 0 to 75 based on severity of injury to the human body divided into three categories: A (face/neck/head), B(thorax/abdomen), C(extremities/external/skin). Each category is scored from 0 to 5 using the Abbreviated Injury Scale, from uninjured to critically injured, which is then squared and summed to create the ISS. A score of 6, for “unsurvivable”, can also be used for any of the three categories, and automatically sets the score to 75 regardless of other scores. Depending on the triage situation, this may indicate either that the patient is a first priority for care, or that he or she will not receive care owing to the need to conserve care for more likely survivors.
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 for use by community emergency response teams (CERTs) and firefighters after earthquakes.
Triage separates the injured into four groups:
• The expectant who are beyond help
• The injured who can be helped by immediate transportation
• The injured whose transport can be delayed
• Those with minor injuries, who need help less urgently
Triage also sets priorities for evacuation and transport as follows:
• Deceased are left where they fell. These people are not breathing and an effort to reposition their airway has been unsuccessful.
• Immediate or Priority 1 (red) evacuation by MEDEVAC if available or ambulance as they need advanced medical care at once or within 1 hour. These people are in critical condition and would die without immediate assistance.
• Delayed or Priority 2 (yellow) can have their medical evacuation delayed until all immediate persons have been transported. These people are in stable condition but require medical assistance.
• Minor or Priority 3 (green) are not evacuated until all immediate and delayed persons have been evacuated. These will not need advanced medical care for at least several hours. Continue to re-triage in case their condition worsens. These people are able to walk, and may only require bandages and antiseptic.
Within the hospital system, the first stage on arrival at the emergency room 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 Room 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 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 keep patients moving through the hospital in an efficient and effective manner.
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 neurosurgicalservices. 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
• Black / Expectant: They are so severely injured that they will die of their injuries, possibly in hours or days (large-areaburns, severe trauma, lethal radiation dose), or in life-threatening medical crisis that they are unlikely to survive given the care available (cardiac arrest, septic shock, severe head or chest wounds); their treatment is usually palliative, such as being given painkillers, to reduce suffering.
• Red / Immediate: They require immediate surgery or other life-saving intervention, and have first priority for surgical teams or transport to advanced facilities; they “cannot wait” but are likely to survive with immediate treatment.
• Yellow / Observation: Their condition is stable for the moment but requires watching by trained persons and frequent re-triage, will need hospital care (and would receive immediate priority care under “normal” circumstances).
• Green / Wait (walking wounded): They will require a doctor’s care in several hours or days but not immediately, may wait for a number of hours or be told to go home and come back the next day (broken bones without compound fractures, many soft tissue injuries).
• White / Dismiss (walking wounded): They have minor injuries; first aid and home care are sufficient, a doctor’s care is not required. Injuries are along the lines of cuts and scrapes, or minor burns.