Manchester Triage System

Clockwise from top-left:
COVID-19 triage tent outside of a Swedish Hospital
9/11 triage station out side of the Pentagon
2010 Pakistan floods triage station under a tree
Korean War triage station in modern South Korea
Mass casualty drill at Misawa Air Base
CBRN triage drill at Yokato Air Base

In medicine, triage (/ˈtriːɑːʒ, triˈɑːʒ/) is a process by which care providers such as medical professionals and those with first aid knowledge determine the order of priority for providing treatment to injured individuals and/or inform the rationing of limited supplies so that they go to those who can most benefit from it. Triage is normally relied upon when there are more injured individuals than available care providers (known as a mass casualty incident), or when there are more injured individuals than supplies to treat them.

The methodologies of triage vary by institution, locality, and country, but have the same universal underlying concepts. In most cases, the triage process places the most injured and most able to be helped as the first priority, with the most terminally injured the last priority (except in the case of reverse triage). Triage systems vary dramatically based on a variety of factors, and can follow specific measurable metrics, like trauma scoring systems, or can be based on the medical opinion of the provider. Triage is an imperfect practice, and can be largely subjective, especially when based on general opinion rather than a score. This is because triage needs to balance multiple and sometimes contradictory objectives simultaneously, most of them being fundamental to personhood: likelihood of death, efficacy of treatment, patients' remaining lifespan, ethics and religion.

Etymology and origin

The term triage comes directly from French, where the term means to pick or to sort, it itself coming from the Old French verb trier, meaning to separate, sort, shift, or select; with trier in turn came from late Latin tritare, to grind. Although the concept existed much earlier, at least as far back as the reign of Maximillian I, it wasn't until the 1800s that the Old French trier was used to describe the practice of triage. That year, Baron Dominique-Jean Larrey, the Surgeon in Chief of Napoleon's Imperial Guard laid the groundwork for what would eventually become modern triage introducing the concept of "treat[ing] the wounded according to the observed gravity of their injuries and the urgency for medical care, regardless of their rank or nationality".

History

Pre-Modern History

A page of the Edwin Smith Papyrus

The Edwin Smith Papyrus

The general concept was first described in a 17th-century BCE Egyptian document, the Edwin Smith Papyrus. Discovered in 1862, outside of modern-day Luxor, Egypt, the Edwin Smith Papyrus contains descriptions of the assessment and treatment of a multitude of medical conditions, and divides injuries into three categories:

1. "A medical condition I can heal"
2. "A medical condition I intend to fight with."
3. "A medical condition that cannot be healed."

The Holy Roman Empire

During the reign of Emperor Maximilian I, during wartime, a policy was implemented where soldiers where prioritized over all others in hospitals, and the sickest soldiers received treatment first.

Modern Triage

Larrey's "flying ambulance" design.

Napoleonic Triage

Modern triage grew out of the work of Baron Dominique-Jean Larrey and Barron Francois Percy during the reign of Napoleon. Larrey in particular introduced the concept of a "flying ambulance" (flying in this case meaning rapidly moving) or in its native French, Ambulance Volante.

World War I

Triage continued to gain traction in France, and was utilized 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:

• Those who are likely to live, regardless of what care they receive;
• Those who are unlikely to live, regardless of what care they receive;
• Those for whom immediate care may make a positive difference in outcome.

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, and to improve patient safety and quality of care, several human-in-the-loop decision-support tools have been designed on top of triage systems to standardize and automate the triage process (e.g., eCTAS, NHS 111) in both hospitals and the field. Moreover, the recent development of new machine learning methods offers the possibility to learn optimal triage policies from data and in time could replace or improve upon expert-crafted models.

Vital signs defining the color-coded triage. RR: respiratory rate; SpO2: saturation of peripheral oxygen (pulse oximetry); HR: heart rate; GCS: Glasgow Coma Score; Tp: temperature. Abnormal vital signs are strong predictors for intensive care unit admission and in-hospital mortality in adults triaged in the emergency department.

Concepts in triage

Simple triage

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 a secondary or tertiary care facility, those who require low-intensity care, those who are uninjured, and those who are deceased or will be so imminently. In the United States, this most commonly takes the form of the START triage model, in Canada, the CTAS model, and in Australia the ATS model. Assessment often begins with asking anyone who can walk to walk to a designated area, labeling them the lowest priority, and assessing other patients from there. Upon completion of the initial assessment by the care provider, which is based on the so-called ABCDE approach, patients are generally labelled with there available information, including "patient’s name, gender, injuries, interventions, care-provider IDs, casualty triage score, and an easily visible overall triage category".

ABCDE Assessment

An ABCDE assessment (other variations include ABC, ABCD, ABCDEF, and many others, including those localized to non-English) is rapid patient assessment designed to check bodily function in order of importance.

Tags

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 premade 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 take a variety of forms. Some countries use a nationally standardized triage tag, while in other countries commercially available triage tags are used, which vary by jurisdictional choice. In some cases, international organizations also have standardized tags, as is the case with NATO. The most commonly used commercial systems include the METTAG, the SMARTTAG, E/T LIGHT 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.

Advanced triage

In advanced triage, those with advanced training, such as doctors, nurses and paramedics make further care determinations based on more in-depth assessments, and may make use of advanced diagnostics like CT scans. This can also be a form of secondary triage, where the evaluation occurs at a secondary location like a hospital, or after the arrival of more qualified care providers.

Reverse triage

There are a three primary concepts referred to as Reverse Triage. The first is concerned with the discharge of patients from hospital often to prepare for an incoming mass casualty. The second concept of Reverse Triage is utilized for certain conditions such as lightning injuries, where those appearing to be dead may be treated ahead of other patients, as they can typically be resuscitated successfully. The third is the concept of treating the least injured, often to return them to functional capability. This approach originated in the military, where returning combatants to the theatre of war may lead to overall victory (and survivability).

Undertriage and overtriage

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). The rate of undertriage generally varies by the location of the triage, with a 2014 review of triage practices in emergency rooms finding that in-hospital undertriaging occurred 34% of the time in the United States, while reviews of pre-hospital triage finding undertriage rates of 14%.

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.

Telephone triage

In telephone triage, care providers like nurses assess symptoms and medical history, and make a care recommendation over the phone. A review of available literature found that these services provide accurate and safe information about 90% of the time.

Palliative care

In triage, palliative care takes on a wider applicability, as some conditions which may be survivable outside of extreme circumstances become unsurvivable due to the nature of a mass casualty incident. For these patients, as well as those who are deemed to be unsavable, palliative care can mean the difference of a painful death, and a relatively peaceful one. During the COVID-19 pandemic issues of palliative care in triage became more obvious as some countries were forced to deny care to large groups of individuals due to lack of supplies and ventilators.

Evacuation

In the field, evacuation of all casualties is the ultimate goal, so that the site of the incident can ultimately be cleared, if necessary investigated, and eventually rendered safe. Additional considerations must be made to avoid overwhelming local resources, and in some extreme cases, this can mean evacuating some patients to other countries.

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.

Specific triage systems and methods

A triage sign at a Mexican emergency department indicating the waiting time for patients based on the severity of their condition

Most simply, the general purpose of triage is to sort patients by level of acuity to inform care decisions; so that the most people possible can be saved. Although a multitude of systems, color codes, codewords, and categories exist to help direct it, in all cases, triage follows the same basic process. In all systems, patients are first assessed for injuries, then, they are categorized based on the severity of those injuries. Although the number of categories differs from system to system, all have at least three in common; high severity, low severity, and deceased. Some systems involve features like scoring systems, such as the Revised Trauma Score, the Injury Severity Score, and the Trauma and Injury Severity Score, the latter of which has been shown to be most effective at determining outcome.

Triage Systems by Methodology

S.T.A.R.T. model

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 was developed at Hoag Hospital in Newport Beach, California for use by emergency services in 1983.

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 include those who aren't breathing and repositioning their airway efforts were unsuccessful.
• Immediate or Priority 1 (red) evacuation by MEDEVAC if available or ambulance as they need advanced medical care at once or within one 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 people 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 need bandages and antiseptic.

JumpSTART triage

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).

Triage Systems by Country

Australia and New Zealand

In hospital settings, Australia and New Zealand rely on the Australasian Triage Scale (abbreviated ATS and formally known as the National Triage Scale). 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).

In field settings, various standardized triage systems are used, and there is no area wide standard.

Canada

In 1995, the CAEP Triage and Acuity scale was launched in Canada relying on a simplified version of the Australian National Triage Scale. This scale used three categories, emergent, urgent, and non-urgent. This scale was deprecated in 1999 with the introduction of the Canadian Triage and Acuity Scale (CTAS), which is used across the country to sort 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 not currently used for mass casualty triage, and instead the START protocol and METTAG triage tags is used.

France

In France, the Prehospital triage in case of a disaster uses a multi-tier scale:

• Décédé (deceased), or urgence dépassée (beyond urgency)
• Extrême urgence (extreme urgency): requiring care within a half hour.
• Urgence absolue (absolute urgency): requiring care within an hour.
• Urgence relative (relative urgency): requiring care, but not immediately.
• Blessé léger (slightly injured)
• Impliqué (involved, but not directly injured)

This triage is performed by a physician called médecin trieur (sorting medic).

Germany

The German triage system uses four color codes:

Hong Kong

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 mass casualty incidents, the START triage system is used.

Japan

In Japan, the triage system is mainly used by health professionals. The categories of triage, in corresponding color codes, are:

•   Category I: Used for viable victims with potentially life-threatening conditions.
•   Category II: Used for victims with non-life-threatening injuries, but who urgently require treatment.
•   Category III: Used for victims with minor injuries that do not require ambulance transport.
•   Category 0: Used for victims who are dead, or whose injuries make survival unlikely.

Singapore

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.

In mass casualty incidents, the START triage system is used.

Spain

In Spain, there are 2 models which are the most common found in hospitals around the country:

• The Sistema Estructurado de Triaje (SET), which is an adaptation of the Model Andorrà de Triatge (MAT). The system uses 650 reasons for medical appointment in 32 symptomatic categories, that together with some patient information and basic exploratory data, classifies the emergency within 5 levels of urgency.
• The "Manchester", based on the system with the same name in the UK, use 51 reasons for consultation. Through some yes/no questions, addressed in a diagram, it classifies the emergency in 5 severities.

In mass casualty incidents, the Modelo Extrahospitalario de Triaje Avanzado (META)/Advanced Triage Out of Hospital Model system is used. META is a seven-stage system, classifying patients as: Red 1st, Red 2nd, Red 3rd, Yellow 1st, Yellow 2nd, Green, and Deceased. The system aligns with the ABCDE framework.

United Kingdom

In April 2023, the NHS and ambulance services adopted the Major Incident Triage Tool, a new triage tool that is used in mass causality incidents. This tool is a result of large multi-disciplinary review led by the NHS but its implementation became more urgent after the Manchester Arena Inquiry made it a monitored recommendation for the NHS and National Ambulance Resilience Unit to adopt.

United States

A multitude of triage systems exist in the United States, and there is no national standard. Among local, regional, state, and interstate systems, the START triage method is most commonly used.

United States Armed Forces

The U.S. armed forced utilize a four-stage system, A battlefield situation, care providers rank casualties for precedence, treat those who they can safely, and transport casualties who need it to a higher level of care, either a Forward Surgical Team or Combat Support Hospital.

The triage categories (with corresponding color codes), in order of priority, are:

Limitations of current practices

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:

• lacking the clear goal of maximizing the number of lives saved, as well as the focus, design and objective methodology to accomplish that goal (a protocol of taking the worst Immediate – lowest chances for survival – first can be statistically invalid and dangerous)
• using trauma measures that are problematic (e.g., capillary refill) and grouping into broad color-coded categories that are not in accordance with injury severities, medical evidence and needs. Categories do not differentiate among injury severities and survival probabilities, and are invalid based on categorical definitions and evacuation priorities
• ordering (prioritization) and allocating resources subjectively within Immediate and Delayed categories, which are neither reproducible nor scalable, with little chance of being optimal
• not considering/addressing size of incident, resources, and injury severities and prioritization within its categories – e.g., protocol does not change whether 3, 30 or 3,000 casualties require its use, and regardless of available resources to be rationed
• not considering differences in injury severities and survival probabilities between types of trauma (blunt versus penetrating, etc.) and ages
• resulting in inconsistent tagging and prioritizing/ordering of casualties and substantial overtriage

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:

• tremendous investment in time and money since 9/11 to develop and improve responders' triage skills
• cited benefits from standardization of triage methodology, reproducibility and interoperability, and NIMS compatibilities
• avoided capital costs for taxpayer investment in additional EMS and trauma infrastructure
• wasteful daily resource utilization and increased operating costs from acceptance of substantial levels of overtriage
• prescribed values of a statistical life and estimated savings in human lives that could reasonably be expected using evidence-based triage practices
• ongoing performance improvements that could reasonably be expected from a more objective optimization-based triage system and practices

Ethical considerations

Because treatment is intentionally delayed or withheld from individuals under this system, triage has ethical implications that complicate the decision-making process. Individuals involved in triage must take a comprehensive view of the process to ensure fidelity, veracity, justice, autonomy, and beneficence are safeguarded.

Ethical implications vary between different settings and the type of triage system employed, culminating in no single gold-standard approach to triage. Emergency departments are advised 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.

There is widespread agreement among ethicists that, in practice, during the COVID-19 pandemic triage should prioritize "those who have the best chance of surviving" and follow guidelines with strict criteria that consider both short-term and long-term survivability. Likewise, the triage of other health services has been adjusted during the pandemic to limit resource strain on hospitals.

Utilitarian approach and critique

Under the utilitarian model, triage works to maximize the survival outcomes of the most people possible. This approach implies that some individuals may likely suffer or die, in order for the majority to survive. Triage officers must allocate limited resources and weigh an individual's needs along with the needs of the population as a whole.

Some ethicists argue the utilitarian approach to triage is not an impartial mechanism, but rather a partial one that fails to address the social conditions that prevent optimal outcomes in marginalized communities, rendering it a practical but inadequate means of distributing health resources.

Special population groups

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 to 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.

Proposed frameworks in conflict

A variety of logistical challenges complicate the triage and ultimate provision of care in conflict situations. Humanitarian actors acknowledge challenges like disruptions in food and medical supply chains, lack of suitable facilities, and existence of policies that prohibit administration of care to certain communities and populations as elements that directly impede the successful delivery of care. The logistical realities of humanitarian emergencies and conflict situations threatens the bioethical principle of beneficence, the obligation to act for the benefit of others.

Technical challenges of triage in conflict settings

To address the ethical concerns that underpin triage in conflict situations and humanitarian crises, new triage frameworks and classification systems have been suggested that aim to uphold human rights. Scholars have argued that new frameworks must prioritize informed consent and rely on established medical criteria only in order to respect the human rights considerations set forth by the Geneva Convention of 1864 and the Universal Declaration of Human Rights, but no comprehensive triage model has been adopted by international bodies.

Veterinary triage

Emergency veterinarian Jessica Fragola wrote in 2022 about the ethics of animal triage. She said that pressures on veterinarians having been exacerbated by staffing shortages that resulted from the Covid pandemic, coupled with growth in spending on veterinary care and on pet insurance.

See also

External links

• The dictionary definition of triage at Wiktionary
• Media related to Triage at Wikimedia Commons