Triage

In medicine, triage 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 usually relied upon when there are more injured individuals than available care providers, 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. 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 triage, meaning the action of picking or sorting, it itself coming from the Old French verb, meaning to separate, sort, shift, or select; with 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 was not 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 the wounded according to the observed gravity of their injuries and the urgency for medical care, regardless of their rank or nationality".

Concepts in triage

Simple triage

Simple triage is usually used in a scene of an accident or "mass-casualty incident", in order to sort patients into those who need critical attention and immediate transport to a secondary or tertiary care facility to survive, those who require low-intensity care to survive, 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 their 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 is rapid patient assessment designed to check bodily function in order of importance.

Letter	Term	Meaning
A	Airway	Checking for airway obstruction
B	Breathing	Checking if the patient is breathing and if the breathing is normal
C	Circulation	Checking to see if the heart rate and capillary refill time is normal
D	Disability	Checking the patient's alertness, awareness, and response to painful stimuli
E	Exposure	Checking the patient for trauma, bleeding, temperature, and other skin signs

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 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.

Undertriage and overtriage

Undertriage is underestimating the severity of an illness or injury. An example of this would be categorizing a Priority 1 patient as a Priority 2 or Priority 3. 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 patient as a Priority 2 or Priority 1. 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.

Pre-modern history of triage

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:

"A medical condition I can heal"
"A medical condition I intend to fight with."
"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 were prioritized over all others in hospitals, and the sickest soldiers received treatment first.

Modern history of triage

Napoleonic triage

Modern triage grew out of the work of Baron Dominique-Jean Larrey and Pierre-François Percy during the reign of Napoleon. Larrey in particular introduced the concept of a "flying ambulance" or in its native French, Ambulance Volante.