Triage is the systematic process of sorting patients to determine the order and priority for receiving medical treatment when the number of injured or ill individuals exceeds the available resources. This methodology ensures that the most critically ill patients are seen first. In the emergency department, triage facilitates efficient patient flow and directly impacts patient outcomes by reducing delays to care for those in most need.
Foundational Principles of Patient Assessment
The initial assessment performed by the triage provider is designed to be extremely rapid to identify immediate life threats. This process begins with a quick visual scan, the “first look,” to observe the patient’s general appearance, mental status, and obvious signs of distress, such as difficulty breathing or severe bleeding. The provider collects the Chief Complaint, which is the patient’s primary reason for seeking care, providing immediate context for the severity of their condition.
The provider then rapidly evaluates the patient using the universally recognized primary survey framework, focusing on Airway, Breathing, and Circulation (ABCs). An open and protected airway is assessed first, followed by the quality and rate of breathing, as compromise in either area can lead to rapid deterioration. Circulation assessment includes checking for a pulse, evaluating skin color and temperature, and controlling any significant external hemorrhage.
Mental status is simultaneously assessed using a simple scale to determine if the patient is Alert, responsive to Voice, responsive only to Pain, or Unresponsive (AVPU). Any deviation from alertness is a significant indicator of a potential life-threatening problem. The identification of any compromise in the ABCs or a severe alteration in mental status is the immediate determinant for assigning the highest priority for treatment.
Standardized Prioritization Scales
In the structured setting of a hospital emergency department, standardized prioritization scales are used to assign a treatment acuity level. Modern systems typically employ a five-level model, which offers greater reliability and validity in classifying patient urgency compared to older three-level systems. This multi-level approach allows for a more granular distinction between patients who require immediate physician intervention and those who can safely wait.
Assignment of a specific triage level is driven by the presence of an immediate life threat or high-risk situation, and the prediction of necessary hospital resources. Patients who show signs of hemodynamic instability or severe pain are automatically assigned to the most urgent levels. For example, a patient with chest pain suggestive of a heart attack or a respiratory rate severely outside the normal range would be categorized at the highest level.
For patients who do not present with an immediate life threat, the triage decision relies on estimating the number of hospital resources they will consume, such as laboratory tests, X-rays, or intravenous fluids. A patient likely needing two or more resources may be placed in a more urgent category than a patient only requiring a single resource, like a simple prescription. This resource-driven component helps manage departmental flow by clustering similar patients and anticipating bed space and staff needs.
The five levels are designed to correlate with an expected maximum safe waiting time for a physician evaluation, ensuring that urgency is translated into a time-based protocol. The least urgent category is reserved for patients with minor, non-life-threatening injuries who require no resources and can safely wait the longest. This systematic process ensures that all patients are placed into a clear queue based on the severity of their medical condition.
Triage During Mass Casualty Events
Triage during a Mass Casualty Event (MCI) shifts its philosophy from providing maximum care to a single patient to achieving the “greatest good for the greatest number” of people. This means resources are rationed to maximize the number of survivors in a resource-strained environment. Field-based systems must be executed rapidly, with minimal treatment provided before classification and transport.
The Simple Triage and Rapid Treatment (START) system is one of the most widely used methods for MCI triage, classifying patients into four distinct categories identified by color-coded tags. The first step in START is asking all individuals who can walk to move to a designated safe area. Non-ambulatory patients are then quickly assessed based on their respiration, perfusion, and mental status.
The four categories are:
- Red (Immediate): Patients have life-threatening injuries requiring rapid intervention but have a high probability of survival if treated promptly. This group includes individuals with a respiratory rate above 30 breaths per minute or those who cannot follow simple commands.
- Yellow (Delayed): Patients have serious injuries that are not immediately life-threatening; they can wait for treatment until the Red patients have been addressed.
- Green (Walking Wounded): These are the lowest priority for immediate transport, reserved for individuals who are ambulatory.
- Black (Expectant): Reserved for those who are deceased or have injuries so severe that survival is unlikely even with maximal resources. This difficult determination ensures that limited medical resources are not diverted, allowing those with a better prognosis to receive life-saving care.