Triage is the process of sorting multiple casualties by the severity of their injuries to ensure that limited medical resources are used to save the greatest number of lives. In a mass casualty incident (MCI), the goal shifts from “doing everything for every patient” to “doing the most good for the most patients.”

AED defibrillator used in triage during mass casualty incidents — Triage is the systematic sorting of patients based on injury severity to allocate limited resources effectively in mass casualty incidents. Source: Unsplash.

Core Principle of Triage

In everyday emergencies, a single patient receives all available resources. In a mass casualty incident, resources (personnel, equipment, transport) are overwhelmed. Triage prioritizes patients who can benefit most from immediate intervention while deferring care for those who can wait and providing comfort for those who cannot survive.

Triage Categories — The Four-Level System

Immediate (RED). Life-threatening injuries that require immediate intervention to save life. These patients have the best chance of survival with rapid treatment. Examples: airway obstruction, tension pneumothorax, uncontrolled hemorrhage (tourniquet-amenable), open fractures with vascular compromise, shock, severe burns with airway involvement.

Delayed (YELLOW). Serious injuries that require medical care but can safely wait 45-60 minutes without immediate threat to life. Examples: stable open fractures, large soft-tissue wounds with controlled bleeding, burns without airway compromise, major amputations with controlled bleeding, spinal injuries.

Minimal (GREEN). “Walking wounded” — minor injuries that do not require immediate medical attention. These patients can often help with light tasks or wait until more urgent cases are addressed. Examples: minor cuts and bruises, sprains and strains, minor burns (superficial, small area), anxiety or psychological distress.

Expectant (BLACK). Catastrophic injuries with very low probability of survival given available resources. These patients receive comfort care but not aggressive treatment when resources are scarce. Examples: massive head trauma with brain matter visible, cardiac arrest (in MCI context), burns covering more than 90% body surface area, signs of death (rigor mortis, dependent lividity, decapitation, decomposition).

⚠ Caution

Triage is a dynamic process — patients may worsen or improve, requiring reassignment to a different category. A GREEN patient with seemingly minor injuries may deteriorate internally and become RED. A RED patient who worsens beyond hope of survival may become BLACK. Continuous reassessment is essential. Triage should be repeated whenever resources (new personnel, additional transport) become available or when a patient’s condition changes.

CPR training for triage responders — CPR training prepares responders to provide life-saving care during triage and mass casualty incidents. Source: Unsplash.

The START System

The Simple Triage and Rapid Treatment (START) system was developed for use by first responders in MCIs. It is designed to be completed in under 60 seconds per patient. Patients are assessed using the RPM mnemonic: Respirations, Perfusion, Mental Status.

Step 1 — Respirations

First, determine if the patient is breathing. If not, open the airway (head-tilt/chin-lift). If still not breathing, tag the patient BLACK (expectant). Do not begin rescue breathing in a START-based MCI (resources are too limited). If breathing is present, assess the respiratory rate: rate more than 30 breaths per minute → RED (immediate); rate less than 30 breaths per minute → proceed to perfusion check.

Step 2 — Perfusion

Check for a radial pulse (at the wrist). If no radial pulse (indicating hypotension), tag the patient RED (immediate). If radial pulse is present, check capillary refill: press the fingernail or the thenar eminence for 2 seconds. If refill takes longer than 2 seconds, tag RED. If refill is less than 2 seconds, proceed to mental status.

Step 3 — Mental Status

Ask the patient a simple command: “Open your eyes” or “Squeeze my hand.” If the patient does not respond or responds inappropriately (confused, disoriented), tag RED. If the patient can follow commands appropriately, assess further for injuries and tag YELLOW (delayed) or GREEN (minimal/ambulatory).

START Summary

RED (Immediate): RR > 30, or no radial pulse / capillary refill > 2 seconds, or unable to follow commands
YELLOW (Delayed): RR < 30, radial pulse present, can follow commands — but cannot walk
GREEN (Minimal): Can walk and follow commands — “walking wounded”
BLACK (Expectant): Not breathing after airway opening, or obviously fatal injuries

The SALT Triage System

The SALT (Sort, Assess, Life-saving interventions, Treatment/Transport) system is a newer, more comprehensive triage framework endorsed by the CDC and American College of Emergency Physicians. It adds a life-saving intervention step before final category assignment.

Step 1 — Sort (Global Sorting)

Ask all patients who can walk to move to a designated area (GREEN). Wave your hand and call out. Those who move are tagged GREEN (minimal). Those who do not move need further assessment.

Step 2 — Assess (Individual Assessment)

For each patient who cannot walk, assess: airway and breathing, perfusion (radial pulse, capillary refill), and mental status (ability to follow commands). If the patient is not breathing after opening the airway → BLACK.

Step 3 — Life-Saving Interventions (LSI)

Before assigning the final triage category, perform one or two rapid, simple interventions that could shift the patient from a fatal to salvageable category. LSIs include: control major hemorrhage with tourniquet, open the airway with a jaw thrust or simple adjunct, relieve tension pneumothorax with needle decompression (if trained), and administer antidote (e.g., naloxone for opioid overdose).

Step 4 — Treatment and Transport Assignment

After SALT, assign the patient to a triage category (RED, YELLOW, GREEN, or BLACK) using the same criteria as START but with the benefit of having performed LSIs first.

Incident Command and Scene Safety

Triage does not begin until the scene is safe. The first arriving unit establishes incident command and conducts a scene size-up. Key steps: ensure scene safety (do not become a victim), call for additional resources (activate the MCI plan), designate a triage officer (usually the first medically trained responder), establish a treatment area (collection point), establish a transport area (ambulance loading zone), begin triage using the chosen system, and document patient counts and triage categories.

JumpSTART for Pediatric Triage

The JumpSTART system modifies START for children ages 1-8 years. Children have different physiology and may be triaged inappropriately by adult systems. Modifications: respirations: RED if RR is < 15 or > 45 (or apneic with pulse present — give 5 rescue breaths and reassess), perfusion: same as START (radial pulse or capillary refill), mental status: use AVPU (Alert, Verbal, Pain, Unresponsive) instead of ability to follow commands; RED if the child does not respond to verbal stimuli. Children who are apneic but have a pulse receive 5 rescue breaths in JumpSTART (unlike adult START, where apneic = BLACK). This accounts for primary respiratory arrest (common in children) vs. primary cardiac arrest (common in adults).

Practical Triage Decision-Making

Common Challenges

Over-triage. Assigning a patient to a higher category than needed (e.g., tagging a YELLOW as RED). This is better than under-triage (it allows for deterioration), but excessive over-triage depletes resources for truly critical patients. Acceptable over-triage rate in MCIs: up to 50%.

Under-triage. Assigning a patient to a lower category than needed (e.g., tagging a RED as YELLOW). This is dangerous — a patient who needs immediate care may not receive it. Under-triage should be minimized to less than 5%.

Primary vs. secondary triage. Primary triage occurs at the scene (field triage). Secondary triage occurs at the casualty collection point or treatment area, where more detailed assessment and re-categorization can occur.

Emotional toll. Triage decisions are psychologically stressful. Making the decision to tag a patient as BLACK (expectant) conflicts with the rescuer’s instinct to help everyone. If possible, rotate personnel through high-stress roles. Debriefing after the incident is important.

⚠ Clinical Correlation

The most common triage errors in mass casualty incidents: spending too much time on a single patient (the goal is < 60 seconds per patient with START), failing to reassess and re-categorize patients as conditions change, neglecting scene safety (entering a hazardous area before it is secured), under-triaging elderly patients (age-related physiological changes can mask shock — an elderly person may appear stable despite significant internal bleeding), and forgetting documentation (using triage tags, recording patient counts, tracking transport destinations). Documentation becomes critical for family reunification and hospital resource planning.

Summary

Triage is the systematic sorting of multiple casualties to maximize survival. The START system (Respirations, Perfusion, Mental Status) provides rapid assessment in under 60 seconds per patient. The SALT system adds life-saving interventions before final category assignment. Categories are Immediate (RED), Delayed (YELLOW), Minimal (GREEN), and Expectant (BLACK). Pediatric patients require modified triage using JumpSTART. Scene safety, incident command, continuous reassessment, and documentation are essential components of effective MCI management. Triage is not about deciding who lives and dies — it is about making the best use of limited resources.