The Basics of Mass Casualty Triage

“Ambulance 206 is on scene, Highway 227 and mile marker 154. There are two vehicles with significant damage-stand by.”

“Dispatch Ambulance 206, update on last transmission, there are three additional cars off the road, down the embankment. There are a total of five vehicles involved that we’re aware of. Please send additional ambulances.”

You park the ambulance behind the first vehicle. As you exit, you’re approached by a state patrol officer who reports a driver entered into oncoming traffic, sparking a chain reaction of collisions.

There’s significant damage to several of the vehicles. Two EMS providers are on scene, and a fire apparatus and other ambulances¬†are on the way. A helicopter’s on standby, but as of now, you and your partner are alone. Where do you begin?

The first action is to establish that the scene is safe. In this case, there’s a concern for other traffic, unstable vehicles or spilled fuel. Call for resources as necessary to manage unsafe scenes as soon as they’re identified. Management of many of those tasks can be turned over to police and firefighters.

Patient Assessment

After the scene is determined to be safe, providers at a mass casualty incident (MCI) must analyze the number and severity of patients. Triage identifies the most severely injured patients with the greatest chance of surviving. This means that when you’re dealing with multiple patients and limited resources, there may be a patient who appears to be the most severely injured (e.g., they have agonal breathing and a head injury with exposed brain matter), but their chance of survival is lower compared to the others.

Patients with severe injuries that are less life-threatening should be cared for and transported first. There are different models that can be used to triage MCIs, such as START (Simple Triage and Rapid Treatment) and SALT (Sort, Assess, Lifesaving Interventions, Treatment/Transport).

Regardless of the system used, the primary goal is to quickly sort patients into transport categories and identify each of them with triage tags, colored tape or other means.

Red is commonly used to identify patients who must be transported immediately. Yellow is typically used to identify patients who are urgent, but could be transported in a second group. Green tags indicate non-life-threatening injuries, and black or grey tags identify patients who are found to be deceased.


Triage can be difficult because minimal treatment is provided throughout the process. For example, when a patient is discovered to be breathing shallow and slow, the provider should make an attempt to open and clear the airway. If the patient doesn’t begin to breathe adequately on their own, they’re labeled as expectant and the provider should move on to the next patient. This is counterintuitive to what EMS providers have learned and may want to do, but during an MCI, the greatest good needs to be offered to the greatest amount of people.

With more resources on the way, it must be determined where the arriving vehicles should stage. Freelancing without direction on an MCI scene will only create confusion. As an arriving EMS crew, you should go where you’re directed, not where it looks like you should go. The crew on scene, which is often referred to as “command,” has a better idea of what’s happened and what needs to be done.

Establishing where the injured patients will be moved to await transport is also necessary. On smaller scenes with multiple patients, arriving ambulance crews can be directed to a specific vehicle to find their patient. With larger events, a treatment area and loading area should be determined. Within this area, patients who’ve been triaged can be moved to await transport. During this time, some initial treatment can be established.

In addition to overwhelming prehospital services, an MCI can overwhelm local hospitals. Once an event has been identified, local hospitals should also be notified too. This will give them additional time to prepare to receive multiple injured patients.


The World Health Organization describes MCIs as disasters and major incidents characterized by a quantity, severity and diversity of injuries in patients that can rapidly overwhelm the ability of local medical resources to deliver comprehensive and definitive medical care. It’s good to review, learn from and use major events to prepare for potential future ones. Remember that an MCI could happen on any day in your hometown, veiled in the dispatch of an everyday call. Be safe, and be prepared.

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