Deciding which patients to evacuate first during a disaster or mass casualty incident (MCI) shifts away from typical medical priorities. Triage is necessary when the number of injured individuals overwhelms available resources, such as medical personnel, equipment, and transportation capabilities. The objective is to make rapid, life-saving decisions to prevent further loss of life. This systematic prioritization must be executed quickly to clear the scene and facilitate the transfer of patients to a higher level of care.
The Core Principle of Evacuation Prioritization
Evacuation prioritization fundamentally differs from the triage encountered in a typical hospital emergency room. In a daily setting, the goal is to provide the best possible outcome for every individual patient, starting with the most critically ill. During a disaster, the strategy must change to maximize the overall number of survivors, often summarized as “doing the greatest good for the greatest number.” This requires a pragmatic allocation of limited time and resources.
The focus shifts from treating the most severely injured person to identifying patients who have the highest probability of survival with simple, immediate intervention. Patients severely injured but unlikely to survive, even with extensive care, are often deferred. This prevents consuming resources that could save multiple other lives, allowing responders to concentrate on those who are salvageable.
Assessing Patients Using Triage Categories
To achieve rapid and standardized assessment, responders utilize simple triage methods to assign patients into one of four primary categories based purely on their medical status. These categories dictate the order in which patients will be moved from the incident scene to definitive care.
- Immediate (Red Tag): Reserved for patients with life-threatening injuries who can be saved by rapid intervention. This group includes individuals with conditions like shock, easily correctable airway compromise, or uncontrolled hemorrhage.
- Delayed (Yellow Tag): Consists of patients who have serious injuries but whose condition is stable enough to wait a few hours without an immediate threat to life. This includes significant non-life-threatening injuries, such as major fractures without severe bleeding.
- Minor (Green Tag): Includes the walking wounded who have minor injuries and can often care for themselves. These patients are the last to be evacuated based on their medical severity.
- Expectant (Black Tag): Assigned to patients who are either deceased or have catastrophic injuries making survival highly unlikely. Triage principles dictate that no resources should be used on Expectant patients until all Immediate and Delayed patients have been treated and evacuated.
The actual evacuation order often prioritizes the Immediate (Red) and Delayed (Yellow) patients. However, the Minor (Green) patients may be moved first to clear the area and make resources available.
Situational Factors That Override Medical Status
While medical status is the initial determinant, external circumstances frequently force a modification of the standard triage-based evacuation order. The most compelling factor that overrides a patient’s medical tag is an immediate threat to life from the environment. A patient with only a minor injury (Green tag) who is trapped near a spreading fire, a collapsing structure, or a hazardous material spill must be moved first, before a more severely injured patient (Yellow tag) who is in a secure, safe location.
Logistical constraints and the nature of the available transport also play a significant role in determining the evacuation sequence. If resources are limited, the decision may favor the patient who requires the least time and effort to move. The ability of a patient to move themselves is a powerful prioritization tool, often leading to the Minor (Green) patients being moved first to clear the scene. This action efficiently frees up rescue personnel to focus on the non-ambulatory patients who require assisted transport.