A mass casualty incident (MCI) is defined as an event where the number and severity of injured individuals rapidly overwhelm the capacity of local medical services and resources. In these high-stress situations, the timing of patient transport requires a careful balance between the urgent need for definitive care and the necessity of a stable, organized scene. Moving patients too quickly can lead to chaos at receiving hospitals and inefficient use of limited ambulances. Conversely, delaying transport can result in preventable deaths among the most severely injured. The decision to begin movement is a controlled process, dependent on the completion of initial assessment and the readiness of the logistical support system.
Establishing Scene Control and Triage
The foundation for all subsequent actions in an MCI, including transport, rests on the rapid establishment of an organizational framework known as the Incident Command System (ICS). This structure designates a Medical Sector Officer, who then assigns specialists, such as Triage and Treatment Sector Officers, to manage the patient population. The Triage Officer is responsible for the immediate, on-scene sorting of victims to categorize injury severity and determine priority for care.
The Simple Triage and Rapid Treatment (START) methodology is a widely used system to quickly assess a patient’s breathing, circulation, and mental status, assigning them one of four color-coded categories. This systematic tagging ensures every patient is accounted for and categorized before any movement is considered.
- Red (Immediate): Patients have life-threatening injuries that require rapid intervention and transport for survival.
- Yellow (Delayed): Patients have serious injuries but can tolerate a wait of several hours before transport.
- Green (Minor): These patients, often called the “walking wounded,” have minor injuries and can move themselves to a designated collection area.
- Black (Deceased/Expectant): Tags are given to those who are deceased or whose injuries are so severe that survival is unlikely given the limited resources of the MCI.
Operational Triggers for Transport Initiation
Transport of the injured should begin when two primary operational conditions are met and confirmed by the Incident Commander or Operations Section Chief. The first condition is the completion of primary triage for all patients, focusing on identifying and stabilizing the most immediate Red-tagged patients. This step ensures that the highest priority patients are ready for movement and that their clinical needs are known.
The second condition is the confirmation that adequate transport resources have arrived, are staged in a secure area, and are ready for deployment. This readiness includes the assignment of a Transport Group Supervisor (TGS), whose function is to manage the flow of ambulances and patients. The TGS must have a secured transport corridor and a dedicated loading zone established to ensure efficient and safe movement.
The critical trigger for transport is the explicit command issued by the Incident Commander to the TGS to initiate patient movement. This command typically coincides with the first Red-tagged patient being physically ready to load into an ambulance. Waiting for this formal command prevents self-dispatching by ambulance crews and ensures that the entire system, from scene to hospital, is synchronized and prepared to receive the incoming surge of patients.
Prioritizing Patient Flow and Destinations
Once the transport operation has been formally initiated, patient movement must adhere to a strict prioritization based on the initial triage categories. Red (Immediate) patients must be transported first, as their survival depends on rapid access to definitive surgical or medical care at a hospital. They are followed by Yellow (Delayed) patients, whose condition is serious but stable enough to withstand a delay in transport.
The logistical flow is managed through a dedicated Transport Sector, which includes an ambulance staging area and a separate, secured loading zone. Ambulances are called from staging to the loading zone by the Transport Group Supervisor only when a patient is ready for loading, preventing congestion and maximizing efficiency. The supervisor also coordinates with a Hospital Notification Officer to assign each patient a specific destination based on facility capacity and the patient’s specialty care needs.
Green (Minor) patients are transported last, often in a group using non-ambulance vehicles such as buses, or released with instructions for self-care. This strategy reserves the limited, high-acuity transport resources for the Red and Yellow patients who require paramedic monitoring during transit.
Conclusion of Transport Operations
The transport phase of an MCI concludes when a specific operational benchmark is reached, signaling that the immediate medical emergency at the scene has passed. This benchmark is typically the point at which all viable patients (Red, Yellow, and Green) have been successfully moved from the incident scene. At this time, the focus shifts to demobilization and final accountability.
Once the last viable patient has departed, the remaining Black-tagged patients are addressed according to jurisdiction-specific fatality management procedures. The Transport Group Supervisor conducts a final accountability check to confirm that all patients assigned for transport were successfully moved and that all responding resources are accounted for. This administrative closure is essential for compiling the necessary documentation for the overall incident report.