First On Scene at the Mass Casualty Incident

By Barry Bouwsema

Potentially, sometime in every emergency responder’s career, he may be faced with the emergency call where the needs of situation overwhelm the resources available. Whether it is a bus crash, building collapse, or hurricane, if there are more injured patients than there are responders, the scene can be considered a mass casualty incident (MCI). Creating order out of chaos is not an easy task, but having an organized approach can go far in making a bad situation better.

On arriving on the scene of a MCI, the first-due unit has the extremely important task of creating an organized structure for mitigating the incident. Taking a visible command role and effectively communicating the situation and needs will go far in helping to create order out of chaos. The first-arriving unit should give a verbal report on the scene size-up to incoming resources. The first unit in should also assume and announce command, confirm the location of the incident, and then begin with the Five Ss, an easy mnemonic to help remember key items in handling an MCI scene. They are as follows:

    Safety Assessment. Assess the scene, observing for:
  • Electrical hazards.

  • Flammable liquids.

  • Hazardous Materials/Dangerous Goods.

  • Other life-threatening situations.

    Size up the scene. How big and how bad is it? Survey incident scene for:
  • Type, nature and cause of incident.

  • Approximate number of casualties.

  • Severity level of injuries (major or minor).

  • Area involved, including problems with scene access.

    Send information:
  • Contact the dispatch with your size-up information.

  • Request additional resources.

    Set up the scene for management of the casualties:
  • Establish a casualty collection area (CCA).

  • Establish staging (if required).

  • Identify access and egress routes.

  • Establish hazard control zones (as appropriate)

  • Identify adequate work areas for triage, treatment, and transport.

    Start triage:
  • Begin where you are.

  • Ask anyone who can walk to move to the designated CCA.

  • Use surveyor’s tape or triage tags to mark patients.

  • Move quickly from patient to patient.

  • Maintain a patient count.

  • Provide only minimal treatment.

  • Keep moving!

During a mass casualty incident, operational procedures are designed to organize a response to a specific incident or need, with efficiency as the goal. Normal patient care procedures are relatively inefficient in terms of speed and resource commitment in an MCI situation. If these same procedures are used in a multiple or mass casualty event, they result in unacceptably long times to clear all patients from the emergency scene. Therefore, an MCI requires using emergency triage procedures to reduce provider-to-patient ratios and transport multiple patients per ambulance unit; for successful scene management and improved patient outcomes.

Failure to use an organized approach to an MCI can result in several problems, including the following:


  • Inappropriate use of vital resources.

  • Failure to transport the most critically injured patients first.

  • Incorrect scene management in which triage is based on emotional, not objective criteria.

  • Victims remaining on scene for extended periods of time, and

  • Worker dissatisfaction resulting from chaotic instead of organized scene.

Proper triage is a crucial step that helps prevent these problems. Several different triage methods are available to help the emergency responder make these difficult decisions; one of the most common triage systems is the Simple Triage and Rapid Treatment (START) method.

Proper handling of an MCI requires a systematic approach to the triage, treatment, and rapid transport of multiple casualties. This type of response requires a change in the normal operating procedure to achieve the greatest good for the greatest number of casualties without expending an inordinate amount of limited resources. The basic principles applied in the handling of an MCI include the following:


  1. Achieve the greatest good for the greatest number.

  2. Make the best use of personnel, equipment, and facility resources.

  3. Do not relocate the disaster.

Handling the MCI scene can be overwhelming for many emergency responders. Hopefully, having the proper procedures in place prior to the incident can avoid many of the anticipated problems.

Barry Bouwsema is a fire officer and paramedic with the Strathcona County Emergency Services in Alberta, Canada, with 21 years of experience in the field.

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