A mass casualty incident (often shortened to MCI and sometimes called a multiple-casualty incident or multiple-casualty situation) is any incident in which emergency medical services resources, such as personnel and equipment, are overwhelmed by the number and severity of casualties. For example, an incident where a two-person crew is responding to a motor vehicle collision with three severely injured people could be considered a mass casualty incident. The general public more commonly recognizes events such as building collapses, train and bus collisions, earthquakes and other large-scale emergencies as mass casualty incidents. Events such as the Oklahoma City bombing in 1995 and the September 11 attacks in 2001 are well-publicized examples of mass casualty incidents.
Declaration of an MCI
A mass casualty incident will usually be declared by the first arriving unit at the scene of the incident, though it can be declared by a dispatcher based on the information available from people who call an emergency number, such as 9-1-1 in the US, about the incident. A formal declaration of an MCI is usually made by an officer or chief of the agency in charge. Initially, the senior paramedic at the scene will be in charge of the incident, but as additional resources arrive, a senior officer or chief will take command, usually using an incident command system structure to form a unified command to run all aspects of the incident. In the United States, the Incident Command System is known as the National Incident Management System (NIMS), and according to the Federal Emergency Management Agency, "NIMS provides the template for the management of incidents."
Agencies and responders
A mass casualty incident can involve many and varied types of responders and agencies, including (but not limited to) the ones listed here:
- Certified first responders may be part of local emergency medical services or may arrive on their own. They will assist with all aspects of patient care, including triage and treatment at the scene, and transport from the scene to the hospital.
- Paramedic and emergency medical technician (EMT) personnel may arrive in ambulances, in their personal vehicles, or from another agency. They will have the lead in all aspects of patient care as assigned by the medical officer or incident commander.
- Ground ambulances will be assigned to the transport sector to transport patients and personnel to and from the incident scene, emergency departments of hospitals, and a designated helipad. These may be municipal services, volunteer services or from private corporations.
- Air ambulances will transport patients from the scene or from designated helipads to receiving hospitals.
- Firefighters will perform all initial rescue related operations, as well as fire suppression and prevention. They may also provide medical care if they are trained and assigned to do so. They may arrive on a fire truck, in their personal vehicles, or from another agency. Many areas near airports will have automatic mutual aid agreements with airport fire departments in the event of a plane crash outside of the airport boundaries.
- Police officers will secure the scene to ensure that only properly authorized people are present to ensure safety and smooth operation.
- Specialized rescue teams may be part of the local fire department; they may be dispatched and associated with the state, provincial, or federal governments; or they may be privately operated teams. These teams are specialists in specific types of rescue, such as Urban search and rescue (USAR) or Confined Space Rescue.
- Utility Services are responsible for ensuring that utilities to the area are turned off as necessary in order to prevent further injury or damage at the scene.
- HazMat teams are responsible for cleaning up and neutralizing any hazardous materials at the scene. Sometimes these will be specialized CBRNE (chemical, biological, radiological, nuclear and high-yield explosives) teams.
- Hospitals with emergency departments will have a mass casualty incident protocol which they initiate as soon as they are notified of a mass casualty incident in their community. They will receive all of the injured and have preparations in place to do so, including calling in more staff, pulling extra and spare equipment out of storage, and clearing non-acute patients out of the hospital. Some hospitals will send doctors to the scene of the incident to assist with triage, treatment, and transport of injured persons to the hospital.
- Railways and transportation agencies will be notified if an incident involves their tracks or right-of-way, or if they are required to cease operations in and through affected areas. Transportation agencies will provide buses for transportation of lightly injured people to the hospital, as well as to provide shelter at the scene if required.
- The media play an important role in keeping the general public informed about the incident and in keeping them away from the incident area.
- Non-governmental organizations such as St. John Ambulance, the Order of Malta, the Red Cross, the Red Crescent and the Salvation Army will provide valuable assistance with all aspects of a mass casualty incident including trained medical staff, vehicles, individual registration and tracking, temporary shelter, food service, and many other important services.
- National Guard Units have medics specifically trained in mass-cassualty triage and may be called in to respond to a disaster related incident.
This is not an exhaustive list, and many other agencies and groups of people could be involved in a mass casualty incident.
Flow of an MCI
Once an MCI has been declared, a definite and well co-ordinated flow of events will occur, using three separate phases: triage, treatment, and transportation.
As soon as additional crews are en route to the emergency, the first-arriving crew will conduct triage. Pre-hospital emergency triage generally consists of a check for immediate life-threatening concerns, usually lasting no more than one minute per patient. In North America, the START system (Simple Triage and Rapid Treatment) is the most common and considered the easiest to use. This system checks three things: breathing, circulation, and consciousness and, based upon the medical responder's findings, assigns each casualty to one of four colour-coded triage levels. "Walking Wounded" or "Green Tagged" is the second-lowest level of triage, and is assigned to those with minor injuries who can get out of the incident area and to a treatment area under their own power. "Delayed Treatment" or "Yellow Tagged" is the next highest level of triage, and is assigned to those who have non-life-threatening injuries, but cannot get to a treatment area under their own power. "Immediate Treatment" or "Red Tagged" is the highest level of triage, and is assigned to those with major life-threatening injuries who are salvageable. That is to say people who need immediate advanced care, but can wait until additional crews arrive. The lowest level of triage is called "Dead/Non-Salvageable" or "Black Tagged" and is assigned to those who are obviously deceased, or whose injuries are so severe that care rendered to them would require more effort than is practical. For example, a patient who needed cardiopulmonary resuscitation (CPR) or artificial respiration would be classified as "Dead/Non-Salvageable" because their care would mean that at least one responder would have to treat them and not be able to assist other people. This obviously poses some serious moral and ethical issues for emergency responders who respond to mass casualty incidents as they must make a determination as to who does and does not receive treatment. While treatment is not the priority during this phase, when triaging, responders will attempt to ensure a patent airway, and provide short-term interventions for injuries such as a major bleed. Triage can usually be accomplished by a small group of responders, usually the first two or three crews on-scene. When responding to a chemical or biological incident it is crucial to establish safety zones. One of the first things that should be determined is the clean zone. The clean zone should be roughly 200–300 yards from the incident and uphill and upwind from the incident. Clean zones are also known as cold zones. Cold zones is considered a safe zone and is usually where incident command is established. The hot zone is the contaminated zone and the warm zone is where decontamination occurs. The warm zone should remain at least 50 yards up hill up wind from the cold zone. These zones should be clearly identified and with engineer tapes, lights, or cones. All responders and patients must leave the hot zone in designated pathways into the warm zone where they will be decontaminated. A designated officer should be posted at the hot zone and warm zone to make sure all contaminated personal are treated and decontaminated before entering the cold zone.
Once casualties have been triaged, they can then be moved on to their appropriate treatment areas. Unless a patient is Green Tagged, litter bearers will have to transport patients from the incident scene to more secure and safe treatment areas located nearby. These treatment areas will always be within walking distance and will be staffed by appropriate numbers of properly certified medical personnel and support people. The litter bearers do not have to be advanced medical personnel; their role is to simply place casualties onto carrying devices such as a portable stretcher (such as a Ferno #9), wheeled stretcher (such as a Ferno 35X or Stryker MXPRO), emergency litter (such as a pole stretcher), or other carrying device (such as a scoop stretcher or backboard for patients with spinal injuries) and carry them to the appropriate treatment area. Casualties should be transported in order of treatment priority, with Red Tagged patients being transported first, followed by Yellow-Tagged, Green-Tagged, and finally Black-Tagged. Treatment areas are often defined by coloured tarpaulins, flagging tape, signs, or tents, and each level of care receives its own treatment area (i.e. Red Tagged patients are not treated in the Green Tagged treatment area). Upon arrival in the treatment area, the casualties are re-assessed and their injuries are given initial treatment to stabilize them until they can be released (in the case of green-tagged casualties), transported for further treatment (in the case of red and yellow tagged casualties), or transported to the morgue or medical examiner's facility (in the case of black tagged casualties). Treatment areas can be staffed by any combination of First Responders, Emergency Medical Technicians, Paramedics, Nurses, Doctors, and Firefighters; depending on the area, available personnel on-scene and the training/experience of those available.
In some mass casualty incidents, it is necessary to have an on-site morgue to handle the bodies of the deceased persons at the scene while awaiting transfer to a permanent morgue, or when the deceased persons have to be removed in order to access those who are injured. When this is used, care and consideration is given to respect for the deceased, family members, the public at the scene, and the responders at the scene. Most often, this is set up on the far side of the incident, away from public sight, and is in an enclosed area such as a temporary tent, or nearby building.
After triage and treatment have been accomplished, the final stage in the pre-hospital management of a mass casualty incident is the transport of the injured and ill to a hospital for more definitive care. This is usually accomplished using ambulances, but can also be accomplished using other emergency vehicles such as a police car, firetruck, helicopter Emergency Medical Service or civilian vehicles such as personal vehicles or transit buses. As with treatment, transport priority is decided based on the severity of the patient's injuries. Usually, the most seriously injured are transported first, with the least serious transported only after all the serious patients have been transported. However, in an effort to remove as many lightly injured civilians as possible, an incident commander may choose to have those least seriously injured transported to local hospitals or interim-care centres in order to provide more room for emergency personnel to work. It is also possible that lightly injured casualties will be transported first when access to those who are more severely injured will be delayed due to heavy or difficult rescue efforts.
The care that is rendered at the scene of an MCI is usually only temporary and designed to stabilize the casualties until they can receive more definitive care at a hospital or an interim-care centre.
An interim-care centre is a temporary treatment centre which allows for the assessment and treatment of patients until they can either be discharged or transported to a hospital. These are often placed in gymnasiums, schools, arenas, community centres, hotels, and anywhere else that can support a field hospital set-up. Permanent buildings are preferred to tents as they provide shelter, power, and running water, but many governments maintain complete field hospital setups that can be deployed anywhere within their jurisdiction within 12–24 hours. While full field hospitals require a significant amount of time to deploy (in relation to the length of most incidents), temporary interim-care centres can be set up by emergency services fairly quickly if needed using the personnel and resources they have on-hand. These centres are usually staffed by a combination of doctors, nurses, paramedics/emergency medical technicians, first responders, and social workers such as those from the Red Cross who work to get families reunited after a disaster.
Mass casualty event
Generally in the healthcare field the term mass casualty event is used instead of mass casualty incident with the distinct difference being that in the first one hospital resources are overwhelmed, and in the latter, public safety resources are overwhelmed. In the event of one of these incidents where a hospitals resources are going to be overwhelmed, it is important to discharge all fit patients, dedicate more resources to the emergency department, and to expand their intensive care unit to accommodate the long term care. While as much as 80% victims will be transported from the scene to hospitals, others who are less injured might walk themselves to these facilities and increase the load at the closest one to the incident.
There are many different kinds of MCEs. The Centers for Disease Control and Prevention break up the types of MCEs into bioterrorism, chemical emergencies, radiation emergencies, natural disasters like weather (CDC, 2009). Cities are also equipped with receiving facilities for all of these first responders to transport to, such as hospitals.
- Pentagon MASCAL (an exercise in 2000)
- Brady Prehospital Emergency Care Sixth Edition; Mistovich, Joseph J. et al pg, 866
- Brady Prehospital Emergency Care Sixth Edition; Mistovich, Joseph J. et al pg, 867
- http://www.fema.gov/pdf/emergency/nims/NIMS_core.pdf page 13
- Ramesh, Aruna; Kumar, S (29 November 2013). The Journal of Pharmacy and Bioallied Sciences 2: 239–247. Check date values in:
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- Trunkey 2008, p 68
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