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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.
Contents
Declaration of an MCI
A mass casualty incident will usually be declared by the first arriving unit at the scene of the incident. However, it may alternately be declared by a dispatcher, based on the information available from people who call their local emergency telephone number 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). 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 a variety of responders and agencies. The most common are listed below.
Emergency medical services
Fire and rescue
Public safety
Specialized teams
Public services
Hospitals
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
Ideally, once an MCI has been declared, a well-coordinated flow of events will occur, using three separate phases: triage, treatment, and transportation.
Triage
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 is considered the easiest to use. Using START, the medical responder assigns each patient to one of four color-coded triage levels, based on their breathing, circulation, and mental status. The triage levels are:
Triage personnel do not conduct treatment, with the exception of:
Generally, a small group of responders, usually the first two or three crews on scene, can complete triage.
When responding to a chemical, biological, or radiological incident, the first-arriving crew must establish safety zones prior to entering the scene. Safety zones include:
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.
Treatment
Once casualties have been triaged, they can be moved to appropriate treatment areas. Unless a patient is Green Tagged and ambulatory, litter bearers will have to transport patients from the incident scene to safer treatment areas located nearby. These treatment areas must 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 and transport them to the appropriate treatment area. Casualties should be transported in order of treatment priority: Red-Tagged patients first, followed by Yellow-Tagged, then Green-Tagged, and finally Black-Tagged.
Each colored triage category will have its own treatment area. Treatment areas are often defined by coloured tarpaulins, flagging tape, signs, or tents. Upon arrival in the treatment area, the casualties are re-assessed and they are treated with the goal of stabilizing them until they can be transported to hospitals; transported to the morgue or medical examiner's office; or released.
On-site morgue
Some mass-casualty incidents require an on-site morgue, for several reasons:
Most often, on-site morgues are set up on the far side of the incident, is in an enclosed area such as a temporary tent or nearby building.
Transport
The final stage in the pre-hospital management of a mass-casualty incident is the transport of casualties to hospitals for more definitive care. If an insufficient number of ambulances is available, other vehicles may transport patients, such as police cars, firetrucks, air ambulances, transit buses, or personal vehicles. 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 critical 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.
Definitive care
The care that is rendered at the scene of an MCI is usually only temporary and is designed to stabilize the casualties until they can receive more definitive care at a hospital or an interim-care centre.
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 or other locations that can support a field hospital setup. 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), emergency personnel can set up temporary interim-care centres 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 (for example, 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" (MCE) is used when hospital resources are overwhelmed by the number or severity of casualties. During these incidents, hospitals can discharge all fit patients, dedicate more resources to the emergency department, and expand their intensive care unit to accommodate anticipated long-term care needs. While up to 80% of 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 facility to the incident.
MCEs can include bioterrorism attacks, chemical emergencies, radiation emergencies, and natural disasters like weather.