Treatment Area Considerations for Mass Casualty Incidents

There are many facets of responding to a mass casualty event: initial scene assessment and set-up, triage, movement of patients to the casualty collection points, treatment, and, ultimately, transportation of patients for definitive care.

A well-designed system will provide both for responder safety and the efficient triage, treatment and transportation of the incident's victims. As part of this system, a treatment area must be set up appropriately and staffed adequately. The actual treatment/stabilization of MCI patients is of the utmost importance, but will not be effective in an improperly set up and maintained treatment area. Consideration of set-up, staffing and other special issues should be included in order to ensure that the core of the medical incident command structure operates efficiently.

Set-Up
Just as with the initial scene assessment by first-arriving personnel and initial triage efforts, the decisions made in setting up a treatment area are critical to this unit's success or failure. The goal is to have the treatment area set up and ready to receive patients prior to their arrival. This is not always practical, based on the circumstances of the call; however, preplanning efforts in this area should emphasize this point. The initial steps in establishing any treatment area should answer the following questions:

• Where will it be
• Does the location allow for easy access by litter-bearers bringing in field-triaged victims?
• How large should it be, and can it be expanded if needed?
• Does the set-up allow for access to needed medical caches?
• Is it adjacent to and does it provide for unimpeded access to the transportation area?
• Is there a need for an onsite morgue, and how will it be secured?
• Is weather a consideration?
• How should the area be secured?

The treatment area officer must ensure that the treatment area is set up close enough to the triaged victims to allow for their safe and efficient movement to the entry area for re-triage and assignment into a treatment category. However, in considering where to locate, remember safety of both the responders and patients. Should the incident involve a hazmat problem, have geographical/remote location concerns, or if terrorist activities are suspected, then close proximity to the actual incident site might not be prudent.

The area should also allow for direct access to the transportation area to allow for patient loading and to the forward triage areas. Do not set up the area in a manner that causes incoming patients from triage to cross the transportation area, thus lending to confusion of who is going where. The patient flow should be singular, so that patients flow into one side of the treatment area and out the other side to the patient loading area (see the treatment area diagram).

Once the treatment area is established, its placement should be announced to everyone on the scene. It should also be clearly marked and visible. The entrance, as depicted below, should be marked with cones or flags, and everyone on scene should practice and understand that this is the only place of access for inbound patients. This will allow for re-triage of all patients to determine any changes in patient condition since the initial field triage took place, and will help limit delays in treatment to the most severely injured.

Staffing
Once the decision to establish a dedicated area to treat patients during an MCI has been made, quick decisions pertaining to anticipated staffing levels must be made. The Medical Branch Supervisor or the Treatment Area Officer, once one has been appointed, must quickly gain an understanding of the scope of the incident and determine resources versus patient load. If enough resources are already available, and the situation is determined to be stable and not escalating, then this function may not be needed. However, a key point to remember is: Of all of the tactical-level management units involved in a multiple-casualty incident, the operational demands and support to the Treatment Unit typically require the heaviest commitment of personnel. A rule of thumb might be to call for more personnel than you anticipate needing and to do this early in the process. These resources can always be cancelled or deployed to other areas of the command structure if they are not needed in the treatment areas; however, severely injured and dying patients cannot wait for additional personnel to arrive to provide treatment.

In preplanning response to any mass casualty event, primary things to consider are the area's resources as a whole, the capabilities of these resources and the time lags involved in placing these resources onto the scene. Not everyone has the luxury of having 20 or 30 ambulances immediately available. Most systems would be immediately overwhelmed by a bus accident with 50 or 60 persons on board. Thus, predetermined mutual aid plans and having knowledge of the capabilities and estimated response time of these resources are crucial components of any preplanning. This information will aid in determining how quickly a dedicated treatment area can be staffed and patients effectively treated.

Table 1 offers suggested staffing levels, depending on the size of the incident, for treatment area staffing. Obviously, this is not meant to be absolute. Individual variations can and should depend on resources available in the area as determined during the preplanning phase of the response. Having at least a basic framework of workable staffing levels will aid greatly in determining how quickly to begin calling for additional outside resources during any major or extended operation.

Treating large numbers of injured persons is taxing, both physically and mentally. In addition to determining staff needed during the initial response, it will be crucial to consider the possibility of extended operations and the need to rotate personnel. If adequate personnel are available, rotations should be frequent, especially in the red treatment areas. These personnel should be rehabilitated in an area away from the treatment area and offered rest, meals and access to stress management experts.

Special Considerations
In addition to the above set-up and staffing issues, weather, geography and the type of event are important considerations. Weather impacts almost everything in emergency response, and MCI operations are no different. Rain, snow/sleet, cold, and even hot, sunny weather are serious impediments to both patient care and responder safety. Shelters should be considered in the treatment area to shield patients and responders from the elements. This will depend on the resources available and should be predetermined. Also remember that shelters are not just for rain or other inclement weather. Should operations be taking place during hot, sunny weather, shelter may also be needed during extended operations or where there will be delays in transporting patients.

Geography should also be considered in treatment area implementation. This can include road access and egress to the area, the terrain at the incident site, or the size and scope of the incident itself. Patients may be spread over a large area; thus, consider two separate treatment areas. This would not be an ideal situation, but it may be prudent in order to facilitate treatment and to provide for better oversight of multiple treatment locations should area commands under the ICS system be needed.

If the MCI is a suspected terrorist event, measures should be taken to ensure the safety and security of the responders operating in and patients being brought to any treatment area for stabilization. A rule of thumb is, if the incident is known or reasonably suspected to be a terrorist event, locate EMS operations no less than 1,000 feet from the call location and secure the area so that persons are controlled both entering and exiting. Terrorist/hazmat events present logistical problems to the treatment areas in that patients being transferred from forward triage areas will take longer to arrive, possibly with worsening conditions or with contaminants still on them, even after initial decontamination procedures. Additionally, due to the possibility of chemical exposure, these patients could present with conditions requiring special treatment medications and protocols. Incorporating trained haz-tox medics into the treatment area might be necessary in these circumstances to provide stabilization efforts until transportation is available.

Summary
Mass casualty response is one of the most difficult aspects of emergency medical services. The medical incident command system is designed to treat and stabilize patients in a safe and effective manner. At the center of this is the treatment area. A well-thought-out, adequately staffed treatment area will greatly enhance any system's ability to meet and exceed the demands of almost any multicasualty event.

Steven Cotter, BS, NREMT-P, is the director of Emergency Medical Services for Laurens County in South Carolina. He has been involved with EMS for 15 years and is completing a Master of Business Administration degree at Clemson University.