Fire-EMS Management of Multicasualty Incidents

By Ken Miller, M.D., Ph.D.

The modern fire service has been challenged many ways over the past few decades: changing fire suppression strategies, hazardous materials, air operations, urban search and rescue, emergency medical services, and most recently weapons of mass destruction and terrorism. Multicasualty emergencies are nothing new to the fire service; they have occurred throughout its history. What has changed are the magnitude and scope of some multicasualty incidents, multicasualty/multifatality incidents, potential mechanisms of injury or illness, medical infrastructure supporting multicasualty management, and most recently the addition of multicasualty public health emergencies. Our mentors in this profession could probably never have imagined the complexities facing the modern firefighter.

Natural disaster multicasualty incidents have occurred throughout the history of the fire service: floods, fires (urban and wildland), hurricanes, tornadoes, earthquakes, and heat emergencies. As transportation modes have progressed, so have transportation multicasualty emergencies: rail, aircraft, passenger vehicle, and watercraft. Urban structural failures from engineering or design flaws or structural fatigue have been known to the fire service, but recently high explosives and incendiaries have resulted in multicasualty urban emergencies on a scale previously unimaginable. Explosive devices may even be used to disperse radioactive isotopes. Technological emergencies have followed the evolution of commercial and industrial development, hazardous materials leaks, fires involving hazardous materials, nuclear power station emergency planning, and now critical infrastructure vulnerability assessment and potential cyberterrorism. Infectious diseases have certainly affected the fire service’s need for infection control programs, protective equipment and engineering, and occupational health. However, the use of infectious agents as weapons has added another previously unimaginable dimension to the response challenges of the fire service.

Trauma is the predominant medical problem in many multicasualty incidents, followed probably by thermal burn injury. Trauma and burn define a particular triage and rapid transport strategy. Toxicological emergencies, whether criminal or technological, confound this strategy in that triage schemes for trauma may not effectively select the most critically affected victims. Physiological observations like altered mental status, tachypnea, and tachycardia may also not reflect patient outcomes in toxicological exposures as they may in trauma. Indeed, some toxicological exposures are field-treatable, and their effects are reversible despite ominous initial physiological assessment. Nerve agents and other organophosphates are particularly good examples. Decontamination may be an additional operational consideration; and in some cases, selected antidotes can even reverse the symptoms in the critically affected victims, making field treatment a potentially important priority.

Multicasualty Scene Management
Before effective and timely triage and movement of victims can occur, critical hazard mitigation and scene organization must be accomplished. Fire threatening survivors and critical exposures, ongoing hazardous substance release, structural instability, and secondary devices designed to harm first responders or evacuating survivors are among the critical hazards that may need to be considered or managed concurrently with nonambulatory victim rescue. In larger incidents, this can be an overwhelming task for the first-arriving companies.

The initial companies will need to allocate personnel to establish incident command and communications, initiate critical hazard mitigation, and initiate triage. Early notification of and medical communications with local medical and healthcare resources of the occurrence of a multicasualty emergency can expedite the initiation of care of the first-arriving victims. This is particularly true in larger multicasualty incidents because in many recent instances ambulatory victims have found their own transportation to local and even distant hospitals.

Early notification of regional hospitals and specialty centers (trauma, burn, and pediatric facilities) will allow them to

  1. Direct emergency department staff to open beds for the impending arrival of victims.
  2. Allocate on-duty hospital staff to support the emergency department.
  3. Allocate staff in radiology and laboratory services.
  4. Open operating rooms and allocate surgical resources.
  5. Organize medical staff to manage outpatient and inpatient care and facilitate discharge or transfer of existing inpatients.
  6. Activate the internal hospital disaster plan. It is estimated that 10 to 15 percent of victims of a multicasualty trauma incident will be severely injured and could potentially benefit from specialty trauma services.1
    If, for example, a hospital can mobilize four trauma teams to work simultaneously, then a realistic estimate of caseload for that facility might be 30 to 40 victims.

As resources begin arriving on-scene, activity can still be focused on triage but additionally a ground ambulance coordinator and treatment unit can be established. When ground ambulances are available, highest-priority triage victims should be moved directly from triage or the operational area to the ambulance. Lower-priority triage victims can be staged and later treated in the treatment unit. Forward patient movement early in the incident depends on the coordination of three key incident command positions: triage unit leader, medical communications coordinator, and ground ambulance coordinator. Once a treatment unit leader is established to organize staged victims, coordination shifts to the treatment unit leader, medical communications coordinator, and ground ambulance coordinator. The medical communications coordinator determines which hospitals are able to receive victims of each triage category and communicates that to either the triage unit leader earlier in the incident or the treatment unit leader later in the incident. These positions then facilitate delivery of appropriate triage category and number of victims to the ground ambulance coordinator, who organizes ambulance staging, loading, destination verification, and victim tracking. Each community will need to assess the role of air ambulances in multicasualty emergencies. In urban settings, air ambulances use a disproportionate amount of scene resources for their limited victim transport capacity. An air ambulance coordinator and engine company supporting the landing zone may better be used in victim triage, treatment, and movement when ground ambulance operations are efficient and timely.

When the number or flow of victims exceeds the ambulance availability, staging in the treatment unit may be necessary. Although scene treatment of trauma is usually limited by the need for rapid transport or the availability of resources, there are a few medical priorities to consider. Basic or advanced airway management guided by local protocols for victims with head injury or those showing significant physiological compromise is justifiable. Assisted ventilation may not occur in larger multicasualty incidents, since most triage schemes place victims without spontaneous ventilation after opening of the airway as dead or expectant. However, this may well be a treatment priority in smaller multicasualty incidents. Spinal immobilization is a priority. However, if protocols are in place for field evaluation and clinical clearance of the spine in selected victims, this is a good setting to apply them. Unnecessary spinal immobilization increases the need for both scene and ambulance resources. In addition, victims may be immobilized for long periods of time before reevaluation at a higher level of care is possible. Needle decompression of a tension pneumothorax would be a scene treatment priority, as would control of external exsanguinating hemorrhage. Splinting of extremity fractures may be an effective and simple means of pain control.

There is ample data to argue against the use of field intravenous fluid infusion for the purpose of normalizing blood pressure in victims of trauma with uncontrollable internal hemorrhage. When active internal bleeding can’t be controlled, increasing the blood pressure with intravenous fluid infusion increases the rate of bleeding and worsens the clinical outcome. When time and resources allow, a justifiable strategy might be establishing large bore intravenous access using a saline lock before peripheral venous access becomes more difficult because of compensatory venous constriction. However, this does not mean that fluid infusion to stabilize vital signs should be avoided when the bleeding is external and controllable as in extremity soft tissue injuries involving major vessels, traumatic amputations, or partial amputations. Although controversial, a strong argument can be made to maintain vital signs with intravenous fluid infusion in victims with both multisystem trauma and head injury. Hypoxia and/or hypotension can worsen the clinical outcome of head injury. The challenge in the treatment unit is to balance the victims’ medical needs with the availability of timely transport and emergency medical resources.

Occasionally hospitals or healthcare systems will attempt to send medical personnel to the scene to augment emergency medical services, whether requested by incident command or not. For scene safety, personnel accountability, credential verification, and operational familiarity reasons, this practice should be discouraged whenever possible. When healthcare personnel do arrive on-scene, it is essential to organize them, give them an initial briefing, and then employ them in the treatment unit, which is usually well away from the most immediate hazards. When possible, it is best to avoid placing untrained and unprotected medical personnel in forward triage or operational areas.

Triage Strategies
The principal strategic difference between triage in everyday individual victim incidents and multicasualty incidents is the need to determine the “greatest good for the greatest number” of victims in the shortest time to maximize success with limited resources. What that means tactically is that multicasualty triage schemes prioritize victims based on manifest physiological instability using limited parameters whereas ordinary triage schemes may use more extensive physiological parameters and assessment of the potential for injury (e.g., mechanism of injury or anatomic site of injury). One of the more widely used multicasualty triage schemes is START (Simple Triage and Rapid Treatment). One of the problems facing all multicasualty triage schemes is the scientific difficulty in validating them. A study from Australia published recently attempts to retrospectively compare four triage schemes.3 START did well, with the mental status assessment (inability to follow simple commands) and systolic blood pressure less than 80 (as determined by absent radial pulse) most closely associated with severe injury. Sensitivity (START is abnormal in the presence of severe injury) was 84% and specificity (START is normal in the absence of severe injury) was 91%.

It’s important to point out that all physiologically based triage schemes are dynamic. Retriage must occur systematically as long as the victim is on-scene awaiting transport. If sentinel physiological parameters become abnormal, that victim must be raised in transport priority. Although science is lacking, physiological triage schemes probably work better in adult blunt trauma victims than in penetrating trauma, burn, inhalation injury, and pediatric victims. The reason is that penetrating trauma, burn, and pediatric injuries can temporarily remain physiologically normal and stable despite significant injury. By the time physiological parameters do become abnormal, the injury may have advanced substantially. On the other hand, inhalation injury-in toxicological incidents, for example-may cause respiratory distress sufficient to place the victim as a high transport priority when that victim is physiologically quite stable. Exposure to the blast wave of high explosives is another confounding factor. Other injuries being equal, the potential to develop primary pulmonary blast injury may increase triage priority.4 Besides the gradual development of progressive respiratory distress (another example of the importance of continuous retriage), a sudden loss of hearing from eardrum rupture will indicate the exposure to the blast wave. Experience in Israel shows eardrum rupture as a poor predictor of the development of primary pulmonary blast injury but is the only practical assessment tool in the field.5 The explosive radiological dispersion device is a special case worth mentioning. Radioisotopes dispersed using high explosives present a substantially lesser threat to the victim (and personnel) than the trauma from the blast or secondary structural collapse or fire. Extensive decontamination operations must not interfere with timely triage and transport of the highest-priority victims. Communications with the receiving hospitals to mobilize their radiation safety officer will help balance the need to reduce the extent of spread of radiological contamination with the need for timely trauma management.

Another triage challenge is the concept of secondary triage. The physiological triage schemes are intended to be used only as a primary triage tool and have limitations, as discussed earlier. Each community will need to decide whether and to what extent to engage its medical specialty centers (trauma, burn, pediatric) for multicasualty emergencies. That may not be practical or even possible in larger multicasualty incidents but it may well be both possible and desirable in small to moderate multicasualty incidents determined by the resources and geography of the region. All hospitals may become “equal” when victim needs exceed local resources. However, when resources are sufficient (scene personnel, ambulances, and specialty center services), local “routine” triage schemes may be applied secondarily to the primary physiological triage scheme to select those victims most likely to benefit from specialty centers.

Public Health Emergencies: When There Is No “Scene” to Manage
The latest challenge to the fire service is the threat of biological terrorism. Unless a threat or a dispersion device is discovered, the inherent delay in onset of symptoms in victims following exposure to toxins (hours to days), bacteria, or viruses (days to weeks) will result in an evolving escalation of EMS calls for a variety of potential symptoms. Respiratory symptoms with fever are very likely following aerosol exposure. There are several important problems here. One is personnel protection. Until a diagnosis is made, use protection against respiratory or contact spread. This means wearing N-95 fit-tested respirators when caring for patients with respiratory symptoms and exercising usual standard precautions. Not all biological agents undergo person-to-person transmission. Plague pneumonia, smallpox, and to a lesser extent Ebola are examples of potential bioterrorism agents that are transmissible person to person once the disease is established and long after the initial exposure at the site of dispersion. Depending on the agent, local public health may offer postexposure or preemptive chemo- or immunoprophylaxis to fire and ambulance personnel as well as their station and household contacts. This is a complex issue and requires considerable resources once a decision is made to act.

Depending on the agent, medical infrastructure may already be impacted by the time requests for EMS peak. Outpatient care and hospital admissions may stress medical resources with already limited capacity and increase hospital diversion. Results may be increased demand for transport; longer transport times to more distant hospitals; longer wait times at hospitals for the transfer of patients; and sicker patients transported, requiring more equipment, time, and documentation. Since each EMS call will likely be for a single patient, primary triage schemes will have little value over conventional out-of-hospital medical judgment, protocols, and hospital communication. In the more extreme situation, hospitals may begin cohorting patients with the same diagnosis and, under advisement of local public health, limit their acceptance of patients to those with a specific symptom complex, further limiting hospital destination choices. There may be alternative treatment sites identified by local public health other than acute care hospitals for victims with a specific symptom complex and severity set up to receive new cases and affecting EMS destination selection. Early establishment of a health information system and neighborhood information centers should help reduce the numbers of “susceptible worried well” and special populations (children, elderly, pregnant, handicapped, immunosuppressed) from overwhelming acute care facilities, further impacting medical infrastructure capacity.

References

  1. Hirshberg A, Holcomb JB, Mattox KL. Hospital Trauma Care in Multiple Casualty Incidents: A Critical Review. Ann Emerg Med 2001; 37:647-652.
  2. FIRESCOPE Fire Service Field Operations Guide. January 2001.
  3. Garner A, Lee A, Harison K, Schultz CH. Comparative Analysis of Multiple Casualty Incident Triage Algorithms. Ann Emerg Med 2001; 38:541-548.
  4. Wightman JM, Gladish SL. Explosions and Blast Injury. Ann Emerg Med 2001; 37:664-678.
  5. Leibovici D, Gofrit ON, Shapira SC. Eardrum Perforation in Explosion Survivors: Is It a Marker of Pulmonary Blast Injury? Ann Emerg Med 1999; 34:168-172.

Ken Miller, M.D., Ph.D., is a board-certified emergency physician, has a Ph.D. in pharmacology, and is a former firefighter/paramedic. He is the medical director of the Orange County (CA) Fire Authority and assistant medical director of the Orange County Healthcare Agency/EMS. He is the medical team manager of FEMA USAR CA TF-5, chair of the FEMA USAR Medical Working Group, and a FEMA USAR Incident Support Team medical officer. He is also the unit leader of the U.S. Public Health Service Disaster Medical Assistance Team CA-1. He is involved in the development of the Metropolitan Medical Response System in Orange County and serves on the InterAgency Board for Interoperability Medical Subgroup.

No posts to display