Mass casualty, chemical, biological and radiological hazard contingencies

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Chapter 22 Mass casualty, chemical, biological and radiological hazard contingencies

Jeff Wassertheil

AIMS AND OBJECTIVES

Incidents involving mass casualties are infrequent. However, they have the potential to overwhelm usual health resources with very little notice. It is therefore important that contingencies are developed, tested and ready for immediate implementation. Such contingencies outline the responsibilities for overall medical control, coordination and effective casualty management in major emergencies and disaster situations. They include the procedures for triage, first aid and resuscitation, some of which require modification when resource availability needs to be rationed.

Response plans must provide a framework for coordination of transporting injured or incident-affected individuals to appropriate treatment sites. Plans must incorporate procedures to enable the presence of medical, nursing and first aid personnel, as well as other welfare personnel and psychological carers, to provide care at the scene of a mass casualty incident.

At a hospital level, plans need to be developed, implemented, rehearsed and evaluated. This enables hospitals that are often full to manage a large number of patients in excess of usual workloads or capacities and, in certain circumstances, victims with special or specific management needs.

Incorporation of public health resources and interventions is integral to provide guidance and procedures where hygiene, sanitation, communicable disease or biological hazards potentially exist. Contingencies must provide an interface for concurrent activation of recovery plans. Access to appropriate and timely psychological support for victims and care providers is included in both early and ongoing recovery phases. The overall objective is to mitigate disasters by participation in event planning and medical and emergency service activation and training.

PHASES OF A DISASTER

The phases of disaster management are prevention, preparedness, response and recovery.

Prevention

The prevention phase concentrates on strategies that minimise the severity of an incident. It aims to cushion the severity, reduce the effects, minimise adversity and contain the impact of a disaster. Prevention strategies also include incorporation of lessons learned from previous experiences.

Preparedness

Effort in optimal preparedness promotes effective and optimal resource allocation and consumption. This phase occurs with an expectation that the plan will at some time need to be activated. Preparedness occurs from within and external to the health service.

Planning includes providers from both within and stakeholders from outside the health service that would be expected to respond in accordance with emergency management contingency plans. Local community stakeholders—such as the police, ambulance and the fire department—as well as public health and recovery agencies should be included in health service planning committees. Likewise, health service representation should be included in local council, shire or regional planning committees.

As highlighted under prevention, the recommendations from previous operational debriefings, adverse incidents or experience are woven into response plans.

Response

The response is the activation of personnel and other resources in accordance with the pre-determined plan to respond to multicasualty external disasters.

Recovery

Recovery contingencies are implemented and provide for the short- and long-term recovery of the community (victims and helpers) affected by the disaster. This includes the health service staff and the repair and re-instatement of physical resources, consumables and services.

ADMINISTRATIVE AND LEGISLATIVE MANDATES

A national legislative framework for emergency management provides for counter disaster planning for response to and recovery from emergency situations that take place throughout Australia and provides a blue print for state or territory response plans. Separate state emergency recovery plan arrangements, designed to meet long-term assistance to people and communities, are activated during the response phase of an incident to provide early commitment of resources. Specific specialty plans for events such as shore retrieval, major burns management and terrorism have been developed in order to harness a coordinated and cooperative multi-city response.

Very broadly these legislative frameworks provide for:

• disaster planning and response coordination of activities throughout the state to be enacted by the chief commissioner for police or nominated deputies
• roles and responsibilities of control and support organisations and agencies for various types of emergencies or disasters
• the state body for health to be the coordinator of agencies involved in providing recovery actions in communities following major emergencies and disasters.

Accordingly, under these arrangements, the police and the various state or territory emergency service organisations severally develop the non-medical component of the state disaster emergency management plans. Under the various state emergency response arrangements, the health departments have statutory responsibility to provide the necessary planning and response required to deal with matters associated with the general health of the community and to provide medical and hospital services required as a result of a major emergency or disaster.

MEDICAL RESPONSE PLANS AND AGENCIES

A medical response plan (or Medical DISPLAN) provides for a clinical care organisational framework that outlines the roles and responsibilities of the various participating medical and health responders, and provides the necessary integrated procedures for altering and mobilising medical and health personnel, for establishing on-site medical control and for definitive treatment of casualties. The concept is that all arrangements and procedures made within the medical response can be applied from the smallest to the largest incident with a build-up of medical coordination and medical and health resources as necessary, following the general pattern of normal daily operational procedures wherever possible. This extends to contingency planning and has a presence at major events where potential public threat is perceived to exist. Actions can be taken under local aegis in the absence of a declared disaster in order to provide protection from personal liability and to ensure compensation is available for injury to volunteers not covered under other insurance arrangements while training for or participating in emergency response activities.

State medical response plan representation, through medical and health participation in all local, regional and state DISPLAN committees, is mandatory to ensure integrated effective response can be provided in times of emergency.

Components of a state medical response

Agencies or organisations responsible for health

The principal role of the health department is to deal with matters associated with the general health of the community and to provide health and medical services required as a result of a major emergency or disaster.

The health department ensures coordination of:

• provision of hospital and medical services
• provision of transport and hospitalisation for the injured or sick
• supply of medical and first aid teams
• setting up of medical centres and casualty clearing posts
• provision of disease control and other scientific and pathological services required
• health and scientific survey teams
• public health information, advice and warnings, to control and support agencies and for release to the affected communities.

The health department has direct responsibilities as the control agency for:

• infectious disease outbreaks
• contaminated foodstuffs and water
• chemical, biological and radiological (CBR) substance releases.

It is also the support agency for all incidents, and includes advice to all combat and support agencies and to the general public in hazardous material, chemical, biological, radiological and nuclear incidents.

Acute health sector

The senior medical advisor manages the internal administrative functions of the state medical response plan, in support of a medical response group that includes both metropolitan and rural doctors who are appropriately trained in emergency management.

Although specific contingencies and structures vary throughout Australasia, the senior medical adviser generally manages the emergency operations centre when activated in support of the medical response system. The adviser also assists with the distribution of mass casualties to hospitals and, in times of major emergencies, will provide briefings via the health department to the appropriate minister.

Emergency operation centres (EOCs)

EOCs will be activated when a major support effort is required to assist with on-site and central medical coordinator response activities. For longer term recovery assistance, EOCs are essential to coordinate the physical, medical and mental health activities required to assist ongoing needs of communities and public health issues.

Public health agencies

In emergencies where public health is threatened, the health department, local government public health medical practitioners and environmental health officers provide the necessary expertise to preserve general healthy living standards. All work within the framework of the health department public health sector for preventing and controlling outbreaks of communicable diseases, and for the preservation of acceptable standards for safe drinking water and foodstuffs.

The ambulance service

This provides:

• 24-hour operational communications to initiate and instigate the necessary alerts and mobilisation of medical coordinators, hospital medical teams and casualty receiving hospitals in major emergencies
• the initial setting up of a medical controlled area incorporating a casualty collecting post and casualty cleaning stations and for triage and treatment on site until a joint medical command post is established
• assistance with on-site decontamination of people exposed to toxic or microbiological hazards
• transportation of casualties to appropriate hospitals
• coordination of first aid service responses until the establishment of a medical command structure.

Field emergency medical officers

This group of doctors provides the necessary clinical care, medical control and coordination of resources at the disaster scene and centrally and advises on the distribution of casualties to appropriate hospitals. It also provides, through the health department EOC when established, other medical and health resources such as mental health professionals and public health and environmental health staff, and for additional medical and nursing staff to supplement facilities.

A critical role is to minimise surge impact on hospitals. Those not needing hospital or emergency department management can be referred to community-based resources either acutely or subacutely in keeping with regional or municipal plans.

Pre-hospital medical coordination/disaster scene

Although titles, role delineations, responsibilities, definitions and plans vary amongst the states, the following principles are generic. The descriptions below outline the events and actions that are required for proficient on-site disaster medicine management.

Area medical coordinator (AMC)/senior field emergency medical officer

The area medical coordinator (AMC) is responsible for on-site medical coordination of all medical and health resources required and for the command of all health responders. The AMC is responsible for:

• in conjunction with the ambulance coordinator, establishing an effective medical controlled area (casualty collecting post and medical command post) and effecting liaison with the police coordinator and other emergency services
• providing frequent and accurate assessment of the casualty status to a central medical coordinator usually based at the ambulance communications centre
• assessing the on-site conditions and, if necessary, initiating through the central medical coordinator the setting up of an interim casualty clearing station or designating a triage hospital where transport of injured persons from the scene or local area may incur significant delays
• assessing the requirement for relief of or for further medical teams at the scene, for further first aid support and whether psychological services may be needed.

Central medical coordinator (CMC)

The CMC is usually located in the ambulance communications centre. The CMC’s role is to:

• initiate and arrange distribution of casualties to appropriate hospital facilities, in conjunction with an ambulance commander—the concept is to distribute casualties to as many hospitals as practicable to avoid facility overload
• alert and mobilise medical teams and other medical and health responders to the disaster scene
• liaise and request activation of health department emergency operation centres at state and regional level if necessary, and provide situation reports at frequent intervals to EOC and to request further assistance
• instigate stand down of the various medical and health responders as appropriate after consultation with the on-site medical coordinator and other emergency service authorities.

Site medical control

The disaster site medical procedures in place for establishing early medical control for the proper triage, treatment and transportation of casualties are initially provided by officers of the first responding ambulance vehicle. These officers carry out the roles of casualty collecting officer (for assessment of numbers and types of casualties, to carry out a reconnaissance of the area and select an area suitable to set up a casualty collecting post, to report findings to ambulance control and to commence triage of casualties) and transport control officer (to establish suitable access and turn-around for ambulance vehicles and to report this information to ambulance communications centre for further incoming response vehicles).

As an AMC or ambulance commander arrives on site, further assessments will be made and a joint medical command post established. All incoming medical responders report to the command post where tasks within the CCP are allocated. Further medical assistance required on site is requested through the central medical coordinator to avoid convergence and duplication of resources. A typical communication structure is outlined in Figure 22.1.

image

Figure 22.1 On scene communication links and communication pathways

The medical services provided on site will be limited initially, using the principle of doing as little as possible, as simply as possible, as quickly as possible and to as many as possible.

Life-saving procedures, such as airway management, immediate decompression of tension pneumothorax, arrest of haemorrhage, fracture stabilisation and relief of pain where necessary, may be the limit of medical assistance where medical resources are few. Thus effective triage or classification of casualties by a casualty collecting (ambulance) officer (CCO), medical officer or team leader from a medical team is essential.

image

Figure 22.2 Linkage to other emergency services organisations

Triage and reverse triage

Triage generally implies direction of clinical resources to the most seriously ill or injured by a trieur or triage officer. In a mass casualty situation, demand may be in excess of resources availability. It is neither ethical nor practical to classify clearly non-salvageable victims as top priorities. Given this, two methods of field or mass casualty triage are employed, depending upon the number of casualties and the availability of clinical resources. The two methods of triage—SIEVE and SORT—are utilised at different phases of casualty management at disaster sites.

Sieve

This triage method is used during the initial phase of managing mass casualties. It focuses on determining which patients will survive and channels resources to initially moving that cohort of patients from the scene to a casualty clearing post or station. Triaging in this manner is a repeated process to ensure refinement of urgency stratification and to respond appropriately to the ongoing evolution of a casualty’s injury complex and consequent physiology.

Casualty assessment is based upon the findings of a primary survey. If casualties are ambulant, they are initially regarded as walking wounded and are directed or escorted to a casualty clearing post. If not ambulant, a triaging primary survey is performed. This looks at the airway, respiratory rate and capillary refill. Treatment is limited to the institution of simple life-saving primary survey manoeuvres. These are:

• airway clearance by manual or other available methods
• decompression of a tension pneumothorax by needle thoracostomy
• control of external haemorrhage
• appropriate positioning of unconscious patients or patients with head, chest, abdominal pelvic or spinal injuries.

Casualties must be re-triaged on the basis of response, injury pattern and likely prognosis. If critically injured or ill patients are unresponsive to these measures and unlikely to survive, they become second priority casualties. This is sometimes known as reverse triage

A standard clinical reasoning scheme for triage is outlined in Figure 22.3. SIEVE triage categories are as follows:

1. Top priority patients are those who are severely injured and in need of urgent emergency care. They are those in whom there is actual physiological embarrassment. Treatment is generally urgent, quick, simple and minimal in an endeavour to stabilise prior to priority transportation. They are patients who are deemed as able to be saved but will die or suffer major disability if not treated (Table 22.1).
2. Second priority patients are those who may have significant injuries but in whom airway is not problematic and who have normal respiratory or perfusion status assessments. They constitute most of the injuries that are time-critical on a pattern of blunt injury. The implication of being stratified as a second priority patient is that transfer to and treatment at hospital is required.
3. Second priority patients with a black stripe. A black stripe may be drawn on a second priority tag by a trieur. This identifies that injuries sustained are likely to be incompatible with survival and that extensive medical treatment will jeopardise the survival of other casualties. An example is a patient with 90% burns when there are many patients with survivable injuries. Such casualties require a decision to be made to transfer to hospital as third priority or die at scene.
4. Dead. These are deceased individuals. They need to be certified as dead in the history section of the triage tag by a medical practitioner. The deceased becomes the responsibility of the police and the state coroner. They are generally transferred to a mortuary area on site.
5. Walking wounded patients are divided into those who require physical first aid and those who require mental health first aid. In both instances this could be provided at the scene in a field hospital or similar setting and the patient is then discharged to appropriate continuing care providers.
6. Plain walking wounded tag. These are casualties with either physical injuries or who are medically unwell. They are those who have sustained minor injuries or have non-time-critical medical problems unlikely to require hospital admission.
7. Walking wounded tag with black stripe. This tag identifies casualties with acute mental health problems due to psychological trauma or stress. In general, these casualties are suitable for urgent defusing or counselling, preferably on site. Ongoing care can be planned for a later time.
image

Figure 22.3 Approach to triage using the SIEVE method

Table 22.1 Triage groupings and criteria for mass casualty situations

Group Priority Criteria
1 Red—priority 1
Severely injured but salvageable
In need of urgent medical care
Urgent resuscitation and transportation required

2 Yellow—priority 2
Significant injuries and condition stable
Treatment can wait or patient is unlikely to live and extensive medical care will jeopardise the survival of other casualties

3 Green—minor injuries
Casualty ambulant (walking wounded) and hospital admission unlikely
Uninjured psychologically disturbed persons included in this category

4 Black—deceased
Medical officer is required to certify death on card
Body becomes the responsibility of police/coroner’s office

SORT

This triage method is the more formal risk stratification or triage system that identifies the urgency with which most emergency health workers are familiar. SORT identifies time-critical patients and assists in scheduling optimal allocation of available resources. If used in the initial triage, this mode of triage is applicable for incidents involving only a small number of casualties. It is more commonly used on admission to casualty collecting posts or field hospitals.

This method of triage is based on the Revised Trauma Score and is consistent with the Australasian Triage Scale, triage practices taught in emergency management of severe trauma (EMST), emergency life support (ELS), advanced paediatric life support (APLS) and major incident medical management and support (MIMMS) courses. It is identical to the practices employed by ambulance, first responder and other emergency medical services personnel for determining the time-critical patient. It is a repeated process that is dependent upon traditional ongoing patient observation.

SORT is generally implemented in the field utilising the Revised Trauma Score in order to rank physiological embarrassment and allocating an ordinal score. This assists with re-prioritisation or risk stratification of casualties. Scores of 1–10 are associated with the immediate category. A score of 11 identifies an urgent patient. A score of 12 or higher identifies casualties that can wait for delayed management (Figure 22.4).

image

Figure 22.4 The Revised Trauma Score and the SORT method of triage

Further refinement of triage can be assisted by attention to pattern of injuries or mechanism of injuries. However, in a trauma related mass casualty incident, a considerable number of patients may be classified as time-critical on mechanism of injury alone (Table 22.2

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