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CHAPTER 34

Emergency Preparedness: Chemical, Biological, Radiation and Nuclear Incidents

Christopher A. Kahn1, Kristi L. Koenig2, and Matthew Boylan3

1University of California, San Diego, CA, USA 2University of California at Irvine, Orange, CA, USA 3Royal Centre for Defence Medicine, University Hospitals Birmingham, Birmingham, UK

OVERVIEW

By the end of this chapter you should:

• Understand how to recognize a CBRN incident

• Understand the basic principles of managing a CBRN incident

• Understand the importance of rescuer protection

• Understand the importance of decontamination

• Understand how to identify and manage CBRN casualties.

Introduction

Chemical, biological, radiologic and nuclear (CBRN) events present unique challenges that complicate the management of prehospital casualties. These can be successfully managed with careful planning, training in use of protective gear and decontamination techniques, and exquisite attention to provider and facility safety. Good com- munication between all response entities will facilitate safe and effective management.

This chapter will assist prehospital personnel in the basic man- agement of a CBRN incident.

Scene management

CBRN scenes should be managed using an incident command system (ICS). ICS provides a universally understood framework which delineates authority, responsibility and expectations of each responder. Personnel who may be responding to CBRN or other disaster scenes should have training in ICS or the local equivalent.

Assessment and safety As with all incidents involving hazardous materials, a rapid but thorough assessment of the scene to ensure that it is safe to approach the victims is necessary. Failure to ensure scene safety prior to initiating rescue and medical aid can cause prehospital personnel to become additional victims.

In addition to standard scene safety assessment techniques, CBRN responders should be aware of the following:

• Not all CBRN agents can be easily seen, smelled or otherwise sensed.

• In some scenarios (such as an aerosolized release of a biological agent), there may not be a discrete scene that can be readily identified by prehospital personnel.

• In terrorist incidents, a small primary release or explosion may be followed by a larger, secondary one designed to harm rescuers (the so-called ‘secondary device’).

It is often not immediately obvious that a CBRN event has occurred. While concern may be raised due to specific threats or observation of suspicious powders, many CBRN events will only be properly identified through toxidrome recognition after treatment of initial casualties has begun or through assessment by a CBRN team. The ‘Safety Triggers for Emergency Personnel (STEP) 1-2-3’ approach is a useful method to use when approaching an incident of unclear etiology (Figure 34.1).

Scene organization Although terminology may vary, most systems organize the CBRN scene into zones (Figure 34.2). The area containing the toxic hazard is known as the hot zone. The warm zone is where casualties

STEP 1 1 Casualty

STEP 2 2 Casualties

STEP 3 3+ Casualties

Approach using normal procedures

Approach with caution, consider all options Report on arrival, update control

Do NOT approach Withdraw Contain Report Isolate yourself and SEND for SPECIALIST HELP

Figure 34.1 The STEP 1–2–3 approach.

185Nutbeam, T., & Boylan, M. (Eds.). (2013). Abc of prehospital emergency medicine. John Wiley & Sons, Incorporated. Created from apus on 2023-10-16 21:30:32.

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186 ABC of Prehospital Emergency Medicine

Warm Zone Cold ZoneHot Zone

Incident Decontamination Casualty Clearing Station

← Wind Direction

← Ground Slope

Inner cordon (Clean-Dirty Line)

Outer cordon

CBRN Incident Layout

Figure 34.2 Chemical, biological, radiation and nuclear (CBRN) incident layout.

undergo decontamination and the cold zone is where casualties undergo conventional medical assessment, treatment and onward evacuation. The warm zone and cold zone are separated from each other by the ‘clean–dirty line’.

There have been recent moves in some countries to push life- saving clinical interventions (e.g. tourniquet application, airway positioning), therapies (e.g. nerve agent antidotes) and clinical judgement (e.g. CBRN triage) forward into the hot zone using specially trained CBRN medical teams.

Provider protection Several types of protective clothing exist, offering various levels of protection. In general, rescuers working within the hot zone will be hazmat specialists with dedicated training and experi- ence using extended duration breathing apparatus and gas tight suits (Figure 34.3). Those rescuers working within the warm zone to provide emergency medical care and decontamination will require chemical-resistant suits with respiratory protection to protect against chemical splash and off-gassing (Figure 34.4). Res- cuers in the cold zone should not need this level of equipment but should use standard precautions universal precautions (including gloves, gown, mask and eye shielding).

Figure 34.3 Extended duration breathing apparatus (EDBA) and gas tight suits. (Courtesy of www.justinedesmondphotography.co.uk).

Figure 34.4 Powered respirator protective suit. (Courtesy of Respirex International Ltd).

Some countries issue electronic personal dosimeters to prehos- pital medical responders. These devices alarm when the wearer is exposed to dangerous levels of ionising radiation and also measure cumulative radiation exposure.

Patient decontamination

All patients suspected of being exposed to a CBRN agent should undergo decontamination unless agent identification has occurred and decontamination is deemed unnecessary (e.g. asymptomatic after cyanide gas exposure).

Clothing removal is the first and most important phase of decontamination as the clothes hold 90% of the contaminant load (liquid chemical or radioactive material). Removed clothing should be placed in a sealed container marked with the patient’s name for evidence collection and possible repatriation.

Once clothes are removed any remaining surface contaminants are removed using the RINSE–WIPE–RINSE method of decontam- ination (Figure 34.5). For ambulatory patients this will usually be

RINSE – WIPE – RINSE Decontamination technique

Step 1 RINSE

Gently wash affected areas with soapy water (0.9% saline for open wounds and eyes) this dilutes the contaminant and removes particles and water based chemicals

Step 2 WIPE

Wipe affected areas gently but thoroughly with sponge or soft brush or washcloth: this removes organic chemicals and petrochemicals

Step 3 RINSE

Gently rinse affected areas

Figure 34.5 Decontamination – ‘Rinse–Wipe–Rinse’.

Nutbeam, T., & Boylan, M. (Eds.). (2013). Abc of prehospital emergency medicine. John Wiley & Sons, Incorporated. Created from apus on 2023-10-16 21:30:32.

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Emergency Preparedness: Chemical, Biological, Radiation and Nuclear Incidents 187

Figure 34.6 Mass decontamination (Courtesy Mr David Broomfield of Hampshire Fire and Rescue Service).

undertaken in a formal decontamination shower tent (Figure 34.6), except when numbers are large when improvised mass decontam- ination may be employed using standard fire service equipment. Non-ambulatory casualties should be decontaminated by decon- tamination teams in formal decontamination tents. Roller systems may be employed to improve casualty flow though such a system. Water from decontamination procedures should be collected, but may be directed to storm drains if no other option is available. Rescuers that have been operating within the warm or hot zones will also require decontamination (Figure 34.7).

Figure 34.7 Decontamination of rescuers (Courtesy Mr David Broomfield of Hampshire Fire and Rescue Service).

Chemical casualties

Chemical casualties generally present shortly after exposure, making it easier to determine that a release has occurred. Latency of symptoms ranges from seconds to about a day. Agent detection equipment may assist in early identification of some chemical agents. Chemical agents fall into four major classes: nerve agents, cyanides, vesicants and pulmonary agents.

Nerve agents (e.g. Sarin, VX) inhibit the enzyme acetyl- cholinesterase, which breaks down the neurotransmitter acetylcholine leading to overstimulation of the parasympathetic nervous system and progressive motor paralysis. Mild exposure leads to eye irritation, pain and miosis. Moderate exposure is characterized by parasympathetic cholinergic symptoms : saliva- tion, lacrimation, urination, defecation, gastrointestinal distress and emesis (SLUDGE). Bronchospasm and sweating are also seen at this stage. Severe exposure is characterized by progressive paralysis of the respiratory muscles, seizures and death. Treatment is with atropine, and oxime (e.g. pralidoxime/obidoxime) antidote kits along with supportive care for seizures (e.g. diazepam) and respiratory failure (e.g. ventilation). Atropine and pralidoxime are available in autoinjectors that can be deployed forward in the hot or warm zone if required (Figure 34.8). After decontamination atropine should be titrated to relief of symptoms (e.g. drying of secretions), not to heart rate or amount of pupillary dilation. Large amounts may be required.

Cyanides are chemical asphyxiants that inhibit mitochondrial enzymes within cells and prevent normal aerobic respiration. Severe exposure can cause death within minutes, with victims experiencing dyspnoea, hypotension and syncope, followed by cardiorespira- tory arrest. These patients are likely to die before the prehospital responders arrive. Moderate exposure may lead to confusion and hyperventilation. These patients have a significant metabolic aci- dosis due to excessive anaerobic cellular respiration. Patients with milder exposures present with nausea, dizziness and agitation. Cyanide antidote kits (e.g. dicobalt edetate or sodium/amyl nitrite and sodium thiosulphate) must be rapidly administered after

Figure 34.8 Nerve agent autoinjector (atropine/pralidoxime).

Nutbeam, T., & Boylan, M. (Eds.). (2013). Abc of prehospital emergency medicine. John Wiley & Sons, Incorporated. Created from apus on 2023-10-16 21:30:32.

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188 ABC of Prehospital Emergency Medicine

decontamination in severe or moderate exposures (long before laboratory verification of the agent will be available) to be effective. Near-patient lactate testing may help identify this patient set. All cyanide casualties should be given high-flow oxygen.

Vesicants such as mustard or Lewisite damage DNA, result- ing in cell death within exposed tissue of the skin and airways. Symptoms develop over minutes to hours, with ocular involve- ment (pain, irritation) being followed by respiratory symptoms (irritation, inhalational burns, acute lung injury) and then by skin blistering. Decontamination and symptomatic burn management are required.

Pulmonary agents such as chlorine and phosgene damage the cell membranes within the respiratory tract and lungs leading to progressive airway irritation, pulmonary oedema and in severe exposures death. Symptoms can present rapidly, although some may be delayed by hours. Mild exposure causes eye irritation alone. Supportive care is appropriate with oxygen and ventilatory support if required.

Biological casualties

Delayed presentation often complicates the presentation of bio- logical casualties, and it can be difficult to initially discriminate between a few sick patients and a group of victims intentionally exposed to a biological agent. Additionally, many biological agents that are considered to be possible components of biowarfare or bioterrorism plots are also endemic to certain areas of the world (e.g. anthrax), further complicating the identification of a biological release. Consequently, a high index of suspicion regarding unusual clusters of disease or presentations of a disease unusual to the area or in the wrong season is key to identifying a biological agent exposure and initiating the investigative process.

Although diseases caused by bioterror agents have a wide range of presentations, courses and treatments, they are similar in that they do not require specific prehospital therapy. Supportive care, along with attention paid to appropriate standard precautions, constitute the mainstay of prehospital management. If a patient is known or strongly suspected to suffer from a contagious illness, the local medical director may consider instituting a destination system that takes resources such as isolation beds and ventilator capacity into account. Consideration may also need to be given to designated transport teams and equipment (e.g. patient isolation unit) in an effort to minimize contamination of non-infected individuals (Figure 34.9).

Radiological and nuclear casualties

Presentation of radiological casualties can occur any time, from immediately after an exposure to weeks later depending on the dose and type of radiation source. Delayed presentations can lead to challenges in establishing the correct diagnosis. These radia- tion exposed patients may have disorders of several organ systems, including the integumentary (skin), gastrointestinal, nervous, car- diac, and haematopoietic systems. Nuclear casualties, in contrast, are promptly exposed to high levels of radiation, and if they are in the area of the detonation are also exposed to typical explosive/blast

Figure 34.9 Biological patient isolation unit (Courtesy of Gentex).

effects such as pressure waves, thermal exposure, and debris-related injuries including shrapnel.

Once stabilized from potentially life-threatening traumatic injuries, patients exposed to radiation should undergo prompt decontamination to avoid spreading particles of radioactive material; once decontaminated, there is minimal risk to healthcare providers (who should still, as a matter of course, observe standard precautions). Pure radiation exposure without contact with any material does not cause a patient to become radioactively dangerous to others. Patients who have ingested radioactive material may receive decorporation therapy at the hospital, but are not likely to be a significant source of exposure to prehospital personnel. A few specific types of radiation sources, when ingested, are amenable to particular antidotal therapies; however, these are not sufficiently time critical to require field antidote treatment unless the event is of sufficient magnitude to overwhelm local transportation and hospital resources. Radioisotopes that have specific antidotes include 131I and 137Cs.

Dirty bomb A dirty bomb, or radiological dispersion device (RDD), consists of radioactive material incorporated into a conventional explosive device. When detonated, there is not a nuclear event, but radioactive material is dispersed into the area in addition to the typical sequelae of an explosion. In these events, the victims are at much higher immediate risk from explosion-related trauma than the radiation exposure, and should be treated as trauma patients. When possible, after immediate life-stabilizing treatment, decontamination can then be performed to minimize spread of radiation and risk to healthcare personnel. Additional debridement and decorporation therapy will probably be provided in the hospital setting. As with any radiation exposure, the principle of ‘time–distance–shielding’ is paramount, i.e. providers should minimize the amount of time of exposure to contaminated patients or radioactive sources, increase the distance between themselves and the source(s) and separate themselves by physical barriers when possible (e.g., lead shields, buildings). Personal dosimeters can help identify and monitor ongoing radiological hazards.

Nutbeam, T., & Boylan, M. (Eds.). (2013). Abc of prehospital emergency medicine. John Wiley & Sons, Incorporated. Created from apus on 2023-10-16 21:30:32.

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Emergency Preparedness: Chemical, Biological, Radiation and Nuclear Incidents 189

Summary

• CBRN events require special consideration beyond typical pre- hospital responses.

• Providers and facilities may need to delay patient care to assure their own safety

• Standard precautions are the most basic standard for provider protection; specially trained providers working closer to the actual incident sites may require higher-level protection.

• Clothing removal, followed by washing with mild soap and water is the most widely applicable and effective decontamination method.

• Some chemicals have specific antidotes that need to be used rapidly to be effective.

Tips from the field

• If a CBRN event is suspected do not proceed into the scene, remain uphill and upwind and inform control immediately

• As it may be difficult to identify CBRN events, standard precautions are advisable for all multiple casualty responses

• Use basic decontamination measures on all patients with suspected exposures

• Be suspicious of odd presentations of patients, such as clusters of unusual disease, events following a terror warning or witnessed exposure to unknown powders, fumes or liquids followed by onset of symptoms.