1.The following disease agents are believed to have the greatest potential for bioter- rorism:
a. Anthrax (bacteria) b.Tularemia (bacteria) c. Plague (bacteria) d.Smallpox (virus)
e. Viral hemorrhagic fevers (virus) f.Botulinum (toxin)
2.The route of exposure of greatest concern with biologic terrorist attacks is inhalation of the agent. Oral routes of exposure for biologic agents are less important but still significant. Ensuring that food and water supply is free of contamination is an important function of public health after a biologic attack.
Dermal exposure is unusual but possible, especially if the skin is damaged.
3.The most effective and important prophylaxis against biologic agents is phys- ical protection. A full-face respirator prevents exposure of the respiratory and mucous membranes to infectious agents. Dermal exposures should be treated immediately by washing with soap and water.
4.Identification of an attack with biologic agents is often challenging. Symptoms may be delayed during an incubation period, victims may present to a variety of practitioners for care, (i.e., EDs, urgent care centers, or family physicians) and often symptoms may mimic more common disease entities such as influenza.
Early recognition of a bioterrorism event is the key to success. The following are indications of a possible biologic attack:
a. Disease entity that is unusual or does not occur naturally in a given geographic area
b.Suspected aerosol route of exposure c. Massive point-source outbreak d.High morbidity and mortality
Chapter 18 rDisasters, Mass Casualty Incidents 191 E. Chemical agents.Chemical agents have been used in warfare and are now part of the terrorist armamentarium. Chemicals used for terrorism may be military chem- ical weapons, industrial chemicals, or chemicals created de novo.
1.The potential results of a chemical attack include:
a. Inflicting mass casualties
b.Harm to first responders and hospital personnel c. Hysteria, anxiety, and panic in the general population
2.Most chemical warfare agents are liquids. Chemical agents in liquid form must be dispersed in order to be maximally effective. This can be done in three general ways:
a. Aerosolizing with an aerial sprayer (such as done with pesticides) b.Aerosolizing in an explosion
c. Allowing the liquid to evaporate and dispersing the vapor
3.Often the offending chemical agent is unknown. This can delay the appropriate treatment including the administration of antidotes. Knowing the toxidromes associated with each class of chemical agents may help speed the identification of the agent and provide insight into treatment options.
4.The five principle classes of chemical agents and their toxidromes are:
a. Nerve agents. Including sarin, tabun, soman, VX
i. Presentation includes cholinergic crisis: Salivation, lacrimation, urina- tion, gastrointestinal symptoms, miosis, weakness, and seizures.
ii. Exposure is typically via aerosolized liquid. Toxicity can occur from direct contact with the skin.
iii. Treatment includes decontamination, symptomatic treatment (benzo- diazepines for seizures) and the administration of antidotes including atropine, and 2-PAM.
b.Vesicants (blistering agents). Mustard agents and Lewisite are examples of vesicants.
i.Exposure to gas or liquid causes skin erythema, ocular burns, systemic symptoms including shock.
ii.Treatment includes decontamination and treatment of symptoms.
c. Blood agents. Cyanide and carbon monoxide are blood agents.
i. Symptoms include dyspnea, tachycardia, confusion, arrhythmias and coma.
ii. Exposure varies by the agent but in general can occur by inhalation or ingestion.
iii. Treatment includes removal from the exposure, oxygen, and the use of antidotes for cyanide (sodium nitrate or hydroxocobalamin).
d.Pulmonary agents. Chlorine and phosgene are pulmonary agents.
i.These agents cause cutaneous irritation, ocular burning, and respiratory symptoms that can progress to pulmonary edema. Exposure is typically inhalation.
ii.Treatment is symptomatic.
e. Riot control agents
i.There are a variety of riot control agents (often called “tear gas”) that temporarily incapacitate individuals by causing lacrimation, sneezing, and respiratory distress.
ii.Symptoms are self-limiting and treatment is supportive.
F. Radioactive agents.Radioactive material from medical, industrial, military, or clandestine sources could be used in a terrorist attack. Like all of the other forms of WMDs, radiation has a high potential to cause mass destruction and hysteria. While the detonation of a nuclear weapon is highly unlikely, the possibility of exposure to radioactive material via explosion of a conventional weapon contaminated with nuclear material is real.
1.Nuclear material use by terrorists would likely involve one of four scenarios:
a. detonation of a nuclear device b.meltdown of a nuclear reactor
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c. Dispersal of material through use of conventional explosives: A radiation dis- persal device (RDD) or “dirty bomb.” Some first responder agencies routinely monitor all explosion scenes for radiation.
d.Exposure to nuclear material (i.e., placing radioactive materials in public places).
2.Irradiation versus contamination. A key factor is to understand the difference between irradiation versus contamination.
a. Casualties who have been irradiated but have not had radioactive material deposited on or in their bodies (“fallout”) are not themselves radioactive.
These patients have been exposed to radiation but do not pose a contamina- tion risk to responders or hospital personnel. Since the clinical effects of all but the most severe radiation exposures are delayed, the clinical presentation of exposed casualties will be primarily related to conventional injuries, and normal trauma triage procedures should be employed.
b.External contamination occurs when radioactive material is deposited on the outside of the body. Internal contamination is the result of radioactive mate- rial entering the body via ingestion, inhalation, or wounds. Contaminated victims can expose and contaminate responders and hospital personnel. How- ever, use of standard universal precautions will allow medical personnel to provide life-saving treatments (i.e., establishing an airway, treating a tension pneumothorax, etc.).
i. The majority of external contamination can be removed by undressing victims. Skin can be cleaned with copious amounts of soap and water.
Special attention should be paid to the hair and intertriginous areas where radioactive material can collect.
ii. Open wounds must be decontaminated to remove radioactive material and protected during total body decontamination.
c. Internal contamination must be prevented. Pharmacologic agents can be used to remove or chelate specific radiologic agents. Consultation of local radi- ologic experts or the Radiation Emergency Assistance Center/Training Site (REAC/TS 865-576-1005) can guide therapy.
3.Involve local radiation safety experts. Because of military, industrial, and health care experience with radiation, local expertise is often available.
a. Many jurisdictions and most hospitals have radiation safety personnel. They can assist with patient screening, emergency personnel monitoring, and decontamination issues.
b.Radiation oncologists deal with therapeutic exposures to radiation on a daily basis. They can assist with patient monitoring and therapy.
4.Key points with respect to the care of victims from a WMD event with potential radiation exposure/contamination:
a. Consider screening casualties from any event involving an explosion for radi- ation contamination. Some hospitals have placed screening devices in their EDs. Note that patients and staff that have received diagnostic or therapeutic doses of radiation may also trigger these devices.
b.If possible, remove the victim’s clothing prior to or immediately upon arrival at the hospital. This removes a considerable amount of the radioactive con- tamination. Note that the clothing, once removed, still has the potential to contaminate and irradiate hospital personnel. Potentially contaminated items should be placed in a safe and secure area away from people.
c. Treat life-threatening injuries.
d.Decontaminate wounds and skin.
i. Protect wounds from re-contamination. Use monitoring devices (i.e., Geiger counters) to measure the need for additional decontamina- tion.
ii. Address internal contamination if required.
e. Limit the exposure of emergency and hospital personnel.
i. Exposure can be reduced by the following principles:
a)Time. Rotate personnel to limit the exposure of any one individual.
Chapter 18 rDisasters, Mass Casualty Incidents 193 b) Distance. Radiation exposure decreases as the square of the distance from the source. Care givers should stay at a distance from contami- nated patients until required to perform an evaluation or intervention.
c) Shielding. Most low-level radiation will not penetrate standard hospi- tal protective gowns. Protection from higher energy radiation requires significant shielding. (Much more than a standard lead apron.) ii.Use monitoring devices to estimate exposure.
f.Avoid contamination of hospital.
i.Preplan areas of the ED and hospital that will be used to care for poten- tially contaminated patients.
ii.Determine paths of entrance and exit from care areas to minimize con- tamination of the hospital.
g. Involve local radiation safety experts.
AXIOMS
■Disasters are complex events that can include a broad spectrum of threats and challenges.
The location and nature of the next disaster cannot be predicted. An all-hazards approach is a key principle of disaster preparedness.
■Disaster medical care is fundamentally different from conventional medical care. Disaster medical care attempts to provide the greatest good for the greatest number of patients.
■While the nature and locations of disasters may vary, there are common themes in every event including the need to address basic medical care and public health concerns.
■Hospitals must be prepared to receive multiple casualties over a short time period. Triage and unidirectional patient flow guidelines must be in place prior to an event.
■Mass casualty events with the accidental or intentional release of toxic or infectious mate- rials are the most challenging for responders. Nuclear, biologic, and chemical weapons can contaminate victims and the environment putting responders and hospital personnel at risk.
■Responders and hospitals must be prepared to deal with psychogenic casualties that may prevail during WMD events.