Prehospital Care
An important concept to keep in mind is that rescue personnel, if not properly protected, can become victims. The cornerstones of prehospital management are based on rapid termination of the exposure, treating any life-threatening emergencies, and administration of antidotes, whenever indicated and available.
Ideally, decontaminate prior to transportation of the victim. Move decontaminated victims to a clean area to prevent cross-contamination of patients and medical personnel. Decontamination techniques vary with the extent and route of exposure. Based on the Tokyo sarin attack and other mass casualty experiences, as many as 85% of victims may present directly to hospitals. This means that hospital personnel must also be trained in terrorism response, including self-protection, triage, treatment, and decontamination.
Prehospital management includes the following:
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With a vapor exposure, removal of the victim from the area of contamination, disrobing, and provision of fresh air are the most important steps, and often the only ones needed
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If the exposure is dermal, undress the patient. If droplets can be seen, blot them away without forceful wiping. Abrading the skin increases absorption of the agent. In general, agents are best removed with copious amounts of soap and water followed by a water rinse. However, avoid unnecessary delays of decontamination while looking for soap if water is readily available. Agent neutralization and use of dilute bleach are no longer recommended for decontamination. [16]
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In a study conducted by Josse and colleagues, showering hair with water one-hour post exposure led to 72% reduction of contamination of agent VX. The addition of detergent slightly increased the decontamination effectiveness. Hair treatment with Fuller's Earth (FE) or the Reactive Skin Decontamination Lotion (RSDL) 30 min prior to showering also improved the decontamination rate. The combination of FE use and showering, which yielded a decontamination factor of 41, was demonstrated to be the most effective hair decontamination procedure. In addition, hair wiping after showering further contributed to hair decontamination. These results of highlight the importance of including hair decontamination as part of decontamination protocols. [17]
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The military has developed Autoinjector kits (Mark 1 kits) that contain two antidotes, an oxime (an AChE reactivator) and atropine. Antidote Treatment Nerve Agent Autoinjector (ATNAA) kits combine both antidotes in a single autoinjector and are now available. Some ambulance systems and hazardous materials (HAZMAT) teams also have these kits available to use in the prehospital setting. These kits also are now available commercially.
During a mass casualty incident, most patients arrive to the emergency department (ED) without the benefit of emergency medical services (EMS) or HAZMAT team treatment. In the Tokyo subway sarin attack, 85% of patients arrived by private car. This emphasizes the importance of proper planning, decontamination facilities, training, and personnel at the ED, since most victims are likely to be contaminated upon their arrival at the hospital.
Emergency Department Care
If decontamination has not occurred, ED personnel should be able to provide this intervention prior to the patient's entrance to the hospital. If weather permits, decontamination stations can be set up outside.
All hospital personnel in contact with contaminated individuals must wear full personal protective equipment (PPE) at the A, B, or C levels.
Level A PPE refers to the highest level of respiratory protection and protective clothing. It is a fully encapsulated, chemical-resistant, vapor-protective suit that provides vapor protection to the respiratory and mucous membranes and skin. A self-contained breathing apparatus (SCBA) with a full face piece must be worn inside the suit.
Level B still provides the highest level of respiratory protection with SCBA but with a lesser level of skin protection. level B suits are not encapsulated and do not protect the skin from vapor exposures.
Level C provides respiratory protection with Air Purifying Respirators (APR) using filters appropriate for chemical incident response. Not approriate for use at the incident site, they may be a safe and reasonable alternative to level A or B suits for hospital-based first receivers (ie, healthcare workers at a hospital receiving contaminated victims for treatment).
The Occupational Safety & Health Administration (OSHA) has developed a set of best practices for hospital-based first receivers of victims from mass casualty incidents involving the release of hazardous substances. These cover both PPE and training of first receivers. Also see CBRNE - Chemical Decontamination.
Medical management in the ED is discussed in the Medication section.
Consultations
Whenever the diagnosis of nerve agent exposure is suspected, contact the regional poison center for treatment advice (1-800-222-1222). In a multiple casualty incident, activate the hospital emergency plan and notify local authorities.
Tables
Code Name |
Chemical Name |
VX |
O-Ethyl-S-[2(diisopropylamino)ethyl] methylphosphonothioate |
VE |
O-Ethyl-S-[2-(diethylamino)ethyl] ethylphosphonothioate |
VG |
O,O-Diethyl-S-[2-(diethylamino)ethyl] phosphorothioate |
VM |
O-Ethyl-S-[2-(diethylamino)ethyl] methylphosphonothioate |
V-gas |
Russian equivalent of VX |
Agent |
LCt50 (mg ⋅ min/m3) |
LD50 (mg) |
Aging Half-Life |
Tabun (GA) |
400 |
1000 |
46 h |
Sarin (GB) |
100 |
1700 |
5.2-12 h |
Soman (GD) |
50 |
100 |
40 sec to 10 min |
VX |
10 |
10 |
50-60 h |
Receptor Involved |
Clinical Effect |
Acetylcholine, GABA, N -methyl-D -aspartate: Central (CNS) |
Anxiety, restlessness, seizures, failure to concentrate, depression, coma, apnea |
Acetylcholine: Muscarinic Postganglionic parasympathetic |
"DUMBELS" (commonly used mnemonic) D - Diarrhea U - Urination M - Miosis B - Bronchorrhea, bronchoconstriction E - Emesis L - Lacrimation S - Salivation Note: The other commonly used mnemonic "SLUDGE" is not used here, as it does not include an important sign and symptom: bronchorrhea and bronchoconstriction. |
Acetylcholine: Nicotinic Motor endplate Sympathetic and parasympathetic ganglia |
Pallor, tachycardia, hypertension, muscle weakness and/or paralysis, fasciculations Note: Some use the days of the week as an easy mnemonic for these: M - Mydriasis T - Tachycardia W - Weakness tH - Hypertension F - Fasciculations |
* Adapted from Marrs, Maynard, and Sidell. [10] |
|
Severity of Exposure |
Signs and Symptoms - Liquid |
Signs and Symptoms - Vapor |
Onset of symptoms |
Possibly delayed toxicity |
Rapidly manifesting toxicity |
Minimal |
Localized sweating at site Localized fasciculations at site |
Miosis Rhinorrhea Mild dyspnea |
Moderate |
Fasciculations Diaphoresis Nausea, vomiting, and diarrhea Generalized weakness |
Above symptoms and the following: Moderate-to-marked dyspnea (bronchorrhea and/or bronchoconstriction) |
Severe |
Above symptoms and the following: Loss of consciousness Seizures Generalized fasciculations Flaccid paralysis and apnea |
Above symptoms and the following: Loss of consciousness Seizures Generalized fasciculations Flaccid paralysis and apnea |
Drug |
Dose |
Route |
Indications |
Contraindications |
Atropine |
2 mg q5-10min prn Note: the Mark 1 kit contains 2 mg of atropine |
IV/IM/ETT |
Excessive muscarinic symptoms |
Relative - IV route in hypoxia has been associated with ventricular fibrillation |
2-PAM Cl (pralidoxime chloride, Protopam) |
15-25 mg/kg over 20 min; can be repeated after 1 h Note: The Mark 1 kit contains 600 mg of pralidoxime. |
IV/IM |
Symptomatic nerve agent poisoning |
Rapid infusion may result in hypertension |
Diazepam (Valium) |
2-5 mg IV or 10 mg IM |
IV/IM |
Active seizures; administer as prophylaxis if moderate or severe signs of poisoning are present |
None |
*Adapted from Sidell. |
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Severity/Route of Exposure |
Atropine |
2-PAM Cl |
Diazepam |
Other |
Suspected |
No |
No |
No |
Decontamination and 18-h observation for liquid exposures |
Mild |
2 mg for severe rhinorrhea or dyspnea; may repeat prn |
Administer if patient has nonimproving dyspnea or GI symptoms |
No |
Decontamination and 18-h observation for liquid exposures; oxygen |
Moderate |
6 mg; may require repeat doses |
Administer with atropine |
Administer even in absence of seizures |
Decontamination, oxygen |
Severe |
Start with 6 mg; may need to repeat |
Administer with atropine; should repeat once or twice |
Administer even in absence of seizures |
ABCs, decontamination |
*Adapted from Sidell. |
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