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CBRNE - Nerve Agents, V-series: Ve, Vg, Vm, Vx: Treatment & Medication
Updated: Dec 19, 2007
- Overview
- Differential Diagnoses & Workup
- Treatment & Medication
- Follow-up
- Multimedia
Treatment
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.
- With a vapor exposure, removal of the victim and provision of fresh air is the most important step, and often the only one needed.
- 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. Agents also can be neutralized with alkaline solutions such as soap and water or 0.5% hypochlorite solution, which releases chlorine, followed by a water rinse. However, avoid unnecessary delays of decontamination while looking for hypochlorite solution if simple soap and water is readily available.
- The military has developed Autoinjector kits (Mark 1 kits) that contain 2 antidotes, an oxime (an AChE reactivator) and atropine. 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 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 either the A or B 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.
- 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.
Medication
Table 5 summarizes different agents used to treat nerve agent–poisoned patients. Table 6 provides an overview of general treatment guidelines.
Table 5. Drugs Used to Treat Nerve Agent–Poisoned Patients*
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Table
Drug | Dose | Route | Indications | Contraindications |
Atropine | 2 mg q5-10min prn | 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 | 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 |
Drug | Dose | Route | Indications | Contraindications |
Atropine | 2 mg q5-10min prn | 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 | 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 |
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Table
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 |
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 |
Gases
All but the mildest exposures have some degree of respiratory compromise. For this reason, oxygen should be readily available. Most of these symptoms result from bronchorrhea and bronchoconstriction and improve after administration of antidotes, especially atropine. In the severely poisoned patient, respiratory muscle paralysis adds to the problem. Intubation and mechanical ventilation are required for these patients.
Oxygen
Assists patients with respiratory compromise.
Adult
Supplement as needed
Pediatric
Supplement as needed
None reported
None reported
Pregnancy
A - Fetal risk not revealed in controlled studies in humans
Precautions
Inspired oxygen concentrations of 50-100% carry a substantial risk of lung damage if used over long periods of time (not considered important during emergency resuscitation of nerve agent victims)
Anticholinergic
Antagonizes ACh at the muscarinic receptor.
Atropine (Isopto, Atropair, Atropisol)
Antagonizes ACh at its receptor; acts only at muscarinic receptor, leaving nicotinic receptors unaffected; in contrast to organophosphate insecticides, nerve agents rarely require >20 mg; administer until excess muscarinic symptoms improve; this can be gauged by improved ease of breathing in conscious patient or improvement in ease of ventilation of intubated patient; airway patency is critical, life-saving endpoint in treatment.
Adult
Usual starting dose: 2 mg IV/IM/ETT; dose can be repeated after 5-10 min in boluses of 2-4 mg
Pediatric
Usual starting dose: 0.02 mg IV/ETT (minimal dose 0.1 mg); dose can be repeated q5-10min, titrated to clinical response
Coadministration with other anticholinergics has additive effects; pharmacologic effects of atenolol and digoxin may increase with atropine; antipsychotic effects of phenothiazines may decrease with this medication; TCAs with anticholinergic activity may increase effects of atropine
Documented hypersensitivity; thyrotoxicosis; narrow-angle glaucoma; tachycardia
Pregnancy
B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals
Precautions
Caution in Down syndrome and/or children with brain injury to the possibility of an exaggerated response; caution also in coronary heart disease, tachycardia, congestive heart failure, cardiac arrhythmias, hypertension, peritonitis, ulcerative colitis, hepatic disease, and hiatal hernia with reflux esophagitis; in prostatic hypertrophy, prostatism can have dysuria and may require catheterization
Oximes
Reactivators of AChE; 2-PAM Cl, also known as pralidoxime, is widely available in the US; administer concomitantly with atropine. After aging (irreversible binding of agent with AChE enzyme) occurs, usefulness of pralidoxime is negligible. VX has a slow aging process (aging half-life has been calculated at 48 h or more), so delayed treatment with oximes is considered beneficial. Pralidoxime has a half-life of 1 hour. Pralidoxime and TMB-4 have similar characteristics and are widely used outside of the US.
Another subset of oximes termed the H oximes (H is for Hagedorn) include agents such as HI-6, HGG-12, and HGG-42; studies exist using these antidotes in the military setting, but the drugs currently are not widely available for use in the US.
Pralidoxime (2-PAM Cl, Protopam)
Reactivators of AChE.
Adult
Recommended dose: 15-25 mg/kg IV/IM (military Autoinjectors are IM); infuse IV over 20 min to prevent hypertension (one of the most common complications); can repeat in 1 h if needed
Pediatric
Administer as in adults
Use barbiturates with caution because action of barbiturates is potentiated by AChE inhibitors; antagonism with neostigmine, pyridostigmine, and edrophonium; morphine, theophylline, aminophylline, succinylcholine, reserpine, and phenothiazines can worsen condition of patients poisoned by organophosphate insecticides or nerve agents (do not administer)
Documented hypersensitivity
Pregnancy
B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals
Precautions
Infuse IV dose over 20 min to prevent hypertension (one of most common complications), which usually is transient but can be treated with phentolamine (5 mg IV) if severe; rapid injection can cause tachycardia, laryngospasm, muscle rigidity, pain at injection site, blurred vision, diplopia, impaired accommodation, dizziness, drowsiness, nausea, tachycardia, hypertension, and hyperventilation; can precipitate myasthenia crisis in patients with myasthenia gravis and muscle rigidity in normal volunteers; decrease in renal function increases drug levels in the blood because 2-PAM is excreted in urine; can produce transient elevation in creatine phosphokinase; 1 of 6 patients has an elevation in SGOT and/or SGPT
Benzodiazepines
Seizures can result from severe nerve agent poisoning; for this reason, treatment with benzodiazepines has been advocated as part of the antidotal armamentarium. Experts advocate use in moderately-to-severely poisoned patients, even prior to seizure onset, as well as in actively seizing patients.
Diazepam (Valium, Diazemuls)
Belongs to benzodiazepine family, the members of which act by stimulating GABA, the main Inhibitory neurotransmitter in the CNS. Stimulation of GABA results in sedation and increased seizure threshold. The military has a 10-mg autoinjector form available, known as the CANA kit. Unlike the atropine and pralidoxime autoinjectors, this device is not used for self-administration.
Adult
2-5 mg IV or 10 mg IM
Pediatric
0.2-0.4 mg/kg IV
Increases toxicity of benzodiazepines in CNS with coadministration of phenothiazines, barbiturates, alcohols, and MAOIs
Documented hypersensitivity; narrow-angle glaucoma
Pregnancy
A - Fetal risk not revealed in controlled studies in humans
Precautions
Large doses can result in excessive sedation and potential airway compromise; caution with other CNS depressants, low albumin levels, or hepatic disease (may increase toxicity)
More on CBRNE - Nerve Agents, V-series: Ve, Vg, Vm, Vx |
| Overview: CBRNE - Nerve Agents, V-series: Ve, Vg, Vm, Vx |
| Differential Diagnoses & Workup: CBRNE - Nerve Agents, V-series: Ve, Vg, Vm, Vx |
 Treatment & Medication: CBRNE - Nerve Agents, V-series: Ve, Vg, Vm, Vx |
| Follow-up: CBRNE - Nerve Agents, V-series: Ve, Vg, Vm, Vx |
| Multimedia: CBRNE - Nerve Agents, V-series: Ve, Vg, Vm, Vx |
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Further Reading
Keywords
persistent agents, G agents, VX, O-ethyl S-(2-diisopropylaminoethyl) methylphosphonothioate, nerve agents, chemical warfare, V-series agents, Vx, Ve, Vg, Vm, V-series weapons, V agents
