CBRNE - Nerve Agents, V-series - Ve, Vg, Vm, Vx Treatment & Management

  • Author: Daniel C Keyes, MD, MPH; Chief Editor: Robert G Darling, MD, FACEP   more...
 
Updated: Mar 16, 2010
 

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.
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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.

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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.

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Contributor Information and Disclosures
Author

Daniel C Keyes, MD, MPH  Vice Chair, Academic Affairs, Department of Emergency Medicine, John Peter Smith Health Network; Clinical Associate Professor, Department of Surgery, Division of Emergency Medicine and Toxicology, University of Texas Southwestern School of Medicine

Daniel C Keyes, MD, MPH is a member of the following medical societies: American College of Emergency Physicians, American College of Medical Toxicology, American College of Occupational and Environmental Medicine, and American College of Physicians-American Society of Internal Medicine

Disclosure: Nothing to disclose.

Coauthor(s)

Fernando L Benitez, MD  Assistant Medical Director, Dallas Metropolitan BioTel (EMS) System; Associate Professor in Emergency Medicine, Department of Surgery, Division of Emergency Medicine, University of Texas Southwestern Medical Center and Parkland Health and Hospital

Fernando L Benitez, MD is a member of the following medical societies: American College of Emergency Physicians, American Medical Association, and National Association of EMS Physicians

Disclosure: Nothing to disclose.

Larissa I Velez-Daubon, MD  Associate Professor, Associate Program Director, Department of Surgery, Division of Emergency Medicine, University of Texas Southwestern Medical School, Parkland Memorial Hospital; Associate Program Director and Staff Toxicologist, Department of Surgery, Division of Emergency Medicine, North Texas Poison Center, Parkland Memorial Hospital

Larissa I Velez-Daubon, MD is a member of the following medical societies: Alpha Omega Alpha, American College of Emergency Physicians, American College of Medical Toxicology, and Society for Academic Emergency Medicine

Disclosure: Nothing to disclose.

Specialty Editor Board

Fred Henretig, MD  Director, Section of Clinical Toxicology, Professor, Medical Director, Delaware Valley Regional Poison Control Center, Departments of Emergency Medicine and Pediatrics, University of Pennsylvania School of Medicine, Children's Hospital

Disclosure: Nothing to disclose.

Francisco Talavera, PharmD, PhD  Senior Pharmacy Editor, eMedicine

Disclosure: eMedicine Salary Employment

Rick Kulkarni, MD 

Rick Kulkarni, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Emergency Medicine, American College of Emergency Physicians, American Medical Association, American Medical Informatics Association, Phi Beta Kappa, and Society for Academic Emergency Medicine

Disclosure: WebMD Salary Employment

John D Halamka, MD, MS  Associate Professor of Medicine, Harvard Medical School, Beth Israel Deaconess Medical Center; Chief Information Officer, CareGroup Healthcare System and Harvard Medical School; Attending Physician, Division of Emergency Medicine, Beth Israel Deaconess Medical Center

John D Halamka, MD, MS is a member of the following medical societies: American College of Emergency Physicians, American Medical Informatics Association, Phi Beta Kappa, and Society for Academic Emergency Medicine

Disclosure: Nothing to disclose.

Chief Editor

Robert G Darling, MD, FACEP  Adjunct Clinical Assistant Professor of Military and Emergency Medicine, Uniformed Services University of the Health Sciences, F Edward Hebert School of Medicine; Associate Director, Center for Disaster and Humanitarian Assistance Medicine

Robert G Darling, MD, FACEP is a member of the following medical societies: American College of Emergency Physicians, American Medical Association, American Telemedicine Association, and Association of Military Surgeons of the US

Disclosure: Nothing to disclose.

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Chemical Terrorism Agents and Syndromes. Signs and symptoms. Chart courtesy of North Carolina Statewide Program for Infection Control and Epidemiology (SPICE), copyright University of North Carolina at Chapel Hill, www.unc.edu/depts/spice/chemical.html.
Table 1. Code and Chemical Names for the V-Series Agents
Code NameChemical Name
VXO-Ethyl-S-[2(diisopropylamino)ethyl] methylphosphonothioate
VEO-Ethyl-S-[2-(diethylamino)ethyl] ethylphosphonothioate
VGO,O-Diethyl-S-[2-(diethylamino)ethyl] phosphorothioate
VMO-Ethyl-S-[2-(diethylamino)ethyl] methylphosphonothioate
V-gasRussian equivalent of VX
Table 2
AgentLCt50 (mg·min/m3)LD50 (mg)Aging Half-Life
Tabun (GA)400100046 h
Sarin (GB)10017005.2-12 h
Soman (GD)5010040 sec to 10 min
VX101050-60 h
Table 3. Pharmacologic Effects of Nerve Agents*
Receptor InvolvedClinical 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.[1]
Table 4. Severity of Toxicity from Liquid and Vapor Exposures
Severity of ExposureSigns and Symptoms - LiquidSigns and Symptoms - Vapor
Onset of symptomsPossibly delayed toxicityRapidly manifesting toxicity
MinimalLocalized sweating at site



Localized fasciculations at site



Miosis



Rhinorrhea



Mild dyspnea



ModerateFasciculations



Diaphoresis



Nausea, vomiting, and diarrhea



Generalized weakness



Above symptoms and the following:



Moderate-to-marked dyspnea (bronchorrhea and/or bronchoconstriction)



SevereAbove 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



Table 5. Drugs Used to Treat Nerve Agent–Poisoned Patients*
DrugDoseRouteIndicationsContraindications
Atropine2 mg q5-10min prn



Note: the Mark 1 kit contains 2 mg of atropine



IV/IM/ETTExcessive muscarinic symptomsRelative - 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/IMSymptomatic nerve agent poisoningRapid infusion may result in hypertension
Diazepam (Valium)2-5 mg IV or 10 mg IMIV/IMActive seizures; administer as prophylaxis if moderate or severe signs of poisoning are presentNone
*Adapted from Sidell.
Table 6. Summary of Treatment Modalities According to Severity of Exposure*
Severity/Route of ExposureAtropine2-PAM ClDiazepamOther
SuspectedNoNoNoDecontamination and 18-h observation for liquid exposures
Mild2 mg for severe rhinorrhea or dyspnea; may repeat prnAdminister if patient has nonimproving dyspnea or GI symptomsNoDecontamination and 18-h observation for liquid exposures; oxygen
Moderate6 mg; may require repeat dosesAdminister with atropineAdminister even in absence of seizuresDecontamination, oxygen
SevereStart with 6 mg; may need to repeatAdminister with atropine; should repeat once or twiceAdminister even in absence of seizuresABCs, decontamination
*Adapted from Sidell.
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