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Nerve Agents (GA, GB, GD, GF, VX) Tabun (GA), Sarin (GB), Soman (GD)

Nerve Agents (GA, GB, GD, GF, VX)
Tabun (GA), Sarin (GB), Soman (GD)

Diagnosis

1.
Vapor; small exposure: miosis (takes up to 2 mths to normalize), rhinorrhea, mild difficulty breathing

2.
Liquid on skin; small to moderate exposure: localized sweating, nausea, vomiting, feeling of weakness

3.
Large exposure (vapor or skin): loss of consciousness, convulsions (soman likely), apnea, flaccid paralysis, miosis, copious secretions, sinus bradycardia

4.
Lab: erythrocyte cholinesterase activity; levels <10% of normal indicates severe exposure
History

1.
Developed in pre-WWII Germany

2.
US has stockpiles contains the nerve agents sarin (GB) and VX

3.
Matsumoto GB attack 1994

4.
Tokyo subway GB attack 1995
Pathophysiology

1.
Organic esters of phosphoric acid; cause cholinergic syndromes through AChE inhibition

2.
Most toxic of known chemical agents; liquids

3.
Tabun (GA), Sarin (GB), Soman (GD)

4.
Lethal dermal dose (70 kg adult):

Sarin: 1.7 g

Tabun: 1 g

Soman: 100 mg

VX: 6 mg

5.
Onset of action (G compounds): 5 mins by inhalation; 1 hr by dermal

6.
G agents are volatile: dermal and inhalation threat

7.
VX: low volatility; dermal threat

8.
Agent: LCt50; ICt50; MCt50; LD50 (skin):

GA: 400; 300; 2-3;1000

GB: 100; 75; 3; 1700

GD: 70; UNK; <1; 50

GF: UNK; UNK; <1; 30

VX: 50; 35; 0.04; 10
Decontamination

1.
M291 kit

2.
M258A1 kit

3.
1-5% Hypochlorite soln; can destabilize these agents

4.
Contaminated equipment: 10% hypochlorite soln

5.
Large amounts of water

6.
If bleach not available use gentle blotting with alkaline soap
Treatment

1.
Charcoal if ingested

2.
Pretreatment: pyridostigmine bromide 30 mg q8h x 21 tabs (esp soman)

3.
MARK I Kits (atropine 2 mg & pralidoxime chloride 600 mg)

4.
Diazepam 10 mg to decrease convulsive activity and reduce brain damage caused by prolonged seizure activity

5.
Pralidoxime chloride:

IV 1-2 g over 10 mins

Repeat in 1 hr if weakness occurs then q4-12h

Give within 3 hrs post sarin exposure; may not work for tabun or soman

6.
Obidoxime:

May work against tabun, sarin or GF

250 mg IM or slow IV

Repeat q2h up to total of 750 mg

7.
Atropine 10-20 mg IV cumulatively in 2-3 hrs; warfare agents require < insecticides

8.
Moderate skin exposure: 1 Mark I kit; 18 hr observation

9.
Severe skin exposure: 3 Mark I kits & diazepam

10.
Ventilate & suction airway for respiratory distress

11.
100% O2
Disposition

1.
Admit

2.
Notify CDC & local health dept
Military Detection/Treatment Kits
(See Chemical Agent ID/Detection)

1.
M256A1, CAM, M8 paper, M9 paper, M8A1, M8

* Material is taken from the PEPID database
* Copyrighted material – All Rights Reserved
* For more information visit http://www.pepid.com

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One comment on “Nerve Agents (GA, GB, GD, GF, VX) Tabun (GA), Sarin (GB), Soman (GD)

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