Emergency Management of Nerve Agent Casualties

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Emergency Management of Nerve Agent Casualties
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Hospital Provider Management of Chemical Agent
Casualties
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EMS Management of Chemical Agent Casualties
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Objectives

• Describe physiological actions of nerve agents
• Recognize signs and symptoms of nerve agent
  exposure
• Describe emergency management of nerve agent
  victims

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Nerve Agents

• Tabun (GA), Sarin (GB), Soman (GD), VX
• Most toxic of the chemical agents
• Penetrate skin, eyes, lungs
• Loss of consciousness, seizures, apnea, death
  after large amount
• Diagnosis made clinically confirmed in
  laboratory (cholinesterase)

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Normal Nerve Function
ACh
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Normal Nerve Function
ACh
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Normal Nerve Function
AChE
ACh
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How Nerve Agents Work
AChE
GB
ACh
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Effects of Nerve Agents
Two types of cholinergic receptors

• Muscarinic
• Smooth muscles
• Exocrine glands
• Cranial nerves (vagus)
• Nicotinic
• Skeletal muscles
• Ganglia

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Signs and Symptoms of Nerve Agents Mnemonic

• SLUDGE-M
• Salivation
• Lacrimation
• Urination
• Defecation
• GI upset nausea/vomiting, cramps, diarrhea
• Emesis
• Muscle twitching

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Signs and Symptoms of Nerve Agents Newer Mnemonic

• DUMBELS
• Diarrhea
• Urination
• Miosis
• Bradycardia, Bronchorrhea, Bronchospasm
• Emesis
• Lacrimation
• Salivation, Sweating

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Signs and Symptoms of Nerve Agents Muscarinic
Sites

• Increased secretions
• Saliva
• Tears
• Runny nose
• Secretions in airways
• Secretions in gastrointestinal tract
• Sweating

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Signs and Symptoms of Nerve AgentsMuscarinic
Sites

• Smooth muscle contraction
• Eyes miosis
• Airways bronchoconstriction (shortness of
  breath)
• Gastrointestinal hyperactivity (nausea,
  vomiting, and diarrhea)

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Signs and Symptoms of Nerve Agents Nicotinic Sites

• Skeletal muscles
• Fasciculations
• Twitching
• Weakness
• Flaccid paralysis
• Other (ganglionic)
• Tachycardia
• Hypertension

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Nerve AgentsOther Signs and Symptoms

• Cardiovascular
• Tachycardia, bradycardia
• Heart block, ventricular arrhythmias
• Central Nervous System
• Acute
• Loss of consciousness
• Seizures
• Apnea
• Prolonged (4-6 weeks)
• Psychological effects

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Signs and Symptoms of Nerve Agents Vapor Exposure

• Mild exposure
• Miosis (dim vision, eye pain), rhinorrhea,
  dyspnea
• Moderate exposure
• Pronounced dyspnea, nausea, vomiting, diarrhea,
  weakness
• Severe exposure
• Immediate loss of consciousness, seizures, apnea,
  and flaccid paralysis
• Vapor effects occur within seconds, peak
  within minutes no late onset

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Signs and Symptoms of Nerve Agents Liquid Exposure

• Mild exposure (to 18 hours)
• Localized sweating
• Fasciculations
• No miosis
• Moderate exposure (ltLD50) (to 18hours)
• Gastrointestinal effects
• Miosis uncommon
• Severe exposure (LD50) (lt30 minutes)
• Sudden loss of consciousness
• Seizures
• Apnea
• Flaccid paralysis
• Death

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Diagnosis of Nerve Agent Exposure

• Symptomatic
• May be systemic or organ-specific
• Combination of symptoms is more definitive
• Situational
• Multiple casualties with similar symptoms
• Time or location factors in common

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Nerve AgentsTreatment

• Removal from exposure
• Decontamination
• Airway/ventilation
• High resistance
• Antidotes
• Atropine
• 2-PAMCl
• Diazepam

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Nerve Agents Treatment

• Atropine
• Antagonizes muscarinic effects
• Dries secretions relaxes smooth muscles
• Given IV, IM, ET
• No effect on pupils
• No effect on skeletal muscles
• IV in hypoxic patient Ù ventricular fibrillation

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Nerve AgentsTreatment

• Starting dose - 2 mg
• Maximum cumulative dose - 20 mg
• Total dose calculated over time but enough must
  be administered to abate severe symptoms if
  casualty is to survive
• Insecticide poisoning requires much more
• Side effects in normal people
• Mydriasis
• Blurred vision
• Tachycardia
• Decreased secretions and sweating

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Nerve AgentsTreatment

• Atropine - How much to give?
• Until secretions are drying or dry
• Until ventilation is easy
• If conscious or casualty is comfortable
• Do not rely on heart rate/pupil size

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Nerve AgentsTreatment

• Pralidoxime Chloride (2-PAMCl)
• Remove nerve agent from AChE in absence of aging
• 1 gram slowly (20-30 minutes) in IV infusion
• Hypertension with rapid infusion
  
• No effects at muscarinic sites
• Helps at nicotinic sites

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Nerve AgentsTreatment - Autoinjectors
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MARK I Injection IM vs. IV
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MARK I InjectionsDispersal
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Nerve AgentsTreatment

• Diazepam
• Decreases seizure activity
• Reduces seizure-induced brain injury
• Give to severely intoxicated casualties whether
  convulsing or not

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Nerve AgentsTreatment

• No signs/symptoms
• Reassure
• Observe
• Vapor 1 hour
• Liquid Up to 18 hours

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Nerve AgentsTreatment
Treat with

• Mild vapor exposure
• Miosis, rhinorrhea - observation only
• Increasing SOB treat
• Mild liquid exposure
• Localized fasiculations sweating - treat

• One MARK I kit (2 mg atropine/ 600 mg 2-PAMCl)
• OR
• 1 gram 2-PAMCl IV
• 2 mg atropine, IM or IV
• Parenteral atropine will not reverse miosis

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Nerve AgentsTreatment

• Moderate vapor or liquid exposure
• More severe respiratory distress
• Muscular weakness
• Nausea, vomiting, and diarrhea

Treat with

• One or two MARK I kits
• OR
• IV
• 2 to 4 mg atropine
• 1gm 2-PAMCl (infusion)

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Nerve AgentsTreatment

• Severe vapor or liquid exposure
• Unconscious
• Seizing or post-ictal
• Apneic or severe dyspnea
• Twitching or flaccid
• Effects in 2 or more body system

• 3 MARK I kits OR
• 6 mg atropine IV and
• 1 gram of 2-PAMCl IV
• Airway
• Ventilation/O2
• Consider diazepam 10 mg IM (2 to 5 mg IV)
• Repeat atropine every 5 to 10 minutes as needed
• Repeat 2-PAMCl in one hour

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Nerve AgentsAge-Related Treatment

• Atropine
• Infant (0 to 2) 0.5 mg IM
• Child (2 to 10) 1.0 mg IM
• Adolescent (gt 10) 2.0 mg IM
• Elderly 1.0 mg IM
• IV for infants and children 0.02 mg/kg

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Nerve AgentsAge-Related Treatment

• 2-PAMCl
• lt 20 kg 15 mg/kg IV
• gt 20 kg 600-mg IM autoinjector
• Elderly 1/2 adult dose (7.5 mg/kg IV)
• 2-PAMCl-induced hypertension
• Phentolamine Adult - 5 mg IV
• Child - 1 mg IV

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Nerve AgentsAge-Related Treatment

• Diazepam
• - Infants gt 30 days old 0.2 - 0.5 mg/kg IV
• to 5 years q 2 to 5 min
• (max 5 mg)
• - Children gt 5 years 1 mg IV
• q 2 to 5 min
• (max 10 mg)

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Nerve AgentsSummary

• Vapor exposure
• Symptoms develop suddenly
• Most ambulatory victims require minimal
  intervention
• Risk of secondary contamination, which is
  minimized by removing the victims clothing
• Requires immediate access to antidotes

• Liquid exposure
• Symptoms delayed minutes to hours
• Greater need for decontamination
• High risk of secondary contamination victims
  require decontamination (clothing removal
  washdown)
• Requires immediate access to antidotes

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Reference
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