Transcript Chemical Casualties

The Chemical Incident
Management of Chemical
Casualties
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Hospital Provider Management of
Chemical Agent Casualties
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Chemical Warfare Agents
Terminal Objective
• Describe types of chemical warfare agents
• Recognize signs and symptoms of exposure
• Describe management of chemical agent attack
victims
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Chemical Warfare Agents
Historical Perspective
• Chemicals used in military operations to kill,
injure, or incapacitate
• Battlefield use
– World War I and Middle East conflicts
• Terrorist use
– Matsumoto and Tokyo, Japan
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Chemical Agent Terrorist Attacks
• Matsumoto:
– Approximately
injured
– 7 dead
280
• Tokyo
– 12 dead
– Approximately 1,000
hospitalized
– 5,500 sought medical care
– 10% of first responders
injured
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Chemical Warfare Agents
• Nerve Agents
Tabun, Sarin, Soman, VX
• Vesicants
Mustard, Lewisite
• Industrial Chemicals
Phosgene, Chlorine, Ammonia,
Cyanide
• Riot Control Agents
Mace®, Pepper Spray
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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
ACh
GB
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Effects of Nerve Agents
Organs with cholinergic receptors
• Muscarinic
– Smooth muscles
– Glands
• Nicotinic
– Skeletal muscles
– Ganglia
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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 Agents
Muscarinic 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
ACh
• Other (ganglionic)
– Tachycardia
– Hypertension
GB
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Nerve Agents
Other 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 (<LD50) (to 18 hours)
– Gastrointestinal effects
– Miosis uncommon
• Severe exposure (LD50) (<30 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 Agent
Treatment
• Airway/ventilation
– High resistance
• Antidotes
– Atropine
– 2-PAMCl
– Diazepam
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Nerve Agent
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  ventricular fibrillation
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Nerve Agent
Treatment
• 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 Agent
Treatment
• 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 Agent
Treatment
• Pralidoxime Chloride (2PAM-Cl)
– Remove nerve agent from AChE in absence of aging
– 1 gram slowly (20-30 minutes) in IV infusion
• Hypertension with
rapid infusion
Nerve Agent
– No effects at
muscarinic sites
– Helps at nicotinic sites
AChE
2-PAMCl
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Nerve Agent
Treatment - Autoinjectors
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MARK I Injection vs. IM or IV
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Nerve Agent
Treatment
• Diazepam
– Decreases seizure
activity
– Reduces seizureinduced brain injury
– Give to severelyintoxicated
casualties whether
convulsing or not
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Nerve Agent
Treatment
• Treatment regimen
– No signs/symptoms
• Reassure
• Observe
– Vapor: 1 hour
– Liquid: Up to 18 hours
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Nerve Agent
Treatment
• 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 Agent
Treatment
• Moderate vapor or liquid exposure
– One or two MARK I kits
– Or give IV:
• 2 to 4 mg atropine
• 1gm 2-PAMCl (infusion)
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Nerve Agent
Treatment
• Severe - vapor or liquid
– Give 3 MARK I kits or 6 mg atropine and 1 gram of
2-PAMCl as soon as possible
– Airway
– Ventilation/O2
– Consider diazepam 10 mg IM (2 to 5 mg IV)
– Repeat atropine every 5 to10 minutes as needed
– Repeat 2-PAMCl in one hour
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Nerve Agent
Age-Related Treatment
• Atropine
– Infant (0 to 2)
0.5 mg IM
– IV for infants and children
0.02 mg/kg
– Child (2 to 10)
1.0 mg IM
– Adolescent (> 10)
2.0 mg
– Elderly
1.0 mg IM
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Nerve Agent
Age-Related Treatment
• 2-PAMCl
– < 20 kg
15 mg/kg IV
– > 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 Agent
Age-Related Treatment
• Diazepam
- Infants > 30 days old
to 5 years
0.2 - 0.5 mg/kg IV
q 2 to 5 min
(max 5 mg)
- Children > 5 years
1 mg IV
q 2 to 5 min
(max 10 mg)
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Nerve Agent Summary
• Vapor exposure
– Symptoms develop suddenly
– Most ambulatory victims
require minimal intervention
– Risk of secondary
contamination, which is
minimized by removing the
victim’s 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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Vesicants (Blister Agents)
• Vesicants
- Sulfur mustard
- Lewisite
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Mustard
• Properties
- Vapor & liquid threat
- Latent period between
exposure & effects
- Systemically toxic similar to radiation
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Mustard Effects
• Quickly cyclizes in
tissue
• Alkylates cell
components, including
DNA
• DNA damage, cell
death
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Mustard Effects
Eye Injury
• Mild conjunctivitis
• Moderate/severe conjunctivitis, lid inflammation and
edema, blepharospasm, and corneal roughening
• Corneal opacification, ulceration, and/or perforation
• Well over 95% had only mild to moderate
conjunctivitis
• Under 1% had permanent damage to cornea
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Mustard Effects
Eye Injury
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Mustard Effects
Skin Injury
• Erythema
• Small vesicles; later
coalesce
• Blisters/bulla
• Possible coagulation
necrosis with liquid
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Mustard Effects
Airway Injury
• Upper: nose sinuses, pharynx
– (epistaxis, sore throat, hacking
cough)
• Mid: Larynx (hoarseness)
• Lower: Bronchioles (dyspnea,
productive cough)
• Pulmonary edema is rare
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Mustard Effects
GI Injury
• Gastrointestinal
– Within 24 hours
• Nausea and vomiting
• Cholinergic effects
• After 3 to 5 days
– Tissue destruction
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Mustard Effects
Bone Marrow Damage
• Damages stem cells
• Decreased WBC, RBC,
platelets after 3 - 5 days
• Survival rare if WBC < 200
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Skin Treatment
• Decontamination must be done within minutes to
reduce damage
• Delays in decontamination will not prevent
illness, but will prevent cross-contamination
• Supportive care - soothing lotions, frequent
irrigation, topical antibiotics, pain medication
• Do NOT overhydrate; not a thermal burn
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Eye Treatment
• Topical mydriatics
• Topical antibiotics
• Vaseline on lid edges
• Topical steroids (only in
the first 24 hrs)
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Airway Treatment
• Cool mist, cough suppressants for mild
symptoms
• Oxygen
• Assisted ventilation
• Early intubation
• Bronchodilators (steroids)
• Antibiotics AFTER organism identified
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Lewisite Effects
• Causes severe irritation to eyes, skin, and
airways IMMEDIATELY on exposure (no delay)
• Tissue necrosis,
pseudomembranes
• Increased capillary
permeability
• No bone marrow
effects
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Lewisite - Treatment
• Immediate decontamination
• British anti-Lewisite (BAL) for systemic effects
• Supportive Care
– Oxygen
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Vesicant Agent Summary
• Agents damage eyes, skin, respiratory system; cause
additional systemic effects
– Mustard
• Fast acting; symptoms delayed, no specific antidote
– Lewisite
• Fast acting, symptoms immediate, BAL antidote available
• Decontamination is best initial treatment
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Phosgene
• At high concentrations:
– Irritates eyes, nose, upper airways; possible laryngospasm
Cl
• Toxic to lungs by inhalation
C=O
• Carbonyl group damages alveolar-capillary membrane
• Non-cardiac pulmonary edema: onset 2 to 12 hours
Cl
– Dyspnea, cough with sputum
• Management of non-cardiac pulmonary edema
– Hypoxia, fluid loss; requires pulmonary care, careful fluid replacement
• ABSOLUTE REST POST-EXPOSURE
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Chlorine
• High concentration or prolonged exposure
– Pulmonary edema, sudden death
• Eye irritation, cough, dyspnea
• More severe airway and lung
damage with high concentration
• Management
– Remove from exposure; manage airway
• Oxygen, ventilation, PEEP
• Intubation, bronchodilators
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Ammonia
• Anhydrous Ammonia
– pH>12; (household ammonia pH < 12)
– Wide industrial use
• Plastics, fertilizer, explosives
– Irritating, corrosive; causes necrosis,
severe pain
– Serious injury to eyes, lungs, skin, GI tract
• Management
– Remove from exposure, decontaminate
– Symptomatic; maintain airway
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Riot Control Agents
• Irritating agents, lacrimators,
“tear gas”
• Cause reaction in
– Eyes: burning, tearing, eyelid spasm,
redness
– Airways: burning, coughing, dyspnea
– Skin: burning, erythema
• Eye irrigation and supportive care
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Chemical Agent Summary
• Vapor exposure
– Nerve agent symptoms develop suddenly, mustard and
phosgene symptoms are delayed
– Most ambulatory victims require minimal intervention
– Risk of secondary contamination
– Requires airway management; antidotes for nerve
agents and Lewisite
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Chemical Agent Summary
• Liquid exposure
– Symptoms delayed minutes to hours
– Greater need for decontamination
– Risk of secondary contamination, victims require clothing
removal & decontamination
– Requires immediate access to antidotes
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