®
Chemical Agents
Chapter 6
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Overview
• History of chemical disasters /
terrorism
• D-I-S-A-S-T-E-R Paradigm for chemical
agents
• Specific Agents
– Nerve agents
– Choking / Irritant Gases
– Cyanide
– Blister / Vesicants Agents
– Incapacitating agents
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Potential
Chemical Agents
Nerve Agents
Blood Agents
(cyanide)
Irritant
Agents
Incapacitatin
g agents
Vessicants
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Tabun, Sarin, Soman, VX
Hydrogen Cyanide,
Cyanogen Chloride
Phosgene, chlorine,
ammonia, mace, pepper
spray
BZ
Mustard, Lewisite,
Phosgene oxime
3
History: World War I
First large-scale
use
• Ypres, Belgium
–April 1915
–Chlorine, 168
tons
–5,000 deaths
–5 mile front
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Chemical Casualties in WWI
Country
Britain
France
Russia
Italy
U.S.
AustriaHungary
Germany
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Non-fatal
180,597
182,000
419,340
55,373
71,345
97,000
Deaths
8,109
8,000
56,000
4,627
1,462
3,000
191,000
9,000
5
Terrorist Attacks
Matsumoto,
June 1994
–280 injured
–7 dead
• Tokyo,
March 1995
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Tokyo: Hospital Response
• 5,500 victims
• 11 Dead
• 641- St. Luke’s
International
Hospital
• No decon
• No EMS
involvement for
most
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Tokyo, Japan 1995
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Bhopal India 1984
• 40 Tons of Methyl
Isocyanate
• Population of 900,000
• Estimates of affected
– 6,000-10,000
– ? Affected ~ 400,000
• Lack of safety devices
• Manuals in English
• “Mini-Bhopals in US?”
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D: Detection
I: Incident Command
S: Safety & Security
A: Assess Hazards
S: Support
T: Triage & Treatment
E: Evacuation
R: Recovery
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D: Detection
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I: Incident Command
S: Safety & Security
A: Assess Hazards
S: Support
T: Triage & Treatment
E: Evacuation
R: Recovery
11
Detection
• Rapid onset
– little or no warning
• Common
symptoms
• Low lying clouds
or vapors
• Dying animals or
insects
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• Unexplained odors
• Concentrations of
Dead, dying, or sick
people at the scene
12
Detection
• Likely based on symptoms
–DUMBELS – Nerve Agent
–Respiratory symptoms – irritant
gases
–Skin symptoms – vesicants
–Altered mental status and anticholinergic syndrome – BZ
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D: Detection
I: Incident Command
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S: Safety & Security
A: Assess Hazards
S: Support
T: Triage & Treatment
E: Evacuation
R: Recovery
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Incident Command
• Must supply the following information:
– number and type of casualties
– substances involved
– estimated time of arrival to hospital
– time of the incident and incident site
– method of contamination (vapor or liquid)
– necessary decontamination
– hazards to health care providers
– role of the health care facility in the incident
– updated information
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D: Detection
I: Incident Command
S: Safety & Security
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A: Assess Hazards
S: Support
T: Triage & Treatment
E: Evacuation
R: Recovery
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Scene Security
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Scene Security
• Scene must be secured to prevent
more casualties
• Most (4/5) victims will go to the
hospital by private/ public
transportation vehicle!!!
• PREVENT THE HOSPITAL FROM
BECOMING CONTAMINATED
– all personnel involved in
decontamination must wear PPE
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Scene Security
Minimum Site Boundaries
Open Area Chemical Release
COLD ZONE
CCP
Uphill if agent heavier than air,
downhill or level if lighter than air
WARM ZONE
300 ft
WIND
DIRECTION
60 ft
HOT ZONE
WARM ZONE
RS
COLD ZONE
Casualty Collection
Point
6,000 ft
HOT ZONE
6,000 ft
RS= Release Site
Adapted from Illinois
Emergency Management
Agency Chem-Bio
Handbook.
April 2000
Figure 5
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D: Detection
I: Incident Command
S: Safety & Security
A: Assess Hazards
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S: Support
T: Triage & Treatment
E: Evacuation
R: Recovery
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Assess Hazards
• Ongoing threat of contamination to
other individuals
– contamination control must be continually
assessed and enforced by safety officer
– badges must be given to hospital
personnel
– guards must wear PPE at ingress points
– law enforcement assist with crowds,
traffic, and casualty flow
• Secondary devices?
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D: Detection
I: Incident Command
S: Safety & Security
A: Assess Hazards
S: Support
T: Triage & Treatment
E: Evacuation
R: Recovery
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Support
• Public health
organizations
• Poison control centers
• Health care providers
• Medical research
centers
• Medical examiners
• Emergency response
units and first
responder
organizations
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• DMAT’s
• State Disaster Teams
• Safety and medical
equipment
manufacturers
• Federal agencies
• FBI
– Hazardous Materials Response
Unit
• Local law enforcement
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Support:
Health care providers
• Use primary
care clinics and
urgent care
centers
• Volunteers
• All individuals
should be
oriented to the
disaster plan
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Support:
Supplies / Pharmaceuticals
• Vendor Agreements
– ventilators
– other equipment
• Essential
pharmaceuticals
• Atropine can be
stockpiled
– powder form
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D: Detection
I: Incident Command
S: Safety & Security
A: Assess Hazards
S: Support
T: Triage &Treatment
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E: Evacuation
R: Recovery
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D: Detection
I: Incident Command
S: Safety & Security
A: Assess Hazards
S: Support
T: Triage &Treatment
E: Evacuation
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R: Recovery
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Evacuation
• Most victims will self transport
• Consider school buses for minimal pts
• Caution
– Contaminated pts
– Off-gassing
– Open windows
– Use vents
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D: Detection
I: Incident Command
S: Safety & Security
A: Assess Hazards
S: Support
T: Triage & Treatment
E: Evacuation
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R: Recovery
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Recovery
• Most difficult aspect of
a chemical event
• All areas of the hospital,
buses, ambulances,
equipment checked for
persistence of chemicals
• Law enforcement investigate human remains for
evidence
• Psychological sequelae
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Nerve Agents
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Nerve Agents
• Organophosphates
• Are similar to
insecticides:
– Malathion
– Diazinon
– Chlorpyrifos
Sarin
VX
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Tabun
Soman
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Nerve Agents
• Nerve agents
• G-agents
– Volatile
– Nonpersistent
– vapor and liquid
threat
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– liquids ambient
temperatures
– Vapor heavier
than air
• VX
– Nonvolatile
– Persistent
– liquid threat
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Nerve Agent Properties
Agent
Tabun
(GA)
Sarin
(GB)
Soman
(GD)
VX
LCt50
Mg(min)/m3
400
100
50
10
Vapor
Density
(air = 1)
Topical
LD50 mg
5.63
4.86
6.33
9.20
1000
1700
100
10
14 hours
5 hours
2-6 minutes
48 hours
Aging
half-life
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Nerve Agent Pathophysiology
• Acetylcholine
–Neurotransmitter
parasympathetic
nervous system
–neuromuscular
endplate
–Ganglia
• Sympathetic
• parasympathetic
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Cholinergic
Nerve Function
AChE
ACh
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Cholinergic
Nerve Function
AChE
ACh
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GB
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Acetycholine Metabolism
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Acetylcholinesterase Inhibition
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Nerve Agent Symptoms
•
•
•
•
Diarrhea
Urination
Miosis
Bradycardia,
Bronchoconstriction,
Bronchorrhea
• Emesis
• Lacrimation
• Salivations,
Secretions,
Sweating
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Nerve Agent Symptoms:
Nicotinic
• Mnemonic for the days of the
week
–M: mydriasis (pupil dilation)
–T: tachycardia
–W: weakness
–tH: hypertension
–F: fasciculations
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Nerve agent exposure Vapor
• Low exposure
– Meiosis (dim vision, eye pain)
– Rhinorrhea
– Dyspnea
• High exposure
– Immediate loss of consciousness
– Seizures
– Apnea
– Flaccid paralysis
• Vapor effects occur within second,
peak within minutes: no late onset
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Nerve Agents: Liquid
• Small amount (up
to 18 hrs)
– Localized sweating
– Fasiculations
– No miosis
• Moderate amount
(<LD50) (18 hrs)
– GI effects
– Miosis uncommon
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• Large amount
(LD50) (<30
minutes)
– Sudden loss of
consciousness
– Seizures
– Apnea
– Flaccid paralysis
– Death
43
Nerve Agent-Triage
• Tokyo Sarin
–3/6 victims in cardiac arrest
resuscitated
–Majority were worried well
• Consider cardiac
arrest as
immediate?
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Nerve Agents: Treatment
• ABC’s, supportive care
• Antidotes
–Atropine 2 mg IV/IM/ET
• Repeat doses as
necessary
• End point is dry
secretions, easier ventilation
–2-PAMCl
• 1 gram slow IV or Mark I kit IM (600 mg)
– Benzodiazepines, PRN for seizures
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Nerve agent: Treatment
• Atropine Starting dose - 2 mg
• Maximum cumulative dose - 20 mg
– 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 the patient is
comfortable
–Do not rely on heart rate or pupil size
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Nerve Agents:
Treatment 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
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• 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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Irritant Gases
(Choking Agents)
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Irritant Agents
• Irritate respiratory tract
or damage lung tissue
– Combine with moisture to
form acids or bases
• Three groups based on
water solubility
– Highly water soluble
– Moderately water soluble
– Low water solubility
• Examples:
– Ammonia, chlorine,
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Irritant Gas Symptoms
Highly water
soluble ammonia
Moderately water
soluble - chlorine
Poorly water
soluble phosgene
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Irritant Gas - Symptoms
• Mucous membrane irritation and
excess mucous production
• Conjunctivitis
• Coughing
• Dysphonia (hoarseness)
• Stridor and aphonia
• Bronchospasm
• Shortness of breath
• Non- cardiogenic pulmonary edema
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Highly Water Soluble
Irritant Gases
• Ammonia
• Formaldehyde
• Hydrogen Chloride
• Sulfur Dioxide
• Mostly upper airway to vocal
cords
–laryngospasm
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Moderately Water Soluble
Irritant Gases
• Chlorine
–Hydrochloric acid
–Hypochlorus acid
–Greenish-yellow gas
• Slightly slower to combine with
water
• Affects upper airway
• Affects lower airways
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Poorly Water Soluble
Irritant Gases
• Phosgene (COCl2)
–Forms hydrochloric acid
• Nitrogen dioxide (NO2)
–Forms nitric acid
• Inhaled into alveoli before
combining with water
• Results in pulmonary edema (20
min to 24 hrs)
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Phosgene (CG)
• Most dangerous of pulmonary agents
• Use in WWI
• Developed as warfare agent, first use
1917
• U.S. Produces > 1 billion pounds/yr for
industrial uses
• Odor of New Mown Hay
• Poor Warning Properties
– odor may not be detected
– accumulates in low areas (trenches)
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Phosgene (CG)
• Low concentrations
– mild cough, chest tightness, shortness of
breath
• Moderate concentrations
– lacrimation
• High concentrations
– pulmonary edema (2-6 hours)
– death (24-48 hours)
• Initial presence/absence of symptoms
do not predict severity of exposure
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Irritant Gases: Triage
•
•
•
•
Majority – Worried well?
Airway compromise – immediate
Severe shortness of breath- immediate
Mild SOB, No airway compromise –
delayed
• Mild mucous membrane symptoms –
minimal
• Respiratory arrest – expectant
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Irritant Gases: Treatment
•
•
•
•
•
Dry decontamination usually adequate
Water for mucous membrane irritation
ABC’s
Oxygen PRN
Early airway management
– highly and moderately water soluble exposures
• Inhaled beta agonist PRN wheezing
• Observation and support
– phosgene 12- 24 hrs?
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Irritant Gas - Summary
• Solubility determines physiologic effect
• Dry decon is usually all that is needed
• Incident Command and treatment areas–
upwind
• Treatment is supportive
– Early airway management critical
– Consider intubation for stridor
– Be prepared for surgical airway
• Transport contaminated separate from
decontaminated
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Cyanide
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Cyanide (AC, CK)
•
•
•
•
Formerly referred to as “blood agents”
Hydrogen Cyanide AC
Cyanogen Chloride CK
Odor “bitter almonds”? – “musty”
smell
• Odor not a reliable indicator (genetic)
• Combines with Cytochrome a3 and
Inhibits Oxygen Utilization (bright red
venous blood)
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O2
O + H+ O2 O2
H0
O2
2
Cyt c
Cyt a
cyt a3
Cu
2
ADP
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ATP
63
Cyanide - Sources
• Pits of many plants
– Cherries, peaches, almonds, lima beans
– Cassava plant root
• Combustion of carbon -> cyanide
– Plastics- acrylonitriles
• U.S. sources manufacture 300,000
tons of hydrogen cyanide annually
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Terrorist Use of Cyanide
• Tylenol – 1982 – Killed 7
• Rev Jim Jones – 1978 – Killed 900
• 1995 Aum Shinrikyo
– Several subway restrooms after attack
– Found acid and cyanide salt
– cyanide salt + acid
cyanide gas
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Cyanide Triage
• M-A-S-S Triage
• Likely few critical victims
–Most either dead
–Others with minor exposure
• Good supportive care may save
many in absence of antidote
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Cyanide Treatment
• Remove to Fresh Air
• Oxygen, supportive care
• Pasadena Kit (Was Lilly Kit)
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Cyanide Treatment
• Step 1
– amyl nitrite
• inhale 30 sec/min until IV)
• Step 2
– Sodium nitrite
• 10 ml of 3% IV over 5-10 minutes
• Step 3
– Sodium thiosulfate
• 50ml of 25% IV over 20 minutes
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rbc
Cyt a3
Fe2+-Hb
Amyl nitrite
Sodium nitrite
Fe3+-Hb
MetHb
Fe3+-Hb
Sodium thiosulfate
Excreted in urine
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thiocyanate
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Cyanide
Treatment Summary
• Induce methemoglobinemia
• Amyl nitrite, Sodium nitrite
• Create thiocyante
• Sodium thiosulfate
• Good supportive care even in
absence of antidote
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Blister Agents/Vesicants
 Sulfur mustard
 Phosgene Oxime CX
 Nitrogen mustard
 Lewisite L
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Mustard Physical
Characteristics
• Oily liquid so poorly volatile
• Light Yellow in Color
• Garlic odor
• Freezes at 57 F
• Penetrates
rubber
gloves
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Lewisite Characteristics
• Organic arsenical with
vesicant properties
• Colorless, oily liquid
• Odor of geraniums
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Vesicant Mechanism
• RAPIDLY penetrates cells and
generates toxic intermediate
• Alkylates DNA, RNA, protein->disrupts cell function-->cell
death
• Rapidly dividing cells most
susceptible
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Vesicant Symptoms
• Binds Irreversibly within minutes
“Fixing”.
• Onset of symptoms 4-8 hours
• Tissue Damage Within Minutes
Without Symptoms for Hours
• Topical – Eyes, Airway, Skin
• Systemic – Bone Marrow, GI,
CNS
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Mustard - Skin
• Erythema 2-24 hours
• Small vesicles may
coalesce to form
bullae
• High dose exposure
– central zone of
coagulation
necrosis
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Vesicant Treatment
• Immediate decontamination (2 minutes)
• Victim may not undergo
decontamination since symptoms
delayed
• Remove clothes and wash skin with
soap and water
• Avoid overhydration; fluid losses less
than with thermal burns
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Lewisite Treatment
• British Anti-Lewisite (BAL)
–chelating agent
–only administer to victims with shock
or severe pulmonary injury in
consultation with the poison center
–3-5 mg/kg IM every 4 hours x 4 doses
–Side effects: nausea/vomiting,
headache, burning sensation of lips,
chest pain, anxiety
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Incapacitating Agents
• Not meant to be lethal
• “inability to perform one’s
mission”
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Incapacitating Agents:
BZ
• BZ--3-quinuclidinyl benzilate
• Anticholinergic Agent
• 25-times more potent than
atropine
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BZ: Symptoms
• “Mad as a Hatter”
• “Dry as a Bone”
• “Blind as a Bat”
• “Hot as a Hare”
• “Red as a Beet”
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BZ: Treatment
• Control patient
• KEEP VICTIM COOL
• Physostigmine
–1-2 mg IV
–atropine at bedside
–seizures and cardiac arrhythmias
rare
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BZ: Summary
• Sx:
–Red, Hot, AMS, Tachycardia
• Not all chemical exposures are
nerve agents
• Supportive care / cooling
• Physostigmine
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Summary: Chemical Agents
• ABC’s & supportive
• Decontamination
• Nerve Agents
• Cyanide
– Amyl nitrite/ sodium
nitrite
– Sodium thiosulfate
– DUMBELS
•
– Treatment: atropine/ 2PAM
• Irritant Gases
– Sx’s based on water
solubility
– Aggressive airway
management
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Vessicants
– Decon a must
– Supportive care
– BAL for lewisite
• BZ
– AMS, red and hot
– Physostigmine
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Questions?
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