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Chemical Agents. Chapter 6. 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. Potential Chemical Agents. History: World War I.

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Chemical agents

Chemical Agents

Chapter 6


Overview
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


Potential Chemical Agents


History world war i
History: World War I

First large-scale use

  • Ypres, Belgium

    • April 1915

    • Chlorine, 168 tons

    • 5,000 deaths

    • 5 mile front



Terrorist Attacks

Matsumoto, June 1994

  • 280 injured

  • 7 dead

  • Tokyo, March 1995


  • Tokyo hospital response
    Tokyo: Hospital Response

    • 5,500 victims

    • 11 Dead

    • 641- St. Luke’s International Hospital

    • No decon

    • No EMS involvement for most



    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?”


    D:Detection

    I: Incident Command

    S: Safety & Security

    A: Assess Hazards

    S: Support

    T: Triage & Treatment

    E: Evacuation

    R: Recovery


    D: Detection

    I: Incident Command

    S: Safety & Security

    A: Assess Hazards

    S: Support

    T: Triage & Treatment

    E: Evacuation

    R: Recovery


    Detection

    Rapid onset

    little or no warning

    Common symptoms

    Low lying clouds or vapors

    Dying animals or insects

    Unexplained odors

    Concentrations of Dead, dying, or sick people at the scene

    Detection


    Detection1
    Detection

    • Likely based on symptoms

      • DUMBELS – Nerve Agent

      • Respiratory symptoms – irritant gases

      • Skin symptoms – vesicants

      • Altered mental status and anti-cholinergic syndrome – BZ


    D: Detection

    I:Incident Command

    S: Safety & Security

    A: Assess Hazards

    S: Support

    T: Triage & Treatment

    E: Evacuation

    R: Recovery


    Incident command
    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


    D: Detection

    I:Incident Command

    S:Safety & Security

    A: Assess Hazards

    S: Support

    T: Triage & Treatment

    E: Evacuation

    R: Recovery



    Scene security1
    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


    Scene security2
    Scene Security

    Minimum Site BoundariesOpen Area Chemical Release

    COLD ZONE

    CCP

    Uphill if agent heavier than air, downhill or level iflighter than air

    WARM ZONE

    300 ft

    WIND DIRECTION

    HOT ZONE

    60 ft

    WARM ZONE

    RS

    COLD ZONE

    Casualty Collection Point

    6,000 ft

    RS= Release Site

    Adapted from Illinois Emergency Management Agency Chem-Bio Handbook. April 2000

    HOT ZONE

    6,000 ft

    Figure 5


    D: Detection

    I:Incident Command

    S: Safety & Security

    A:Assess Hazards

    S: Support

    T: Triage & Treatment

    E: Evacuation

    R: Recovery


    Assess hazards
    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?


    D: Detection

    I:Incident Command

    S: Safety & Security

    A: Assess Hazards

    S:Support

    T: Triage & Treatment

    E: Evacuation

    R: Recovery


    Support

    Public health organizations

    Poison control centers

    Health care providers

    Medical research centers

    Medical examiners

    Emergency response units and first responder organizations

    DMAT’s

    State Disaster Teams

    Safety and medical equipment manufacturers

    Federal agencies

    FBI

    Hazardous Materials Response Unit

    Local law enforcement

    Support


    Support health care providers

    Use primary care clinics and urgent care centers

    Volunteers

    All individuals should be oriented to the disaster plan

    Support:Health care providers


    Support supplies pharmaceuticals
    Support:Supplies / Pharmaceuticals

    • Vendor Agreements

      • ventilators

      • other equipment

    • Essential pharmaceuticals

    • Atropine can be stockpiled

      • powder form


    D: Detection

    I:Incident Command

    S: Safety & Security

    A: Assess Hazards

    S: Support

    T:Triage &Treatment

    E: Evacuation

    R: Recovery


    D: Detection

    I:Incident Command

    S: Safety & Security

    A: Assess Hazards

    S: Support

    T: Triage &Treatment

    E:Evacuation

    R: Recovery


    Evacuation
    Evacuation

    • Most victims will self transport

    • Consider school buses for minimal pts

    • Caution

      • Contaminated pts

      • Off-gassing

      • Open windows

      • Use vents


    D: Detection

    I:Incident Command

    S: Safety & Security

    A: Assess Hazards

    S: Support

    T: Triage & Treatment

    E: Evacuation

    R:Recovery


    Recovery
    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



    Nerve Agents

    • Organophosphates

    • Are similar to insecticides:

      • Malathion

      • Diazinon

      • Chlorpyrifos

    Sarin

    VX

    Soman

    Tabun


    Nerve Agents

    G-agents

    Volatile

    Nonpersistent

    vapor and liquid threat

    • Nerve agents

      • liquids ambient temperatures

      • Vapor heavier than air

    • VX

      • Nonvolatile

      • Persistent

      • liquid threat


    Agent

    Tabun (GA)

    Sarin (GB)

    Soman (GD)

    VX

    LCt50

    Mg(min)/m3

    400

    100

    50

    10

    Vapor Density

    (air = 1)

    5.63

    4.86

    6.33

    9.20

    Topical LD50 mg

    1000

    1700

    100

    10

    Aging half-life

    14 hours

    5 hours

    2-6 minutes

    48 hours

    Nerve Agent Properties


    Nerve agent pathophysiology
    Nerve Agent Pathophysiology

    • Acetylcholine

      • Neurotransmitter parasympathetic nervous system

      • neuromuscular endplate

      • Ganglia

        • Sympathetic

        • parasympathetic


    Cholinergic Nerve Function

    AChE

    ACh


    Cholinergic Nerve Function

    AChE

    GB

    ACh




    Nerve agent symptoms
    Nerve Agent Symptoms

    • Diarrhea

    • Urination

    • Miosis

    • Bradycardia, Bronchoconstriction, Bronchorrhea

    • Emesis

    • Lacrimation

    • Salivations, Secretions,Sweating

    (dumbells)


    Nerve agent symptoms nicotinic
    Nerve Agent Symptoms: Nicotinic

    • Mnemonic for the days of the week

      • M: mydriasis (pupil dilation)

      • T: tachycardia

      • W: weakness

      • tH: hypertension

      • F: fasciculations


    Nerve agent exposure vapor
    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


    Nerve agents liquid

    Small amount (up to 18 hrs)

    Localized sweating

    Fasiculations

    No miosis

    Moderate amount (<LD50) (18 hrs)

    GI effects

    Miosis uncommon

    Large amount (LD50) (<30 minutes)

    Sudden loss of consciousness

    Seizures

    Apnea

    Flaccid paralysis

    Death

    Nerve Agents: Liquid


    Nerve agent triage
    Nerve Agent-Triage

    • Tokyo Sarin

      • 3/6 victims in cardiac arrest resuscitated

      • Majority were worried well

    • Consider cardiac arrest as immediate?


    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


    Nerve agent treatment
    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


    Nerve agent treatment1
    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


    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

    • 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


    Irritant gases choking agents
    Irritant Gases (Choking Agents)


    Irritant agents
    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, phosgene


    Irritant gas symptoms
    Irritant Gas Symptoms

    Highly water soluble - ammonia

    Moderately water soluble - chlorine

    Poorly water soluble - phosgene


    Irritant gas symptoms1
    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


    Highly water soluble irritant gases
    Highly Water Soluble Irritant Gases

    • Ammonia

    • Formaldehyde

    • Hydrogen Chloride

    • Sulfur Dioxide

    • Mostly upper airway to vocal cords

      • laryngospasm


    Moderately water soluble irritant gases
    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


    Poorly water soluble irritant gases
    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)


    Phosgene cg
    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)


    Phosgene cg1
    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


    Irritant gases triage
    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


    Irritant gases treatment
    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?


    Irritant gas summary
    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



    Cyanide ac ck
    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)


    O2

    O2

    CN-

    O2

    O2 + H+

    Cyt a cyt a3 Cu

    Cyt c

    O2

    H20

    ADP

    ATP


    Cyanide sources
    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


    Terrorist use of cyanide
    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


    Cyanide triage
    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


    Cyanide treatment
    Cyanide Treatment

    • Remove to Fresh Air

    • Oxygen, supportive care

    • Pasadena Kit (Was Lilly Kit)


    Cyanide treatment1
    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


    rbc

    CN-

    Fe2+-Hb

    Cyt a3

    Amyl nitrite

    Sodium nitrite

    Fe3+-Hb

    Fe3+-Hb

    MetHb

    CN-

    Sodium thiosulfate

    thiocyanate

    Excreted in urine


    Cyanide treatment summary
    Cyanide Treatment Summary

    • Induce methemoglobinemia

      • Amyl nitrite, Sodium nitrite

  • Create thiocyante

    • Sodium thiosulfate

  • Good supportive care even in absence of antidote


  • Blister agents vesicants
    Blister Agents/Vesicants

    • Sulfur mustard

    • Phosgene Oxime CX

    • Nitrogen mustard

    • Lewisite L


    Mustard physical characteristics
    Mustard Physical Characteristics

    • Oily liquid so poorly volatile

    • Light Yellow in Color

    • Garlic odor

    • Freezes at 57 F

    • Penetrates rubber gloves


    Lewisite Characteristics

    • Organic arsenical with vesicant properties

    • Colorless, oily liquid

    • Odor of geraniums


    Vesicant mechanism
    Vesicant Mechanism

    • RAPIDLY penetrates cells and generates toxic intermediate

    • Alkylates DNA, RNA, protein-->disrupts cell function-->cell death

    • Rapidly dividing cells most susceptible


    Vesicant symptoms
    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


    Mustard skin
    Mustard - Skin

    • Erythema 2-24 hours

    • Small vesicles may coalesce to form bullae

    • High dose exposure – central zone of coagulationnecrosis


    Vesicant treatment
    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


    Lewisite treatment
    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


    Incapacitating agents
    Incapacitating Agents

    • Not meant to be lethal

    • “inability to perform one’s mission”


    Incapacitating agents bz
    Incapacitating Agents:BZ

    • BZ--3-quinuclidinyl benzilate

    • Anticholinergic Agent

    • 25-times more potent than atropine


    Bz symptoms
    BZ: Symptoms

    • “Mad as a Hatter”

    • “Dry as a Bone”

    • “Blind as a Bat”

    • “Hot as a Hare”

    • “Red as a Beet”


    Bz treatment
    BZ: Treatment

    • Control patient

    • KEEP VICTIM COOL

    • Physostigmine

      • 1-2 mg IV

      • atropine at bedside

      • seizures and cardiac arrhythmias rare


    Bz summary
    BZ: Summary

    • Sx:

      • Red, Hot, AMS, Tachycardia

    • Not all chemical exposures are nerve agents

    • Supportive care / cooling

    • Physostigmine


    Summary chemical agents

    ABC’s & supportive

    Decontamination

    Nerve Agents

    DUMBELS

    Treatment: atropine/ 2PAM

    Irritant Gases

    Sx’s based on water solubility

    Aggressive airway management

    Cyanide

    Amyl nitrite/ sodium nitrite

    Sodium thiosulfate

    Vessicants

    Decon a must

    Supportive care

    BAL for lewisite

    BZ

    AMS, red and hot

    Physostigmine

    Summary: Chemical Agents



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