chemical agents and mass casualties

7/29/2019 Chemical Agents and Mass Casualties

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Chemical Agents andMass Casualties

Sabeer Mohamed MEM PGY


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Objectives

Introduction

Hazardous Materials Exposure Limit Guide

Hazardous Materials Scene Response

ED Hazardous Materials Response

High Risk Chemicals and types


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Introduction


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Hazardous Materials Exposure Limit

Guidelines

American Conference of Governmental Industr

Hygienists

National Institute of Occupational Safety and

Health

Environmental Protection Agency-three-tieredAcute Exposure Guideline Level (AEGL)

AEGL 1 discomfort

AEGL-2 -irreversible, long-lasting effects

AEGL-3 -serious disease or death


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INDIAN SCENARIO


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Hazardous Materials Scene Response Community Risk Assessment

Recognition of an Event

Identification of the Substances Involved

Isolation and Scene Control

Hot Zone

Warm ZoneCold Zone

Decontamination in the Warm Zone

Stabilization and Triage in the Cold Zone


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ED Hazardous Materials Response

Exposure determines decontamination

Decontaminate one patient at a time

Decontamination outside of the ED

Sufficient equipment for multiple personnel

Effective decontamination-disrobing, brushing &

washing face.

Warm water -universal decontamination fluid


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CONTINUED

After decontamination -hospital clothing-

followed by triage

Irrigation of eyes - sterile normal saline

contaminated wounds will additional irrigation

Radiation survey sweep

Staff -annual training and practice drills


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High Risk Chemicals

TOXIC GASES

Displacement of Oxygen from Air

Irritant Gases - Interrupt Pulmonary Diffusion

Interrupt Oxygen Transport

Interfere with Cellular Oxygen Utilization


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TOXIC GASES

Displacement of Oxygen from Air: Simple Asphyxiants

inert gases - carbon dioxide, hydrogen, nitrogen

noble gases -helium, neon, argon, krypton, xenon, radon

simple hydrocarbons -methane, butane, propane

Restoration of FIO2-with supplemental oxygen


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TOXIC GASES

Irritant Gases - Interrupt Pulmonary Diffusion

Classified according to water solubility

Highly water soluble

Ammonia, sulfur dioxide , hydrogen chloride, hydrogen flu

Intermediate water soluble-chlorine

hydrochloric and hydrochlorous acids

Minimal water soluble-phosgene


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TOXIC GASES

Agents that Interrupt Oxygen Transport

Carbon monoxide & methylene chloride -carboxyhemoglobin

Nitrites, benzocaine, phenazopyridine -divalent Fe2+ to trivalent

methemoglobin

High concentrations o2

Methylene blue -electron donor


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TOXIC GASES

Interfere with Cellular Oxygen Utilization

interfere with oxygen utilization -ETC in mitochondria

cyanide, hydrogen sulfide, phosphine, and sodium azide

headache, altered consciousness, seizures, & severe acido


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TOXIC GASES

Cyanide antidote kit-

perles of amyl nitrite, induce methemoglobinem

ampule of sodium nitrite

ampule of sodium thiosulfate- stimulate the conversion of c

sodium thiocyanate


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NERVE GASES Tabun,sarin,soman

Organophosphates

Inhibit acetylcholinesterase

bind to acetylcholinesterase in a two-stage process

1

ST

reversible with the antidote pralidoxime (2-PAM)

2ND (aging process) makes the enzyme unavailable


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NERVE GASES

SLUD syndrome at muscarinic sites

muscular fasciculation ,muscular weakness, complete paraly

neuromuscular junction/ nicotinic receptor

coma and seizures-brain


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NERVE GASES

Atropine -muscarinic effects.

2-PAM -nicotinic effects.

Benzodiazepines enhance atropine and stop seizures

Avoid succinylcholine-prolongs duration


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Biotoxins

Botulinum Toxin

Antitoxin early

only prevent progression of symptoms

cannot reverse paralysis


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Biotoxins

Ricin

castor bean, Ricinus communis/destruction of RNA

inhalation exposure-pulmonary edema ,necrotizing pneum

parenteral administration-weakness , flu-like symptoms,

nausea, vomiting, fever, localized lymphadenopathy

hypotension, leukocytosis, DIC, multi-organ system fail


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Biotoxins

Staphylococcal Enterotoxin B

Superantigen produce cascade effect -through T-cell stimulation

Respiratory symptoms

Treatment is supportive


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THANK YOU


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