Section 5: Chemicals Flashcards
5.1 Given an inhalation exposure, identify which substance is responsible.
- Utilize general knowledge of expected symptoms to determine responsible substance from a presented scenario.
5.2 Given an exposure with a cluster of patients, identify which chemical weapon of mass destruction is responsible.
- Nerve agents
a. Ex: Tabun, Sarin, Soman, VX
b. S/S: organophosphorus agents with muscarinic and nicotinic stimulation (SLUDGE) - Vesicant (blistering) agents
a. Ex: Nitrogen and Sulfur mustard, Lewisite (contains arsenic), Phosgene
b. S/S: skin, ocular, pulmonary damage - Choking agents
a. Ex: Chlorine, lacrimator agents, Phosgene
b. S/S: mucous membrane and respiratory irritation - Blood agents
a. Ex: Cyanide
b. S/S: neuro and CV collapse
5.3 Identify the toxicity and symptoms of chemical exposures.
- Acids
a. Immediate coagulation-type necrosis
b. Creates eschar and self-limits further damage - Gun Blue (Selenious acid)
a. Upper GI corrosive injury, emesis, diarrhea, hypersalivation, garlic odor on breath, rapid deterioration of mental status progressing to coma, hypotension, resp depression, death
b. 15ml of 2% selenious acid has been fatal - Alkali
a. Liquefactive necrosis with continued penetration into deeper tissues
b. Extensive tissue damage - Nitrites and Nitrates
a. Smooth muscle relaxation (decreased preload and afterload with vasodilation)
b. Cause hypotension and methemoglobinemia (cyanosis) (nitrates)
c. Nitrites have potentiation of effects when used with phosphodiesterase inhibitors (sildenafil/Viagra)
5.4 Gases
5.4 Identify the toxicity and symptoms from exposure to gases.
- Ammonia
a. Gas and aqueous forms found in fertilizers, refrigerants, cleaning solutions, explosives
i. Household cleaners concentration 5% to 10%
ii. Commercial cleaners concentration 25% to 30%
b. Alkaline. Corrosive on contact with moist tissues
c. Exposure may be dermal, ophthalmic, respiratory, or GI
i. Ammonia (Dermal)
- S/S: Mild to severe burns
- Treatment
a. Remove from source
b. Irrigate
ii. Ammonia (Ophthalmic)
- S/S: Pain, redness, lacrimation, burns, vision loss
- Treatment
a. Irrigate (up to several liters of saline) until pH 7.4
b. Fluorescein exam
c. Ophthalmology consult if corneal involvement
iii. Ammonia (Respiratory)
- S/S: Burning of nose/throat and cough
a. Obstruction (stridor, hoarseness, wheezing, croupy sounds)
b. Lower respiratory tract injury (wheezing or pulmonary edema) - Treatment
a. Remove from source
b. Supplemental O2
c. Early intubation if needed
d. Bronchodilators for wheezing
e. PEEP and avoid excess fluids to treat pulmonary edema
iv. Ammonia (GI)
- S/S: Oral/pharyngeal pain, dysphagia, difficulty maintaining secretions,
chest/abdominal pain, possible esophageal or gastric perforation - Treatment
a. Water or milk to dilute
b. No charcoal, induced emesis, or neutralization with acid
c. Gastric Suction with NG (small tube)
d. Chest and abdominal radiograph
e. If solution >= 10% or dysphagia, drooling or pain, consider upper endoscopy
- Chloramine
a. Ammonia combined with chlorine or hypochlorite solutions produce chloramine gas
b. Irritant.
c. Exposure is generally respiratory
d. S/S: Similar to chlorine gas exposure
i. Chloramine fumes cause pneumonitis
ii. Less water soluble than chlorine. Symptoms may be more delayed
e. Treatment
i. Remove from source
ii. High flow O2
- Chlorine
a. Found in chemical manufacturing, bleaching, swimming pools, and disinfectants
i. Hypochlorite is aqueous solution of chlorine with water
b. Acidic. Irritant
i. Heavier than air
ii. Irritating odor; yellow-green gas
c. Exposure route dermal, respiratory, GI
d. S/S: Oxidative and corrosive when contacting moist tissues
Chlorine (Dermal)
- Irritation, burns
- Treatment
a. Remove from source
b. Remove clothes and decontaminate
Chlorine (Respiratory)
- Irritation, wheezing, cough, rhinorrhea, respiratory distress, syncope, pulmonary edema
- Treatment
a. Remove from source
b. Humidified O2
c. Bronchodilators for wheezing
d. Low threshold for intubation
e. Possible use of nebulized sodium bicarb
No thermal injury appears to occur
Chlorine (GI)
- Burns, dysphagia, drooling, hematemesis, perforation
- Treatment
a. Dilute with water
b. Do NOT induce emesis
c. Consider NG tube for gastric aspiration
d. Possible need for endoscopy
Chlorine Evaluation:
i. Watch for hypochloremia & acidosis
ii. ABG for hypoxia
iii. CXR for pneumonitis and pulmonary edema
- Freon and other propellants
a. Mild CNS depressants/asphyxiants.
i. Well absorbed by inhalation or ingestion.
ii. Usually rapidly excreted in the breath within 15-60 min
b. Exposure route usually dermal or respiratory
c. Freon S/S
i. Mild irritant
ii. Direct freezing of the skin
iii. Hepatotoxic with large exposure
iv. May potentiate cardiac arrhythmias by sensitizing the myocardium
- Avoid epinephrine
- Tachyarrythmias may be treated with propranolol or esmolol
- Fume fevers (metal, polymer)
a. Source is often inhaled zinc oxide; can have symptoms from welding, melting, and flame
cutting of galvanized metal
b. S/S
i. Fever
ii. Malaise
iii. Myalgia
iv. Headache
v. *Should not have hypoxia or pulmonary infiltrates
1. If present, suspect chemical pneumonitis from another source
c. Treatment
i. S/S should self-resolve
ii. No decontamination is required. By time of s/s onset, exposure is past
- Hydrogen sulfide
a. Byproduct of decaying organic material. Pools of sewage or sludge, liquid manure. Industrial processes often found in petroleum refineries, tanneries, mines, pulp-making factories, sulfur hot springs, carbon disulfide production, commercial fishing holds, hot asphalt fumes.
b. Knock-down gas
i. “pit gas” – heavier than air
ii. Known for rotten egg smell
iii. cellular asphyxia (similar to cyanide)
c. Exposure route generally respiratory
d. Hydrogen Sulfide S/S
i. Chemical irritant at low doses
1. Upper airway, eye, skin, irritation
2. Chemical pneumonitis, non-cardiogenic pulmonary edema
ii. Acute systemic effects
1. n/v, headache, dizziness, confusion, sz, coma,
iii. Massive exposure
1. Immediate cardiovascular collapse, respiratory arrest and death
e. Hydrogen Sulfide Treatment
i. Remove from source
ii. Possible use of nitrites (sodium nitrite and amyl nitrite)
1. To promote methemoglobin (binds a component of the poisonous gas)
2. May cause hypotension and impaired O2 delivery
iii. Possible use of hydroxycobalamin
1. Not proven
iv. Possible use of hyperbaric oxygen
- Phosgene
a. Found in manufacture of dyes, resins, plastics, and pesticides; used as a war gas
b. Irritant
i. Heavier than air
ii. Smell of freshly mown hay
iii. Poorly water soluble
Enters lower airways
Does not cause immediate irritation
c. Phosgene S/S
i. Initial mild cough and minimal mucous membrane irritation
ii. Delayed dyspnea and hypoxemia (30 min-8 hrs)
iii. Resultant noncardiogenic pulmonary edema (up to 24 hrs)
d. Phosgene Treatment
i. Remove from source
ii. Remove clothes and decon
iii. Maintain airway
iv. Low threshold for intubation. Use large ETT (frequent suction)
v. monitor asymptomatic patient for 24 hrs after exposure
vi. No antidote
- Simple asphyxiants
a. Inert gases or vapors that displace oxygen from air when present in high concentrations.
i. In low concentrations they have no effects.
b. Ex. Nitrogen, argon, helium, methane, propane, CO2
5.5 Identify the toxicity and symptoms from carbon monoxide exposure.
- Chemical asphyxiant (other chemical asphyxiants: hydrogen sulfide and cyanide)
- Exposure sources (CO)
a. Gas appliances
b. Charcoal grills
c. Combustion engine exhaust
d. Smoke from any fire
e. Cigarettes
- CO has 240x greater affinity for hemoglobin than oxygen
- For CO uptake to body dependent on?
a. Concentration of inspired CO
b. Pt’s minute ventilation
c. Duration of exposure
- Binds to hemoglobin. Can also bind to myoglobin
- CO S/S
a. n/v, headache, fatigue, dizziness, confusion, ataxia, syncope, sz, coma
b. dyspnea, chest pain, dysrhythmias, hypotension
c. death
- CO Treatment
a. 100% oxygen (NRB or Vent)
b. Check co-ox panel
c. Consider hyperbaric for hx of:
- i. Loss of consciousness, coma or seizures
- ii. Pregnancy
1. CO has higher affinity to fetal hemoglobin
- iii. CO level >40%
5.6 Identify the toxicity and symptoms of exposure to heavy metals.
Ex. Arsenic, lead, mercury,
cadmium, thallium, chromium, etc
- Arsenic
a. Most commonly ingested in contaminated food or water.
i. Inorganic is the more problematic form
ii. Frequently used as a wood preservative in industrial applications
iii. Some compounds are radio-opaque and may be seen on xray
iv. Arsine is a colorless, nonirritating, garlic-odored gas from industrial settings
b. Clinical presentation (Arsenic)
i. Phase one (fairly rapid within hours)
ii. Phase two (after 1-7 d)
iii. Phase three (after 1-4 wks)
iv. Acute poisoning s/s after 1-6 wks
i. Arsenic - Phase one (fairly rapid within hours)
- Profound cholera-like gastroenteritis (n/v/d/abd pain)
a. Tachycardia, hypotension, hemodynamic collapse, metabolic acidosis, rhabdo, renal failure
ii. Arsenic - Phase two (after 1-7 d)
- GI s/s and hypotension resolve
- Cardiovascular compromise
a. Congestive cardiomyopathy, cardiogenic and non-cardiogenic
pulmonary edema, prolonged QTc - Encephalopathy
a. Delirium, agitation, coma - Elevated transaminases and proteinuria
iii. Arsenic - Phase three (after 1-4 wks)
- Begins with sensorimotor peripheral neuropathy
a. Abnormal sensations in stocking-glove pattern
b. Ascending sensory and motor deficits
c. Pancytopenia
iv. Arsenic - Acute poisoning s/s after 1-6 wks
- Diffuse maculopapular rash
- Desquamation of palms and soles
- Periorbital edema
- Herpetic-like lesions
- Mees’ lines (white transverse striae on nails 4-6 wks post ingestion)
c. Arsenic Labs
i. Rapid blood levels are not useful
ii. May use 24-hr urine test
d. Arsenic Treatment
i. Avoid quinidine, procainamide and other type 1a antiarrhythmic agents due to
QT prolonging effect
ii. Avoid phenothiazines for antiemetics or antipsychotics d/t QT prolongation and
lowering of seizure threshold
iii. Chelate if seriously symptomatic
- 1. Unithiol (IV) or Dimercaprol/BAL (IM) (no BAL if peanut allergy)
- 2. Oral unithiol or oral succimer (DMSA)
- Lead
a. Exposure is most commonly due to ingestion. Lead is radiopaque.
i. Children are more sensitive than adults. Common symptoms in chronic
exposure include constipation and abdominal pain.