Pulmonary Intoxicant

Aka: Pulmonary Intoxicant, Green Cross Agent, Phosgene, Chlorine, Irritant Gas Syndrome, Lung Irritant Chemical Warfare Agent

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II. Background

  1. History
    1. Phosgene synthesized in 1812 by John Davy
    2. First used as Chemical Weapon 1917 by Germany
    3. Transported as liquid on rail lines
  2. Current
    1. Chlorine used as precursor for chemical manufacturing and as disinfectant

III. Risk Factors: Worse course with respiratory comorbid conditions

  1. Asthma or reactive airway disease
  2. COPD
  3. Tobacco Smoking

IV. Pathophysiology: Toxicity

  1. Chlorine LCt50: 6000 mg-min/m3
  2. Phosgene LCt50: 3200 mg-min/m3

V. Preparations

  1. Chlorine (CL)
    1. Appearance
      1. Green-yellow gas
      2. Low lying gas (twice the density of air)
      3. Liquid when in pressurized canister, but becomes gas at room Temperature out of container
    2. Odor
      1. Pungent, swimming pool odor
      2. Household bleach
    3. Common use as disinfectant in the U.S.
      1. Drinking Water Disinfection
      2. Swimming pool chlorination
      3. Industrial waste cleaning solution
      4. Household cleaning solutions (e.g. Bleach)
  2. Phosgene (CG)
    1. Vesicant (Blister Agent) when in liquid form
    2. More lethal than Chlorine
    3. Appearance
      1. Forms white cloud on explosion or dispersion
      2. Settles into colorless low lying gas
    4. Odor
      1. Sweet, newly mown hay
      2. Freshly cut grass
      3. Corn
  3. Diphosgene (DP)
  4. Chloropicrin (PS)
  5. Perfluoroisobutylene (PFIB)
    1. Teflon combustion (e.g. aircraft insulated wiring)
  6. HC smoke (smoke containing zinc)
    1. Smoke grenades: white obscurant smoke
  7. Oxides of nitrogen (burning munitions)

VI. Labs: Detection

  1. See specific agents as above for characteristics
  2. Detector kits sensitivity for Phosgene
    1. MINICAMS (50 ppbv)
    2. Monitox Plus (0.25 TWA)
    3. Draeger tubes (0.02-0.6 ppm)
    4. ICAD (25 mg/m3)
    5. M18A2 (12.0 mg/m3)
    6. M90 (>50 ppm)
    7. M93A1 Fox (115 mg/m3)

VII. Findings: Symptoms and Signs

  1. Nasopharynx irritation (mild exposure)
    1. Eye irritation and tearing
    2. Nose irritation, Rhinorrhea, sneezing
    3. Throat irritation
  2. Lung and airway (more severe exposure)
    1. Cough
    2. Dyspnea
    3. Hypoxia
    4. Hoarseness, Stridor or choking Sensation (laryngeal edema, tracheitis)
    5. Wheezing (bronchospasm)
    6. Chest tightness
    7. Copious watery airway secretions
    8. Delayed Pulmonary Edema (at least 2-4 hours from time of exposure)

VIII. Differential Diagnosis

  1. Riot Control Agents
  2. Nerve Agents
  3. Vesicant Agents

IX. Labs

  1. No specific Lab testing
  2. Hematocrit increased
  3. Arterial Blood Gas (ABG)
    1. Low PaO2
    2. Low PaCO2
  4. Peak Expiratory Flow decreased

X. Prognosis: Indicators of severe exposure

  1. Signs or symptom onset in first 4 hours after exposure

XI. Imaging

  1. Chest XRay
    1. Hyperinflation
    2. Delayed Pulmonary Edema
    3. No cardiomegaly
    4. Pneumomediastinum has been reported
  2. CT Chest
  3. Ventilation Perfusion Scan (V/Q Scan)
    1. High Test Sensitivity but not specific

XII. Management: General

  1. Terminate exposure immediately
    1. Degree of injury is directly proportional to the exposure duration
  2. Decontamination
    1. Vapor exposure
      1. Fresh air
    2. Liquid exposure
      1. Copious water irrigation
      2. Hypochlorite 0.5%
      3. M291
  3. ABC Management
  4. Pulmonary Management
    1. Oxygen
    2. Treat Bronchospasm
      1. Beta-adrenergic Bronchodilators (Nebulized Albuterol)
      2. Consider Solu-Medrol (e.g. 125 mg every 6 hours) in severe cases
      3. Consider nebulized Sodium Bicarbonate
        1. May improve symptoms and improve pulmonary function (studied in Chlorine gas exposure)
    3. Observe for signs respiratory distress
      1. Evaluate for Pulmonary Edema
    4. Positive Pressure Ventilation
      1. Keep pressures as low as possible to avoid Barotrauma
      2. Consider Non-Invasive Positive Pressure Ventilation (e.g. BIPAP)
      3. Mechanical Ventilation if indicated in severe cases
  5. Intravenous Fluid hydration with crystalloid
  6. Rest and Observation

XIII. Management: Triage of Patients presenting within 12 hours

  1. Immediate
    1. Pulmonary Edema with ICU available
  2. Delayed
    1. Dyspnea without other signs
    2. Re-triage hourly
  3. Minimal
    1. Asymptomatic with exposure
    2. Re-triage every 2 hours
  4. Expectant
    1. Pulmonary Edema, Cyanosis, or Hypotension
    2. Ominous if onset within 6 hours of exposure

XIV. Management: Triage of Patients presenting over 12 hours

  1. Immediate
    1. Pulmonary Edema if ICU within hours
  2. Delayed
    1. Re-triage every 2 hours
    2. Discharge if recovering and 24 hours observation
  3. Minimal
    1. Asymptomatic
  4. Expectant
    1. Persistent Hypotension despite ICU

XV. Prevention

  1. Activated Charcoal in chemical protective mask
    1. Absorbs Phosgene and offers complete protection

XVI. Complications

  1. Acute Pulmonary Edema
  2. Pulmonary fibrosis

XVII. References

  1. Ashoo (2018) EM:Rap 18(2): 4-5
  2. Seeyave (2015) Crit Dec Emerg Med 29(5): 13-21
  3. Medical Response to Chemical Warfare and Terrorism
    1. US Army Medical Research Institute Chemical Defense
    2. Video-Teleconference: 4/20/00 to 4/22/99
    3. Video-Teleconference: 12/5/00 to 12/7/00
    4. Text: 3rd Edition, December 1998

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