Phosgene

CAS RN: 75-44-5

Treatment Overview

0.4.3 INHALATION EXPOSURE
  • A) MANAGEMENT OF TOXICITY
    • 1) INHALATION EXPOSURE: INITIAL CARE: Remove patient
      • (s) from exposure and monitor for respiratory distress. Monitor vital signs. Begin oxygen therapy after phosgene inhalation, if the victim shows signs of hypoxemia or respiratory distress or has a pulse oximetry reading of less than 94%. Assist ventilation as needed. Reassure the patient, by providing a calm environment.
    • 2) IRRITANT EFFECTS: Treatment is symptomatic and supportive. Oxygen (humidified is preferred) therapy should be used in patients with dyspnea, wheezing, or pulse oximetry reading of SaO2 of less than 94%. If bronchospasm and wheezing occur, consider treatment with inhaled sympathomimetic agents.
    • 3) PULMONARY EFFECTS: Monitor patients for 24 hours after exposure because of the possibility of delayed pulmonary edema. Early use of positive pressure airway management and mechanical ventilation may be needed in patients with severe toxicity. The following agents have been suggested as early PROPHYLACTIC treatment of pulmonary effects to block the inflammatory cascade that occurs following a significant exposure. The following are based on an estimated phosgene exposure. INHALATION EXPOSURE of 50 to 150 ppm-min (pulmonary edema unlikely): CORTICOSTEROIDS: Aerosolized: Maximal dosage based on the specific corticosteroid therapy and/or Intravenous: 250 mg methylprednisolone or equivalent. Use of steroids in this setting has not been proven. INHALATION EXPOSURE of 150 ppm-min or more (pulmonary edema probable) CORTICOSTEROIDS: Aerosolized: Maximal dosage based on the specific corticosteroid therapy and/or Intravenous: 1 g methylprednisolone. N-ACETYLCYSTEINE: 20 mL of a 20% solution via nebulizer. BETA-2 ADRENERGIC AGONISTS: Consider salbutamol 5 mg via nebulizer every 4 hours. It should be used early post exposure to minimize or reduce lung inflammation. Intravenous use is not recommended. INHALATION EXPOSURE of 300 ppm-min or above (life-threatening pulmonary edema expected): Same treatment as described above for an exposure of 150 ppm-min or more. Vasopressors may be indicated if significant hypotension develops.
      • a) REST: A decrease in oxygen consumption (ie, decreased physical exertion/activity) may be a factor in reducing the risk of developing pulmonary edema.
      • b) ACUTE LUNG INJURY: Maintain ventilation and oxygenation and evaluate with frequent arterial blood gases and/or pulse oximetry monitoring. Early use of positive pressure airway management and mechanical ventilation may be needed. Consider recommendations by ARDSnet for protective ventilation in patients with evidence of pulmonary edema.
      • c) EXTRACORPOREAL MEMBRANE OXYGENATION (ECMO): There are no reports of ECMO use following phosgene exposure; however, a consult with a pulmonologist or intensivist should be considered in a patient with a 150 ppm-min or greater exposure, a direct spray to the face and/or chest to a high concentration of phosgene in a solvent without the use of protective gear; or a suspected significant exposure that cannot be confirmed by a badge reading. Ideally, the patient should be transferred during the latency phase to an ECMO center if clinical symptoms require a transfer to a higher level of care (ie, tertiary care center).
  • B) DECONTAMINATION
    • 1) PREHOSPITAL: For inhalational exposures, the mainstay of treatment is removal of the patient
      • (s) from phosgene exposure to fresh air. DERMAL: Remove clothing suspected of being contaminated with liquid or gaseous phosgene or solvents containing phosgene to avoid contamination of other individuals by direct contact or through off-gassing of phosgene. Double-bag all items for proper disposal. Skin contamination with liquid or gaseous phosgene or solvents containing phosgene, should be washed copiously with warm water for at least 15 minutes. OCULAR EXPOSURE: Copiously irrigate eyes with plain water or saline following exposure to liquids containing phosgene. FROSTBITE: Frostbite has not been commonly reported but is a potential risk following contact with liquid phosgene. If frostbite has developed after eye or skin exposure, seek medical attention immediately and do NOT flush exposed area with water. Carefully observe patients for signs of systemic symptoms and administer treatment as necessary.
    • 2) HOSPITAL: There is no indication for activated charcoal, gastric lavage and whole bowel irrigation. DERMAL and/or OCULAR EXPOSURE: See PREHOSPITAL decontamination.
  • C) AIRWAY MANAGEMENT
    • 1) Airway management is likely to be an issue in patients who develop pulmonary edema after severe exposures. Early or elective endotracheal intubation and mechanical ventilation may be needed in patients that exhibit respiratory distress. Consider recommendations by ARDSnet for protective ventilation in patients with evidence of pulmonary edema.
  • D) ANTIDOTE
    • 1) There is no specific antidote for phosgene.
  • E) ENHANCED ELIMINATION
    • 1) There is no evidence for the use of dialysis, hemoperfusion, urinary alkalinization or multiple dose activated charcoal. It is highly unlikely that any modes of enhanced elimination would have any direct benefit to a patient poisoned with phosgene.
  • F) PATIENT DISPOSITION
    • 1) OBSERVATION CRITERIA: TRIAGE MEASURES FOR ACUTE EXPOSURE: Asymptomatic patients following an inhalational exposure to a dose of less than 25 ppm-min require no immediate medical attention. Patients with anxiety and irritant effects (ie, eyes, upper airway) following an inhalational exposure to a low-dose, require symptomatic care until symptoms have resolved. Patients with a significant exposure (ie, greater than 150 ppm-min) require immediate prophylactic care. Patients with an unknown exposure should be closely observed and can be discharged after 8 hours if the patient remains asymptomatic along with a negative chest x-ray performed 8 hours after exposure. If a chest x-ray is not available, the patient should be observed for 24 hours.
    • 2) ADMISSION CRITERIA: Patients with worsening symptoms or severe respiratory distress should be admitted to the hospital. If the patient is stable, patients should be admitted for ongoing monitoring of vital signs, cardiac and respiratory function, and pulse oximetry. If worsening symptoms (ie, pulmonary edema) develop or there is a need for intubation and ventilation, the patient requires intensive care. Patients should remain in the hospital until they are clearly improving and stable from a respiratory standpoint.
    • 3) CONSULT CRITERIA: Consult a pulmonologist or intensivist for any patient with significant respiratory symptoms (ie, hypoxia, dyspnea, pulmonary edema) to manage ongoing treatment needs.
    • 4) TRANSFER CRITERIA: If it is determined that a patient requires ECMO therapy, following consultation with a pulmonologist or an intensivist, transfer to a tertiary care center may be required. To locate a facility go to Extracorporeal Life Support Organization at http://www.elso.org. .
  • G) PITFALLS
    • 1) Non-irritant respiratory symptoms may be delayed for up to 24 to 72 hours; patients who are discharged should be given careful instructions to return if symptoms develop. In addition, odor recognition is unreliable to warn of exposure. Upper airway irritation does not always precede pulmonary edema or death. Signs and symptoms of pulmonary edema will often be delayed by at least several hours. The following may be independent factors: odor recognition, upper airway irritation, pulmonary edema and death. Anxiety, headache, and/or nausea may occur following a perceived exposure and may not reflect either the concentration or exposure dose to phosgene.
  • H) TOXICOKINETICS
    • 1) Symptoms from dermal or eye exposures to liquefied phosgene are immediate. Irritant properties from exposure to phosgene gas should be immediate as well, but more severe respiratory symptoms may be delayed from 24 to 72 hours in patients with lower concentration more prolonged exposure.
  • I) PREDISPOSING CONDITIONS
    • 1) PROGNOSTIC INDICATOR: In general, the shorter the latency period (delayed response), the worse the prognosis.
    • 2) Patients with underlying lung disease such as asthma or chronic obstructive pulmonary disease may be more susceptible to the irritant properties of phosgene gas.
  • J) DIFFERENTIAL DIAGNOSIS
    • 1) Other irritant gases such as ozone and nitrogen dioxide can cause similar symptoms.
0.4.4 EYE EXPOSURE
  • A) Copiously irrigate eyes with plain water or saline following exposure to liquids containing phosgene.
  • B) FROSTBITE: Frostbite has not been commonly reported but is a potential risk following contact with liquid phosgene. If frostbite has developed after eye or skin exposure, seek medical attention immediately and do NOT flush exposed area with water. If frostbite has not developed, exposed skin and eyes should be copiously flushed with water or saline. Carefully observe patients for signs of systemic symptoms and administer treatment as necessary.
0.4.5 DERMAL EXPOSURE
  • A) OVERVIEW
    • 1) Remove clothing suspected of being contaminated with liquid or gaseous phosgene or solvents containing phosgene to avoid contamination of other individuals by direct contact or through off-gassing of phosgene. Double-bag all items for proper disposal. Skin contamination with liquid or gaseous phosgene or solvents containing phosgene, should be washed copiously with warm water for at least 15 minutes. Carefully observe patients for signs of systemic symptoms and administer treatment as necessary.
    • 2) FROSTBITE: Frostbite has not been commonly reported but is a potential risk following contact with liquid phosgene. If frostbite has developed after eye or skin exposure, seek medical attention immediately and do NOT flush exposed area with water. If frostbite has not developed, exposed skin and eyes should be copiously flushed with water or saline. Carefully observe patients for signs of systemic symptoms and administer treatment as necessary.
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