Phosgene Toxicity Treatment & Management

To avoid further exposures, hazardous materials (Hazmat) prehospital providers should always ensure that the environment is safe.^[8] A self-contained breathing apparatus (SCBA) should be worn at the exposure site.^[13] Remove the patient's clothes to prevent further contamination. If the eyes and skin are exposed, begin irrigation on site.

In the field, standard management of ABCs usually is sufficient. Severe exposures may require ET intubation and suctioning. If a significant bronchospastic component is present, bronchodilators may be used with caution.^{[8, 14]}

Past wartime experience has demonstrated that, in a mass casualty situation, phosgene exposures should be classified as immediate because of the impending need for intubation and positive end-expiratory pressure (PEEP) to maintain distal airway opening.^[15]

Always consider the need for decontamination in any toxic exposure to minimize the risk of poisoning hospital personnel. Inhalational exposure of phosgene should not occur unless in the proximity of the gas. If external decontamination has not been performed in the field, use personal protective equipment, as necessary, including dermal, eye, and facial protection. A decontamination shower unit may be used.^{[8, 13]}

Initiate humidified oxygen supplementation. Intubation with continuous positive airway pressure (CPAP) ventilation and pressure support is usually required to improve oxygenation. Frequent suctioning may improve conditions.

Bronchodilators may improve existing bronchospasm. In animal studies, beneficial effect has been shown with the administration of numerous drugs, including leukotriene antagonists, ibuprofen, colchicine, cyclophosphamide, terbutaline, aminophylline, and N -acetylcysteine.^{[16, 17]} Nebulized sodium bicarbonate treatment theoretically may be beneficial; however, consider it as second line after the drugs noted above.

Avoid excessive fluid administration. Pulmonary artery catheter monitoring may be required to maintain appropriate fluid balance while treating hypotension caused by fluid shifts.

In severe cases, extracorporeal membrane oxygenation (ECMO) may be considered refractory to supportive care.

Minimize fluid administration except when it is needed to correct hypotension. Avoid diuretics because the patient typically is volume-depleted from fluid shifts.

Avoid exertion during treatment and for several weeks after recovery.

Prophylactic antibiotics have been recommended by some authors based on the findings of pneumonia and bronchitis in virtually all autopsy specimens.

Corticosteroid administration postexposure has been recommended to reduce the degree of pulmonary edema by reducing the inflammatory response. Some sources recommend administration begin within 15 minutes or as soon as possible after exposure.

No specific antidote or effective elimination process exists. During both world wars, the Germans and Russians believed that hexamethylene tetramine was the antidote. Subsequent studies have shown some preexposure benefit but no definite postexposure benefit.

Tomelukast, a leukotriene receptor antagonist, prevents pulmonary edema in phosgene-exposed rabbits. Experimentally, ibuprofen has been shown to reduce phosgene-induced pulmonary edema.^[18] Colchicine and cyclophosphamide reduce neutrophil influx when administered to mice 30 minutes following phosgene exposure. These drugs reduce lung injury and mortality in mice.^[19]

Intratracheal dibutyryl cyclic adenosine monophosphate (DBcAMP), a cyclic adenosine monophosphate (cAMP) analogue, inhibits the release of leukotrienes that contribute to the disease process.^{[20, 21]} In phosgene-exposed rabbits, terbutaline and aminophylline (cAMP enhancers) limit the pulmonary capillary leakage. Also, intratracheal N -acetylcysteine (NAC), administered to rabbits 45 minutes postexposure, reduces leukotriene formation and pulmonary edema.^[22] Theoretically, nebulized NAC also should be effective.

• Consult the regional poison control center and a medical toxicologist for additional useful information and patient care recommendations.
• Prolonged critical care management often is required for the pulmonary complications of phosgene exposure.