What is the appropriate initial and ongoing management for a patient with suspected phosgene inhalation injury?

Management of Phosgene Inhalation Injury

Immediately remove the patient from exposure, provide 100% oxygen, and admit for mandatory 24-hour observation regardless of initial symptom severity, as phosgene characteristically causes delayed-onset non-cardiogenic pulmonary edema that can be fatal 12-24 hours post-exposure. 1, 2

Immediate Scene Management and Decontamination

• Remove the patient from the contaminated area immediately and ensure scene safety for responders 1
• Healthcare providers responding to phosgene exposure should wear N95 respirators (or higher) with full PPE including gown, gloves, and eye protection, as phosgene is a highly toxic gas that can be generated during fires involving plastics and chlorine-containing chemicals 3, 1
• Decontaminate the patient by removing all clothing and washing exposed skin with copious amounts of water or soap and water 2
• Phosgene does not require extensive decontamination like other chemical agents, as it is a gas that does not persist on clothing or skin after removal from exposure 2

Initial Respiratory Support

• Administer 100% high-flow oxygen immediately to all patients with suspected phosgene exposure, regardless of initial oxygen saturation, as hypoxemia develops insidiously 1, 2
• Maintain the patient in a semi-recumbent or upright position and enforce strict rest, as physical exertion increases oxygen demand and can precipitate or worsen pulmonary edema 2, 4
• Avoid positive pressure ventilation initially unless absolutely necessary for respiratory failure, as it may worsen alveolar-capillary membrane damage in the early phase 2
• However, early CPAP (continuous positive airway pressure) initiated within 1 hour of exposure has been shown to significantly improve survival and reduce lung injury severity, and should be strongly considered before overt respiratory failure develops 5

Mandatory Observation Period

• Admit ALL patients with confirmed or suspected phosgene exposure for a minimum of 24 hours of continuous monitoring, even if asymptomatic on presentation 1, 2
• This is critical because phosgene causes a characteristic latent period of 2-24 hours (typically 4-8 hours) during which patients may feel well or have only mild symptoms, followed by sudden onset of severe, life-threatening pulmonary edema 1, 4
• Monitor continuously for: respiratory rate, oxygen saturation, work of breathing, chest auscultation for crackles, arterial blood gases, and chest radiography 1, 2

Supportive Care During Observation

• Establish large-bore IV access early in all patients 6, 2
• Fluid management is controversial: traditional teaching emphasized fluid restriction to minimize pulmonary edema, but current evidence suggests judicious IV fluids may be necessary to maintain adequate perfusion while avoiding volume overload 2, 4
• Bronchodilators (inhaled beta-agonists) may provide symptomatic relief for bronchospasm and wheezing 2
• Corticosteroids have NOT been proven effective in preventing or treating phosgene-induced lung injury and are not routinely recommended 7, 2, 4

Advanced Respiratory Support for Deterioration

• If the patient develops progressive hypoxemia despite high-flow oxygen, escalate to non-invasive positive pressure ventilation (CPAP/BiPAP) as the next step 5
• If non-invasive ventilation fails or the patient develops acute respiratory distress syndrome (ARDS), proceed to endotracheal intubation with mechanical ventilation using lung-protective strategies (low tidal volumes 6 mL/kg ideal body weight, plateau pressure <30 cm H2O, PEEP titration) 7, 2, 4
• When intubating, use videolaryngoscopy if available and ensure the most experienced operator performs the procedure with appropriate PPE including N95 respirator 8

Critical Pitfalls to Avoid

• Never discharge a patient within 24 hours of phosgene exposure, even if asymptomatic, as delayed pulmonary edema can be rapidly fatal 1
• Do not allow physical exertion during the observation period, as this dramatically increases the risk of precipitating pulmonary edema 2, 4
• Do not rely on initial chest X-ray or symptoms to determine disposition—the latent period means early findings are falsely reassuring 1, 2
• Avoid excessive IV fluids that could worsen pulmonary edema, but also avoid hypovolemia that impairs tissue oxygen delivery 2

Prognosis and Disposition

• Patients who remain asymptomatic with normal oxygen saturation, respiratory rate, and chest examination after 24 hours of observation may be discharged with strict return precautions 1, 2
• Those who develop pulmonary edema require ICU admission with aggressive respiratory support, as mortality remains high (historically 10-30% in severe exposures) despite modern critical care 7, 1, 4
• No specific antidote exists for phosgene poisoning; all treatment remains supportive 7, 4