What is the appropriate management for a patient with inhalational chemical exposure, considering factors such as pre-existing respiratory conditions like asthma or chronic obstructive pulmonary disease (COPD)?

Management of Inhalational Chemical Exposure

Immediate skin and respiratory decontamination with copious water irrigation for at least 15 minutes is the cornerstone of management, followed by removal from exposure, oxygen support, and bronchodilator therapy for patients with respiratory symptoms. 1

Immediate Decontamination and Scene Safety

• Remove the patient from the contaminated environment immediately and ensure personal protective equipment is worn by responders to prevent secondary contamination 1
• Irrigate exposed skin with running water for at least 15 minutes unless chemical-specific guidelines recommend otherwise 1
• Remove all contaminated clothing, jewelry, and surrounding materials from the exposure area to prevent continued absorption 1
• For dry chemicals, brush off excess powder before water irrigation to prevent exothermic reactions 1
• Contact regional poison control centers for chemical-specific decontamination procedures, as some caustic agents may require specialized treatment beyond water irrigation 1

Respiratory Assessment and Support

• Call EMS immediately if the patient develops respiratory symptoms, systemic symptoms, or had large chemical exposures 1
• Assess for signs of respiratory distress including dyspnea, inability to complete sentences, respiratory rate >25/min, and heart rate >110/min 2
• Provide supplemental oxygen as needed, but use caution in patients with known COPD - if carbon dioxide retention is suspected, drive nebulizers with air rather than high-flow oxygen and use 24% Venturi masks between treatments 2
• Measure arterial blood gases in severe cases to assess for hypoxemia and carbon dioxide retention 2

Bronchodilator Therapy for Respiratory Symptoms

For patients developing bronchospasm or wheezing after inhalational chemical exposure:

• Start with nebulized short-acting β-agonist (albuterol 2.5-5 mg) as first-line therapy 2, 3
• Administer via nebulizer over 5-15 minutes using proper flow rates 1
• If response is inadequate, add ipratropium bromide 250-500 µg to the nebulizer for combination therapy 2
• The combination produces additive bronchodilator effects and is more effective than single-agent therapy in moderate-to-severe cases 2
• Supervise the first treatment in elderly patients or those with cardiac history, as β-agonists may precipitate angina 2, 3
• Use a mouthpiece rather than face mask for ipratropium in patients with glaucoma to minimize ocular exposure 2

Corticosteroid Therapy

• Add oral corticosteroids if the patient meets severity criteria (cannot complete sentences, RR >25/min, HR >110/min) or has signs of significant airway inflammation 2
• Corticosteroids address the inflammatory component of chemical-induced airway injury and should be given alongside bronchodilators in acute severe presentations 2
• Note that corticosteroid efficacy for direct chemical pulmonary injury has not been definitively proven, though they are frequently used and recommended 4

Special Considerations for Pre-existing Respiratory Disease

For patients with asthma:

• Chemical irritants can trigger bronchospasm through nonimmunologic airway irritation in pre-existing asthma 1
• These patients may develop reactive airways dysfunction syndrome (RADS) after single high-level exposures, with persistent asthma-like symptoms developing within hours 1
• Treat aggressively with bronchodilators and corticosteroids as the increased nonallergic hyperresponsiveness can persist even after exposure termination 1

For patients with COPD:

• Chemical exposures represent a common trigger for acute exacerbations alongside infections 1, 5
• Use bronchodilators as the essential treatment, with steroids targeting inflammation 5
• Be cautious with oxygen delivery - avoid high-flow oxygen in patients with carbon dioxide retention 2
• If sputum becomes purulent, add empirical antibiotics (amoxicillin, tetracycline derivatives, or amoxicillin/clavulanic acid) for 7-14 days 2

Monitoring and Disposition

• Observe for delayed pulmonary edema, which can occur hours after exposure to certain irritant gases 4, 6
• Monitor for development of non-cardiogenic pulmonary edema, adult respiratory distress syndrome, or acute pneumonitis 7, 4
• Most patients are expected to survive and recover with supportive care, though some may develop long-term sequelae including bronchiolitis obliterans, chronic airflow obstruction, or persistent bronchial hyperreactivity 4
• Once acute symptoms improve, transition from nebulized to handheld inhaler therapy and observe for 24-48 hours before discharge 2

Common Pitfalls

• Do not delay decontamination - immediate irrigation within 10 minutes significantly decreases full-thickness burns and hospital length of stay compared to delayed treatment 1
• Do not use high-flow oxygen to drive nebulizers in COPD patients with suspected CO2 retention - this can worsen respiratory acidosis 2
• Do not assume single-agent bronchodilator therapy is sufficient - combination therapy with β-agonist plus anticholinergic is often needed for adequate response 2
• Do not discharge patients immediately after symptom improvement - delayed pulmonary complications can occur hours after exposure 4, 6