What are the criteria for diagnosing and managing inhalation injury burns in patients with a history of exposure to fires or hazardous environments?

Criteria for Inhalation Injury Burns

Suspect inhalation injury based on clinical criteria including fire in an enclosed space, facial burns, soot around nose/mouth, singed nasal hairs, respiratory distress, dysphonia, wheezing, carbonaceous sputum, or stridor, and confirm diagnosis with flexible bronchoscopy as the gold standard. 1, 2

Clinical Diagnostic Criteria

High-Risk Exposure History

• Fire in an enclosed space is the single most important historical factor that should immediately raise suspicion for smoke inhalation injury 1, 2
• Exposure to vapors or inhaled smoke in the context of face/neck burns requires close continuous monitoring due to risk of progressive glottic edema 1, 2

Physical Examination Findings

• Carbonaceous (blackish) sputum is the most indicative finding of inhalation injury, representing direct evidence of smoke particle deposition in lower airways 2
• Soot around the nose or mouth, or presence of soot on the face 1, 2
• Singed nasal hairs or singed facial hairs 1, 2
• Facial burns, particularly deep burns involving the whole face 1
• Deep circular neck burns 1

Respiratory Signs and Symptoms

• Difficulty breathing or respiratory distress 1
• Dysphonia (voice changes) 1, 2
• Wheezing 1, 2
• Stridor 1
• Dyspnea 2

Critical Diagnostic Pitfalls

Normal Tests Do NOT Exclude Inhalation Injury

• Normal oxygen saturation (>90%), normal chest X-ray, and normal arterial blood gases do not exclude inhalation injury and should not provide false reassurance 1, 2
• Normal FEV1/FVC ratio cannot exclude inhalation injury 2
• Oxygen saturation may remain normal initially despite significant airway damage 2
• No single diagnostic test alone can exclude burn-associated inhalation injury 2

Gold Standard Diagnostic Method

Flexible Bronchoscopy

• Flexible bronchoscopy is the gold standard for diagnosing smoke inhalation injury 1, 2
• Severity of bronchoscopic findings correlates with morbidity, ICU length of stay, duration of mechanical ventilation, and hypoxemia severity 1, 2
• Bronchoscopy should only be performed in patients who are already intubated due to risk of airway compromise during the procedure 1
• Bronchoscopy only assesses the proximal airway and does not provide comprehensive analysis of pulmonary insult 2

Immediate Management Criteria

Indications for Immediate Intubation

• Intubate immediately without delay if any of the following are present: 1

  • Severe respiratory distress
  • Severe hypoxia or hypercapnia
  • Coma or altered mental status
  • Symptoms of airway obstruction

• For patients with severe burns involving the whole face, intubate if: 1

  • Deep circular neck burn present
  • Symptoms of airway obstruction
  • Very extensive burns (TBSA ≥40%)

Monitoring Requirements

• Patients with face/neck burns who were exposed to vapors or inhaled smoke require close continuous monitoring even with initially normal diagnostic tests 1, 2
• Regular reassessment is critical as inhalation injury can progress over time 2

Burn Center Transfer Criteria

American Burn Association Criteria for Burn Center Treatment

• Smoke inhalation injury alone is an indication for burn center transfer 3, 1
• Second- or third-degree burns involving face, hands, feet, genitals, or >10% body surface area (>5% in children) 1
• Direct admission to a burn center is strongly preferred over staged transfer, as it reduces time to definitive treatment and improves morbidity and mortality 1
• Transfer should not be delayed for extensive diagnostic testing 2

Pediatric Considerations

• Smoke inhalation increases pediatric mortality three-fold and significantly increases morbidity even with TBSA <10% 1
• In children, TBSA >10%, deep burns >5%, infants (<1 year), or smoke inhalation injuries are criteria for severe burns requiring specialized care 3