Fire Related Inhalation Injuries – Summary

Pathophysiology

  • Direct local injury – often SUPRAglottic
    • Infraglottic injury due to inhalation of aerosolized, smaller chemicals – not direct
  • Secondary Inflammation – response of inhalation injury -> ROS formation
    • bronchospasm/vasospasm, bronchorrhea, alveolar flooding, bronchial exudate/cast formation, V/Q mismatch
  • Anoxia
  • CO Exposure – reduced O2 delivery and utilization
    • Carboxyhemoglobin levels
      • 10-20%: headache, nausea
      • 20-30%: muscle weakness, impaired cognition
      • 30-50%: cardiac ischemia, unconsciousness
  • Cyanide – interferes w/ O2 utilization at cytochrome level
    • Persistent acidosis
  • Secondary Infection & Respiration
    • Mucosal slough -> incr. debris in airways & reduced clearance
    • Incr risk of: small airway occlusion, atelectasis, V/Q mismatch, infection

Diagnosis

  • Clinical
    • Burns in enclosed space, cutaneous burns around nose & mouth, singed nasal hair, soot in airway, carbonaceous sputum, hoarseness, wheezing, stridor
  • Bronchoscopy
    • Immediate removal of debris not shown to be useful
      • More useful LATER in course for pulmonary clearance
  • Imaging
    • CXR: usually normal
    • V/Q: inhomogeneous clearing of tracer -> small-airway obstruction & inhalation injury
      • However test is cumbersome and not universally reliable
    • CT Scan: maybe useful for stratification, but not a game changer

Management

  • Early After Exposure (0-72 hours)
    • Cutaneous burns < 20% BSA & no threats to airway patency THEN:
      • elevate HOB, humidify air, observe closely
    • INTUBATE: facial edema, hoarseness/stridor, large cutaneous burns with suspected impending facial edema
      • Bronchospasm – nebulized beta-agonists
      • Prophylactic abx and empirical glucocorticoids NOT advised
      • Early hypoxia -> pressure-control ventilation with PEEP
    • CO Poisoning
      • 100% normobaric O2 x 6 hours
    • Cyanide – persistent acidosis despite hemodynamic normalization
      • Not empirically tested for or treated in most burn centers
      • If suspected -> empiric hydroxycobalamin
  • Intermediate after exposure (3 to 21 days)
    • Mucosal slough + loss of ciliary clearance -> low pulmonary clearance
      • Tx: suctioning, chest physiotherapy, bronchoscopy
        • ? usefulness of nebulized heparin & NAC
    • Intubation > 3 weeks = trach
  • Long-Term
    • Few late complications in most survivors
    • May stem from direct thermal damage, ETT access injury – some may require reconstructive surgery

Source: NEJM – Fire-Related Lung Injuries

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s