Pulmonary Barotrauma

Aka: Pulmonary Barotrauma, Pulmonary Decompression Injury, Pulmonary Blast Injury, Blast Lung, Pulmonary Overpressurization Syndrome

1. Causes
   1. Scuba Diving related injury (esp. breath holding)
   2. Blast Injury
2. Pathophysiology
   1. Lungs are especially sensitive to barotrauma
   2. Lung gas expands on ascent (Boyle's Law)
   3. Expanding gas without release causes lung barotrauma
3. Precautions
   1. Findings may be delayed up to 48 hours
4. Risk Factors
   1. Obstructive Lung Disease (Asthma, COPD)
   2. Concurrent serious Blast Injury
      1. Skull Fracture
      2. Burn Injury >10% BSA
      3. Penetrating injury to the head or torso
5. Signs
   1. Head and neck
      1. Hypopharyngeal Petechiae
   2. Lung findings
      1. Dyspnea
      2. Cough
      3. Wheezing
      4. Hemoptysis
      5. Chest Pain
      6. Hypoxia
      7. Apnea
      8. Decreased breath sounds
   3. Cardiovascular findings
      1. Bradycardia
      2. Hypotension
      3. Cyanosis
   4. Skin findings
      1. Subcutaneous Emphysema
6. Imaging
   1. Chest XRay
      1. May demonstrate butterfly pattern (seen in Pulmonary Contusion)
7. Complications: Pulmonary Barotrauma
   1. Arterial Gas Embolism
   2. Pulmonary Contusion (most common Pulmonary Blast Injury, presentation may be delayed 48 hours)
   3. Pneumothorax
   4. Pneumomediastinum
   5. Interstitial Emphysema
   6. Mediastinal Emphysema
   7. Subcutaneous Emphysema
8. Management
   1. Endotracheal Intubation indications
      1. Massive heomptysis
      2. Impending airway compromise
      3. Respiratory Failure
   2. Management similar to Pulmonary Contusion
      1. Adequate fluid Resuscitation but avoid Fluid Overload
      2. Prevent Hypoxemia with High Flow Oxygen
   3. Avoid excessive Positive Pressure Ventilation
      1. Risks pulmonary alveolar rupture and Arterial Gas Embolism
      2. Limit peak inspiratory pressures to <40 cm H2O
   4. Manage Pneumothorax or Hemothorax
      1. Prompt Chest Tube placement for decompression
   5. Severe case options
      1. Extracorporeal Membrane Oxygenation (ECMO)
9. Prognosis
   1. Highest mortality (11%) of all blast injuries
10. References
    1. (2016) CALS Manual, 14th edition 1: 42-3
    2. Jagminas (2015) Crit Dec Emerg Med 29(5): 2-11
    3. Mackenzie (2011) Philos Trans R Soc Lond B Biol Sci 366(1562): 295–299 [PubMed]