Arterial Gas Embolism

1. See Also
   1. Blast Injury
   2. Scuba Diving
2. Epidemiology
   1. Accounts for 25% of annual fatalities in divers
3. Pathophysiology
   1. Gas enters the aorta and distributes to organs
   2. Most significant adverse effects occur with spinal or cerebral emboli (CVA) or coronary emboli (ACS)
   3. Neurologic symptoms predominate
   4. Vision Loss occurs when Retinal arteries are involved
   5. Small vessel emboli to Muscles or viscera tend to be well tolerated
4. Causes
   1. Barotrauma and lung hyperexpansion
      1. Scuba injury resulting from Pulmonary Barotrauma
      2. Blast Injury
   2. Cardiopulmonary bypass pump or Extracorporeal Membrane Oxygenation (ECMO)
   3. Venous Thromboembolism
      1. Patent Foramen Ovale
      2. Massive embolism that enters arterial circulation
5. Symptoms
   1. When due to SCUBA, occurs within 5 minutes of ascent in 80% of cases
   2. Altered Level of Consciousness
      1. Stupor or confusion (24%)
      2. Coma without Seizures (22%)
      3. Coma with Seizures (18%)
   3. Unilateral motor deficits (14%)
   4. Visual disturbances and Acute Vision Loss (9%)
   5. Vertigo (8%)
   6. Unilateral sensory deficits (8%)
   7. Bilateral motor deficits (8%)
6. Exam
   1. Fundoscopy
      1. Retinal arterial gas bubbles
   2. Cardiovascular exam
      1. Dysrhythmia
   3. Neurologic Exam
      1. Focal neurologic deficit
   4. Skin
      1. Skin mottling
7. Differential diagnosis
   1. When due to Blast Injury
      1. Consider other direct Trauma (e.g. globe injury, Closed Head Injury)
8. Management
   1. Supplemental Oxygen (as close to 100% FIO2 as possible)
   2. Left lateral decubitus position (if possible)
      1. Replaces prior recommendations for trandelenburg position (head down position)
   3. Hyperbaric oxygen chamber
      1. Preferred definitive management
   4. Other measures
      1. Aspirin may reduce injury secondary to inflammation
   5. Monitor and treat associated conditions
      1. Seizure
      2. Arrhythmia
      3. Shock
      4. Hyperglycemia
9. Resources
   1. Life in the Fast Lane
      1. http://lifeinthefastlane.com/ccc/arterial-gas-embolism/
10. References
    1. Jagminas (2015) Crit Dec Emerg Med 29(5): 2-11
    2. Clenney (1996) Am Fam Physician 53(5):1761-6 [PubMed]
    3. Newton (2001) Am Fam Physician 63(11): 2211-2226 [PubMed]