Arterial gas embolism

Background

  • Also known as "air embolism"
  • May be fatal when air entry reaches 200-300 mL (pressure gradient of 5 mmHg across 14 ga catheter entrains air at 100 mL/sec)[1]
  • Dialysis related
    • Due to negative intrathoracic pressure from spontaneous breathing
  • Scuba related
    • Results from pulmonary barotrauma (most common) and decompression sickness

Prevention

  • Positive pressure mechanical ventilation reduces positive pressure gradient
  • Trendelenburg for insertion/removal of IJV and subclav lines
  • Reverse Trendelenburg for femoral

Clinical Features

  • Asymptomatic
  • Mild: dyspnea, cough
  • Cardiogenic shock: hypotension, oliguria, altered mental status, chest pain
  • Dialysis related
    • Acute dyspnea, chest tightness, LOC, cardiac arrest
  • Scuba related
    • Symptoms develop during ascent or immediately upon surfacing
    • Causes variety of stroke syndromes depending on part of brain affected
      • Immediate death, loss of consciousness, seizure, blindness, hemiplegia

Differential Diagnosis

Dialysis Complications

Scuba Diving Emergencies

Evaluation

  • Low ETCO2 in significant venous air embolism
  • TEE: most sensitive, invasive not available in emergencies
  • Doppler US: noninvasive; air in chamber = high pitch sound

Management[2][3]

  • Central line aspiration of air from right heart
  • 100% O2 non-rebreather
  • Hemodynamic support with positive inotropes
  • Rapid CPR in large air embolus
  • Positioning
    • Durant's maneuver - left lateral decubitus and Trendelenburg
    • Traps air in apex of RV, relieves obstruction of pulmonary outflow tract
  • May require open surgical or angiography for recovery of residual intracardiac or intrapulmonary air

Dialysis Related

  • Prevent any further air entry
    • Immediately cover puncture site with saline soaked gauze

Scuba Related

  • IVF (increases tissue perfusion)
  • Rapid recompression

See Also

External Links

References

  1. Vascular Access. In: Marino, P. The ICU Book. 4th, North American Edition. Philadelphia, PA: Wolters Kluwer Health/Lippincott Williams & Wilkins; 2013
  2. *Shaikh N., Ummunisa F. Acute management of vascular air embolism. J Emerg Trauma Shock. 2009 Sep-Dec; 2(3): 180–185.
  3. Gordy S and Rowell S. Vascular air embolism. Int J Crit Illn Inj Sci. 2013 Jan-Mar; 3(1): 73–76.