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
  • Diving related
    • Results from pulmonary barotrauma (most common) and decompression sickness, most commonly in last 10m of ascent.
    • Classically presents as LOC within 2 minutes of surfacing, can lead to stroke-like symptoms.

Prevention

  • Positive pressure mechanical ventilation reduces positive pressure gradient
  • Trendelenburg for insertion/removal of IJV and subclav lines
  • Reverse Trendelenburg for femoral
  • Slow and controlled ascent when diving, with special precaution to exhale during ascent in the last 10m so the lungs do not over-pressurize.

Clinical Features

Differential Diagnosis

Diving Emergencies

Dialysis Complications

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[3][4]

  • Central line aspiration of air from right heart
  • 100% O2 non-rebreather
    • Regardless of SaO2 (to reduce embolism size)
  • Hemodynamic support with positive inotropes
  • 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
  • Prevent any further air entry
    • Immediately cover puncture site with saline soaked gauze

Disposition

  • Likely admission

See Also

References

  1. Vascular Access. In: Marino, P. The ICU Book. 4th, North American Edition. Philadelphia, PA: Wolters Kluwer Health/Lippincott Williams & Wilkins; 2013
  2. Diving Medicine, Karen B. Van Hoesen and Michael A. Lang, Auerbach's Wilderness Medicine, Chapter 71, 1583-1618.e6
    • 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.
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