Which physical findings are characteristic of venous air embolism (VAE)?

Updated: Dec 30, 2017
  • Author: Brenda L Natal, MD, MPH; Chief Editor: Erik D Schraga, MD  more...
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Answer

Many cases of VAE are subclinical and do not result in untoward outcomes. However, severe cases are characterized by cardiovascular collapse and/or acute vascular insufficiency of several specific organs, including, but not limited to, the brain, spinal cord, heart, and skin. As mentioned earlier, the spectrum of effects is largely dependent on the rate and volume of entrained VAE. [1, 6, 15]

Two additional contributing factors include whether or not the patient is spontaneously breathing (yielding negative thoracic pressure) or is under controlled positive-pressure ventilation. [1]  These two factors facilitate the entry of air down a pressure gradient.

The clinical presentation is also dependent on the patient's body position at the time of the event. Generally, if the patient is in a sitting position, gas will travel retrograde via the internal jugular vein to the cerebral circulation, leading to neurologic symptoms secondary to increased intracranial pressure. In a recumbent position, gas proceeds into the right ventricle and pulmonary circulation, subsequently causing pulmonary hypertension and systemic hypotension. [15]

An arterial air embolism can also form if passage of air occurred through a right-to-left shunt, as in the case of a patent foramen ovale. [2, 3]  The arterial air emboli can then lodge in the coronary or cerebral circulation, causing myocardial infarction or stroke.

The following hemodynamic, pulmonary, and neurologic complications primarily result from gas gaining entry into the systemic circulation, occluding the microcirculation and causing ischemic damage to these end organs. Animal studies have also suggested the presence of secondary tissue damage resulting from the release of inflammatory mediators and oxygen free radicals that occur in response to air embolism.


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