“Air embolism is a rare but potentially fatal complication of surgical procedures. Rapid
recognition and intervention is critical for reducing morbidity and mortality.”

“Iatrogenic procedures are the main cause of vascular air embolism (VAE). This rare complication can arise in a wide range of clinical scenarios involving line placement, trauma, barotrauma, and several types of surgical procedures including cardiac, vascular, and neurosurgery. Traditionally, surgery and trauma were the most significant causes of systemic and cerebral air embolism; however, endoscopy, angiography, tissue biopsy, thoracocentesis, hemodialysis, and central/peripheral venous access now comprise a greater proportion. The insertion and maintenance of advanced vascular
access devices are increasingly being performed within multiple clinical specialties. Moreover, the bulk of interventional radiology (IR) procedures commence with the placement of an intravascular sheath, which is a major risk factor for air embolism throughout the duration of the procedure. Endovascular procedures complicated by an intravascular air embolism result in significant morbidity and mortality.
VAE is a potentially preventable condition, which arises as a result of a pressure gradient that allows air to enter the blood stream, which can subsequently cause blockages in blood flow. VAE has an estimated incidence of 1 in 772 according to one series, while another study found that the incidence of iatrogenic gas embolism complicates 2.65 per 100,000 hospitalizations; however, these figures are considered lower than the true incidence due to many unreported instances and undiagnosed asymptomatic patients.”

“Air embolism may cause end-organ ischemia or infarction if there is insufficient collateral supply.
Air emboli to the coronary or cerebral circulation can have major adverse consequences, even when the volume of air is small. A venous gas embolism (VGE) occurs when air enters the venous system and eventually causes an obstruction in the pulmonary circulation. This can arise as a result of a trauma or from a multitude of iatrogenic procedures. An anatomic cardiac defect—or in certain conditions, oxygen toxicity and excessive volumes of gas—can lead to the passage of air bubbles through the pulmonary vasculature. The gradient between external atmospheric pressure and the intravascular central venous pressure (CVP) is especially increased by hypovolemia or during inspiration by creating a negative intrathoracic pressure, which can enhance the possibility of air entry. As CVP may be
sub-atmospheric at baseline in up to 40% of patients, those patients in an upright position or those undergoing IR procedures such as hemodialysis catheter placements are particularly susceptible.”

McCarthy, Colin J et al. “Air Embolism: Diagnosis, Clinical Management and Outcomes.” Diagnostics (Basel, Switzerland) vol. 7,1 5. 17 Jan. 2017 Free Full Text