Air Embolism Causes and Prevention

Introduction to Air Embolism

Air embolism is caused primarily by the entrainment of air or exogenously delivered gas from the operative field or other environmental communication into the venous or arterial vasculature, producing potentially life-threatening systemic effects, as stated by the European Society of Cardiology 1

Central venous catheter procedures are the most common iatrogenic cause, occurring during insertion, manipulation, or removal of central venous catheters and hemodialysis catheters, according to the European Society of Anaesthesiology 2, 3
Surgical procedures, particularly neurosurgical procedures performed in the sitting position and other surgeries with exposure of venous sinuses, can cause air embolism, as reported by the European Heart Journal 4

The primary mechanism of air embolism is the obstruction of the right ventricular pulmonary outflow tract or pulmonary arterioles by air bubbles and fibrin clots, causing hemodynamic effects such as cardiovascular dysfunction and failure, as described by the European Heart Journal 4, 1
Systemic effects can occur when air crosses to systemic circulation, causing cerebral or coronary ischemia, as stated by the Thorax journal 5

The presence of right-to-left shunts increases the risk of paradoxical embolism, as reported by the European Heart Journal 1
Deep inspiration during catheter insertion or removal creates negative intrathoracic pressure that can draw air in, according to the European Society of Anaesthesiology 3
Proper positioning, such as placing patients in Trendelenburg position during central line insertion and removal, can help prevent air embolism, as recommended by the European Society of Anaesthesiology 3
Meticulous technique during catheter insertion and removal, as well as the use of ECG monitoring during upper body CVC insertions, can also help prevent air embolism, as stated by the European Society of Anaesthesiology 2

The severity of air embolism is directly related to the volume and rate of air entrainment, as reported by the European Heart Journal 4
Air embolism can occur at any time from catheter insertion to removal, and presentation can range from subtle neurological, respiratory, or cardiovascular signs to shock, loss of consciousness, and cardiac arrest, as described by the European Society of Anaesthesiology 2
Delayed presentation can occur, so continued monitoring after high-risk procedures is essential, as stated by the Thorax journal 5

Failure to maintain control of guidewires, inadequate catheter fixation, and improper access technique can contribute to air embolism during central line placement, as reported by the Anaesthesia journal 6
Improper access technique, including difficult or multiple cannulation attempts of the same vessel, can increase the risk of air embolism, according to Anaesthesia and Critical Care journals 6, 7
Failure to use ultrasound guidance for central line placement can lead to multiple puncture attempts and increased risk of complications, as stated by the Journal of the American College of Radiology 8
Improper handling when accessing the catheter, including careless manipulation during use or maintenance, can contribute to air embolism, as noted by the Anaesthesia journal 6

The use of real-time ultrasound guidance for all non-emergent central venous access procedures can help prevent air embolism, as recommended by the Journal of the American College of Radiology 8
ECG monitoring throughout upper body CVC insertions can help detect potential complications, including air embolism, as suggested by the Anaesthesia journal 6

Air embolism during central line placement can present with neurological symptoms, including altered mental status, focal neurological deficits, and loss of consciousness, as reported by the Anaesthesia journal 6
The severity spectrum of air embolism can range from subtle signs to shock and cardiac arrest, as described by the Anaesthesia journal 6

Air embolism is a rare complication of central venous catheter insertion with an incidence of approximately 0.5% to 0.8% of all central line placements, according to the American Society of Anesthesiologists guidelines 9
The American Society of Anesthesiologists reports air embolism incidence during central venous access at approximately 0.5% 9
Air embolism is classified as one of the immediate complications of central venous catheterization, occurring at the time of the procedure 10

Air embolism (0.5%) is less common than other immediate complications of CVC insertion such as cardiac arrhythmia (23-25%), accidental arterial puncture (0-15%), pneumothorax (1-4%), and hemothorax (0.1-11%) 10

The American College of Cardiology and American Heart Association recommend that patients with Eisenmenger syndrome should have exclusion of air bubbles in intravenous tubing as essential during treatment, with a Class I recommendation and Level of Evidence C 11
Patients with right-to-left intracardiac shunts, such as those with atrial septal defects or patent foramen ovale, require meticulous air exclusion from IV tubing to prevent paradoxical air embolism, which can cause stroke or coronary ischemia 11
Patients with pulmonary arteriovenous malformations have anatomic right-to-left shunts and face a small but real risk of air embolism during IV contrast administration, requiring adequate precautions 12, 13, 14, 15

For high-risk patients with right-to-left shunts, meticulous technique is mandatory, and consideration of air filters on all venous catheters may be beneficial, according to the American College of Cardiology 11
Priming all IV tubing completely to ensure no visible air bubbles is recommended for high-risk patients 11
Using inline air filters for continuous infusions may be considered for high-risk patients 11