Air embolism after peripheral IV contrast injection

CAUSES OF VENOUS AIR EMBOLISM

Venous air embolism is a potentially catastrophic complication when it occludes blood flow to the pulmonary, cardiac, or cerebral circulation. It is most often associated with neurologic and otolaryngologic surgery, thoracic or abdominal trauma (including barotrauma from mechanical ventilation), and vascular interventions such as central and peripheral intravenous access.¹ It can also occur when central venous pressure is low, such as when a catheter is inserted during inspiration, when the patient is upright, or if the patient is hypovolemic.^1,2 Alternatively, incorrectly flushed lines or pressurized injection of fluids, such as contrast media, may force air into the vasculature.^3,4

While venous air embolism is a known risk associated with intravenous access, many cases are asymptomatic and therefore go undetected, likely leading to an underestimation of the true incidence.⁴ A study of more than 11,000 central venous catheter insertions using optimal positioning and technique found an incidence of 0.13%.¹ A study of 677 patients who underwent peripheral contrast injection observed an incidence of 11.7%.⁴

MANAGEMENT

Management of venous air embolism depends on the location and volume of the emboli. In most cases, the air is resorbed without complications. However, large emboli or those in patients with shunts that can result in paradoxical emboli may present with cardiopulmonary or neurologic symptoms.^1,2 As little as 0.5 mL of air in the coronary arteries can cause ventricular fibrillation, and 2 to 3 mL of air in the cerebral circulation can be fatal.⁵

High-flow oxygen therapy helps maintain adequate oxygenation and promotes air resorption.¹ Placing the patient in the Trendelenburg or left lateral decubitus position (Durant maneuver) encourages air emboli to migrate away from the right ventricular outflow tract and toward the right atrium, avoiding possible cardiopulmonary collapse.^1,6 If available, hyperbaric oxygen therapy is the definitive treatment for severe cases and has been shown to improve recovery when administered early.¹

MINIMIZING THE RISK

The risk of venous air embolism can be minimized when inserting or removing a central venous catheter by placing the patient in the supine or Trendelenburg position and ensuring that the patient is hydrated. Catheter insertion should be avoided during inspiration, and removal should be performed while the patient performs a Valsalva maneuver or during exhalation.

Before contrast injection, the catheter lumen should be flushed, and components such as stopcocks and Luer locks should be inspected and secured.

Incidentally detected intracardiac air emboli rarely cause hemodynamic compromise. However, as in our patient, appropriate management is straightforward and effective in preventing potentially life-threatening cardiopulmonary and neurologic complications.