Air embolism is entry into and entrapment of air or exogenous gases in veins or arteries. Venous air embolism can result in transit of the air embolism to the right ventricle and pulmonary circulation. In the setting of intracardiac or intrapulmonary shunts, it can transit to the arterial system. Arterial air embolism can transit to any systemic circulation and is often most severe when transiting to the cerebral circulation.

Air can be introduced to the vascular system (venous or arterial) in the setting of trauma or from surgical or medical procedures, particularly central line intravenous (IV) catheterization introducing a pressure gradient favoring venous air intake. Air embolism can also occur with barotrauma due to mechanical ventilation and in the setting of decompression sickness in scuba divers.

Venous air embolism is characterized by sudden-onset respiratory distress associated with an appropriate risk factor (eg, trauma, intravascular catheter insertion, or procedure). Arterial air embolism should be considered when an acute neurologic event occurs in the setting of such risk factors.

Symptoms of venous air embolism are dependent on the inoculum of air involved. Minor cases may be minimally symptomatic to asymptomatic. In cases of large air embolisms, patients develop dyspnea, chest pain, and lightheadedness, and may progress to cardiac collapse in the setting of right heart failure. Initial sounds of cough or gasp reflex, sucking sound, and mill-wheel murmur represent entry of the embolism into pulmonary circulation. Symptoms of arterial air embolism depend on the area of the brain involved.

Prognosis may be favorable with prompt intervention, preventing further air entrapment, proper positioning of patient, reducing air volume, and providing hemodynamic support. Management involves a number of therapies to support airway, breathing, and circulation (ABC). High-flow oxygen reduces air bubble size and treats ischemia.