Fatal Cerebral Air Embolism: A Case Series and Literature Review

Abstract

Cerebral air embolism (CAE) is an infrequently reported complication of routine medical procedures. We present two cases of CAE. The first patient was a 55-year-old male presenting with vomiting and loss of consciousness one day after his hemodialysis session. Physical exam was significant for hypotension and hypoxia with no focal neurologic deficits. Computed tomography (CT) scan of head showed gas in cerebral venous circulation. The patient did not undergo any procedures prior to presentation, and his last hemodialysis session was uneventful. Retrograde rise of venous air to the cerebral circulation was the likely mechanism for venous CAE. The second patient was a 46-year-old female presenting with fever, shortness of breath, and hematemesis. She was febrile, tachypneic, and tachycardic and required intubation and mechanical ventilation. An orogastric tube inserted drained 2500 mL of bright red blood. Flexible laryngoscopy and esophagogastroduodenoscopy were performed. She also underwent central venous catheter placement. CT scan of head performed the next day due to absent brain stem reflexes revealed intravascular air within cerebral arteries. A transthoracic echocardiogram with bubble study ruled out patent foramen ovale. The patient had a paradoxical CAE in the absence of a patent foramen ovale.

Cortical Blindness and Altered Mental Status following Routine Hemodialysis, a Case of Iatrogenic Cerebral Air Embolism

“…Though many safeguards and medical protocols exist on proper flushing of lines, catheters, and patient positioning, this complication remains possible and has proven to be deadly when emboli occlude pulmonary, cardiac, or neurologic vasculature [ 13 ]. In addition, hemodialysis devices, despite being fitted with air traps and ultrasonic detectors are not infallible in filtering microbubbles originating from luer lock connector tubing or from insufficient priming of dialysis hardware [ 12 , 14 , 15 ]. The bubbles may pass through the system without triggering the system alarm, especially when the bubbles are <50 μ L in diameter or flow rates are below the International Electrotechnical Commission standard for infusion pumps and dialysis machines, 0.1 ml/kg body weight for bolus infusion or 0.03 ml/kg/minute for continuous infusion [ 12 , 16 ].…”

“…In a recent emergency department retrospective study, pneumocephalus from introduction of air into venous circulation appears in one in 3000 noncontrast head CTs [ 15 ]. Cerebral air embolus occurs when an air bubble travels through the venous system by rising up through the bloodstream in an upright or mobile patient.…”

“…Additional case reports have noted pneumocephaly from injected air via peripheral IV placement [ 19 ]. Risk factors for developing cerebral air embolus during invasive vascular manipulations include hypovolemia, increased intrathoracic pressure in deep inspiration, and mobile or upright patients [ 2 , 15 , 20 ]. In this patient, the air embolus likely traveled retrogradely through the patient's vascular matrix into the cerebral vessels when the patient was seated upright during dialysis.…”

Gyriform infarction in cerebral air embolism: Imaging mimicker of status epilepticus

“…The retrograde mechanism involves reflux of air through jugular venous system leading to venous CAE, while paradoxical embolism involves trespassing of venous air to arterial system through cardiac or pulmonary shunts leading to arterial CAE. [ 9 ]…”

Cerebral Air Embolism Caused by Persistent Cough

“…Cerebral air embolism can be a potentially lethal complication. It is often caused iatrogenically when positive-pressure maneuvers are performed ( 1 , 2 ). We suspect that the patient's air embolism was caused by coughing which could have led to positive pressure pushing air into the pulmonary vein, which was permeable due to the infection.…”