Cerebral air embolism: neurologic manifestations, prognosis, and outcome

Abstract

Background: Cerebral air embolism (CAE) is an uncommon medical emergency with a potentially fatal course. We have retrospectively analyzed a set of patients treated with CAE at our comprehensive stroke center and a hyperbaric medicine center. An overview of the pathophysiology, causes, diagnosis, and treatment of CAE is provided.

Results: We retrospectively identified 11 patients with cerebral venous and arterial air emboli that highlight the diversity in etiologies, manifestations, and disease courses encountered clinically. Acute-onset stroke syndrome and a progressive impairment of consciousness were the two most common presentations in four patients each (36%). Two patients (18%) suffered from an acute-onset coma, and one (9%) was asymptomatic. Four patients (36%) were treated with hyperbaric oxygen therapy (HBTO), high-flow oxygen therapy without HBOT was started in two patients (18%), two patients (18%) were in critical care at the time of diagnosis and three (27%) received no additional treatment. CAE was fatal in five cases (46%), caused severe disability in two (18%), mild disability in three (27%), and a single patient had no lasting deficit (9%).

Conclusion: Cerebral air embolism is a dangerous condition that necessitates high clinical vigilance. Due to its diverse presentation, the diagnosis can be missed or delayed in critically ill patients and result in long-lasting or fatal neurological complications. Preventative measures and a proper diagnostic and treatment approach reduce CAE's incidence and impact.

Keywords: air embolism; cerebral embolism; cerebral stroke; hyperbaric oxygen therapy; neurological emergency.

Figure 1

Imaging for cases 1 (A,B) and 2 (C–F). (A) Coronal plane of the native CT of the lungs showing a typical image of a primary lung tumor in the upper right lobe. (B) Axial CT scan of the brain in Minimum intensity projection (MinIP) shows the number of air bubbles in the cerebral circulation (white arrows, MinIP is an imaging technique used to identify low-density structures within a specific volume). (C,D) Axial contrast-enhanced CT scans of the brain with gas bubbles in the internal jugular veins (red arrows) and cavernous sinuses bilaterally (yellow arrows). (E,F) Axial contrast-enhanced CT scans of the upper thorax with air bubbles in the right subclavian vein and right and left brachiocephalic veins (white arrows).

Figure 2

Imaging for case 3. (A) Axial native CT scan of the lungs showing a solid nodulus with an inserted percutaneous biopsy needle (white arrow). (B) Follow-up native CT scan of the lungs after the biopsy with a small pneumothorax and intraparenchymal hemorrhage behind the lesion due to damage to the integrity of the vascularity (white arrow). (C) Axial native CT scan of the brain in MinIP shows a smaller amount of air bubbles in the cerebral circulation (white arrows). (D) Axial contrast-enhanced CT scan of the distal part of the neck with air in the left internal jugular vein (white arrow). (E) Follow-up axial CT scan of the brain in MinIP shows a single residual air bubble in the region of the falx cerebri (white arrow). (F) Axial DWI brain scan showing no diffusion restriction and no evidence of acute ischemia.

Figure 3

Imaging for cases 4 (A,B) and 5 (C–G). (A) Axial native CT scan of the brain in MinIP shows a very significant amount of air bubbles in the cerebral circulation in the right hemisphere (white arrows). (B) Axial CT scan of the brain reveals extensive delineated ischemia of almost the entire right cerebral hemisphere (white arrow). (C) Axial CTA of the brain showing occlusion of the M1 segment of the left middle cerebral artery (black arrow). (D) Axial native CT scan with a significant volume of air in the brain circulation on the left side (red arrows). (E) Native axial CT scan with contrast agent extravasation and intracerebral and subarachnoid hemorrhage (yellow arrows). (F) Axial native CT scan of the brain with developing extensive acute ischemia in the left middle cerebral artery territory (white arrow). (G) Cerebral panangiography without intracranial arterial flow, demonstrating brain death.

Figure 4

Imaging for cases 6 (A,B), 7 (C), and 11 (D–F). (A) Axial CTA scan of the brain with air bubbles in cavernous sinuses (white arrows). (B) CTA of the brain vasculature on the next day showing complete regression of the air emboli. (C) Axial CT scan of the brain in MinIP shows a very significant amount of air bubbles in the cerebral circulation of the right hemisphere (white arrows). (D) Axial brain CTA with occlusion of the M1 segment of the left middle cerebral artery (black arrow). (E) Axial native CT scan of the brain in MinIP shows a significant amount of air bubbles in the cerebral circulation in the left hemisphere (white arrows). (F) Native axial CT scan of the brain with developing extensive ischemia in the left middle cerebral artery territory, temporal, and occipital region (lower white arrow), and basal ganglia (upper white arrow). Air bubbles have disappeared.