In patients with ischemic penumbra and blood-brain barrier disruption, hyperoxygenation therapy may mitigate ischemia and remove air, and hyperoxic reperfusion could lead to oxidative stress through the disrupted blood-brain barrier, according to a case study published in the American Journal of Respiratory and Critical Care Medicine.
A 79-year-old man who underwent a computed tomography (CT)-guided biopsy of a lung mass was agitated and confused post-procedure. A neurologic exam showed left hemiparesis and neglect symptoms, and a chest CT revealed air bubbles in the pulmonary vein and left atrium. After oxygen was administered, a brain CT and routine magnetic resonance imaging (MRI) were unremarkable, but right hemisphere profusion delay was revealed via perfusion-weighted imaging, and right hemisphere diffuse leptomeningeal enhancement was seen via T1-enhanced imaging.
The patient was too irritable to tolerate hyperbaric oxygen therapy, but nevertheless, his focal neurologic deficits resolved the following day. The initially abnormal findings were no longer present on follow-up MRI performed 5 days after the procedure.
The study authors concluded, “The most remarkable aspects of this case were ischemic penumbra (perfusion-diffusion mismatch) and blood-brain barrier disruption (leptomeningeal enhancement). Hyperoxygenation therapy may remove air and mitigate ischemia. Conversely, hyperoxic reperfusion may cause oxidative stress via a disrupted blood-brain barrier. Our findings may shed light on the mechanisms of brain injury and therapeutic implications in the context of cerebral air embolism.”
Ko M-A, Lee JH, Jeon S-B. Ischemic penumbra and blood-brain barrier disruption in cerebral air embolism [published online August 27, 2019]. Am J Respir Crit Care Med. doi:10.1164/rccm.201809-1620IM