Neuropathological findings in comatose patients with venoarterial extracorporeal membrane oxygenation

We sought to describe the relation between neuropathology and clinical information including neurological examination and electroencephalogram findings in extracorporeal membrane oxygenation. We reviewed the patients who had undergone brain autopsy from November 2017 through December 2018. Four patients with neuromonitoring had post mortem examination with brain autopsy. The median age was 56, and all had venoarterial extracorporeal membrane oxygenation cannulation. There was no known acute neurologic injury prior to extracorporeal membrane oxygenation. While on extracorporeal membrane oxygenation, all were persistently comatose off sedation. Continuous encephalogram was done on all four, all of which showed delta frequency with absent reactivity. In Case 1, the pathological evaluation demonstrated small infarcts in cerebral cortices. In Case 2, it showed cortical microhemorrhages and chronic microinfarcts in basal ganglia. In Cases 3 and 4, the neuropathological assessment demonstrated diffuse hypoxic-ischemic brain injury. The clinical presentation was consistent with the widespread neuropathologic injury in two cases (Cases 3 and 4) but not in the other two (Cases 1 and 2). While "poor neurological status" was provided in the end-of-life discussion in all four, only two had significant brain injuries. There is limited understanding about brain injury in extracorporeal membrane oxygenation. Extrapolations related to prognostication from experience in other brain injury needs to be approached cautiously.