A nonobese 35-year-old man with history of polysubstance use was transported to the Emergency Department following unwitnessed cardiopulmonary arrest. His initial rhythm was pulseless electric activity with return of spontaneous circulation after 25 min of chest compressions. Initial evaluation revealed an unremarkable electrocardiogram, undetectable blood glucose level and a Full Outline of UnResponsiveness (FOUR) score of 1 (E0M0B0R1). Urine toxicology was positive for cocaine and fentanyl. Neurological examination demonstrated generalized myoclonus and increased muscle tone in the lower extremities with sustained clonus at both ankles. Initial computed tomography (CT) head showed preserved gray-white differentiation and hypodensity in the left cerebellar hemisphere. He was further resuscitated in the intensive care unit (ICU) and subsequently cooled to 33°C for 24 h according to our institutional protocol. Neuron specific enolase was elevated at 28.7 ng/ml. Continuous electroencephalogram (cEEG) showed background suppression ratio of 85% which improved to 10% overnight (). On hospital day 3, his FOUR score improved to 9 (E4M0B4R1) while cEEG revealed continuous reactive background with theta-delta slowing. His eyes opened spontaneously, but he did not react to noxious stimuli. Somatosensory evoked potential (SSEP) revealed bilaterally absent cortical potentials. Given the discrepancy between neurological examination, cEEG and SSEP findings, magnetic resonance imaging (MRI) of brain and cervical spine revealed symmetrical diffusion restriction with surrounding edema in the juxtacortical white matter, hippocampi, superior cerebellar peduncles, dorsal pons, dorsolateral medulla within the nucleus tractus solitarius (NTS), and cerebellum. Punctate hyperintensities were apparent in the left ventral spinal cord at C3-C4 on fluid-attenuated inversion recovery (FLAIR) sequences indicating subacute infarct (,). There were no vascular abnormalities identified on magnetic resonance angiogram (MRA) of head and neck vessels. On hospital day 10, repeated SSEP again showed bilaterally absent cortical potentials. After discussion with family, tracheostomy and percutaneous endoscopic gastrostomy tubes were placed. His arousal continued to improve over time and began to track with his eyes and eventually was able to follow commands and communicate. Despite his improving neurological condition, unexplained hypotension requiring vasopressors as well as bradypnea necessitated retention in the ICU. While he was able to breathe voluntarily, his involuntary respiratory rate consistently ranged from between 4 and 6 times per minute with symptomatic hypercarbia developing after variable periods of unassisted breathing. While the administration of pseudoephedrine improved his blood pressure, a trial of theophylline as a respiratory stimulant was ineffective in preventing the development of symptomatic hypercarbia. On hospital day 42 repeat MRI revealed persistent FLAIR abnormalities in the dorsolateral medulla, caudal pons and cerebellar hemispheres, and resolution of FLAIR abnormalities in the hippocampi, juxtacortical white matters and upper cervical cord (,). Given his overall improvement in neurological condition and imaging findings, he was transferred to a long term-acute care facility for ongoing ventilator weaning 50 days after hospital admission. Pseudoephedrine was subsequently discontinued with normal blood pressure. He was successfully liberated from mechanical ventilation approximately 70 days after arrest.