Accidental Environmental Hypothermia in a Nonagenarian Resulting in Cardiac Arrest

Accidental hypothermia after environmental exposure and/or impaired thermoregulation resulting in significant decrease in body temperature and cardiac arrest (CA) is linked to 1,500 deaths annually in the United States. Hypothermic CA treatment has specific presentation and clinical features. With appropriate treatment, its survival can reach 27-70%, contrasting ~ 10% in medical CA. Majority of accidental hypothermic CA survivors recover with favourable neurologic outcome. An integrated, dedicated multi-disciplinary team-approach is essential to maximize the chances of survival. We report on a 91-year-old female who was found outside and unresponsive in freezing temperatures. During transport, she required bag-and-mask ventilation. An esophageal temperature recorded 24.5 °C. Shortly after rapid sequence intubation, she developed CA. She was successfully resuscitated with chest compressions, epinephrine, atropine, and two defibrillations. Due to persistent hypothermia and bradycardia, she was rewarmed using extracorporeal membrane oxygenation. Perioperative transesophageal echocardiography showed normal cardiac function. She was extubated the next day. She remained stable for the rest of her hospital stay without focal neurological deficits on serial examinations. However, her post-arrest stay was complicated by acute delirium, likely from underlying dementia, with a waxing and waning level of consciousness, confusion, agitation and hallucinations. She was discharged on post-operative day 5. Her long-term recovery was complicated by repeated aspiration pneumonias, and gradual decline of her mental status due to Alzheimer's dementia. She died approximately two years later at the age of 93. Thus, full neurologic recovery remains possible after CA induced by severe hypothermia from environmental exposure, despite extreme age and frailty.