Outcome of survivors of accidental deep hypothermia and circulatory arrest treated with extracorporeal blood warming

Background Cardiopulmonary bypass has been used to rewarm victims of accidental deep hypothermia. Unlike other rewarming techniques, it restores organ perfusion immediately in patients with inadequate circulation. This study evaluated the long-term outcome of survivors of accidental deep hypothermia with circulatory arrest who had been rewarmed with cardiopulmonary bypass. Methods Deep hypothermia (core temperature, <28 degrees C) with circulatory arrest was found in 46 of 234 patients with accidental hypothermia. In 32 of the 46 patients, rewarming with cardiopulmonary bypass was attempted, resulting in 15 long-term survivors. In most of these patients, deep hypothermia developed after mountaineering accidents or suicide attempts. After an average (+/-SD) of 6.7+/-4.0 years of follow-up, we obtained the patients' medical histories and performed neurologic and neuropsychological examinations, neurovascular ultrasound studies, electroencephalography, and magnetic resonance imaging of the brain. Results The average age of the patients was 25.2+/-9.9 years; seven were female and eight were male. The mean interval from discovery of the pa tient to rewarming with cardiopulmonary bypass was 141+/-50 minutes (range, 30 to 240). At follow-up there were no hypothermia-related sequelae that impaired quality of life. Neurologic and neuropsychological deficits observed in the early period after rewarming had fully or almost completely disappeared. One patient had cerebellar atrophy on magnetic resonance imaging with mild clinical signs, a condition that may have been caused by hypothermia. Other clinical abnormalities were either preexisting or due to injuries not related to hypothermia. Conclusions This clinical experience demonstrates that young, otherwise healthy people can survive accidental deep hypothermia with no or minimal cerebral impairment, even with prolonged circulatory arrest. Cardiopulmonary bypass appears to be an efficacious rewarming technique. (C) 1997, Massachusetts Medical Society.