Increased Brain Tolerance for Ischemia in Accidental Deep Hypothermia and Circulatory Arrest

This Swiss multicenter study evaluates the long-term outcome of survivors of accidental deep hypothermia (17–28 degrees Celsius) with circulatory arrest who were rewarmed with cardiocirculatory bypass. Deep hypothermia with circulatory arrest was found in 46 of 134 patients with accidental hypothermia. In 32 patients cardiopulmonary bypass rewarming was attempted resulting in 15 long-term survivors (6 glacier-crevasse, 1 avalanche, 7 cold air, 1 cold water exposure). None of the patients suffered asphyxia and thus hypoxic brain damage before cooling down, as often occurs in avalanche or drowning. At follow-up (mean of 7 years) medical history, magnetic resonance imaging, electroencephalography and neurovascular ultrasound were obtained. MRI with volumetric measurements of the cerebral compartments was performed in 13 of the patients. At follow-up there were no hypothermia-related sequelae impairing quality of life. Neurological and neuropsychological deficits observed in the early postwarming period had f...