Brain stem auditory evoked potential monitoring during profound hypothermia and circulatory arrest

The effects of decreased temperature on brain stem auditory evoked potentials (BAEP) have been previously described in mild to moderate hypothermia. This report describes BAEP monitoring during profound hypothermia (11 degrees C) and circulatory arrest for repair of an aortic arch aneurysm. Recording of BAEP were interpretable during cooling to 14 degrees C, and demonstrated increasing interpeak (I-V) latency compatible with prolongation of brain stem conduction time. The changes rapidly returned to normal during rewarming from profound hypothermia, in a fashion similar to that seen after mild hypothermia, and therefore appear to be completely reversible.