Neurophysiology of surgical procedures for repair of the aortic arch.

Neurophysiologic monitoring during surgical procedures involving the aortic arch is very complex because of the number of different phases of the procedure, the high mortality rate, and the use of hypothermia. In this paper, the critical goals of neurophysiologic monitoring are discussed in the context of the different surgical events and the surgical options during the different phases of the procedure. These include establishing a neurophysiologic baseline and identifying any evidence of cerebral ischemia that might suggest a reduction in cerebral perfusion. The role of EEG and evoked potentials in assessing the effect of hypothermia and circulatory arrest is also discussed. As these effects are predictable in large part, the neurophysiologist will be able to determine when changes in the neurophysiologic tests outside the norm occur and provide prompt warnings to the surgeon.