Anesthesia and evoked potentials: overview.

Evoked potentials are increasingly used for intraoperative monitoring. Their use is based on their ability to detect early changes caused by surgical maneuvers which may result in post operative deficits. However, not all changes are surgically related and any decrease in the non surgical causes of evoked potential changes increases the yield of intraoperative monitoring. In this review I will discuss the anesthetic effects on evoked potentials; these include a general description of the anesthetic effects on evoked potentials followed by the effects of premedication, induction, and maintenance agents. Also, described are the effects of adjunct anesthetic agents and techniques. Changes related to anesthesia are not similar and the knowledge of such differences is essential for the planing of anesthesia during the use of evoked potentials. An out line of the anesthetic techniques are described at the end of this review.