Abstract
Motor evoked potential (MEP) monitoring is one of the most reliable measures for detecting spinal cord ischemia during descending thoracic and thoracoabdominal aortic aneurysmal surgery. Although MEP monitoring can help to determine the segmental arteries that should be reattached, it often shows false positive results, which may be due to a variety of factors including the use of anesthetic agents, body temperature, cardiopulmonary bypass, age, perioperative neurologic function, the muscle selected for recording, operating time, and obesity. Among these factors, we regard anesthetic agents, body temperature, and cardiopulmonary bypass as the most important contributors to false-positive results because cardiopulmonary bypass with low body temperature can change the pharmacodynamics and pharmacokinetics of anesthetic agents. Titration of the dose of these agents should decrease the false-positive rate. Establishing guidelines for MEP monitoring during aortic aneurysmal surgery that include the optimal dosing regimen for anesthetic agents would be beneficial.
