The Modulatory Effects of Anesthetics and Analgesics on Neurophysiological Monitoring and Underlying Mechanisms.

Abstract

Intraoperative Neurophysiological Monitoring (IONM) is an indispensable surgical tool that offers invaluable insights into neurological function across a spectrum of anatomical areas. By comprehensively assessing the integrity of the brain, brainstem, spinal cord, cranial nerves, and peripheral nerves, IONM plays a pivotal role in guiding surgical decision-making and optimizing patient outcomes, particularly in the context of high-risk procedures. Intraoperative drugs, especially anesthetics and/or analgesics, differentially modulate neurophysiological monitoring, which remarkably affects the application of neurophysiological monitoring under specific conditions and indicates the neurobiological mechanisms of anesthetics/analgesics. This review will describe various neurophysiological modalities utilized in intraoperative procedures, each employing a wide variety of physiological principles; summarize the modulatory effects of anesthetics/analgesics on these neurophysiological monitoring parameters; and elucidate their underlying mechanisms, with a particular emphasis on evoked potentials. Insights gleaned from this review can inform strategies of anesthesia management for surgeries that require IONM and guide future investigations on the mechanisms of anesthesia/analgesia.