Effects of physiological parameters on intraoperative somatosensory-evoked potential monitoring: Results of a multifactor analysis

Abstract

Background: In scoliosis surgery, intraoperative somatosensory-evoked potentials (SEPs) are affected by physiological parameters, which also have a complicated interaction with each other. Previous studies have reported on how these parameters individually affect SEPs. However, there has been no systematic analysis of these effects. The purpose of this study was to investigate the relationships between variations in intraoperative SEPs and various physiological parameters. Material/Methods: Seventy scoliosis patients who underwent intraoperative SEP monitoring were enrolled in this retrospective study. Variations in latency and amplitude were analyzed to evaluate their relationships to blood pressure, heart rate, temperature, and partial pressure of alveolar carbon dioxide (PaCO2) using gray correlation degree analysis. Results: Variations in latency and amplitude correlated most closely with variations in temperature, PaCO2, and heart rate, followed by variations in diastolic and then systolic blood pressure. Conclusions: Variations in different physiological parameters are related to variations in intraoperative SEPs to different degrees. Monitoring specialists should take this into consideration when making decisions based on abnormal SEPs. © Med Sci Monit, 2009.