Perioperative Monitoring of Autonomic Nervous Activity

The role of autonomous nervous system (ANS) is becoming more evident as accumulating information about human physiology arises. Therefore, monitoring its activity during periods of abrupt changes, like those in perioperative settings, becomes essential for understanding, predicting, and managing their effects. There are several methods for measuring ANS, although none of them is yet broadly applied in perioperative period. Electrodermal activity tracks autonomic nervous activity via skin electrical properties. Heart rate variability and surgical stress index integrate mainly cardiovascular monitoring, digital pupillometry records pupil's dynamics; other methods use laboratory measurements. No matter the focus of each method, careful consideration for its limitation should be made before its use. Summarizing, it seems that, instead of searching for the "gold-standard," a combination of methods should be used. The present chapter presents selected tools used for perioperative autonomic nervous activity monitoring. Future research perspectives are also offered.