Intraoperative nociception. “If you can’t measure it, you can’t manage it”

In clinical practice, analgesia is still empirically monitored by using variation of heart rate, blood pressure, and sweating, as the result of the sympathetic activation, or movements. The challenge of monitoring analgesia in anesthetized patients is related to the interference of hypnosis and cardiovascular drugs used during general anesthesia, and to the rapid changes of the sympathetic system activation observed during surgery. Clinical studies showed that the ANI, the SPI, and pupillary dilatation were superior to clinical signs in detecting changes in the antinociception nociception balance in patients undergoing total general anesthesia. The role of currently available devices for intraoperative nociception monitoring is still unclear, but, for adequate analgesia management during surgery, the need for an objective measurement as an alternative to the current clinical standard of care is imminent.