4. Discussion
SE, postoperative hyperalgesia, tissue damage, pain
Nociception is defined as the neural encoding of actual or imminent tissue damage (such as noxious stimuli), whereas pain is a subjective experience associated with imminent or actual injury.The patients’ SE and RE were used to evaluate the depth of anesthesia, and SPI was used to evaluate the central nervous system response to pain “nociception” during surgery.The SE is calculated based on an electroencephalogram, offering a comprehensive index of electroencephalogram and frontal muscle electromyography that can better reflect the depth of anesthesia. The entropy index and cerebral oxygen metabolism are independently associated with postoperative hyperalgesia.The limitations of this study are as follows: 1. the effect of position on the SPI was not excluded. 2. This was not a multicenter study. 3. Further studies are needed to evaluate the efficacy of SPI for monitoring noxious stimuli during OFA.In conclusion, SPI is as effective as in guiding OFA as in opiate anesthesia, with definite clinical efficacy and stable anesthesia induction. The SE, RE, and Steward scores were higher at extubation and discharge, while the extubation and awake times were shorter.