Depth of anesthesia monitoring: Current evidence, clinical impact, and future directions.

Depth of anesthesia monitoring has become an important component of modern anesthetic practice. Electroencephalography-based technologies, such as the bispectral index, entropy, and Narcotrend, allow clinicians to assess the level of consciousness more objectively and guide anesthetic titration more precisely. This narrative review summarizes current evidence on the relationship between depth of anesthesia monitoring and major perioperative complications. Available evidence suggests that maintaining an appropriate depth of anesthesia reduces the risk of intraoperative awareness, hypotension associated with excessively deep anesthesia, postoperative delirium, and cognitive dysfunction. Electroencephalography-guided anesthesia appears particularly beneficial in older patients, individuals with cardiovascular disease, and other high-risk populations. Although several limitations remain, including algorithm variability and differential sensitivity to anesthetic agents, the integration of multimodal monitoring, brain network analysis, and artificial intelligence is expected to improve the accuracy and individualization of anesthesia management in the future.