A narrative review of electroencephalogram-based monitoring during cardiovascular surgery

The current narrative review focuses on depth of hypnosis monitoring with electroencephalography (EEG) during cardiovascular surgery. There have been important findings in recent years regarding the challenges and limitations of EEG-based monitoring during general anesthesia. The purpose of this review is to summarize key EEG-related concepts, as well as to highlight some of the advantages and disadvantages of processed and unprocessed EEG monitoring, especially for older patients with comorbidities undergoing cardiovascular surgery.

The brain is the target organ of anesthesia. Using the EEG or processed EEG to guide anesthetic administration during cardiovascular surgery conceptually allows precision patient-centered anesthesia. It is suggested that inadequate anesthesia, with the possibility of traumatic intraoperative awareness, can potentially be avoided. Furthermore, excessive anesthesia, with hemodynamic compromise and theoretical risk of delirium, can be minimized. Frail, older patients undergoing major surgery with preexisting neurocognitive disorders might be especially vulnerable to perioperative neurological and other complications. Tailoring anesthetic administration, based on individual patient needs partly guided by certain EEG features, might yield improved perioperative outcomes.

Ability to interpret the EEG during surgery might help anesthesia clinicians to individualize anesthetic administration to prevent adverse events, and optimize postoperative recovery.