The cardiovascular anesthesiologist must frequently assume the care of high-risk patients who will undergo complex and invasive surgeries. In order to ensure patient safety and facilitate decision making, great technological advances have been made to monitor them extensively, such as transesophageal echocardiography and sophisticated hemodynamic monitors. Although hypnotics used during general anesthesia act on the brain, the monitoring of this organ was not considered standard behavior for a long time. The classic electroencephalogram (EEG) appeared as a useful tool to evaluate the changes in neuronal electrical activity induced by general anesthesia and thus detect the different states of consciousness during general anesthesia, i.e., to evaluate the depth of anesthesia (DoA). However, its difficult intraoperative interpretation and the scarce evidence available in its favor were the main limitations for the use of this tool as a hypnosis monitor. Processed EEG (pEEG), derived from EEG decomposition, emerges as an easy-to-interpret alternative for anesthesiologists and useful for assessing anesthetic depth. In cardiac surgery, and especially in cardiopulmonary bypass (CPB), achieving safe and stable hypnosis is a great challenge, since there are critical periods that involve a series of changes in the physiology of the patients and in the administration of hypnotics. Given the above, the monitoring of anesthetic depth in this surgical scenario is currently supported by many authors, the main objectives being to reduce the incidence of awareness with intraoperative recall (AWR) due to hypnotic underdosing, to avoid hemodynamic and neurological adverse effects secondary to hypnotic overdosing, and to collaborate in the evaluation of cerebral perfusion during critical periods.