[Deep anesthesia, poorly tolerated anesthesia?]

Area of Science:

• Anesthesiology
• Neuroscience
• Critical Care Medicine

Background:

• Intraoperative electroencephalography (EEG) patterns, including burst suppression, and low depth of anesthesia (DOA) indices have been linked to adverse postoperative outcomes.
• Previous research, primarily retrospective, suggested increased risks of postoperative cognitive dysfunction and mortality associated with these EEG findings.
• The clinical significance and causality of these associations remain debated.

Purpose of the Study:

• To review existing literature on the correlation between low DOA indices, burst suppression patterns, and postoperative outcomes.
• To evaluate the findings of recent prospective interventional studies in this area.
• To guide future research and clinical recommendations regarding intraoperative EEG monitoring.

Main Methods:

• Systematic review and analysis of 13 studies published over the last decade.
• Examination of both secondary data analyses and retrospective observational studies.
• Inclusion of findings from the first prospective interventional studies on "triple low" and avoidance of excessive EEG suppression.

Main Results:

• Multiple retrospective studies indicated that low DOA indices or burst suppression patterns correlate with increased risks of postoperative cognitive dysfunction or mortality.
• The first prospective interventional study on "triple low" did not confirm this correlation.
• Prospective studies investigating the avoidance of excessive EEG suppression are ongoing.

Conclusions:

• While retrospective data suggest a link between specific EEG patterns and adverse outcomes, prospective studies are crucial for establishing causality.
• Further evidence from ongoing prospective interventional studies is needed to formulate evidence-based recommendations.
• Clarifying whether the observed associations are causal or epiphenomenal is essential for clinical practice.