Processed EEG Artifacts and Pitfalls: A Narrative Review and a Troubleshooting Mnemonic

Processed electroencephalography (EEG) is widely used for depth of anesthesia monitoring. However, multiple interference sources can distort raw EEG data, leading to misinterpretation of quantitative EEG (qEEG) indices, potentially resulting in insufficient or excessive depth of anesthesia or burst suppression. This review summarizes qEEG interference and artifact sources, as well as some paradoxical effects and pitfalls, reported in the literature. These factors can be categorized into pharmacological, electromagnetic and mechanical, pathophysiological, and model-related sources. When unexpected qEEG values lack an immediately apparent explanation, a structured approach can be valuable, particularly in complex circumstances. We provide a relatable mnemonic "ANESTHESIA" for troubleshooting potential interference sources. If artifact removal is impractical, this should be acknowledged when adjusting the anesthetic management plan. A systematic approach to identify qEEG artifacts and acknowledge potential pitfalls may improve the reliability of depth of anesthesia monitoring, ultimately enhancing patient safety.