Burst Suppression During General Anesthesia and Postoperative Outcomes: Mini Review

Abstract

In the last decade, burst suppression has been increasingly studied by many to examine whether it is a mechanism leading to postoperative cognitive impairment. Despite a lack of consensus across trials, the current state of research suggests that electroencephalogram (EEG) burst suppression, duration and EEG emergence trajectory may predict postoperative delirium (POD). A mini literature review regarding evidence about burst suppression impact and susceptibilities was conducted, resulting in conflicting studies. Primarily, studies have used different algorithm values to replace visual burst suppression examination, although many studies have since emerged showing that algorithms underestimate burst suppression duration. As these methods may not be interchangeable with visual analysis of raw data, it is a potential factor for the current heterogeneity between data. Even though additional research trials incorporating the use of raw EEG data are necessary, the data currently show that monitoring with commercial intraoperative EEG machines that use EEG indices to estimate burst suppression may help physicians identify burst suppression and guide anesthetic titration during surgery. These modifications in anesthetics could lead to preventing unfavorable outcomes. Furthermore, some studies suggest that brain age, baseline impairment, and certain medications are risk factors for burst suppression and postoperative delirium. These patient characteristics, in conjunction with intraoperative EEG monitoring, could be used for individualized patient care. Future studies on the feasibility of raw EEG monitoring, new technologies for anesthetic monitoring and titration, and patient-associated risk factors are crucial to our continued understanding of burst suppression and postoperative delirium.

Keywords: burst suppression; cognitive decline; electroencephalogram–EEG; geriatric; postoperative delirium (POD); postoperative outcomes.

FIGURE 1

Spectrogram and EEG raw traces. Suppression episodes during burst suppression in the spectrogram show as periods of blue, vertical lines. (A) Electroencephalogram trace showing burst suppression, burst of activity followed by interburst periods of suppression (seen in the spectrogram from 1,250 to 2,000s). (B) Electroencephalogram trace showing oscillation/activity maintained under under general anesthesia (seen in the spectrogram from 2,500 to 3,500).