Intraoperative Electroencephalogram Suppression Predicts Postoperative Delirium

Abstract

Background Postoperative delirium is a common complication associated increased morbidity and mortality, longer hospital stays, and higher healthcare expenditures. Intraoperative electroencephalogram (EEG) slowing has previously been associated with postoperative delirium, but the relationship between intraoperative EEG suppression and postoperative delirium has not been investigated. Methods In this observational cohort study, 727 adult patients receiving general anesthesia with planned intensive care unit (ICU) admission were included. Duration of intraoperative EEG suppression was recorded from a frontal EEG channel (FP1 to F7). Delirium was assessed twice daily on postoperative days 1 through 5 using the Confusion Assessment Method for the ICU. Thirty days after surgery, quality of life, functional independence, and cognitive ability were measured using the VR-12 survey, the Barthel Index, and the PROMIS Applied Cognition-Abilities-Short Form 4a survey. Results Postoperative delirium was observed in 162 (26%) of 619 patients assessed. When comparing patients with no EEG suppression to those divided into quartiles based on duration of EEG suppression, patients with more suppression were more likely to experience delirium (χ2(4) = 25, p < 0.0001). This effect remained significant after adjusting for potential confounders (odds ratio for log(EEG suppression) 1.22 [99% CI 1.06 to 1.40, p = 0.0002] per 1-minute increase in suppression). EEG suppression may have been associated with reduced functional independence (Spearman partial correlation coefficient −0.15, p = 0.02), but not with changes in quality of life or cognitive ability. Predictors of EEG suppression included higher end-tidal volatile anesthetic concentration and lower intraoperative opioid dose. Conclusions EEG suppression is an independent risk factor for postoperative delirium. Future studies should investigate whether anesthesia titration to minimize EEG suppression decreases the incidence of postoperative delirium. This is a substudy of the SATISFY-SOS surgical outcomes registry (NCT02032030).

Infrared pupillometry helps to detect and predict delirium in the post-anesthesia care unit

“…However, our observations are consistent with the findings of several previous studies [10,[44][45][46], which have demonstrated that hypoactive delirium is the most prevalent delirium subtype, while also the most often underdiagnosed. Hypoactive delirium is more common in the elderly and associated with worse outcomes [43,45], so early detection is paramount to improve perioperative patient care.…”

Perioperative Gabapentin Does Not Reduce Postoperative Delirium in Older Surgical Patients

“…Recently, it has been proposed that deep anesthetic depth contributes to an increased rate of postoperative delirium. 43–46 However, the mechanism of this deep anesthesia effect has not been completely elucidated despite a recent report that burst suppression on electroencephalogram indicative of deep anesthesia may have been the etiologic factor. 46 …”

Intraoperative electroencephalogram suppression at lower volatile anaesthetic concentrations predicts postoperative delirium occurring in the intensive care unit

“…3 These patients also incur greater healthcare costs in the year following surgery and report decreased ability to complete activities of daily living 30 days after surgery. 4,5 The pathophysiology of delirium is complex and obscure, and the aetiology is typically multifactorial, with patient vulnerability (e.g. older age), physiological perturbation (e.g.…”

“…12 Two recent observational studies, including one conducted by our group, have identified an association between longer duration of intraoperative electroencephalogram suppression and postoperative delirium. 5,13 However, it is unclear whether the observed associations indicate that increased exposure to anaesthetic agents cause delirium or if underlying patient characteristics increase the risk both for electroencephalogram suppression and for postoperative delirium. Interestingly, some studies have also reported lowerdnot higherdaverage end-tidal concentration of volatile anaesthetic agent as a risk factor for postoperative delirium.…”