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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).

Methane is important in future energy schemes. The main strategies for storing and transporting methane are compression, liquefaction, and physical adsorption in synthetic porous materials. Here, we show that methane can be stored in a hydrated form using natural amino acids such as leucines as effective promoters to form methane hydrate with a high formation rate and a high capacity. In addition, the methane hydrate formed from the L‐leucine solution dissociates without foaming phenomenon. We also showed that the heavier hydrocarbons in natural gas can enhance the promoting effect of L‐leucine.

A homogeneous dispersion of hexagonal boron nitride nanosheets (BNNSs) in elastomers is obtained by solution compounding methods, and a high orientation of BNNSs is achieved by strong shearing. The composites show high thermal conductivities, especially when BNNS loading exceeds 17.5 vol%, indicating that the material is promising for thermal-management applications which need high thermal conductivity, low dielectric constant, and adequate softness.