Impact of burst suppression duration on delirium and its diagnostic value in mechanically ventilated ICU patients

Intensive care unit (ICU) delirium affects up to 50% of mechanically ventilated patients. This condition is associated with increased morbidity and mortality. Although bispectral index (BIS) monitoring is widely used for sedation assessment, its predictive value for delirium remains limited. Burst suppression (BS) is an electroencephalographic pattern reflecting profound cerebral dysfunction. BS has been proposed as a predictor of delirium. However, the quantitative role of burst suppression duration (BSD) in delirium risk stratification has not been established. This prospective observational study enrolled 300 mechanically ventilated adult ICU patients between April 2021 and October 2024 at Harrison International Peace Hospital. Continuous video-electroencephalogram (vEEG) monitoring was performed. BSD was quantified from the vEEG recordings. Delirium was assessed using the Confusion Assessment Method for the ICU (CAM-ICU). Multivariate logistic regression was used to identify independent risk factors. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the diagnostic performance of BSD. Among 300 patients, 130 (43.3%) developed delirium. The delirium group had significantly longer BSD than the control group (median 81.1 s, IQR 41.5-148.5 vs. 17.2 s, IQR 5.8-32.9; P < 0.001). Multivariate analysis identified BSD (adjusted OR = 1.018, 95% CI 1.012-1.023; P < 0.001), BIS (adjusted OR = 0.964, 95% CI 0.946-0.982; P < 0.001), age (adjusted OR = 1.024, 95% CI 1.002-1.047; P = 0.031), and hypertension (adjusted OR = 1.748, 95% CI 1.002-3.051; P = 0.049) as independent risk factors. ROC analysis demonstrated that BSD achieved an area under the curve (AUC) of 0.871 (95% CI 0.829-0.913). The optimal cutoff of 41.5 s yielded a sensitivity of 80.8% and a specificity of 78.2%. The combination of BSD and BIS improved the AUC to 0.914 (95% CI 0.882-0.946). BSD is an independent risk factor for delirium in mechanically ventilated ICU patients. It demonstrates high diagnostic accuracy as a quantitative biomarker. The combination of BSD and BIS provides superior predictive performance. This combined approach offers a practical quantitative tool for early delirium risk stratification.