Intraoperative enhancement of effective connectivity in the default mode network predicts postoperative delirium following cardiovascular surgery

Postoperative delirium is a common and preventable complication after cardiovascular surgery and is associated with increased risk of morbidity and mortality. However, strategies for identifying at-risk patients are limited. In this prospective observational study, intraoperative electroencephalography data of 50 patients undergoing cardiovascular surgery were collected. Twenty-five patients of them experienced delirium after surgery and 25 patients did not. The partial directional coherence method was used to evaluate the effective connectivity within the default mode network (DMN) regions in four frequency bands. Statistically significant features were considered as input signals in the CatBoost classifier to predict postoperative delirium. Compared with patients without delirium, patients with postoperative delirium had enhancement of causal effects in the DMN area, especially in the delta band. The accuracy rate of distinguishing patients with postoperative delirium from patients without postoperative delirium could reach 89.1%. These findings might help to explain why information processing was disturbed in patients with delirium and predict postoperative delirium.(c) 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

Postoperative delirium is a common and preventable complication after cardiovascular surgery, with increased morbidity and mortality risk. Limited strategies exist for identifying at-risk patients. This observational study collected intraoperative electroencephalography data from 50 cardiothoracic surgery patients and found that those who experienced delirium postoperatively had enhanced causal effects in the default mode network (DMN), particularly in the delta band. Using these findings, the CatBoost classifier accurately distinguished between delirious and non-delirious patients with an 89.1% success rate. These results help explain disrupted information processing in delirious patients and aid in predicting postoperative delirium.