Electroencephalography-Guided Anesthesia and Delirium in Older Adults After Cardiac Surgery
Authors: Deschamps Alain , Ben Abdallah Arbi , Jacobsohn Eric , Saha Tarit , Djaiani George , El-Gabalawy Renée , Overbeek Charles , Palermo Jennifer , Courbe Athanase , Cloutier Isabelle , Tanzola Rob , Kronzer Alex , Fritz Bradley A. , Schmitt Eva M. , Inouye Sharon K. , Avidan Michael S. ,   Canadian Perioperative Anesthesia Clinical Trials Group, Denault André , Mazer David , Turgeon Alexis , Carrier François Martin , Alain Deschamps , Beattie Scott , Grocott Hilary , Hall Richard , Hare Gregory , Lalu Manoj , Jones Philip , Bryson Greg , Spence Jessica , Syed Summer , Tran Diem , El-Gabalawy Renée , Saha Tarit , Jacobsohn Eric , Djaiani George , Lamarche Yoan 
Published: June 2024

Importance

Intraoperative electroencephalogram (EEG) waveform suppression, suggesting excessive general anesthesia, has been associated with postoperative delirium.

Objective

To assess whether EEG-guided anesthesia decreases the incidence of delirium after cardiac surgery.

Design, Setting, and Participants

Randomized, parallel-group clinical trial of 1140 adults 60 years or older undergoing cardiac surgery at 4 Canadian hospitals. Recruitment was from December 2016 to February 2022, with follow-up until February 2023.

Interventions

Patients were randomized in a 1:1 ratio (stratified by hospital) to receive EEG-guided anesthesia (n = 567) or usual care (n = 573). Patients and those assessing outcomes were blinded to group assignment.

Main Outcomes and Measures

The primary outcome was delirium during postoperative days 1 through 5. Intraoperative measures included anesthetic concentration and EEG suppression time. Secondary outcomes included intensive care and hospital length of stay. Serious adverse events included intraoperative awareness, medical complications, and 30-day mortality.

Results

Of 1140 randomized patients (median [IQR] age, 70 [65-75] years; 282 [24.7%] women), 1131 (99.2%) were assessed for the primary outcome. Delirium during postoperative days 1 to 5 occurred in 102 of 562 patients (18.15%) in the EEG-guided group and 103 of 569 patients (18.10%) in the usual care group (difference, 0.05% [95% CI, −4.57% to 4.67%]). In the EEG-guided group compared with the usual care group, the median volatile anesthetic minimum alveolar concentration was 0.14 (95% CI, 0.15 to 0.13) lower (0.66 vs 0.80) and there was a 7.7-minute (95% CI, 10.6 to 4.7) decrease in the median total time spent with EEG suppression (4.0 vs 11.7 min). There were no significant differences between groups in median length of intensive care unit (difference, 0 days [95% CI, −0.31 to 0.31]) or hospital stay (difference, 0 days [95% CI, −0.94 to 0.94]). No patients reported intraoperative awareness. Medical complications occurred in 64 of 567 patients (11.3%) in the EEG-guided group and 73 of 573 (12.7%) in the usual care group. Thirty-day mortality occurred in 8 of 567 patients (1.4%) in the EEG-guided group and 13 of 573 (2.3%) in the usual care group.

Conclusions and Relevance

Among older adults undergoing cardiac surgery, EEG-guided anesthetic administration to minimize EEG suppression, compared with usual care, did not decrease the incidence of postoperative delirium. This finding does not support EEG-guided anesthesia for this indication.

Trial Registration

ClinicalTrials.gov Identifier: NCT02692300