BACKGROUND:
Postoperative neurocognitive disorders (PNDs) are frequent and serious complications that cause an enormous social and economic burden. A previous study demonstrated that certain electroencephalographic (EEG) patterns during emergence from general anesthesia are associated with a higher risk for PND. Compared to patients demonstrating the most favorable trajectory (Traj Ref: delta-dominant slow-wave anesthesia (ddSWA)→spindle-dominant SWA (sdSWA)→non-SWA (nSWA)→wake), patients presenting Traj Abrupt (ddSWA→wake) had 4-fold increased odds to develop PND and patients with Traj High (nSWA→wake) had 8-fold increased odds of developing PND. We hypothesized that commonly used neuromonitoring devices (state entropy [SE], quantium consciousness index [qCON], bispectral index [BIS], and Patient State Index [PSI]) can differentiate between the various trajectories.
METHODS:
From the original database of the study by Hesse et al, we analyzed 59 EEGs from patients emerging from general anesthesia. They were selected according to their trajectory. We included 19 patients who had shown the most favorable trajectory (Traj Ref), 20 who had demonstrated Traj Abrupt, and 20 who had followed Traj High. To evaluate the performance of the neuromonitoring devices, we replayed the patients’ EEGs to the monitors using an EEG player. We compared the index values for the 3 different trajectories (Traj Ref, Traj Abrupt, and Traj High) generated by the different monitoring devices, respectively. Additionally, we evaluated the correlation between the monitoring devices.
RESULTS:
SE and PSI were able to resolve significant differences between Traj Ref and Traj Abrupt during a major part of emergence. Traj Ref showed an almost linear increase of index values, whereas Traj Abrupt led to an episode of low index values followed by a sudden increase. However, when comparing Traj Ref vs Traj High, qCON, PSI, and BIS were the indices showing significant differences, especially at the beginning of emergence. Patients representing Traj Ref patterns had significantly lower index values than those depicting Traj High. Due to the Traj High cases starting in nSWA, their indices were already high at the start of emergence.
CONCLUSIONS:
Our analysis revealed that the course of the different indices reflects spectral EEG patterns during the emergence from general anesthesia. Considering certain emergence trajectories associated with a higher risk of developing PND, our approach might enable the anesthetist to identify patients particularly susceptible to PND by observing the course of index values before admission to the postanesthesia care unit.