Effect of Electroencephalography Spectral Edge Frequency (SEF) and Patient State Index (PSI)-Guided Propofol-Remifentanil Anesthesia on Delirium After Laparoscopic Surgery: The eMODIPOD Randomized Controlled Trial

Abstract

Background: The effect of SedLine electroencephalography (EEG)-guided anesthetic care on postoperative delirium (POD) has not been studied.Methods: This single-center randomized EEG Monitoring tO Decrease the Incidence of Post-Operative Delirium (eMODI-POD) trial involved 1560 patients aged 50 years or above undergoing laparoscopic surgery. Propofol-remifentanil anesthesia was guided either by SedLine (EEG-guided care, n = 779) or not (usual care, n = 781). The goal of EEG-guided care was to maintain spectral edge frequency between 10 and 15 and patient state index (PSI) between 25 and 50. The primary outcome was the incidence of POD on postoperative days 1 to 5. The secondary outcomes included emergence delirium, composite moderate-to-severe complications, length of hospital stay, intensive care unit admission, 30-day hospital readmission and allcause mortality, and intraoperative awareness.Results: Of the 1560 randomized patients, 1545 were included in the modified intention-to-treat analysis. The median propofol administered for anesthesia maintenance was 900 mg and 1000 mg in the EEG-guided and usual care groups, respectively (P = 0.21). POD occurred in 1.0% (8/771) and 1.2% (9/774) of patients in the EEG-guided and usual care groups, respectively (risk ratio: 0.89; 95% confidence interval: 0.35-2.30). There were no between-group differences in all secondary outcome measures. Emergence delirium occurred in 11.8% (91/771) and 13.2% (102/774) of the EEG-guided care and usual care groups, respectively (risk ratio: 0.90; 95% confidence interval: 0.69-1.17; P = 0.41). Three patients from each group reported intraoperative awareness.Conclusions: Compared with usual care, SedLine spectral edge frequency-guided and patient state index-guided propofol-remifentanil anesthetic care neither alters anesthetic delivery nor decreases the unexpected low incidence of POD in relatively young Chinese patients undergoing laparoscopic surgery.

Postoperative Delirium: The Search for Effective Interventions

“…Previous trials investigating the effect of pEEGguided general anesthesia on POD have also shown mixed results for efficacy. However, the incidence of POD in the trial by Wang et al 5 (1.1%) was much lower than the expected incidence in this surgical population (14%). While this lower than expected incidence of POD may have been related to their younger age, avoidance of benzodiazepines, use of propofol or an unknown characteristic of the Chinese population included in the study, the consequence of the low event rate is that the trial had limited power for testing clinically relevant differences between groups.…”

“…Provision of information about protocol adherence is fundamental for appropriate interpretation of results. Fortunately, Wang et al5 provided this information; 8 summary statistics of pEEG adherence are reported. Although 2 parameters (SEF left >15 and SEF left/right >15) were statistically different, total propofol dose was similar between groups (median [interquartile range], 900 [600 to 1320] vs. 1000 [600 to 1350] mg in the pEEG-guided and usual care groups, respectively).…”

“…Trials of pEEG-guided general anesthesia are challenging, and accurate titration to anesthetic depth can be difficult in the context of a trial. Wang et al5 used SEDline, but titration based on PSI and SEF did not result in between group differences. Whether anesthetic dose titration with PSI and SEF exhibit similar problems to the BIS algorithm is uncertain.…”

“…Whether anesthetic dose titration with PSI and SEF exhibit similar problems to the BIS algorithm is uncertain. Nevertheless, Wang et al 5 are to be congratulated on completing the largest randomized controlled trial of this type to date, and for their thorough reporting of the trial. Future studies should concentrate on higher risk groups with higher event rates, and use trial designs that ensure group separation in pEEG or dose to answer this important clinical question.…”

“…However, the BIS algorithm is known to exhibit a flat dose-response curve, particularly in the elderly, and may not be an ideal device to guide general anesthesia. 4 The trial by Wang et al 5 in this issue of the Journal is the first large trial to investigate pEEG-guided general anesthesia and its influence on POD using the Patient State Index (PSI) and Spectral Edge Frequency (SEF) (SEDline, Masimo Corporation, CA) to titrate intravenous general anesthesia. The trial recruited 1545 patients aged 50 years and older with American Society of Anesthesiologists physical status classification 1-3, scheduled for laparoscopic surgery with an expected minimum hospital stay of 3 days.…”