Feasibility of Closed-Loop TCI Based on New EEG Baseline in the Presence of Low Dose of Esketamine: A Randomized Controlled Equivalence Trial

Abstract

Objective: This research aimed to quantify the impact of low dose of esketamine on BIS and validate the feasibility of closed-loop TCI system based on the new BIS baseline with low dose of esketamine. Methods: This study consisted of two phases. The first phase was to quantify the impact of a low dose of esketamine (0.2mg kg−1 bolus, 5μg kg−1 min−1 infusion for 30min) on BIS and establish a new BIS baseline for propofol-remifentanil general anesthesia. The second phase was used to validate the feasibility of closed-loop TCI system based on the new BIS baseline. One hundred and eleven patients were randomly and equally assigned to three groups (group A: adjusted group, group N: non-adjusted group and group C: control group). After administering a low dose of esketamine, group A adjusted drug dosage based on new BIS baseline, while group N based on the original BIS baseline of 50, group C adjusted drug doses based on the original baseline of 50 without esketamine. Main outcome was controller performance (% time within±10units of the BIS setpoint). Secondary outcomes were drug consumption, occurrence of adverse events such as intraoperative awareness, treatment of hemodynamic changes and postoperative recovery quality. Results: In the first phase, after administering a low dose of esketamine, the BIS increased from 49.9±4.5 to 59.6±6.0, p<0.01. In the second phase, the controller performance in group A and N were within the range of high-performance systems, and both were equivalent with control group. Group A showed lower consumption of propofol compared to control group (5.58±1.12 vs 6.69±1.36 (mg·kg−1·h−1), p<0.05). There was no difference in adverse events such as intraoperative awareness, recovery assessment and postoperative VAS, PONV and shivering, QoR-15 assessment after adjusting the BIS baseline. Conclusion: It is feasible to operate the closed-loop TCI system based on the adjusted BIS baseline in the presence of low dose of esketamine.