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

A low dose of esketamine (0.2 mg/kg bolus, 5 μg/kg/min infusion for 30 minutes) raised the Bispectral Index (BIS) from 49.9±4.5 to 59.6±6.0 during propofol-remifentanil general anesthesia. A closed-loop target-controlled infusion (TCI) system that adjusted its drug delivery based on this new BIS baseline performed as well as a system using the original baseline of 50, with both falling within the range of high-performance systems. The adjusted system reduced propofol consumption (5.58±1.12 vs 6.69±1.36 mg·kg⁻¹·h⁻¹) without increasing adverse events such as intraoperative awareness, postoperative pain, nausea, vomiting, or shivering. Operating the closed-loop TCI system with an adjusted BIS baseline is feasible when low-dose esketamine is used.

Study at a glance

Abstract

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. 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. 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. It is feasible to operate the closed-loop TCI system based on the adjusted BIS baseline in the presence of low dose of esketamine.