The Effect of Low-Dose Intraoperative Ketamine on Closed-Loop-Controlled General Anesthesia: A Randomized Controlled...

Area of Science:

• Anesthesiology
• Neuroscience
• Pharmacology

Background:

• Closed-loop anesthesia systems utilize processed electroencephalography (EEG) for depth-of-hypnosis monitoring.
• The NeuroSENSE monitor provides the processed EEG depth-of-hypnosis index (WAVCNS).
• Previous studies described closed-loop control using WAVCNS for propofol-remifentanil anesthesia.

Purpose of the Study:

• To evaluate the performance of a closed-loop propofol-remifentanil controller during anesthesia induction and maintenance.
• To assess controller performance in the presence of a low-dose ketamine infusion compared to a placebo.
• To determine if ketamine affects the accuracy of the WAVCNS index.

Main Methods:

• A double-blind, randomized, placebo-controlled trial was conducted with American Society of Anesthesiologist (ASA) physical status I-II patients.
• Patients received either a ketamine bolus and infusion or a saline placebo before closed-loop anesthesia induction.
• Controller performance was measured as the percentage of time within ±10 units of the WAVCNS setpoint.

Main Results:

• Controller performance was equivalent between the ketamine and control groups (median difference 1.0%, 95% CI -3.6 to 5.0).
• The percentage of time within the target range was similar: 86.6% [79.7, 90.2] in the ketamine group vs. 86.4% [76.5, 89.8] in the control group.
• Higher mean propofol doses were required during maintenance in the ketamine group (median difference 24.9 µg·kg-1·min-1).

Conclusions:

• Low-dose ketamine does not alter the performance of closed-loop propofol-remifentanil anesthesia controlled by WAVCNS.
• Further research is needed to confirm increased propofol requirements and investigate potential effects of ketamine on the WAVCNS index.