Change in auditory evoked potential index and bispectral index during induction of anesthesia with anesthetic drugs

Abstract

The aim of this study was to evaluate the efficacy of the auditory evoked potential (AEP) index (aepEX) as an assessment tool for hypnosis during induction of various anesthetic drugs, and to compare its performance to that of the bispectral index (BIS). A total of 45 cases were divided into three groups based on the drugs used for anesthesia. Before anesthetic induction, BIS and AEP monitors were initiated. Anesthesia was induced through intravenous injection (IV) as follows: MP (n = 15) group, midazolam (0.1 mg/kg IV); TP (n = 15) group, thiopental (4 mg/kg IV); and KP (n = 15) group, ketamine (2 mg/kg IV). After loss of response (LOR), an infusion of 3 μg/ml propofol via a target-controlled infusion was initiated in all groups. AepEX and BIS were measured in the waking state (baseline) and at LOR (1 min after LOR), pre-intubation (1 min after previous intubation) and post-intubation (1 min after tracheal intubation finished). The value of aepEX significantly decreased in all groups with LOR and that of BIS also decreased except of KP group. No significant difference were observed in BIS values between baseline and LOR in the KS group. The aepEX might be more useful than BIS for hypnosis monitoring during anesthetic induction, particularly when drugs such as ketamine are used.

Effective anesthetic management with remimazolam and ketamine without muscle relaxants for parotidectomy in a patient with myotonic dystrophy: A case report

“…[16] However, ketamine is also a dissociative anesthetic agent that suppresses neuronal function in the cortex and thalamus, and leads to aberrant excitatory activity in the limbic system, including the hippocampus, resulting in electroencephalographic changes distinct from those caused by anesthetics. [17] Ketamine induces a greater increase in the BIS value compared to midazolam in the presence of general anesthesia [18] (ketamine 0.4-0.5 mg/kg increases the BIS value in the presence of propofol or sevoflurane anesthesia [19][20][21] ). Moreover, in our patient, we had to particularly refrain from using muscle relaxants intraoperatively since nerve monitoring was needed to preserve the facial nerve, leading to large dose of intraoperative remifentanil.…”

Transient Coma Due To Epidural Anesthesia: The Role of Loss of Sensory Input

“…In a randomized trial in cardiac surgery, these have been shown to reduce the dose requirement for anesthetic agents and the need for intraoperative vasopressors [ 13 ]. Changes in the BAEP index has also been suggested to be more useful than BIS in monitoring the induction of anesthesia, particularly for ketamine [ 14 ].…”

The Use of Middle Latency Auditory Evoked Potentials (MLAEP) as Methodology for Evaluating Sedation Level in Propofol-Drug Induced Sleep Endoscopy (DISE) Procedure

“…The MLAEPi is related to the degree of central depression in response to the use of some anesthetics, and it was proposed as a reliable methodology for assessing the depth of the anesthesia [ 23 , 24 , 25 ]. We used the MLAEPi because it is an index which reflects the morphology of the MLAEP curves [ 19 ]. Due to its dynamicity, the morphology of the MLAEPi is difficult to be interpreted during DISE performance.…”

“…The current standard used in the clinical setting for monitoring the sedation level is the use of a bispectral index (BIS) [ 18 ], which is based on the detection of spontaneous cortex potentials. Middle latency auditory evoked potentials (MLAEPs) are known as indexes of the central nervous system depression induced by Propofol [ 19 , 20 , 21 ], and an MLAEP index (MLAEPi) is a computed index of potentials of MLAEPs. They are detected in a specific time window of auditory evoked potentials (AEP) on the auditory pathway as a consequence of a definite sound stimulus.…”