Numerous articles appeared in literature using different processed Electroencephalography-Depth Of Anesthesia (pEEG-DOA) monitors, such as the Bispectral Index (BIS) to assess cerebral cognitive conditions other than Depth of Anesthesia (DOA). The pEEG-DOA algorithms were retrospectively derived from volunteers’ Electroencephalography (EEG) changes with increasing incremental doses of certain γ-amino butyric acid (GABA)ergic anesthetic agents. Keeping in mind that these pEEG-DOA indices were specifically derived as the dose effect of these (GABA)ergic anesthetic agents, many of us would feel curiosity, angst, and cautious optimism when we read such articles promoting other pEEG-DOA monitors' uses outside anesthesia. However, such pEEG-DOA devices cannot be considered a “true” reflection of the EEG signal nor an independent measure of cerebral or cognitive brain functions. Apparently, authors of these publications treat EEG-derived devices as monitors that somehow simplified, in a single numerical, the complex 10/20 Fast Fourier Transform (FFT) international system derived from 20 EEG electrodes within the complete EEG spectrum of δ, θ, β, and α band amplitudes. These pEEG-DOA devices are certainly not. Even when using the pEEG-DOA devices in the intended target population of anesthetized patients, we often encounter a disparate clinical picture deviating from what these pEEG-DOA devices display. Here I present a balanced exposition of the intrinsic problems we will encounter when using pEEG-DOA devices outside their intended DOA monitoring, while focusing on light and shadow of the pEEG-DOA devices use other than DOA. Could such monitors be off-label utilized outside the scope of DOA, to “grade” and assess other EEG conditions like hepatic encephalopathy? The answer to that question seems to be a very cautious “yes”, but only in very limited clinical conditions when the EEG changes of those clinical conditions’ grades would somehow resemble EEG changes of increasing concentrations of the original anesthetic agents from which these pEEG-DOA algorithms were initially derived. Because the Bispectral Index monitor has a rather appealing scale from 100 to 0, it is very tempting to find numerical cutoff values for already very well clinically graded conditions like hepatic encephalopathy West Haven criteria. This is only because EEG changes with hepatic encephalopathy resemble, to a great extent, those EEG changes of increasing anesthetic agents’ concentrations from which these pEEG-DOA algorithms were initially derived.

Off-Label Use of Bispectral Index to Grade Conditions Other Than Depth of Anesthesia

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发表日期：

2025年

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Ashraf A. Dahaba

摘要

Numerous articles appeared in literature using different processed Electroencephalography-Depth Of Anesthesia (pEEG-DOA) monitors, such as the Bispectral Index (BIS) to assess cerebral cognitive conditions other than Depth of Anesthesia (DOA). The pEEG-DOA algorithms were retrospectively derived from volunteers’ Electroencephalography (EEG) changes with increasing incremental doses of certain γ-amino butyric acid (GABA)ergic anesthetic agents. Keeping in mind that these pEEG-DOA indices were specifically derived as the dose effect of these (GABA)ergic anesthetic agents, many of us would feel curiosity, angst, and cautious optimism when we read such articles promoting other pEEG-DOA monitors' uses outside anesthesia. However, such pEEG-DOA devices cannot be considered a “true” reflection of the EEG signal nor an independent measure of cerebral or cognitive brain functions. Apparently, authors of these publications treat EEG-derived devices as monitors that somehow simplified, in a single numerical, the complex 10/20 Fast Fourier Transform (FFT) international system derived from 20 EEG electrodes within the complete EEG spectrum of δ, θ, β, and α band amplitudes. These pEEG-DOA devices are certainly not. Even when using the pEEG-DOA devices in the intended target population of anesthetized patients, we often encounter a disparate clinical picture deviating from what these pEEG-DOA devices display. Here I present a balanced exposition of the intrinsic problems we will encounter when using pEEG-DOA devices outside their intended DOA monitoring, while focusing on light and shadow of the pEEG-DOA devices use other than DOA. Could such monitors be off-label utilized outside the scope of DOA, to “grade” and assess other EEG conditions like hepatic encephalopathy? The answer to that question seems to be a very cautious “yes”, but only in very limited clinical conditions when the EEG changes of those clinical conditions’ grades would somehow resemble EEG changes of increasing concentrations of the original anesthetic agents from which these pEEG-DOA algorithms were initially derived. Because the Bispectral Index monitor has a rather appealing scale from 100 to 0, it is very tempting to find numerical cutoff values for already very well clinically graded conditions like hepatic encephalopathy West Haven criteria. This is only because EEG changes with hepatic encephalopathy resemble, to a great extent, those EEG changes of increasing anesthetic agents’ concentrations from which these pEEG-DOA algorithms were initially derived.