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A Pilot Investigation Evaluating Relative Changes in Fronto-Occipital Alpha and Beta Spectral Power as Measurement of Anesthesia Hypnotic Depth
Other than clinical observation of a patient’s vegetative response to nociception, monitoring the hypnotic component of general anesthesia (GA) and unconsciousness relies on electroencephalography (EEG)-based indices. These indices exclusively based on frontal EEG activity neglect an important obser...
Autores principales: | , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Lippincott Williams & Wilkins
2023
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10408731/ https://www.ncbi.nlm.nih.gov/pubmed/36961823 http://dx.doi.org/10.1213/ANE.0000000000006398 |
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author | Fehrlin, Eloy S. Hight, Darren Kaiser, Heiko A. Luedi, Markus M. Huber, Markus Zubler, Frédéric Lersch, Friedrich |
author_facet | Fehrlin, Eloy S. Hight, Darren Kaiser, Heiko A. Luedi, Markus M. Huber, Markus Zubler, Frédéric Lersch, Friedrich |
author_sort | Fehrlin, Eloy S. |
collection | PubMed |
description | Other than clinical observation of a patient’s vegetative response to nociception, monitoring the hypnotic component of general anesthesia (GA) and unconsciousness relies on electroencephalography (EEG)-based indices. These indices exclusively based on frontal EEG activity neglect an important observation. One of the main hallmarks of transitions from wakefulness to GA is a shift in alpha oscillations (7.5–12.5 Hz activity) from occipital brain regions toward anterior brain regions (“alpha anteriorization”). Monitoring the degree of this alpha anteriorization may help to guide induction and maintenance of hypnotic depth and prevent intraoperative awareness. However, the occipital region of the brain is completely disregarded and occipital alpha as characteristic of wakefulness and its posterior-to-anterior shift during induction are missed. Here, we propose an application of Narcotrend’s reduced power alpha beta (RPAB) index, originally developed to monitor differences in hemispheric perfusion, for determining the ratio of alpha and beta activity in the anterior-posterior axis. METHODS: Perioperative EEG data of 32 patients undergoing GA in the ophthalmic surgery department of Bern University Hospital were retrospectively analyzed. EEG was recorded with the Narcotrend® monitor using a frontal (Fp1-Fp2) and a posterior (T9-Oz) bipolar derivation with reference electrode over A2. The RPAB index was computed between both bipolar signals, defining the fronto-occipital RPAB (FO-RPAB). FO-RPAB was analyzed during wakefulness, GA maintenance, and emergence, as well as before and after the intraoperative administration of a ketamine bolus. FO-RPAB was compared with a classical quantitative EEG measure—the spectral edge frequency 95% (SEF-95). RESULTS: A significant shift of the FO-RPAB was observed during both induction of and emergence from GA (P < .001). Interestingly, the additional administration of ketamine during GA did not lead to a significant change in FO-RPAB (P = 0.81). In contrast, a significant increase in the SEF-95 in the frontal channel was observed during the 10-minute period after ketamine administration (P < .001). CONCLUSIONS: FO-RPAB appears to qualify as a marker of unconsciousness, reflecting physiological fronto-occipital activity differences during GA. In contrast to frontal SEF-95, it is not disturbed by additional administration of ketamine for analgesia. |
format | Online Article Text |
id | pubmed-10408731 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2023 |
publisher | Lippincott Williams & Wilkins |
record_format | MEDLINE/PubMed |
spelling | pubmed-104087312023-08-09 A Pilot Investigation Evaluating Relative Changes in Fronto-Occipital Alpha and Beta Spectral Power as Measurement of Anesthesia Hypnotic Depth Fehrlin, Eloy S. Hight, Darren Kaiser, Heiko A. Luedi, Markus M. Huber, Markus Zubler, Frédéric Lersch, Friedrich Anesth Analg 21 Other than clinical observation of a patient’s vegetative response to nociception, monitoring the hypnotic component of general anesthesia (GA) and unconsciousness relies on electroencephalography (EEG)-based indices. These indices exclusively based on frontal EEG activity neglect an important observation. One of the main hallmarks of transitions from wakefulness to GA is a shift in alpha oscillations (7.5–12.5 Hz activity) from occipital brain regions toward anterior brain regions (“alpha anteriorization”). Monitoring the degree of this alpha anteriorization may help to guide induction and maintenance of hypnotic depth and prevent intraoperative awareness. However, the occipital region of the brain is completely disregarded and occipital alpha as characteristic of wakefulness and its posterior-to-anterior shift during induction are missed. Here, we propose an application of Narcotrend’s reduced power alpha beta (RPAB) index, originally developed to monitor differences in hemispheric perfusion, for determining the ratio of alpha and beta activity in the anterior-posterior axis. METHODS: Perioperative EEG data of 32 patients undergoing GA in the ophthalmic surgery department of Bern University Hospital were retrospectively analyzed. EEG was recorded with the Narcotrend® monitor using a frontal (Fp1-Fp2) and a posterior (T9-Oz) bipolar derivation with reference electrode over A2. The RPAB index was computed between both bipolar signals, defining the fronto-occipital RPAB (FO-RPAB). FO-RPAB was analyzed during wakefulness, GA maintenance, and emergence, as well as before and after the intraoperative administration of a ketamine bolus. FO-RPAB was compared with a classical quantitative EEG measure—the spectral edge frequency 95% (SEF-95). RESULTS: A significant shift of the FO-RPAB was observed during both induction of and emergence from GA (P < .001). Interestingly, the additional administration of ketamine during GA did not lead to a significant change in FO-RPAB (P = 0.81). In contrast, a significant increase in the SEF-95 in the frontal channel was observed during the 10-minute period after ketamine administration (P < .001). CONCLUSIONS: FO-RPAB appears to qualify as a marker of unconsciousness, reflecting physiological fronto-occipital activity differences during GA. In contrast to frontal SEF-95, it is not disturbed by additional administration of ketamine for analgesia. Lippincott Williams & Wilkins 2023-03-24 2023-09 /pmc/articles/PMC10408731/ /pubmed/36961823 http://dx.doi.org/10.1213/ANE.0000000000006398 Text en Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the International Anesthesia Research Society. https://creativecommons.org/licenses/by-nc-nd/4.0/This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND (https://creativecommons.org/licenses/by-nc-nd/4.0/) ), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal. |
spellingShingle | 21 Fehrlin, Eloy S. Hight, Darren Kaiser, Heiko A. Luedi, Markus M. Huber, Markus Zubler, Frédéric Lersch, Friedrich A Pilot Investigation Evaluating Relative Changes in Fronto-Occipital Alpha and Beta Spectral Power as Measurement of Anesthesia Hypnotic Depth |
title | A Pilot Investigation Evaluating Relative Changes in Fronto-Occipital Alpha and Beta Spectral Power as Measurement of Anesthesia Hypnotic Depth |
title_full | A Pilot Investigation Evaluating Relative Changes in Fronto-Occipital Alpha and Beta Spectral Power as Measurement of Anesthesia Hypnotic Depth |
title_fullStr | A Pilot Investigation Evaluating Relative Changes in Fronto-Occipital Alpha and Beta Spectral Power as Measurement of Anesthesia Hypnotic Depth |
title_full_unstemmed | A Pilot Investigation Evaluating Relative Changes in Fronto-Occipital Alpha and Beta Spectral Power as Measurement of Anesthesia Hypnotic Depth |
title_short | A Pilot Investigation Evaluating Relative Changes in Fronto-Occipital Alpha and Beta Spectral Power as Measurement of Anesthesia Hypnotic Depth |
title_sort | pilot investigation evaluating relative changes in fronto-occipital alpha and beta spectral power as measurement of anesthesia hypnotic depth |
topic | 21 |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10408731/ https://www.ncbi.nlm.nih.gov/pubmed/36961823 http://dx.doi.org/10.1213/ANE.0000000000006398 |
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