Changes in Alpha Frequency and Power of the Electroencephalogram during Volatile-Based General Anesthesia
Oscillations in the electroencephalogram (EEG) at the alpha frequency (8–12 Hz) are thought to be ubiquitous during surgical anesthesia, but the details of how this oscillation responds to ongoing changes in volatile anesthetic concentration have not been well characterized. It is not known how ofte...
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2017-05-01
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| Series: | Frontiers in Systems Neuroscience |
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| Online Access: | http://journal.frontiersin.org/article/10.3389/fnsys.2017.00036/full |
| _version_ | 1811339981276315648 |
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| author | Darren Hight Darren Hight Logan J. Voss Paul S. Garcia Paul S. Garcia Jamie Sleigh Jamie Sleigh |
| author_facet | Darren Hight Darren Hight Logan J. Voss Paul S. Garcia Paul S. Garcia Jamie Sleigh Jamie Sleigh |
| author_sort | Darren Hight |
| collection | DOAJ |
| description | Oscillations in the electroencephalogram (EEG) at the alpha frequency (8–12 Hz) are thought to be ubiquitous during surgical anesthesia, but the details of how this oscillation responds to ongoing changes in volatile anesthetic concentration have not been well characterized. It is not known how often alpha oscillations are absent in the clinical context, how sensitively alpha frequency and power respond to changes in anesthetic concentration, and what effect increased age has on alpha frequency. Bipolar EEG was recorded frontally from 305 patients undergoing surgery with sevoflurane or desflurane providing general anesthesia. A new method of detecting the presence of alpha oscillations based on the stability of the rate of change of the peak frequency in the alpha range was developed. Linear concentration-response curves were fitted to assess the sensitivity of alpha power and frequency measures to changing levels of anesthesia. Alpha oscillations were seen to be inexplicably absent in around 4% of patients. Maximal alpha power increased with increasing volatile anesthetic concentrations in half of the patients, and decreased in the remaining patients. Alpha frequency decreased with increasing anesthetic concentrations in near to 90% of patients. Increasing age was associated with decreased sensitivity to volatile anesthesia concentrations, and with decreased alpha frequency, which sometimes transitioned into the theta range (5–7 Hz). While peak alpha frequency shows a consistent slowing to increasing volatile concentrations, the peak power of the oscillation does not, suggesting that frequency might be more informative of depth of anesthesia than traditional power based measures during volatile-based anesthesia. The alpha oscillation becomes slower with increasing age, even when the decreased anesthetic needs of older patients were taken into account. |
| first_indexed | 2024-04-13T18:35:35Z |
| format | Article |
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| institution | Directory Open Access Journal |
| issn | 1662-5137 |
| language | English |
| last_indexed | 2024-04-13T18:35:35Z |
| publishDate | 2017-05-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Systems Neuroscience |
| spelling | doaj.art-d5b42897135b463eb80786710c48a05a2022-12-22T02:34:55ZengFrontiers Media S.A.Frontiers in Systems Neuroscience1662-51372017-05-011110.3389/fnsys.2017.00036244260Changes in Alpha Frequency and Power of the Electroencephalogram during Volatile-Based General AnesthesiaDarren Hight0Darren Hight1Logan J. Voss2Paul S. Garcia3Paul S. Garcia4Jamie Sleigh5Jamie Sleigh6Department of Anaesthesia, Waikato Clinical Campus, University of AucklandHamilton, New ZealandDepartment of Anaesthesia, Waikato District Health BoardHamilton, New ZealandDepartment of Anaesthesia, Waikato District Health BoardHamilton, New ZealandDepartment of Anesthesiology, Emory University School of MedicineAtlanta, GA, United StatesAnesthesiology and Research Divisions, Atlanta VA Medical CenterAtlanta, GA, United StatesDepartment of Anaesthesia, Waikato Clinical Campus, University of AucklandHamilton, New ZealandDepartment of Anaesthesia, Waikato District Health BoardHamilton, New ZealandOscillations in the electroencephalogram (EEG) at the alpha frequency (8–12 Hz) are thought to be ubiquitous during surgical anesthesia, but the details of how this oscillation responds to ongoing changes in volatile anesthetic concentration have not been well characterized. It is not known how often alpha oscillations are absent in the clinical context, how sensitively alpha frequency and power respond to changes in anesthetic concentration, and what effect increased age has on alpha frequency. Bipolar EEG was recorded frontally from 305 patients undergoing surgery with sevoflurane or desflurane providing general anesthesia. A new method of detecting the presence of alpha oscillations based on the stability of the rate of change of the peak frequency in the alpha range was developed. Linear concentration-response curves were fitted to assess the sensitivity of alpha power and frequency measures to changing levels of anesthesia. Alpha oscillations were seen to be inexplicably absent in around 4% of patients. Maximal alpha power increased with increasing volatile anesthetic concentrations in half of the patients, and decreased in the remaining patients. Alpha frequency decreased with increasing anesthetic concentrations in near to 90% of patients. Increasing age was associated with decreased sensitivity to volatile anesthesia concentrations, and with decreased alpha frequency, which sometimes transitioned into the theta range (5–7 Hz). While peak alpha frequency shows a consistent slowing to increasing volatile concentrations, the peak power of the oscillation does not, suggesting that frequency might be more informative of depth of anesthesia than traditional power based measures during volatile-based anesthesia. The alpha oscillation becomes slower with increasing age, even when the decreased anesthetic needs of older patients were taken into account.http://journal.frontiersin.org/article/10.3389/fnsys.2017.00036/fullEEGgeneral anesthesiaalpha rhythmfrequency tuningalpha power |
| spellingShingle | Darren Hight Darren Hight Logan J. Voss Paul S. Garcia Paul S. Garcia Jamie Sleigh Jamie Sleigh Changes in Alpha Frequency and Power of the Electroencephalogram during Volatile-Based General Anesthesia Frontiers in Systems Neuroscience EEG general anesthesia alpha rhythm frequency tuning alpha power |
| title | Changes in Alpha Frequency and Power of the Electroencephalogram during Volatile-Based General Anesthesia |
| title_full | Changes in Alpha Frequency and Power of the Electroencephalogram during Volatile-Based General Anesthesia |
| title_fullStr | Changes in Alpha Frequency and Power of the Electroencephalogram during Volatile-Based General Anesthesia |
| title_full_unstemmed | Changes in Alpha Frequency and Power of the Electroencephalogram during Volatile-Based General Anesthesia |
| title_short | Changes in Alpha Frequency and Power of the Electroencephalogram during Volatile-Based General Anesthesia |
| title_sort | changes in alpha frequency and power of the electroencephalogram during volatile based general anesthesia |
| topic | EEG general anesthesia alpha rhythm frequency tuning alpha power |
| url | http://journal.frontiersin.org/article/10.3389/fnsys.2017.00036/full |
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