1
|
Schmidt D, English G, Gent TC, Yanik MF, von der Behrens W. Machine learning reveals interhemispheric somatosensory coherence as indicator of anesthetic depth. Front Neuroinform 2022; 16:971231. [PMID: 36172256 PMCID: PMC9510780 DOI: 10.3389/fninf.2022.971231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Accepted: 08/12/2022] [Indexed: 11/13/2022] Open
Abstract
The goal of this study was to identify features in mouse electrocorticogram recordings that indicate the depth of anesthesia as approximated by the administered anesthetic dosage. Anesthetic depth in laboratory animals must be precisely monitored and controlled. However, for the most common lab species (mice) few indicators useful for monitoring anesthetic depth have been established. We used electrocorticogram recordings in mice, coupled with peripheral stimulation, in order to identify features of brain activity modulated by isoflurane anesthesia and explored their usefulness in monitoring anesthetic depth through machine learning techniques. Using a gradient boosting regressor framework we identified interhemispheric somatosensory coherence as the most informative and reliable electrocorticogram feature for determining anesthetic depth, yielding good generalization and performance over many subjects. Knowing that interhemispheric somatosensory coherence indicates the effectively administered isoflurane concentration is an important step for establishing better anesthetic monitoring protocols and closed-loop systems for animal surgeries.
Collapse
Affiliation(s)
- Dominik Schmidt
- Institute of Neuroinformatics, Department of Information Technology and Electrical Engineering (D-ITET), ETH Zurich, University of Zurich, Zurich, Switzerland
| | - Gwendolyn English
- Institute of Neuroinformatics, Department of Information Technology and Electrical Engineering (D-ITET), ETH Zurich, University of Zurich, Zurich, Switzerland
- Neuroscience Center Zurich (ZNZ), Eidgenössische Technische Hochschule Zürich (ETH), University of Zurich, Zurich, Switzerland
| | - Thomas C. Gent
- Institute of Neuroinformatics, Department of Information Technology and Electrical Engineering (D-ITET), ETH Zurich, University of Zurich, Zurich, Switzerland
- Anaesthesiology Section, Vetsuisse Faculty, Department of Clinical Diagnostics and Services, University of Zurich, Zurich, Switzerland
| | - Mehmet Fatih Yanik
- Institute of Neuroinformatics, Department of Information Technology and Electrical Engineering (D-ITET), ETH Zurich, University of Zurich, Zurich, Switzerland
- Neuroscience Center Zurich (ZNZ), Eidgenössische Technische Hochschule Zürich (ETH), University of Zurich, Zurich, Switzerland
| | - Wolfger von der Behrens
- Institute of Neuroinformatics, Department of Information Technology and Electrical Engineering (D-ITET), ETH Zurich, University of Zurich, Zurich, Switzerland
- Neuroscience Center Zurich (ZNZ), Eidgenössische Technische Hochschule Zürich (ETH), University of Zurich, Zurich, Switzerland
- *Correspondence: Wolfger von der Behrens
| |
Collapse
|
2
|
Alf MF, Duarte JMN, Lei H, Krämer SD, Mlynarik V, Schibli R, Gruetter R. MRS glucose mapping and PET joining forces: re-evaluation of the lumped constant in the rat brain under isoflurane anaesthesia. J Neurochem 2014; 129:672-82. [PMID: 24471521 DOI: 10.1111/jnc.12667] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Revised: 01/22/2014] [Accepted: 01/24/2014] [Indexed: 12/17/2022]
Abstract
Although numerous positron emission tomography (PET) studies with (18) F-fluoro-deoxyglucose (FDG) have reported quantitative results on cerebral glucose kinetics and consumption, there is a large variation between the absolute values found in the literature. One of the underlying causes is the inconsistent use of the lumped constants (LCs), the derivation of which is often based on multiple assumptions that render absolute numbers imprecise and errors hard to quantify. We combined a kinetic FDG-PET study with magnetic resonance spectroscopic imaging (MRSI) of glucose dynamics in Sprague-Dawley rats to obtain a more comprehensive view of brain glucose kinetics and determine a reliable value for the LC under isoflurane anaesthesia. Maps of Tmax /CMRglc derived from MRSI data and Tmax determined from PET kinetic modelling allowed to obtain an LC-independent CMRglc . The LC was estimated to range from 0.33 ± 0.07 in retrosplenial cortex to 0.44 ± 0.05 in hippocampus, yielding CMRglc between 62 ± 14 and 54 ± 11 μmol/min/100 g, respectively. These newly determined LCs for four distinct areas in the rat brain under isoflurane anaesthesia provide means of comparing the growing amount of FDG-PET data available from translational studies.
Collapse
Affiliation(s)
- Malte F Alf
- Laboratory of Functional and Metabolic Imaging, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland; Center for Radiopharmaceutical Sciences of ETH Zurich, Zurich, Switzerland
| | | | | | | | | | | | | |
Collapse
|
3
|
Murrell JC, Waters D, Johnson CB. Comparative effects of halothane, isoflurane, sevoflurane and desflurane on the electroencephalogram of the rat. Lab Anim 2008; 42:161-70. [PMID: 18435874 DOI: 10.1258/la.2007.06019e] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Inhalant anaesthetic agents are commonly used in studies investigating the electroencephalographic (EEG) effects of noxious stimuli in animals. Halothane causes less EEG depression than isoflurane, however, the EEG effects of halothane, isoflurane, sevoflurane and desflurane have not been compared in the same model. This study aimed to compare the EEG effects of these inhalational agents in the rat. Forty male Sprague-Dawley rats were assigned to four groups and anaesthetized with halothane, isoflurane, sevoflurane or desflurane. EEG was recorded from the left and right somatosensory cortices for 5 min at three different multiples of minimal alveolar concentration (MAC) (1.25, 1.5 and 1.75). Median, 95% spectral edge frequency and total power were derived and a single mean value for each was calculated for the first 60 s of each recording period. When the raw EEG contained burst suppression (BS), the BS ratio (BSR) over 60 s was calculated. No BS was found in EEG recorded from the halothane group at any concentration. BS was present at all concentrations with the other anaesthetic agents. BS was almost complete at all concentrations of isoflurane, whereas BSR increased significantly with increasing concentrations of sevoflurane and desflurane. No significant differences were found between the BSR due to the 1.75 MAC multiple of isoflurane, sevoflurane or desflurane. Halothane causes significantly less depression of cortical activity than the newer inhalant agents at equivalent multiples of MAC. These data support the hypothesis that halothane has a fundamentally different mechanism of action than the other inhalant agents.
Collapse
Affiliation(s)
- J C Murrell
- Comparative Anatomy and Physiology, Institute of Veterinary, Animal and Biomedical Sciences, College of Sciences, Massey University, Private Bag 11 222, Palmerston North, New Zealand.
| | | | | |
Collapse
|
4
|
Murrell JC, Mitchinson SL, Waters D, Johnson CB. Comparative effect of thermal, mechanical, and electrical noxious stimuli on the electroencephalogram of the rat. Br J Anaesth 2007; 98:366-71. [PMID: 17307780 DOI: 10.1093/bja/ael377] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Thermal, mechanical, and electrical stimuli are often used in acute pain studies and cause qualitatively different pain sensations. Yet, the comparative electroencephalogram (EEG) changes caused by these stimuli have not been studied. We hypothesized that because these stimuli cause different pain sensations, EEG responses would also differ. METHODS Anaesthesia was maintained with halothane in 46 male Sprague-Dawley rats. The EEG was recorded from the primary somatosensory cortices and vertex. Supramaximal noxious stimuli were applied to the tail and comprised mechanical (forceps clamp 20 N), thermal (52 degrees C water bath), and electrical (50 V, 50 Hz for 2 s) stimuli. The EEG descriptors median frequency (F50), spectral edge frequency (F95), and total power (P(tot)) recorded before (baseline) and after noxious stimulation were compared. Data were analysed using two-way factorial ANOVA (stimulus, EEG channel) followed by Bonferroni adjusted post-tests (P < 0.05). RESULTS F50 increased during electrical stimulation compared with all baseline periods in all EEG channels, increases from baseline ranging from 115.3 (SD 34.8) to 122.1 (39.6)% for the various channels. A significant increase in F50 during thermal stimulation was identified in some EEG channels, whereas no changes in F50 during mechanical stimulation occurred. Changes in F95 during any stimulus compared with baseline were not significant. CONCLUSIONS Different noxious stimuli caused differing EEG changes. As the somatosensory cortex contains relatively few exclusively nociceptive neurons, the EEG recorded from this region during the application of predominantly noxious stimuli (mechanical and thermal) may demonstrate minimal cortical activation compared with non-specific electrical noxious stimuli.
Collapse
Affiliation(s)
- J C Murrell
- Institute of Veterinary Animal and Biomedical Sciencesm, College of Sciences, Massey University, Palmerston North, New Zealand.
| | | | | | | |
Collapse
|
5
|
Park KS, Park JC, Moon BK, Lee SY, Kim JS, No HJ. The Effect of Nitrous Oxide on Cerebral Entropy during Isoflurane Inhalational Anesthesia. Korean J Anesthesiol 2007. [DOI: 10.4097/kjae.2007.52.5.543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Affiliation(s)
- Kwan Sik Park
- Department of Anesthesiology and Pain Medicine, College of Medicine, Ajou University, Suwon, Korea
| | - Jong Cook Park
- Department of Anesthesiology and Pain Medicine, College of Medicine, Cheju National University, Jeju, Korea
| | - Bong Ki Moon
- Department of Anesthesiology and Pain Medicine, College of Medicine, Ajou University, Suwon, Korea
| | - Sook Young Lee
- Department of Anesthesiology and Pain Medicine, College of Medicine, Ajou University, Suwon, Korea
| | - Jin Su Kim
- Department of Anesthesiology and Pain Medicine, College of Medicine, Ajou University, Suwon, Korea
| | - Hyun Ju No
- Department of Anesthesiology and Pain Medicine, College of Medicine, Ajou University, Suwon, Korea
| |
Collapse
|
6
|
Orth M, Bravo E, Barter L, Carstens E, Antognini JF. The differential effects of halothane and isoflurane on electroencephalographic responses to electrical microstimulation of the reticular formation. Anesth Analg 2006; 102:1709-14. [PMID: 16717314 DOI: 10.1213/01.ane.0000205752.00303.94] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Isoflurane and halothane cause electroencephalographic (EEG) depression and neuronal depression in the reticular formation, a site critical to consciousness. We hypothesized that isoflurane, more than halothane, would depress EEG activation elicited by electrical microstimulation of the reticular formation. Rats were anesthetized with either halothane or isoflurane and stimulating electrodes were positioned in the reticular formation. In a crossover design, anesthetic concentration was adjusted to 0.8 and 1.2 minimum alveolar concentration (MAC) of halothane or isoflurane and electrical microstimulation was performed and the EEG responses were recorded. Microstimulation increased the spectral edge and median edge frequencies 2-2.5 Hz at 0.8 MAC for halothane and isoflurane and 1.2 MAC halothane. At 1.2 MAC isoflurane, burst suppression occurred and microstimulation decreased the period of isoelectricity (24% +/- 19% to 8% +/- 7%; P < 0.05), whereas the spectral edge and median edge frequencies were unchanged. At anesthetic concentrations required to produce immobility, the cortex remains responsive to electrical microstimulation of the reticular formation, although the EEG response is depressed in the transition from 0.8 to 1.2 MAC. These data indicate that cortical neurons remain responsive to synaptic input during isoflurane and halothane anesthesia.
Collapse
Affiliation(s)
- Mashawn Orth
- Department of Anesthesiology and Pain Medicine, Section of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, California 95616, USA
| | | | | | | | | |
Collapse
|
7
|
Leduc ML, Atherley R, Jinks SL, Antognini JF. Nitrous oxide depresses electroencephalographic responses to repetitive noxious stimulation in the rat. Br J Anaesth 2006; 96:216-21. [PMID: 16377651 DOI: 10.1093/bja/aei309] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Although N(2)O has been widely used as an anaesthetic adjuvant its effect on electroencephalographic (EEG) activity is poorly understood because it is usually studied in the presence of additional anaesthetics, including inhaled anaesthetics. We examined the EEG effects of N(2)O in rats using a hyperbaric chamber that permitted N(2)O to be the sole anaesthetic. METHODS Rats (n=10) were anaesthetized with isoflurane and EEG activity was recorded from skull screws. The rats were placed into a hyperbaric chamber and mechanically ventilated. Isoflurane was eliminated while the chamber was pressurized with N(2)O. The minimum alveolar concentration (MAC) was determined in five rats by adjusting the chamber pressure and N(2)O concentration, and applying a tetanic noxious stimulus to the tail via an electrical pass-through. EEG responses to noxious stimulation (20 electrical pulses at 40 V applied to the tail at 0.1, 1 and 3 Hz, and 50 Hz tetanic stimulation at 60 mA applied for 30 s) were determined at 1.5 and 2 atm N(2)O. RESULTS The N(2)O MAC was 1.7+/-0.1 atm. No consistent EEG activation occurred during electrical stimulation at either partial pressure of N(2)O, although spontaneous EEG activation often occurred. Blood pressure increased after the 3 and 50 Hz stimuli. Four other rats anaesthetized with isoflurane had EEG activation with the 3 and 50 Hz stimuli. CONCLUSIONS These data indicate that N(2)O at peri-MAC partial pressures prevents EEG activation resulting from noxious electrical stimulation. Unlike the situation with isoflurane, stimulus-evoked EEG activation did not occur at peri-MAC anaesthetic concentrations, suggesting that N(2)O potently blocked ascending nociceptive transmission.
Collapse
Affiliation(s)
- M L Leduc
- Department of Anesthesiology and Pain Medicine and Section of Neurobiology, Physiology and Behavior, University of California, Davis, CA, USA
| | | | | | | |
Collapse
|
8
|
Orth M, Barter L, Dominguez C, Atherley R, Carstens E, Antognini JF. Halothane and propofol differentially affect electroencephalographic responses to noxious stimulation. Br J Anaesth 2005; 95:477-84. [PMID: 16051650 DOI: 10.1093/bja/aei208] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Anaesthetics blunt neuronal responses to noxious stimulation, including effects on electroencephalographic (EEG) responses. It is unclear how anaesthetics differ in their ability to modulate noxious stimulation-evoked EEG activation. We investigated the actions of propofol and halothane on EEG responses to noxious stimuli, including repetitive electrical C-fibre stimulation, which normally evokes neuronal wind-up. METHODS Rats were anaesthetized with halothane (n=8) or propofol (n=8), at 0.8x or 1.2x the amount required to produce immobility in response to tail clamping [minimum alveolar concentration (MAC) for halothane and median effective dose (ED(50)) for propofol]. We recorded EEG responses to repetitive electrical stimulus trains (delivered to the tail at 0.1, 1 and 3 Hz) as well as supramaximal noxious tail stimulation (clamp; 50 Hz electrical stimulus, each for 30 s). RESULTS Under halothane anaesthesia, noxious stimuli evoked an EEG activation response manifested by increased spectral edge frequency (SEF) and median edge frequency (MEF). At 0.8 MAC halothane, the tail clamp increased the MEF from approximately 6 to approximately 8.5 Hz, and the SEF from approximately 25.5 to approximately 27 Hz. At both 0.8 and 1.2 MAC halothane, similar patterns of EEG activation were observed with the 1 Hz, 3 Hz and tetanic stimulus trains, but not with 0.1 Hz stimulation, which does not evoke wind-up. Under propofol anaesthesia, noxious stimuli were generally ineffective in causing EEG activation. At 0.8 ED(50) propofol, only the tail clamp and 1 Hz stimuli increased MEF ( approximately 8 to approximately 10-10.5 Hz). At the higher propofol infusion rate (1.2 ED(50)) the repetitive electrical stimuli did not evoke an EEG response, but the tetanic stimulus and the tail clamp paradoxically decreased SEF (from approximately 23 to approximately 21.5 Hz). CONCLUSIONS Propofol has a more significant blunting effect on EEG responses to noxious stimulation compared with halothane.
Collapse
Affiliation(s)
- M Orth
- Department of Anesthesiology and Pain Medicine, University of California, Davis, 95616, USA
| | | | | | | | | | | |
Collapse
|