Effects of noxious stimulation on the electroencephalogram during general anaesthesia: a narrative review and approach to analgesic titration

García, Paul S.; Kreuzer, Matthias; Hight, Darren; Sleigh, James W.

doi:10.1016/j.bja.2020.10.036

Cited by 57 publications

(61 citation statements)

References 95 publications

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“…49 While termed delta arousal, these delta responses may not necessarily imply the progression toward the restoration of consciousness. 48 In our experiments, the delta power and burst duration were increased after optical stimulation, suggesting cortical activation and a decrease in anesthesia depth, but we did not conclude that consciousness was restored after stimulation of the paraventricular thalamus during deep anesthesia with burst suppression. Another unexpected finding was that the activation of the paraventricular thalamus bed nucleus of the stria terminalis pathway was sufficient to induce behavioral arousal during light sevoflurane anesthesia maintenance, which was not seen in isoflurane anesthesia.…”

Section: Discussioncontrasting

confidence: 70%

A Neural Circuit from the Paraventricular Thalamus to the Bed Nucleus of the Stria Terminalis for the Regulation of States of Consciousness during Sevoflurane Anesthesia in Mice

Gao

et al. 2022

Anesthesiology

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Background The neural circuitry underlying sevoflurane-induced modulation of consciousness is poorly understood. We hypothesized that the paraventricular thalamus-bed nucleus of the stria terminalis pathway plays an important role in regulating states of consciousness during sevoflurane anesthesia. Methods Rabies-virus-based transsynaptic tracing techniques were employed to reveal the neural pathway from the paraventricular thalamus to the bed nucleus of the stria terminalis. We investigated the role of this pathway in sevoflurane anesthesia induction, maintenance and emergence using chemogenetic and optogenetic methods combined with cortical electroencephalogram (EEG) recordings. Both male and female mice were used in our study. Results Both GABAergic and glutamatergic neurons in the bed nucleus of the stria terminalis receive paraventricular thalamus glutamatergic projections. Chemogenetic inhibition of paraventricular thalamus glutamatergic neurons prolonged the sevoflurane anesthesia emergence time (mean ± SD, hM4D-CNO vs. mCherry-CNO, 281 ± 88 vs. 172 ± 48 s, p < 0.001, n = 24) and decreased the induction time (101 ± 32 vs. 136 ± 34 s, p = 0.002, n = 24) as well as the EC50 for the loss or recovery of the righting reflex under sevoflurane anesthesia (mean [95% confidence interval]; MACLORR, 1.16 [1.12 to 1.20] vs. 1.49 [1.46 to 1.53] vol%, p < 0.001, n = 20; MACRORR, 0.95 [0.86 to 1.03] vs. 1.34 [1.29 to 1.40] vol%, p < 0.001, n = 20). Similar results were observed during suppression of the paraventricular thalamus- bed nucleus stria terminalis pathway. Optogenetic activation of this pathway produced the opposite effects. Additionally, transient stimulation of this pathway efficiently induced behavioral arousal during continuous steady-state general anesthesia with sevoflurane and reduced the depth of anesthesia during sevoflurane-induced burst suppression. Conclusions In mice, axonal projections from the paraventricular thalamic neurons to the bed nucleus of the stria terminalis contribute to regulating states of consciousness during sevoflurane anesthesia.

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Section: Discussioncontrasting

confidence: 70%

A Neural Circuit from the Paraventricular Thalamus to the Bed Nucleus of the Stria Terminalis for the Regulation of States of Consciousness during Sevoflurane Anesthesia in Mice

Gao

et al. 2022

Anesthesiology

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“…Third, our spectrogram-based anesthetic titration algorithm was based on the idea that excessive (ie, supratherapeutic) volatile anesthetic dosage would result in a decrease in alpha band power and that lowering end-tidal MAC fraction in such cases would increase alpha power. This could be questioned based on data published after our study had started, 36 demonstrating that in contrast to prior studies, 13,14 alpha power decreases with increasing volatile anesthetic concentrations in roughly half of patients, while it increases with increasing volatile anesthetic dosage in the other half. Nonetheless, since alpha band peak frequency changes with anesthetic dosage, 36 it could be used to guide anesthetic titration in future studies.…”

Section: Anesthesia and Analgesiamentioning

confidence: 65%

“…This could be questioned based on data published after our study had started, 36 demonstrating that in contrast to prior studies, 13,14 alpha power decreases with increasing volatile anesthetic concentrations in roughly half of patients, while it increases with increasing volatile anesthetic dosage in the other half. Nonetheless, since alpha band peak frequency changes with anesthetic dosage, 36 it could be used to guide anesthetic titration in future studies. Fourth, our ELC did not cover EEG effects of neuromuscular blockade, nociceptive stimulation, opioids, or acute hypertension.…”

Section: Anesthesia and Analgesiamentioning

confidence: 65%

Developing a Real-Time Electroencephalogram-Guided Anesthesia-Management Curriculum for Educating Residents: A Single-Center Randomized Controlled Trial

Berger

Eleswarpu

Wright

et al. 2021

Anesthesia &Amp; Analgesia

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BACKGROUND: Different anesthetic drugs and patient factors yield unique electroencephalogram (EEG) patterns. Yet, it is unclear how best to teach trainees to interpret EEG time series data and the corresponding spectral information for intraoperative anesthetic titration, or what effect this might have on outcomes. METHODS: We developed an electronic learning curriculum (ELC) that covered EEG spectrogram interpretation and its use in anesthetic titration. Anesthesiology residents at a single academic center were randomized to receive this ELC and given spectrogram monitors for intraoperative use versus standard residency curriculum alone without intraoperative spectrogram monitors. We hypothesized that this intervention would result in lower inhaled anesthetic administration (measured by age-adjusted total minimal alveolar concentration [MAC] fraction and age-adjusted minimal alveolar concentration [aaMAC]) to patients ≥60 old during the postintervention period (the primary study outcome). To study this effect and to determine whether the 2 groups were administering similar anesthetic doses pre-versus postintervention, we compared aaMAC between control versus intervention group residents both before and after the intervention. To measure efficacy in the postintervention period, we included only those cases in the intervention group when the monitor was actually used. Multivariable linear mixed-effects modeling was performed for aaMAC fraction and hospital length of stay (LOS; a non-prespecified secondary outcome), with a random effect for individual resident. A multivariable linear mixed-effects model was also used in a sensitivity analysis to determine if there was a group (intervention versus control group) by time period (post-versus preintervention) interaction for aaMAC. Resident EEG knowledge difference (a prespecified secondary outcome) was compared with a 2-sided 2-group paired t test. RESULTS: Postintervention, there was no significant aaMAC difference in patients cared for by the ELC group (n = 159 patients) versus control group

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“…This is postulated to be due to thalamocortical interactions ( Vijayan et al, 2013 ), though its neurophysiological significance in relation to NCD remains unknown. Though there is limited published evidence on how to promote alpha power on EEG, reducing anesthetic depth ( Kreuzer et al, 2017 ) and providing adequate analgesia ( Garcia et al, 2021 ) have shown utility and have motivated an ongoing clinical trial to assess the intraoperative modulation of alpha power and its relation to POD ( clinicaltrials.gov identifier NCT04443517).…”

Section: Managementmentioning

confidence: 99%

Mitigation of perioperative neurocognitive disorders: A holistic approach

Safavynia

Goldstein

Evered

2022

Front. Aging Neurosci.

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William Morton introduced the world to ether anesthesia for use during surgery in the Bullfinch Building of the Massachusetts General Hospital on October 16, 1846. For nearly two centuries, the prevailing wisdom had been that the effects of general anesthetics were rapidly and fully reversible, with no apparent long-term adverse sequelae. Despite occasional concerns of a possible association between surgery and anesthesia with dementia since 1887 (Savage, 1887), our initial belief was robustly punctured following the publication in 1998 of the International Study of Post-Operative Cognitive Dysfunction [ISPOCD 1] study by Moller et al. (1998) in The Lancet, in which they demonstrated in a prospective fashion that there were in fact persistent adverse effects on neurocognitive function up to 3 months following surgery and that these effects were common. Since the publication of that landmark study, significant strides have been made in redefining the terminology describing cognitive dysfunction, identifying those patients most at risk, and establishing the underlying etiology of the condition, particularly with respect to the relative contributions of anesthesia and surgery. In 2018, the International Nomenclature Consensus Working Group proposed new nomenclature to standardize identification of and classify perioperative cognitive changes under the umbrella of perioperative neurocognitive disorders (PND) (Evered et al., 2018a). Since then, the new nomenclature has tried to describe post-surgical cognitive derangements within a unifying framework and has brought to light the need to standardize methodology in clinical studies and motivate such studies with hypotheses of PND pathogenesis. In this narrative review, we highlight the relevant literature regarding recent key developments in PND identification and management throughout the perioperative period. We provide an overview of the new nomenclature and its implications for interpreting risk factors identified by clinical association studies. We then describe current hypotheses for PND development, using data from clinical association studies and neurophysiologic data where appropriate. Finally, we offer broad clinical guidelines for mitigating PND in the perioperative period, highlighting the role of Brain Enhanced Recovery After Surgery (Brain-ERAS) protocols.

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Effects of noxious stimulation on the electroencephalogram during general anaesthesia: a narrative review and approach to analgesic titration

Cited by 57 publications

References 95 publications

A Neural Circuit from the Paraventricular Thalamus to the Bed Nucleus of the Stria Terminalis for the Regulation of States of Consciousness during Sevoflurane Anesthesia in Mice

A Neural Circuit from the Paraventricular Thalamus to the Bed Nucleus of the Stria Terminalis for the Regulation of States of Consciousness during Sevoflurane Anesthesia in Mice

Developing a Real-Time Electroencephalogram-Guided Anesthesia-Management Curriculum for Educating Residents: A Single-Center Randomized Controlled Trial

Mitigation of perioperative neurocognitive disorders: A holistic approach

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