Effects of subanaesthetic and anaesthetic doses of sevoflurane on regional cerebral blood flow in healthy volunteers. A positron emission tomographic study

Schlünzen, Lise; Vafaee, Manouchehr Seyedi; Cold, Georg E.; Rasmussen, Mads; Nielsen, Jørgen Feldbæk; Gjedde, Albert

doi:10.1111/j.1399-6576.2004.00505.x

Cited by 61 publications

(58 citation statements)

References 40 publications

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“…This increase and scalp location in the left hemisphere are consistent with previous findings in studies on opioid effects on the EEG [4,10,26]. Although the underlying mechanisms of action are not clearly understood, dominant left-side alterations in cerebral blood flow have been observed after sevoflurane administration (an anaesthetic drug) [27]. Likewise, Schlereth et al [28] found a left-hemisphere dominance in early sensory-discriminative dimensions of nociceptive pain processing (particular in left frontal operculum and adjacent dorsal insula).…”

Section: Clinical Correlations Of the Eegsupporting

confidence: 79%

Altered Frequency Distribution in the Electroencephalogram is Correlated to the Analgesic Effect of Remifentanil

Graversen

Malver

Kurita

et al. 2014

Basic Clin Pharma Tox

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Opioids alter resting state brain oscillations by multiple and complex factors, which are still to be elucidated. To increase our knowledge, multi-channel electroencephalography (EEG) was subjected to multivariate pattern analysis (MVPA), to identify the most descriptive frequency bands and scalp locations altered by remifentanil in healthy volunteers. Sixty-two channels of resting EEG followed by independent measures of pain scores to heat and bone pain were recorded in 21 healthy males before and during remifentanil infusion in a placebo-controlled, double-blind crossover study. EEG frequency distributions were extracted by a continuous wavelet transform and normalized into delta, theta, alpha, beta and gamma bands. Alterations relative to pre-treatment responses were calculated for all channels and used as input to the MVPA. Compared to placebo, remifentanil increased the delta band and decreased the theta and alpha band oscillations as a mean over all channels (all p ≤ 0.007). The most discriminative channels in these frequency bands were F1 in delta (83.33%, p = 0.0023) and theta bands (95.24%, p < 0.0001), and C6 in the alpha band (80.95%, p = 0.0054). These alterations were correlated to individual changes in heat pain in the delta (p = 0.045), theta (p = 0.038) and alpha (p = 0.039) bands and to bone pain in the alpha band (p = 0.0092). Hence, MVPA of multi-channel EEG was able to identify frequency bands and corresponding channels most sensitive to altered brain activity during remifentanil treatment. As the EEG alterations were correlated to the analgesic effect, the approach may prove to be a novel methodology for monitoring individual efficacy to opioids.Remifentanil is a selective l-receptor opioid agonist with short onset and duration of action [1,2]. This provides a remarkable titratability, which has proved useful for balanced anaesthesia and analgosedation as well as scientific research in experimental and clinical settings [3]. For scientific research on the underlying mechanisms of action of remifentanil, electroencephalography (EEG) provides information about the time course of electrical activity in the brain. This has been investigated in several previous studies, and the results indicate a relationship between EEG changes and the potency of remifentanil [4,5]. However, although the results of these studies have shed light on many of the underlying mechanisms of remifentanil, data are conflicting and the linkage between altered brain activity and the analgesic effect of remifentanil still remains unclear.Elucidation of the association between pain stimulation/measurement and altered EEG characteristics is therefore warranted. This could be accomplished in a placebo-controlled, crossover study in healthy volunteers treated with low-dose remifentanil, which enables comparison of EEG alterations during remifentanil treatment in comparison with alterations during placebo therapy. In such a low-dose set-up, the healthy volunteer would still be conscious and able to rate pain sensations...

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Section: Clinical Correlations Of the Eegsupporting

confidence: 79%

Altered Frequency Distribution in the Electroencephalogram is Correlated to the Analgesic Effect of Remifentanil

Graversen

Malver

Kurita

et al. 2014

Basic Clin Pharma Tox

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“…At higher sevoflurane concentrations, EEG activity is characterised by overall highamplitude, and low-peak frequency, reflecting increased delta activity [44]. As for propofol, we found increases in delta and alpha-low beta bands from awake to UN-RES and an increase in high beta from awake to SED).…”

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confidence: 48%

Electroencephalogram reactivity to verbal command after dexmedetomidine, propofol and sevoflurane-induced unresponsiveness

et al. 2014

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Summary Although electroencephalogram reactivity (i.e. transient changes in electrical brain activity following external stimulus) might be useful in depth‐of‐anaesthesia monitoring, it has not been systematically examined with different anaesthetics at doses titrated to unresponsiveness. Three 10‐subject groups of healthy volunteers received dexmedetomidine, propofol or sevoflurane in escalating pseudo‐steady‐state concentrations at 10‐min intervals until they did not open their eyes to command. The electroencephalogram was continuously recorded and spectral variables were calculated with short‐time Fourier transform and time‐varying autoregressive modelling. Electroencephalogram reactivity was most prominent in the midfrontal derivations (termed F3 and F4). During drug‐induced unresponsiveness, electroencephalogram reactivity was still present in all drug groups. Dexmedetomidine, propofol and sevoflurane induced distinct suppression patterns on the electroencephalogram reactivity at the same clinical endpoint (unresponsiveness). Reactivity was best maintained with propofol, while only minimally preserved with dexmedetomidine and sevoflurane. Thus, it may be difficult to harness reactivity for depth‐of‐anaesthesia monitoring.

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“…Comparison with results from other modalities, such as PET, suggests that these flows can be related to the rCBF decrease and increase observed by Schlunzen et al [6] in such brain structures involved in the wakefulness regulation as thalamus and the lingual gyrus. These arguments would support the hypothesis of Alkire et al [1] that the thalamus is the structure involved in consciousness control.…”

Section: Discussionmentioning

confidence: 96%

“…with use of PET [6] showing that the decrease in rCBF in the occipital regions (posterior, lingual gyrus, precuneus and cerebellum) was associated with rCBF increase in the insula and superior temporal cortex.…”

Section: Discussionmentioning

confidence: 99%

Estimation of the propagation direction and spectral properties of the EEG signals registered during sevoflurane anaesthesia using Directed Transfer Function method

Olejarczyk¹,

Kamiński²,

Marciniak³

et al. 2011

Polish Journal of Medical Physics and Engineering

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The aim of this study was to estimate spectral properties and propagation of the EEG signals registered during sevoflurane anaesthesia between individual EEG recording channels. The intensities of activity flows were calculated for delta, theta, alpha and beta waves using the Directed Transfer Function integration procedure. It was found that delta waves played the dominant role in the EEG signal propagation during anesthesia and it was suggested that theta and alpha waves propagation could be related to the processes participating in the wakefulness control. Data obtained with DTF method were compared with data received from the analysis of cerebral blood flow with the use of PET in other laboratory. This study showed that analysis of the EEG signal propagation is useful for better understanding and thus safer induction of anaesthesia procedure.

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Effects of subanaesthetic and anaesthetic doses of sevoflurane on regional cerebral blood flow in healthy volunteers. A positron emission tomographic study

Abstract: At sevoflurane concentrations at 0.7% and 2.0% a significant decrease in relative rCBF was detected in the thalamus. Interestingly, some of the most profound changes in rCBF were observed in structures related to pain processing (anterior cingulate and insula).

Cited by 61 publications

References 40 publications

Altered Frequency Distribution in the Electroencephalogram is Correlated to the Analgesic Effect of Remifentanil

Altered Frequency Distribution in the Electroencephalogram is Correlated to the Analgesic Effect of Remifentanil

Electroencephalogram reactivity to verbal command after dexmedetomidine, propofol and sevoflurane-induced unresponsiveness

Estimation of the propagation direction and spectral properties of the EEG signals registered during sevoflurane anaesthesia using Directed Transfer Function method

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