Risk Factors for the Occurrence of Electroencephalogram Abnormalities during Induction of Anesthesia with Sevoflurane in Nonepileptic Patients

Background Recent studies of anesthetic-induced unconsciousness in humans have focused predominantly on the intravenous drug propofol and have identified anterior dominance of alpha rhythms and frontal phase-amplitude coupling patterns as neurophysiological markers. However, it is unclear whether the correlates of propofol-induced unconsciousness are generalizable to inhaled anesthetics, which have distinct molecular targets and which are used more commonly in clinical practice. Methods We recorded 64-channel electroencephalogram in healthy human participants during consciousness, sevoflurane-induced unconsciousness, and recovery (n=10; n=7 suitable for analysis). Spectrograms and scalp distributions of low-frequency (1 Hz) and alpha (10 Hz) power were analyzed, and phase-amplitude modulation between these two frequencies was calculated in frontal and parietal regions. Phase lag index was used to assess phase relationships across the cortex. Results At concentrations sufficient for unconsciousness, sevoflurane did not result in a consistent anteriorization of alpha power; the relationship between low-frequency phase and alpha amplitude in the frontal cortex did not undergo characteristic transitions. By contrast, there was significant cross-frequency coupling in the parietal region during consciousness that was not observed after loss of consciousness. Furthermore, a reversible disruption of anterior-posterior phase relationships in the alpha bandwidth was identified as a correlate of sevoflurane-induced unconsciousness. Conclusion In humans, sevoflurane-induced unconsciousness is not correlated with anteriorization of alpha and related cross-frequency patterns, but rather by a disruption of phase-amplitude coupling in the parietal region and phase-phase relationships across the cortex.

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“…However, this is a dose-dependent phenomenon and typically observed at far higher concentrations than used in the current study. 41 …”

Section: Discussionmentioning

confidence: 99%

Neurophysiological Correlates of Sevoflurane-induced Unconsciousness

et al. 2015

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“…Based on the descriptions of Vakkuri et al [4], the following EEG patterns which were regarded as epileptiform patterns [2] were distinguished: DSP (delta with spikes; delta activity of any frequency with regular or irregular spikes), PSR (rhythmic polyspikes; waveform with more than two negative and positive deflections appearing at regular intervals, associated with slow wave or mixed frequency EEG activity between spike complexes), PED (periodic epileptiform discharges), SSP (suppression with spikes; short episodes consisting mostly of a single spike appearing during complete EEG suppression). Examples are presented in Figure 1 .…”

Section: Methodsmentioning

confidence: 99%

“…Advantages of sevoflurane are that it is nonpungent and that it is characterized by a lack of upper airway irritation [1]. The use of high concentrations of 7–8% sevoflurane has been recommended to accelerate the loss of consciousness and to minimize the risk of body movements, agitation, breath holding, and coughing [2], [3]. The cardiac output is better maintained at deep anaesthesia levels compared with halothane [1].…”

Section: Introductionmentioning

confidence: 99%

“…Epileptiform potentials are observed under deep sevoflurane anaesthesia, sometimes accompanied by tonic-clonic movements [10], but most often without clinical signs [11]. Hyperventilation [4], speed of induction [7], high alveolar concentrations of sevoflurane [4], [8], [12], and female gender [2] are discussed in the literature as factors which may activate seizure-like motor activity as well as EEG abnormalities [13] during sevoflurane administration. As it is still not clear whether these EEG changes are of clinical relevance, some authors recommend to avoid them [14].…”

Section: Introductionmentioning

confidence: 99%

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Influence of the Sevoflurane Concentration on the Occurrence of Epileptiform EEG Patterns

et al. 2014

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Objectives and AimThis study was performed to analyse the effects of different sevoflurane concentrations on the incidence of epileptiform EEG activity during induction of anaesthesia in children in the clinical routine.BackgroundIt was suggested in the literature to use sevoflurane concentrations lower than 8% to avoid epileptiform activity during induction of anaesthesia in children.Methods100 children (age: 4.6±3.0 years, ASA I–III, premedication with midazolam) were anaesthetized with 8% sevoflurane for 3 min or 6% sevoflurane for 5 min in 100% O2 via face mask followed by 4% sevoflurane until propofol and remifentanil were given for intubation. EEGs were recorded continuously and were analysed visually with regard to epileptiform EEG patterns.ResultsFrom start of sevoflurane until propofol/remifentanil administration, 38 patients (76%) with 8% sevoflurane had epileptiform EEG patterns compared to 26 patients (52%) with 6% (p = 0.0106). Epileptiform potentials tended to appear later in the course of the induction with 6% than with 8%. Up to an endtidal concentration of 6% sevoflurane, the number of children with epileptiform potentials was similar in both groups (p = 0.3708). The cumulative number of children with epileptiform activity increased with increasing endtidal sevoflurane concentrations. The time from start of sevoflurane until loss of consciousness was similar in patients with 8% and 6% sevoflurane (42.2±17.5 s vs. 44.9 s ±14.0 s; p = 0.4073). An EEG stage of deep anaesthesia with continuous delta waves <2.0 Hz appeared significantly earlier in the 8% than in the 6% group (64.0±22.2 s vs. 77.9±20.0 s, p = 0.0022).ConclusionThe own analysis and data from the literature show that lower endtidal concentrations of sevoflurane and shorter administration times can be used to reduce epileptiform activity during induction of sevoflurane anaesthesia in children.

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“…Epileptiform discharges were seen in 12 of 40 healthy adult patients who were randomly allocated to different modes of sevoflurane induction with risk factors identified as being a large expired concentration of sevoflurane, the speed of anesthetic induction and female sex. 8 Voss et al 9 report that epileptiform activity has been observed with numerous general anesthetic agents including enflurane, etomidate, sevoflurane and propofol. The true incidence and underlying mechanisms are largely unknown.…”

Section: Discussionmentioning

confidence: 99%

Epileptiform activity during induction of anesthesia with sevoflurane prior to elective carotid endarterectomy

Smith

Bath

2015

Vascular

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The optimal anesthetic technique for carotid endarterectomy is still controversial. For general anesthesia, various induction agents have been used. We present two patients with asymptomatic high-grade carotid stenosis where induction with sevoflurane resulted in epileptiform discharges seen on perioperative electroencephalogram monitoring without adverse clinical sequelae. The occurrence of epileptogenic electroencephalogram during sevoflurane anesthesia has been widely described despite its popular use in pediatric anesthesia. This phenomenon, however, has not been previously described during electroencephalogram monitoring in carotid surgery. The authors suggest that induction anesthesia with sevoflurane should be avoided in this patient population especially where routine electroencephalogram monitoring is not performed.

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Risk Factors for the Occurrence of Electroencephalogram Abnormalities during Induction of Anesthesia with Sevoflurane in Nonepileptic Patients

Cited by 36 publications

References 34 publications

Neurophysiological Correlates of Sevoflurane-induced Unconsciousness

Neurophysiological Correlates of Sevoflurane-induced Unconsciousness

Influence of the Sevoflurane Concentration on the Occurrence of Epileptiform EEG Patterns

Epileptiform activity during induction of anesthesia with sevoflurane prior to elective carotid endarterectomy

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