Activation of the electroencephalogram with intravenous Brietal (methohexitone): the findings in 100 cases

Gumpert, John; Paul, Ronald I.

doi:10.1136/jnnp.34.5.646

Cited by 36 publications

(20 citation statements)

References 8 publications

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“…This time interval exceeds the anticipated duration of action based on plasma half-life, 28 autoradiographic studies of brain distribution, ~' %26 and specific EEG effects of the barbiturate itself. 24 Significant hypotension (55 mm Hg mean) was seen in our series only when anaesthetic doses of barbiturate were used. Yet the EEG seizure pattern was enhanced regardless of barbiturate dosage, although periods of interictal burst suppression were longer with anaesthetic doses.…”

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confidence: 54%

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The influence of intravenous anaesthetics on enflurane-induced central nervous system seizure activity

Darimont¹,

Jenkins

1977

Canad. Anaesth. Soc. J.

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ENFLUIaANE is a halogenated ether which has been recently introduced into clinical anaesthetic practice. Its attractive features include rapid induction and emergence, minimal gastro-intestina] disturbance and limited biotransformation. However, sufficient concern exists about its potential for eliciting excitation of the central nervous system (CNS) that the manufacturer considers a pre-existing seizure disorder a eontraindication to its use. 1 Recent reports indicate that enflurane-induced EEG seizures, sometimes accompanied by convulsive activity, may be seen in patients with no apparent pre-existing CNS disorder3 -5 Identical EEG seizure patterns can be reproduced in healthy animal preparations. ~9 High inspired concentrations of enflurane and/or low carbon dioxide tensions are well established as factors precipitating or augmenting abnormal EEG activity both in man and in laboratory animals.However, little information is available about the influence on enflurane seizure patterns of other anaesthetic agents used concomitantly. Virtue reported the abolition of enflurane-induced myoclonus in dogs with intravenous thiopentone. TM Dobkin and associates noted the absence of motor movements in patients given enflurane in combination with barbiturates and muscle relaxants but, in common with other early clinical evaluations, did not assess these patients for EEG evidence of cerebral irritability23The study reported here was undertaken, therefore, to assess the effects, if any, of several commonly employed intravenous induction agents on both the threshold for enflurane-indueed EEG seizures and on the continuation of established EEG seizure activity. METrIODS AND RESULTSEight adult female cats were used for a total of 28 experiments. These animals were chronic preparations with permanently implanted EEG recording electrodes.Each animal was provided with four stainless steel screws resting on the fi'ontal dura. Subcortical structures were implanted with four bipolar electrodes, corresponding to two bilateral sites. Each animal had two subcortical sites selected fi'om brain stem reticular formation, amygdala or hippocampal nuclei.Implantation was undertaken with intraperitoneal pentobarbitone anaesthesia (35 mg/kg). The animals were mounted in a David Kopf stereotaxie apparatus and the subcortical sites were implanted according to the coordinates of Jasper. la From the

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confidence: 54%

“…11,34 Barbiturate treatment of petit mal may exacerbate or convert petit real to grand real3 3,24 Small doses of methohexitone (40 mg intravenously) may precipitate psychomotor and petit real epi- lepsy when the stimulus of hyperventilation is ineffectual. 24 In fact, methohexitone has been known to provoke seizures de novo. ~n…”

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confidence: 99%

The influence of intravenous anaesthetics on enflurane-induced central nervous system seizure activity

Darimont¹,

Jenkins

1977

Canad. Anaesth. Soc. J.

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“…Invasive EEG recordings confirmed the MSI focus localization with respect to the intralobar area of epileptogenicity in 5 of 6 patients (patients 5,7,10,11,14). In 3 of these patients, however, invasive EEG evaluation showed additional epileptic discharges in the respective lobe.…”

Section: Ictal Meg Data Recorded After Clonidine Administrationmentioning

confidence: 63%

“…Its dosedependent seizure-activating properties (evaluated by scalp EEG recordings) were first described by Pampiglione (6) and were later confirmed by other researchers (7)(8)(9).…”

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confidence: 61%

Clonidine and Methohexital‐Induced Epileptic Magnetoencephalographic Discharges in Patients with Focal Epilepsies

Kirchberger¹,

Hj²,

Hummel³

et al. 1998

Epilepsia

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Summary: Purpose: During presurgical evaluation, 14 patients with medically intractable focal epilepsies underwent magnetoencephalographic (MEG) recordings for focus localization. To increase the number of epileptic discharges required for MEG analysis, we administered methohexital (MHT), a short-acting barbiturate known to provoke epileptic activity. We also investigated the spike-provoking properties of clonidine in comparison with MHT.Methods: Patients were briefly anesthetized with intravenously administered MHT after being premedicated orally with clonidine. Numbers and locations of epileptic MEG discharges were assessed after clonidine premedication as well as during MHT anesthesia. Results were compared with baseline MEG recordings.Results: MHT increased the frequency of focal epileptic discharges in 8 of 13 patients ( I of the 14 patients did not receive MHT after premedication with clonidine). Premedication with clonidine also increased focal epileptic discharges in 9 of 14 patients. The numbers of epileptic signals and numbers of spikes contributing to MEG source localizations were significantly increased in MEG recordings under both treatment conditions (clonidine premedication and MHT anesthesia) as compared with baseline MEG recordings.Conclusions: Our results confirmed the selective proconvulsive effects of MHT on the epileptic focus, as previously suggested by EEG and electrocorticographic (ECoG) investigations. However, our present data establish for the first time that clonidine increases epileptic activity in patients with seizure disorders and indicate that clonidine is suitable as an activating agent for localization of epileptogenic foci by MEG. This effect of clonidine on specific epileptic activity also indicates that specific care must be taken when clonidine is used as an antihypertensive drug in patients with seizure disorders. Key Words: Epilepsy-Magnetoencephalography-Methohexital-Clonidine-Focus localization.The most important goal of presurgical evaluation of patients with focal epilepsies is the exact localization of the primary epileptic focus. Magnetoencephalography (MEG) is a useful noninvasive diagnostic method which often provides important information in presurgical localization of epileptic activity (1-5). Epileptic discharges, however, are not always present during routine MEG recording because the available recording time is limited by the regimen of motionless posture and head fixation of the patient. In addition to standard activation procedures such as hyperventilation, photic stimulation, and sleep, proconvulsive drugs such as methohexital (MHT) can be used to provoke epileptiform activity.MHT is an anesthetic agent of fast onset, short duration of action, and relatively few side effects. Its dosedependent seizure-activating properties (evaluated by

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“…Further investigations by Gibbs and Gibbs (2), and Merlis et al (3) demonstrated that by physiological or drug induced sleep it is possible not only to establish the diagnosis of epilepsy, but also to locate the site of epileptic focus. The last 30 years have seen the publication of numerous studies showing the value of EEG activation by chemical agents (3)(4)(5)(6)(7)(8)(9)(10)(11). In the majority of these studies the results are considered for each individual method.…”

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confidence: 99%

Combined Activation of the EEG with Brietal and Pentetrazol

Ghazy¹,

Veger²

1978

Clinical Electroencephalography

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A group of 101 activations with Brietal and Pentetrazol are reported. Although Brietal proved to be of value in the investigation of all forms of epilepsy, with 55% positive results, there remained groups of patients in whom there was still a call for greater diagnostic precision. Pentetrazol was tried in 21 of these patients with 66% positive activation. It was found that the two agents together were successful in 72% of the patients. Both also add valuable negative evidence in suspected functional fits.

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Activation of the electroencephalogram with intravenous Brietal (methohexitone): the findings in 100 cases

Cited by 36 publications

References 8 publications

The influence of intravenous anaesthetics on enflurane-induced central nervous system seizure activity

The influence of intravenous anaesthetics on enflurane-induced central nervous system seizure activity

Clonidine and Methohexital‐Induced Epileptic Magnetoencephalographic Discharges in Patients with Focal Epilepsies

Combined Activation of the EEG with Brietal and Pentetrazol

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