Article

Activation of electrocorticographic activity with remifentanil and alfentanil during neurosurgical excision of epileptogenic focus

Toronto Western Hospital, Toronto, Ontario, Canada
BJA British Journal of Anaesthesia (Impact Factor: 4.85). 11/2003; 91(5):651-5. DOI: 10.1093/bja/aeg241
Source: PubMed

ABSTRACT

Opioids are known to stimulate surface electroencephalographic activity in patients with temporal lobe epilepsy. The objective of the current study was to compare the electrocorticographic activation effects of the newer short-acting opioid remifentanil with those of alfentanil during epilepsy surgery under general anaesthesia.
Thirteen patients undergoing temporal lobe epilepsy surgery under general anaesthesia received alfentanil 30 microg kg(-1) and remifentanil 1 microg kg(-1) as i.v. boluses in sequence. The design was a randomized double-blind cross-over study. After opening the dura, electrocorticogram (ECoG) electrode contact strips were placed over the temporal and supratemporal neocortex and depth electrodes were inserted in the amygdala and hippocampus. Alfentanil 30 microg kg(-1) or remifentanil 1 microg kg(-1) were administered randomly in a blinded fashion. The ECoG was recorded continuously before and after the injection of each drug. The interictal epileptiform activity (spikes and sharp waves) above baseline was analysed.
Both drugs increased epileptiform activity especially that recorded from depth electrodes in the temporal limbic structures. No epileptiform activity was recorded from the electrodes overlying the supratemporal neocortex before or after drug administration. The more potent activator was alfentanil, which caused an increase in activation from baseline of 99.8% compared with 67.4% for remifentanil. In addition, alfentanil activated the epileptiform activity in 3 patients in which remifentanil had no effect. There were no changes in heart rate after the opioid boluses. Both remifentanil and alfentanil caused significant reductions in blood pressure at 3 and 5 min after administration.
We conclude that at the doses used in this study, alfentanil is the better opioid for intraoperative activation of the ECoG in neurosurgical patients undergoing resection of a temporal lobe epileptic focus. This pharmacological activation of epileptiform activity assists in localizing and confirming the site of surgical excision. Neither alfentanil nor remifentanil activated epileptiform activity in non-epileptic brain tissue.

    • "A caveat is that the size of the seizure zone is usually overestimated when mapped using such pharmacologically induced spikes and such data needs to be interpreted with caution. A number of anesthetic drugs like propofol, fentanyl , remifentanyl, sevoflurane and isoflurane, used either individually, or in combination, are known to influence intra-operative electrocorticography (Herrick et al., 2002; McGuire et al., 2003; Wass et al., 2001; Watts et al., 1999). "
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    ABSTRACT: Background: Anesthetic-induced suppression of cortical electrical activity is a major concern during epilepsy surgery. Dexmedetomidine (Dex) has been recently evaluated in a few small series for its effect on the electrocorticographic spikes intra-operatively. Methods: In this prospective study, electrocorticogram (ECoG) was monitored during dexmedetomidine infusion in 34 patients (M:F=23:11, age=29.2 ± 10.9 years; duration of epilepsy=15.3 ± 8.9 years) undergoing anterior temporal lobe resection with amygdalo-hippocampectomy for drug-resistant mesial temporal lobe epilepsy (Right: 18, Left: 16). Anesthesia was induced with thiopental/propofol and maintained with oxygen-N2O-isoflurane. ECoG was recorded for 5 min after the end tidal MAC of N2O and isoflurane were decreased to zero; anesthesia was maintained with O2:Air=50:50, vecuronium and fentanyl. ECoG was recorded using a 4-contact strip electrode for: (a) 5 min prior to dexmedetomidine (PreDEX), (b) 5 min during dexmedetomidine infusion (DEX; 1 μg/kg) and (c) 5 min after stopping dexmedetomidine (PostDEX). Results: The ECoG spikes were manually counted in all the channels. The mean spike rate in the 2 channels with maximum spikes (MAX CH A and MAX CH B) was normalized to a 3-min duration. RM-ANOVA and post hoc comparison of three phases were used to compare the spike rates. The mean spike rate during Dex phase was higher compared to preDEX (MAX CH B: p=0.007 and MAX CH A: p=0.079) and PostDEX (MAX CH B: p=0.17, MAX CH A: p=0.79) phases. The spike rate increased in 67.6% patients, while 11.8% patients showed ≤ 25% reduction and 20.6% patients showed >25% reduction in spike frequency. Conclusion: Dexmedetomidine is useful during intra-operative ECoG recording in epilepsy surgery as it enhances or does not alter spike rate in most of the cases, without any major adverse effects.
    No preview · Article · Oct 2014 · Epilepsy Research
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    • "La disparition de cette activité e ´ pileptiforme aprè s administration de midazolam renforce l'hypothè se d'un mé canisme e ´ pileptogè ne [7]. Plus ré cemment, les opioı¨des ont e ´ té utilisé s pour la localisation des foyers e ´ pileptogè nes lors de la chirurgie de l'e ´ pilepsie [8]. Notre patients e ´ tait monitoré par le BIS au moment de la survenue des mouvements tonicocloniques. "

    Full-text · Article · Oct 2013 · Annales francaises d'anesthesie et de reanimation
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    • "La disparition de cette activité e ´ pileptiforme aprè s administration de midazolam renforce l'hypothè se d'un mé canisme e ´ pileptogè ne [7]. Plus ré cemment, les opioı¨des ont e ´ té utilisé s pour la localisation des foyers e ´ pileptogè nes lors de la chirurgie de l'e ´ pilepsie [8]. Notre patients e ´ tait monitoré par le BIS au moment de la survenue des mouvements tonicocloniques. "

    Full-text · Article · Jan 2013 · Annales francaises d'anesthesie et de reanimation
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