Changes in the EEG power spectrum after midazolam anaesthesia combined with racemic or S – (+) ketamine

Abstract

Changes in the EEG power spectrum were studied in 50 patients (ASA status I or II), receiving either 2 mg.kg-1 of racemic ketamine or 1 mg.kg-1 of S-(+) ketamine in a randomized and double-blind manner after prior administration of 0.1 mg.kg-1 of midazolam. The patients receiving intramuscular premedication with midazolam about 45 minutes prior to induction of anaesthesia showed, in a deliberately quiet environment and mostly in the early morning, a delta dominated EEG (56% delta power) with a reduced alpha peak (17% alpha power) and an average median of 4 Hz as the baseline findings of the EEG power spectrum. The intravenous administration of midazolam led to activation of the lower beta range (13-18 Hz) and the subsequent injection of ketamine caused an increase in activity in the fast beta range (21-30 Hz), both being accompanied by a reduction of delta power from 56% to 40%. Correspondingly, an increase in the median frequency was noted. Causing nearly the same changes in EEG, S-(+) ketamine was confirmed to be twice as potent as racemic ketamine.

Comparison of Bispectral Index and Composite Auditory Evoked Potential Index for Monitoring Depth of Hypnosis in Children

“…The number of children who accepted sensor placement before anesthesia induction would have been higher had we chosen to premedicate with midazolam. Based on the fact that benzodiazepines have a known impact on the electroencephalogram, 28 we decided not to premedicate our patients.…”

ECoG spectrum changes at different xenon-isoflurane anaesthesia depths

“…These changes vary from low frequencies high amplitude EEG waves to burst suppression patterns and depend, among other things, on the type of anaesthetic used and the age of the patient [3][4][5]. On the other hand, loss of consciousness (LOC) is associated with a decrease of activity and connectivity in the gamma domain [6,7].…”

Erratum zu: Intranasale Medikamentenapplikation im Rettungsdienst bei Kindern

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In der zunächst veröffentlichten OnlineVersion des Beitrags wurden falsche Angaben zur Dosierung von S-Ketamin gemacht.Ketamin und das verwandte S-Ketamin können beide intranasal mittels MAD-Device verabreicht werden.Verschiedenste Studien belegen, dass S-Ketamin verglichen zu Ketamin-Razemat in halber Dosierung einen äquivalen-ten Effekt aufweist [1,2,3]. Aus dieser Tatsache heraus sollte auch bei der intranasalen Applikation zunächst mal die halbe Dosierung verabreicht werden.

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“…Verschiedenste Studien belegen, dass S-Ketamin verglichen zu Ketamin-Razemat in halber Dosierung einen äquivalen-ten Effekt aufweist [1,2,3]. Aus dieser Tatsache heraus sollte auch bei der intranasalen Applikation zunächst mal die halbe Dosierung verabreicht werden.…”