Electroencephalographic slow wave dynamics and loss of behavioural responsiveness induced by ketamine in human volunteers.
Br J Anaesth
; 123(5): 592-600, 2019 11.
Article
em En
| MEDLINE
| ID: mdl-31492526
ABSTRACT
BACKGROUND:
Previous work on the electroencephalographic (EEG) effects of anaesthetic doses of ketamine has identified a characteristic signature of increased high frequency (beta-gamma) and theta waves alternating with episodic slow waves. It is unclear which EEG parameter is optimal for pharmacokinetic-pharmacodynamic modelling of the hypnotic actions of ketamine, or which EEG parameter is most closely linked to loss of behavioural responsiveness.METHODS:
We re-analysed previously published 128-channel scalp EEG data from 15 subjects who had received a 1.5 mg kg-1 bolus i.v. dose of ketamine. We applied standard sigmoid pharmacokinetic-pharmacodynamic models to the drug-induced changes in slow wave activity, theta, and beta-gamma EEG power; and examined the morphology of the slow waves in the time domain for Fz, F3, T3, P3, and Pz average-referenced channels.RESULTS:
Hypnotic doses of ketamine i.v. induced medio-frontal EEG slow waves, and loss of behavioural response when the estimated brain concentration was 1.64 (0.17) µg ml-1. Recovery of responsiveness occurred at 1.06 (0.21) µg.ml-1 after slow wave activity had markedly diminished. Pharmacokinetic-pharmacodynamic modelling fitted best to the slow wave activity and theta power (almost half the beta-gamma channels could not be modelled). Slow wave effect-site equilibration half-time (23 [4] s), and offset, was faster than for theta (47 [22] s).CONCLUSIONS:
Changes in EEG slow wave activity after a hypnotic dose of ketamine could be fitted by a standard sigmoid dose-response model. Their onset, but not their offset, was consistently associated with loss of behavioural response in our small study group.Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Encéfalo
/
Eletroencefalografia
/
Analgésicos
/
Ketamina
Tipo de estudo:
Prognostic_studies
Limite:
Adult
/
Female
/
Humans
/
Male
Idioma:
En
Revista:
Br J Anaesth
Ano de publicação:
2019
Tipo de documento:
Article