Neural Mechanisms of Sevoflurane Induced Anesthesia: an EEG fMRI Study in Healthy Volunteers

Early Phase 1CompletedNCT02149927

Technical University of Munich20 enrolled

Overview

In imaging functional connectivity (FC) analyses of the resting brain, alterations of FC during unconsciousness have been reported. These results are in accordance to recent electroencephalographic studies observing impaired top-down processing during anesthesia. In this study, simultaneous records of functional magnetic resonance imaging (fMRI) and electroencephalogram (EEG) were performed to investigate the causality of neural mechanisms during sevoflurane anesthesia by correlating FC in fMRI and directional connectivity (DC) in electroencephalogram.

Study Type

INTERVENTIONAL

Allocation

Purpose

BASIC_SCIENCE

Masking

NONE

Enrollment

Conditions

Anesthesia Drug Effects

Interventions

Eligibility

Sex: MALEMin age: 18 YearsMax age: 35 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: * ASA I * male * age \> 18y Exclusion Criteria: * drug abuse * history of psychiatric or neurologic diseases * amblyacousia, deafness * contradictions to the study drug (sevoflurane) * implants * piercings, tatoos

Outcomes

Primary Outcomes

Changes of information processing (entropy) in EEG and functional connectivity (BOLD ICA and small group network architecture) in fMRI during sevoflurane anesthesia at states awake, 2vol%, 3vol% and EEG endpoint burst suppression

Changes of fMRI functional connectivity and of EEG information processing during different levels of sevoflurane anesthesia from wakefulness to deep anesthesia: At each anesthetic level at equilibrated states awake, 2vol%, 3vol% and EEG endpoint burst suppression, EEG and fMRI are recorded simultaneously for about 10 minutes. For each level EEG and fMRI connectivity analysis are performed using the recording length of 10 minutes. This results in one outcome parameter for EEG and fMRI connectivity. Furthermore, both modalities are combined resulting in one combined parameter for each level. For EEG analysis permutation entropy as a measure of information content in EEG, and symbolic transfer entropy as a measure of directed interaction in EEG are used. fMRI functional connectivity analysis is based on BOLD ICA and on network analysis of the BOLD time series.

Time frame: 10 minutes for each condition

Secondary Outcomes

Assessment of the brain network structure during recovery in EEG and fMRI

Identical technical setup than main outcome