University of Oulu

EEG changes and C-Trend parameters in healthy patients during induction of anesthesia

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Author: Lonishin, Liubov1
Organizations: 1University of Oulu, Faculty of Information Technology and Electrical Engineering, Department of Computer Science and Engineering, Computer Science
Format: ebook
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 5.4 MB)
Pages: 60
Persistent link:
Language: English
Published: Oulu : L. Lonishin, 2022
Publish Date: 2022-06-15
Thesis type: Master's thesis (tech)
Tutor: Kortelainen, Jukka
Seppänen, Tapio
Reviewer: Kortelainen, Jukka
Seppänen, Tapio


EEG has become technically viable tool in intensive care and there are technologies like C-Trend that compress the complex EEG recording into easy-to-interpret parameters. C-Trend Index is especially designed for evaluation of the brain function during sedation in intensive care patients. In this work, the precepts of EEG, EEG usage during anesthesia practice, including the use of EEG parameters in patients’ overall assessment and C-Trend monitoring in identifying brain states under propofol were discussed. The data consisted of segments of 20 EEG recordings collected from healthy subjects who underwent anesthetic infusions while responding to stimuli to directly determine unconsciousness. The purpose of this work was to evaluate how the parameters that C-Trend provides (C-Trend Index, BSR, aEEG and ADR) behave in patients with healthy brain function during anesthesia and how they correlate with changes that we see in raw EEG and clinical signs such as loss of consciousness. It has been demonstrated that some parameters of qEEG, such as the C-Trend Index and BSR, may predict unconsciousness (results from individual t-test for C-Trend before and after loss of consciousness state are 65.70, p-value is < 0.001 for the smoothed C-Trend Index). Hence, these measures can be utilised in future studies to monitor a neurologically healthy patient’s level of anaesthesia.

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Copyright information: © Liubov Lonishin, 2022. Except otherwise noted, the reuse of this document is authorised under a Creative Commons Attribution 4.0 International (CC-BY 4.0) licence ( This means that reuse is allowed provided appropriate credit is given and any changes are indicated. For any use or reproduction of elements that are not owned by the author(s), permission may need to be directly from the respective right holders.