JultikaUniversity of Oulu repository

Abstract

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.