Brain Power Spectral Density Under Propofol and Its Association With Cerebral Fragility, an Objective Means to Estimate the Probability of Presenting Burst Suppression

Main objective : Extend the traditional use of per-operative EEG to the detection and prediction of various degrees of brain fragility, depending on the depth of anesthesia (DoA).

Indices derived from the EEG signal, Spectral Edge Frequency 95 (SEF95), Patient State Index (PSI) and Bi-spectral Index (BIS) are now widely used in the operating room to monitor the Depth of Anesthesia (DoA). Recent studies suggest that variables extracted from per-operative EEG change as brain ages. A detailed reading of the quantitative EEG (qEEG) under GA has been recently described depending both on the specific drug used and patients' age. For GA induced with Propofol (2,6 di-isopropylphenol), a GABAergic receptor agonist used in Total Intra Venous Anesthesia (TIVA), the EEG signal under frontal derivations exhibits a specific signature characterized by a powerful alpha band. However, the elderly attenuates these EEG characteristics, which might be the results of a change in thalamic-cortical function and decreased neuronal excitability.

The goal of this observational clinical study is to assess the fragility of a patient under GA and based on the EEG SEF13 characteristics, weighted by the amount of Propofol administered.

Measures are based on EEG signal and subfrequency power spectral densities including alpha band as well as the amount of Propofol, each measured for EEG periods where SEF 95 = 8-13Hz.

Experimental design: This is a single-center, interventional, category I prospective study (minimal risks and constraints)