Targeted Interventions to Increase Blood Pressure and Decrease Anaesthetic Concentrations Reduce Intraoperative Burst Suppression: A Randomised, Interventional Clinical Trial.

Marie-Therese Georgii,Stefanie Pilge,Jule Schuessler,Matthias Kreuzer,Antonia Fleischmann,Gerhard Schneider

doi:10.3389/fnsys.2022.786816

Abstract

BackgroundIt has been suggested that intraoperative electroencephalographic (EEG) burst suppression (BSupp) may be associated with post-operative neurocognitive disorders in the elderly, and EEG-guided anaesthesia may help to reduce BSupp. Despite of this suggestion, a standard treatment does not exist, as we have yet to fully understand the phenomenon and its underlying pathomechanism. This study was designed to address two underlying phenomena—cerebral hypoperfusion and individual anaesthetic overdose.ObjectivesWe aimed to demonstrate that targeted anaesthetic interventions—treating intraoperative hypotension and/or reducing the anaesthetic concentration—reduce BSupp.MethodsWe randomly assigned patients to receive EEG-based interventions during anaesthesia or EEG-blinded standard anaesthesia. If BSupp was detected, defined as burst suppression ratio (BSR) > 0, the primary intervention aimed to adjust the mean arterial blood pressure to patient baseline (MAP intervention) followed by reduction of anaesthetic concentration (MAC intervention).ResultsEEG-based intervention significantly reduced total cumulative BSR, BSR duration, and maximum BSR. MAP intervention caused a significant MAP increase at the end of a BSR > 0 episode compared to the control group. Coincidentally, the maximum BSR decreased significantly; in 55% of all MAP interventions, the BSR decreased to 0% without any further action. In the remaining events, additional MAC intervention was required.ConclusionOur results show that targeted interventions (MAC/MAP) reduce total cumulative amount, duration, and maximum BSR > 0 in the elderly undergoing general anaesthesia. Haemodynamic intervention already interrupted or reduced BSupp, strengthening the current reflections that hypotension-induced cerebral hypoperfusion may be seen as potential pathomechanism of intraoperative BSupp.Clinical Trial RegistrationNCT03775356 [ClinicalTrials.gov], DRKS00015839 [German Clinical Trials Register (Deutsches Register klinischer Studien, DRKS)].

Highlights

Intraoperative electroencephalographic (EEG) burst suppression (BSupp) is a non-specific and non-physiological EEG pattern.The occurrence of BSupp has often been attributed to a relative “overdose” of volatile or intravenous anaesthetics (Bruhn et al, 2000b)
We aimed to demonstrate that targeted anaesthetic interventions— treating intraoperative hypotension and/or reducing the anaesthetic concentration— reduce BSupp
Our results show that targeted interventions (MAC/mean arterial blood pressure (MAP)) reduce total cumulative amount, duration, and maximum burst suppression ratio (BSR) > 0 in the elderly undergoing general anaesthesia

Summary

Introduction

The occurrence of BSupp has often been attributed to a relative “overdose” of volatile or intravenous anaesthetics (Bruhn et al, 2000b) This may not necessarily be related to high absolute concentrations, and the occurrence at lower concentrations suggests a vulnerability or increased cerebral sensitivity to (predominantly volatile) anaesthetics in patients at risk (Fritz et al, 2018). It has been suggested that intraoperative electroencephalographic (EEG) burst suppression (BSupp) may be associated with post-operative neurocognitive disorders in the elderly, and EEG-guided anaesthesia may help to reduce BSupp. Despite of this suggestion, a standard treatment does not exist, as we have yet to fully understand the phenomenon and its underlying pathomechanism.

Objectives

Methods

Results

Discussion

Conclusion