Modulation of frontal EEG alpha oscillations during maintenance and emergence phases of general anaesthesia to improve early neurocognitive recovery in older patients: protocol for a randomised controlled trial

• Type of Material: Article
• Authors: Amy Gaskell, University of Auckland; Rebecca Pullon, University of Auckland; Darren Hight, University of Bern; Jonathan Termaat, Waikato District Health Board; Gay Mans, Waikato District Health Board; Logan Voss, University of Auckland; Matthias Kreuzer, Technical University of Munich; Sebastian Schmid, Technical University of Munich; Stephan Kratzer, Technical University of Munich; Amy Rodriguez, Emory University; Gerhard Schneider, Technical University of Munich; Paul Garcia, Emory University; Jamie Sleigh, University of Auckland
• Language: English
• Date: 2019-02-22
• Publisher: BMC (part of Springer Nature)
• Publication Version: Final Published Version
• Copyright Statement: © 2019 The Author(s).
• License: Creative Commons Attribution 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1186/s13063-019-3178-x
• Title of Journal or Parent Work: Trials
• ISSN: 1745-6215
• Volume: 20
• Issue: 1
• Start Page: 146
• End Page: 146
• Grant/Funding Information: Dr. García’s research efforts are supported in part by a Career Q7 Development Award #BX00167 (PI: PS García, MD, PhD) from the United States Department of Veteran Affairs, Biomedical Laboratory Research and Development Service and the James S. McDonnell Foundation Grant #220023046 (PI: PS García, MD, PhD).; Amy Gaskell is supported by a PhD scholarship from the Australian and New Zealand College of Anaesthetists.; This study was also awarded a grant from the Shrimpton Fund (University of Auckland School of Medicine Foundation).; Support is also provided by local departments.
• Keywords: Anaesthesia emergence; ELECTROENCEPHALOGRAM; POSTOPERATIVE DELIRIUM; Medicine, Research & Experimental; INTERVIEW; Elderly; SURGERY; Delirium; SUPPRESSION; PROPOFOL; Science & Technology; Research & Experimental Medicine; Life Sciences & Biomedicine; DECREASES; AWARENESS; AGITATION; General anaesthesia; EEG monitoring; VALIDATION
• Research Categories: Biology, Bioinformatics; Biology, Neuroscience; Health Sciences, Medicine and Surgery

Abstract

Background: Postoperative delirium may manifest in the immediate post-anaesthesia care period. Such episodes appear to be predictive of further episodes of inpatient delirium and associated adverse outcomes. Frontal electroencephalogram (EEG) findings of suppression patterns and low proprietary index values have been associated with postoperative delirium and poor outcomes. However, the efficacy of titrating anaesthesia to proprietary index targets for preventing delirium remains contentious. We aim to assess the efficacy of two strategies which we hypothesise could prevent post-anaesthesia care unit (PACU) delirium by maximising the alpha oscillation observed in frontal EEG channels during the maintenance and emergence phases of anaesthesia. Methods: This is a 2 × 2 factorial, double-blind, stratified, randomised control trial of 600 patients. Eligible patients are those aged 60 years or over who are undergoing non-cardiac, non-intracranial, volatile-based anaesthesia of expected duration of more than 2 h. Patients will be stratified by pre-operative cognitive status, surgery type and site. For the maintenance phase of anaesthesia, patients will be randomised (1:1) to an alpha power-maximisation anaesthesia titration strategy versus standard care avoiding suppression patterns in the EEG. For the emergence phase of anaesthesia, patients will be randomised (1:1) to early cessation of volatile anaesthesia and emergence from an intravenous infusion of propofol versus standard emergence from volatile anaesthesia only. The primary study outcomes are the power of the frontal alpha oscillation during the maintenance and emergence phases of anaesthesia. Our main clinical outcome of interest is PACU delirium. Discussion: This is a largely exploratory study; the extent to which EEG signatures can be modified by titration of pharmacological agents is not known. The underlying concept is maximisation of anaesthetic efficacy by individualised drug titration to a clearly defined EEG feature. The interventions are already clinically used strategies in anaesthetic practice, but have not been formally evaluated. The addition of propofol during the emergence phase of volatile-based general anaesthesia is known to reduce emergence delirium in children; however, the efficacy of this strategy in older patients is not known. Trial registration: Australian and New Zealand Clinical Trial Registry, ID: 12617001354370. Registered on 27/09/2017.