Effect of sedation with inhaled anaesthetics on cognitive and psychiatric outcomes in critically ill adults: a systematic review protocol.

The COVID-19 pandemic has renewed interest in the use of inhaled anaesthetics for sedation of ventilated critically ill patients. Preliminary data show that inhaled anaesthetics reduce lung inflammation, time to extubation and intensive care unit length of stay compared with intravenous sedatives. However, the impact of inhaled anaesthetics on cognitive and psychiatric outcomes is not well described in this setting. Randomised controlled trials are underway to establish if inhaled anaesthetics affect these and other patient and health system outcomes. Our aim is to summarise the known effects of inhaled sedatives on cognitive and psychiatric outcomes. In this systematic review, we will use MEDLINE, EMBASE, and PsycINFO to identify studies from 1970 to 2021 that assessed cognitive and psychiatric outcomes in critically ill adult patients sedated with inhaled anaesthetics. We will include case series, observational and cohort studies and randomised controlled trials. We will exclude case studies due to the heterogeneity of reporting in these studies. For randomised controlled trials comparing inhaled to intravenous sedation, we will report cognitive and psychiatric outcomes for both study arms. Studies will be selected based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist. Data will be extracted using a standardised data extraction tool by two independent reviewers. Studies will be assessed for bias using the Cochrane risk of bias tool for randomised controlled trials, or the Newcastle-Ottawa Scale for cohort and case-control studies. Findings will be reported according to outcome and descriptive statistics will be used to illustrate findings in a narrative fashion. The systematic review uses published data and therefore does not require ethics approval. Results will be disseminated via publication in peer-reviewed journals and presentation at conferences related to the field. CRD42021236455.

© Author(s) (or their employer(s)) 2022. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.

Competing interests: LB, AJ and MS have an ongoing clinical trial (ClinicalTrials.gov, NCT04415060) investigating the use of inhaled anaesthetics in the ICU.