Monitoring depth of anaesthesia in those over 60 yo decreases the incidence of post-operative delirium, though not post-operative cognitive decline.

pearl

• F M Radtke, M Franck, J Lendner, S Krüger, K D Wernecke, and C D Spies.
• Department of Anaesthesiology and Surgical Intensive Care Medicine, Campus Charité Mitte and Campus Virchow-Klinikum, Charité-Universitätsmedizin Berlin, Charitéplatz 1, Berlin 10117, Germany.
• Br J Anaesth. 2013 Jun 1; 110 Suppl 1: i98-105.

BackgroundPostoperative delirium in elderly patients is a frequent complication and associated with poor outcome. The aim of this parallel group study was to determine whether monitoring depth of anaesthesia influences the incidence of postoperative delirium.MethodsPatients who were planned for surgery in general anaesthesia expected to last at least 60 min and who were older than 60 yr were included between March 2009 and May 2010. A total of 1277 patients of a consecutive sample were randomized (n=638 open, n=639 blinded) and the data of 1155 patients were analysed (n=575 open, n=580 blinded). In one group, the anaesthesiologists were allowed to use the bispectral index (BIS) data to guide anaesthesia, while in the other group, BIS monitoring was blinded. Cognitive function was evaluated at baseline, 1 week, and 3 months after operation.ResultsDelirium incidence was lower in patients guided with BIS. Postoperative delirium was detected in 95 patients (16.7%) in the intervention group compared with 124 patients (21.4%) in the control group (P=0.036). In a multivariate analysis, the percentage of episodes of deep anaesthesia (BIS values <20) were independently predictive for postoperative delirium (P=0.006; odds ratio 1.027). BIS monitoring did not alter the incidence of postoperative cognitive dysfunction (7th day P=0.062; 90th day P=0.372).ConclusionsIntraoperative neuromonitoring is associated with a lower incidence of delirium, possibly by reducing extreme low BIS values. Therefore, in high-risk surgical patients, this may give the anaesthesiologist a possibility to influence one precipitating factor in the complex genesis of delirium. Clinical trial registration ISRCTN Register: 36437985. http://www.controlled-trials.com/ISRCTN36437985/.

This article appears in the collections: Does anesthesia cause post-operative delirium and post-operative cognitive decline? and Post-operative awareness monitoring & prevention.

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