This paper should be attributed to the Department of Anaesthesia, Centre of Head and Orthopaedics, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark.
Depth of anaesthesia and post-operative cognitive dysfunction
Article first published online: 17 SEP 2009
© 2009 The Authors. Journal compilation © 2009 The Acta Anaesthesiologica Scandinavica Foundation
Acta Anaesthesiologica Scandinavica
Volume 54, Issue 2, pages 162–168, February 2010
How to Cite
STEINMETZ, J., FUNDER, K. S., DAHL, B. T. and RASMUSSEN, L. S. (2010), Depth of anaesthesia and post-operative cognitive dysfunction. Acta Anaesthesiologica Scandinavica, 54: 162–168. doi: 10.1111/j.1399-6576.2009.02098.x
- Issue published online: 8 JAN 2010
- Article first published online: 17 SEP 2009
- Accepted for publication 3 July 2009
Background: A deep level of anaesthesia measured by the bispectral index has been found to improve processing speed as one aspect of cognitive function after surgery. The purpose of the present study was to assess the possible effect of the level of anaesthesia on post-operative cognitive dysfunction (POCD) 1 week after surgery, as assessed by a neuropsychological test battery.
Methods: We included 70 patients >60 years of age scheduled for elective non-cardiac surgery with general anaesthesia. The depth of anaesthesia was monitored using the cerebral state monitor, which provided a cerebral state index (CSI) value. Cognitive function was assessed by the ISPOCD neuropsychological test battery before and at 1 week (or hospital discharge) after surgery and POCD was defined as a Z score above 1.96.
Results: Five patients were not assessed after surgery. The mean CSI was 40 and 43 in patients with (N=9) and without POCD (N=56), respectively (P=0.41). The cumulated time of both deep anaesthesia (CSI<40) and light anaesthesia (CSI>60) did not differ significantly, and no significant correlation was found between the mean CSI and the Z score.
Conclusion: We were unable to detect a significant association between the depth of anaesthesia and the presence of POCD 1 week after the surgery.