General anaesthesia does not contribute to long-term post-operative cognitive dysfunction in adults: A meta-analysis

CONTEXT: The contribution of anaesthesia itself to post-operative cognitive dysfunction (POCD) or the potential protective effect of one specific type of anaesthesia on the occurrence of POCD is unclear. AIMS: This is a meta-analysis evaluating the effects of the anaesthetic technique (regional vs. general anaesthesia) on POCD of patients undergoing non-cardiac surgery. SETTINGS AND DESIGN: Meta-analysis performed in a University affiliated hospital. METHODS: A search for randomized controlled trials (RCT) comparing regional anaesthesia to general anaesthesia for surgery was done in PUBMED, MEDLINE, EMBASE, EBM Reviews-Cochrane Central Register of Controlled Trials, PsychINFO and Current Contents/all editions in 2009. STATISTICAL ANALYSIS: Data were analyzed with comprehensive Meta-analysis Version 2.2.044. RESULTS: Twenty-six RCTs including 2365 patients: 1169 for regional anaesthesia and 1196 for general anaesthesia were retained. The standardized difference in means for the tests included in the 26 RCTs was -0.08 (95% confidence interval: -0.17-0.01; P value 0.094; I-squared = 0.00%). The assessor was blinded to the anaesthetic technique for 12 of the RCTs including only 798 patients: 393 for regional anaesthesia and 405 for general anaesthesia. The standardized difference in means for these 12 studies is 0.05 (-0.10-0.20; P=0.51; I-squared = 0.00%). CONCLUSIONS: The present meta-analysis does not support the concerns that a single exposure to general anaesthesia in an adult would significantly contribute to permanent POCD after non-cardiac surgery.