Efficacy of bispectral index monitoring for prevention of intraoperative awareness in patients under general anesthesia: a meta-analysis

Abstract

Objective To systematically review the efficacy of bispectral index (BIS) monitoring for prevention of intraoperative awareness in patients under general anesthesia.Methods The Cochrane Central Register of Controlled Trials (Central),PubMed,Medline,and EMBASE were searched for randomized controlled clinical trials involving detection of intraoperative awareness in patients in whom BIS was used or not under general anesthesia.The quality of the studies was evaluated by the method recommended by Cochrane Collaboration.Evaluation indexes included the incidence of intraoperative awareness.Meta-analysis was conducted using RevMan 5.1 software.Results Five randomized controlled clinical trials involving 34181 patients were included in this meta-analysis.There were 17432 cases in whom BIS was applied and the incidence of intraoperative awareness was 0.132％.There were 16749 cases in whom BIS was not used and the incidence of intraoperative awareness was 0.245％.There was no significant difference in the incidence of intraoperative awareness between the two groups (P ＞0.05).Further analysis was performed according to the method of anesthesia.In inhalational anesthesia,there were 13288 cases in whom BIS was applied and the incidence of intraoperative awareness was 0.128％,and there were 13202 cases in whom BIS was not applied and the incidence of intraoperative awareness was 0.113％.There was no significant difference in the incidence of intraoperative awareness between the two groups (P ＞ 0.05).In total intravenous anesthesia,there were 4144 cases in whom BIS was applied and the incidence of intraoperative awareness was 0.145％,and there were 3547 cases in whom BIS was not applied and the incidence of intraoperative awareness was 0.733 ％.The incidence of intraoperative awareness was significantly lower in the patients in whom BIS was applied than those in whom BIS was not applied (P ＜ 0.01).Conclusion BIS monitoring can effectively prevent the development of intraoperative awareness in patients under total intravenous anesthesia,but can not prevent the development of intraoperative awareness in patients under inhalational anesthesia. Key words: Electroencephalography ; Intraoperative complications ; Meta-analysis