Our subjects are randomized controlled studies on the effect of intraoperative anesthetic depth monitoring on the prognosis of patients undergoing general anesthesia in non-cardiac surgery.This system review and meta analysis has been registered on PROSPERO ,the registration number is 232899. It will strictly follow Preferred Reporting Items for Systemic Reviews and Meta-analyses (PRISMA) guidelines.
Eligibility criteria: ;The population is general anesthesia patients over 18 years old undergoing non-cardiac surgery.Intervention measures: all kinds of anesthetic depth monitoring ,which include: Bispectral index of EEG，Auditory evoked potential，Primitive EEG monitoring， narcotrend，index of consciousness monitor，entropy，neuroSENSE monitor， SEDline monitor. Control measures are general clinical indications to regulate the depth of anesthesia. The mian outcomes are the incidence of postoperative delirium and postoperative cognitive impairment one week and 12 weeks after operation, the second outcomes are the postoperative hospital stay, ICU hospital stay and postoperative mortality.
All the study design are randomized controlled trial,observational designs and nonrandomized trials were excluded.
Search Strategy : We search literature in the English databases including the Cochrane Library, pubmed, EMBASE, and Google search，Chinese databases including National Knowledge Infrastructure (CNKI)，Wanfangdata library and VIP network. English search terms: postoperative delirium, postoperative cognitive dysfunction, the depth of anesthesia, electroencephalography, processed electroencephalogram, electroencephalography-guided, bispectral index, BIS, audityevoked potential index (AAI), AEP, narcotrend, CSI, index of consciousness monitor, entropy, neuroSENSE monitor , SEDline monitor, a randomised controlled trial, etc. The search time is set from 1990 to February 1, 2021, because EEG monitoring was only used after 1990. The search strategy is formulated in accordance with the PICOS principles, such as PubMed search strategy:
Study selection and Quality assement
Document screening and data collection are cbined with search results to eliminate identical documents. Read the title and abstract of the literature for a preliminary screening, exclude non-related literature, and then read the full text to find research materials that meet the standards. The data table extracts data, including recording basic information (author, nationality, number of cases, sex ratio, age distribution). The data collection and analysis are completed by two authors independently and checked with each other. If there is any different views, it will be resolved through consultation.
Risk of Bias in Included Studies Quality evaluation adopts the bias risk assessment form of the Review manager 5.3 conducts bias risk assessment on references. The evaluation criteria include: whether to group randomly, whether to double-blind, whether there are incomplete data records (such as whether there are data descriptions of withdrawal from the group or lost to follow-up due to various reasons), and whether there is no selective report of results (such as whether there are obvious results or data The description is missing, missing), whether there is no other bias. "Green" means low risk, "yellow" means uncertain, and "red" means high risk; then draw a bias risk map. Sensitivity testing is done by reanalyzing the data by changing the statistical analysis model.
Data Extraction and Management Two authors independently read the included literature, extract data, and resolve different opinions through consultation. The details of the data include the time the article was published, the author, the characteristics of the included population, the method of anesthesia, the method of surgery, the number of non-cardiac surgery, intervention measures, the number of patients with postoperative delirium and postoperative cognitive dysfunction, the number of hospitalization days, ICU Length of hospitalization and number of deaths, etc.
Data Synthesis:Statistical methods Use Review Manager 5.3 software for statistical analysis. Count data uses Risk ratio (RR) and its 95% CI as the effect size to express the result. The measurement data calculates the mean difference (MD) to indicate the size of the effect. Analyze the heterogeneity of the included studies, P<0.05 indicates significant heterogeneity, and I2 quantitatively describes the heterogeneity difference. If the heterogeneity is significant (I2≥50%), a random effects model is used for Meta -analysis. If I2<50%, use random effects model or fixed effects model.
Sensitivity studies are used to analyze the impact of a single study on the heterogeneity of the overall study. We exclude them one by one for each trial, recalculate the aggregated relative riskfor the remaining trials using the fixed effects model.