A Meta-analysis Of The Value Of Eeg In Early Diagnosis Of Delayed Encephalopathy After Carbon Monoxide Poisoning

Objective:The purpose of this meta-analysis was to evaluate the value of electroencephalogram in the early diagnosis of delayed encephalopathy after carbon monoxide poisoning using a meta-analysis method.Methods:Chinese key words"carbon monoxide poisoning delayed encephalopathy,carbon monoxide toxic encephalopathy,sequelae of carbon monoxide poisoning,carbon monoxide poisoning,gas poisoning, electroencephalography,brain wave"and English key words"carbon monoxide poisoning,brain diseases,electroencephalography"are used as subject term.The databases were searched systematacially by computer,including Chinese databases such as Wan Fang Database,China national knowledge infrastructure,VIP Database,China biology medicine disc,and foreign databases such as Pub Med,Embase,Web of Science,and Cochrane Library.Search scope self-built database until February 2022.After data were extracted and literature quality and bias risk of included studies were evaluated,meta-analysis was performed using Stata 16.0 software.Results:1.A total of 1445 literatures were obtained through retrieval,and 727 were duplicate literatures.According to the inclusion and exclusion criteria,16 articles were finally included,and a total of 1498 people were included in the study.Different researches have counted the abnormal rate of EEG,abnormal wave of EEG,abnormal wave of frontotemporal region and the outcome index of abnormal rate of EEG before and after treatment.2.Abnormal rate of EEG:There were 9 correlation studies with obvious inter-study heterogeneity（I~2=74.9%>50%,P<0.05）OR=8.17,95%CI:2.25-29.62,Z=3.19（P=0.001）for combined effect size test.The incidence of abnormal EEG in DEACMP group was significantly higher than that in control group.3.Abnormal EEG waves:Yu-bao Chen et al.Research data show that the occurrence of DEACMP（δ+θ）/（α+β）is 8.514±1.827,not DEACMP（δ+θ）/（α+β）is4.273±1.046,DEACMP group（δ+θ）/（α+β）value is greater than the control group obviously.The results indicate that（δ+θ）/（α+β）value can also be used as an important index to predict DEACMP.4.Three studies were included on frontotemporal abnormalities.In the study of Hou Yonghua et al.,12 cases of frontotemporal abnormalities were found in the DEACMP group,while no frontotemporal abnormalities were found in the group without DEACMP.In addition,Gu Renjun et al.also found that the number of abnormalities in the frontotemporal region of DEACMP population decreased after treatment.Pu Juan reported that 11 out of 41 DEACMP patients showed localized EEG abnormalities,including 8 frontal abnormalities and 3 frontotemporal abnormalities.This also suggests that patients with DEACMP are more prone to frontotemporal abnormalities.5.Abnormal rate of EEG before and after treatment:A total of 5 RCT studies and1 case-control study were included,involving 241 patients with delayed encephalopathy.The heterogeneity was（I~2=74.1%>50%,P<0.05）,so the random- effect model was used for analysis.Combined effect size OR=36.62,95%CI:5.65-237.28 combined effect size test Z=7.78（P<0.001）,the difference between the two groups was statistically significant.The incidence of abnormal EEG in the DEACMP group was significantly lower after treatment than before,indicating that EEG changed with the evolution of DEACMP condition.Therefore,the change of abnormal EEG rate is helpful to evaluate the therapeutic efficacy and prognosis of DEACMP.Conclusions:The results of meta-analysis showed that the abnormal rate of EEG in patients with DEACMP was significantly higher than that in patients without DEACMP,and some patients had abnormal EEG activity in frontotemporal region,and the abnormal ratio of EEG in patients with DEACMP was also significantly higher than that in the control group.After treatment,the rate of abnormal EEG in patients with DEACMP decreased significantly,indicating that the EEG varied with the disease.Therefore,EEG has certain value in early diagnosis,curative effect evaluation and prognosis evaluation of delayed encephalopathy after carbon monoxide poisoning,and is a beneficial electrophysiological index.