Association Between Intraoperative Hypotension And Postoperative Cognitive Dysfunction: A Meta-analysis

BackgroundWith the coming of aging society and the increasing incidence of postoperative cognitive dysfunction(POCD),many scholars are devoted to the influencing factors,pathogenesis,prevention and treatment of POCD.POCD is more likely to be a multifactor syndrome,involving various clinical manifestations and complex pathogenesis,leading to extreme difficulties in diagnosis and treatment.At present,some researchers have found that intraoperative hypotension and blood pressure fluctuations are associated with POCD.However,others indicate that there is no significant correlation between intraoperative hypotension and POCD.MethodsAn online search was performed to identify peer-reviewed studies that measured postoperative cognitive function of patients with and without intraoperative hypotension by Pub Med,the Cochrane library,EMBASE,ISI Web of Knowledge,Google scholar,CNKI,Weipu and Wanfang data base.Extracted data were analyzed with Review Manager(version 5.3),STATA(version12.0).Tests of heterogeneity,biases,and sensitivity were assessed in the meta-analysis.ResultsA total of 33 studies that measured postoperative cognitive function were included.The current meta-analysis found a significantly higher incidence of POCD 1 day after operations in patients experiencing intraoperative hypotension comparing with those who didn't experience hypotension(RR[95%CI])(1.73[1.10,2.71],p=0.02).No significant differences were found in the incidence of POCD between 2 days and 3 days after operations(RR[95%CI])(11.94[0.69,205.95],p=0.09;2.00[0.64,6.22],p=0.23).In the comparison of postoperative MMSE score we found a significant difference between 6 hours and 1 day after operation(SMD[95%CI])(-0.66[-0.87,-0.45],p<0.00001;-0.37[-0.74,-0.01],p=0.04).No significant differences were found between 2 days,3 days after operation(SMD[95%CI])(-0.40[-0.88,0.09],p=0.11;-0.10[-0.36,0.15],p=0.44).The time of opening eye and tracheal extubation after operation is similar in both groups(SMD[95%CI])(0.20[-0.13,0.54],p=0.24;0.27[-0.02,0.57],p=0.07).However,the amount of bleeding and the operation time were significantly lower in the hypotension group(SMD[95%CI])(-1.67[-2.23,-1.12],p<0.00001;-0.28[-0.50,-0.07],p=0.009).ConclusionsThis study shows that intraoperative hypotension is indeed correlated with the occurrence of POCD and decrease of MMSE score 1day after operation,but there is no statistical difference 2 days,3 days after operation.Intraoperative hypotension doesn't extend the time of eye-opening and tracheal extubation,and reduce the amount of bleeding and duration of operation.