Effect Of Transcutaneous Electrical Acupoint Stimulation On Postoperative Cognition After General Anesthesia In Elderly Patients:a Systematic Review And Meta-analysis

Objective:Perioperative neurocognitive dysfunction（PND）is one of the common postoperative neurological complications.Although controversy exists,transcutaneous electrical acupoint stimulation（TEAS）is deemed to be an effective method for reducing the incidence of POCD.This systematic review and meta-analysis is to study the effect of TEAS on postoperative cognitive function after general anesthesia in elderly patients.Methods:The study has been registered with PROSPERO（registration number CRD42021291200）.China National Knowledge Infrastructure,Wanfang,Chinese Biology Medicine（CBM）,VIP,Embase,Pub Med,Web of Science and Cochrane Library were systematically searched about randomized controlled clinical trials（RCTs）that investigated the effect of TEAS on PND（POCD or POD）in elderly patients under general anesthesia,from the establishment of the databases to February 2022.The main outcome measures were POCD incidence and POD incidence.The secondary outcome measures were Mini-Mental State Examination（MMSE）score,Visual Analogue Scale（VAS）score,and serum inflammatory factor level after surgery.Two researchers independently completed these procedures of study selection,data extraction and quality assessment.In case of a dispute,a third party is invited for arbitration.We evaluated the methodological quality of the RCTs according to the Cochrane risk of bias assessment.Revman 5.3 was applied for data synthesis and meta-analysis.Stata16 software and Egger’s method were used to detect publication bias.Sensitivity analysis was conducted by observing the effect of single effect size on synthetic effect size using Stata16.Results:Eighteen randomized controlled trials（RCTs）were included,comprising1349 participants,with 675 in the TEAS group and 674 in the control group.The choice of acupoints varied in the studies,with the most commonly applied being a combination of several of Sanyinjiao,Neiguan,Hegu,Baihui,and Zusanli,with stimulation parameters of 2/100 Hz,dilatational wave,and duration starting 30 minutes before the beginning of anesthesia and continuing until the end of surgery.The results of Meta analysis showed as follows.（1）TEAS significantly reduced POCD incidence and improved MMSE score on the 1^stand 3^rdpostoperative days with statistical significance（p<0.05）.（2）TEAS had no significant effect on POCD incidence and MMSE score on the 5^thand 7^thpostoperative days（p>0.05）.（3）TEAS can significantly reduce VAS score at 24 h after operation with statistical significance（p<0.05）.（4）TEAS reduced the values of S100βprotein at the end of the surgery and on the 1^stpostoperative day and IL-6 on the 1^stpostoperative day,with statistical significance.（p<0.05）.Conclusion:TEAS can prevent postoperative cognitive function decline after general anesthesia in elderly patients,which is related to the fact that TEAS can reduce the inflammatory response.