AUTHOR=Wang Bin , Mu Chuanlin , Tang Xinhui , Wang Fei , Zhang Gaofeng , Wang Jiahan , Dong Rui , Lin Xu , Bi Yanlin 

TITLE=The relationship between mild cognitive impairment and postoperative delirium undergoing total knee arthroplasty: The PNDABLE study

JOURNAL=Frontiers in Aging Neuroscience

VOLUME=Volume 14 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/aging-neuroscience/articles/10.3389/fnagi.2022.959510

DOI=10.3389/fnagi.2022.959510

ISSN=1663-4365

ABSTRACT=Background: Patients undergoing surgery are at a higher risk of developing postoperative delirium (POD) as a result of anesthesia and surgical procedures. This study examined the association between POD and mild cognitive impairment (MCI) and whether MCI influences POD through the core pathology of POD.
Methods: We enrolled Chinese Han patients undergoing unilateral total knee arthroplasty (aged 50-90, weighing 50-80 kg, and using ASAI-II) combined with epidural anesthesia between October 2020 and June 2021. All participants were assessed using Winblad’s criteria for diagnosing MCI on pre-operation and using the Confusion Assessment Method (CAM) and the Memorial Delirium Assessment Scale (MDAS) postoperative 1–7 days (or before discharge) for diagnosing POD by an anesthesiologist. Cerebrospinal fluid (CSF) biomarkers of POD were measured by ELISA. To examine the mechanism by which POD pathologies affect cognition, causal mediation analyses were performed. 
Results: POD incidence was 20.2%, including 32.5% in the MCI group and 12.4% in the NMCI group. MCI and CSF level of T-tau and P-tau were risk factors and CSF level of Aβ42、Aβ42/ T-tau and Aβ42/ P-tau were protective factors for POD (P＜0.05). Part of the effects of MCI on cognition can be attributed to amyloid pathology and tau.
Conclusion: MCI may be a reasonably good prognostic factor for POD development. Overall, amyloid pathology and tau protein might partially mediate the influence of MCI on POD.