Clinical risk analysis of postoperative delirium in elderly patients undergoing thoracic and abdominal surgery: study protocol of a single-centre observational cohort study.

INTRODUCTION: Postoperative delirium (POD) acts as a common complication in older patients after surgery, accompanied by longer recovery time, prolonged hospital stay, increased hospitalisation costs, etc. Therefore, it is urgent to reduce POD by implementing some intervention strategies. Early identification of associated risk factors was regarded as an effective method to lower the incidence of POD. Currently, the incidence and risk factors of POD have been widely investigated in orthopaedic and cardiac surgery, while remain scarce in thoracic and abdominal surgery. We will perform an observational cohort study to explore the incidence and potential risk variables of POD in thoracic and abdominal surgery, mainly focusing on some prognostic indicators including age-adjusted Charlson Comorbidity Index (ACCI), Prognostic Nutrition Index (PNI) and Fibrinogen to Albumin Ratio (FAR). In addition, we will further develop a predictive model based on related data to provide a novel method for preventing POD.

METHODS AND ANALYSIS: A single-centre observational study is conducted among patients aged ≥60 years old undergoing thoracic and abdominal surgery from 28 February 2022 to 31 December 2022. The patients will be divided into POD group and non-POD group following the Diagnostic and Statistical Manual of Mental Disorders, fifth edition. Related variables mainly including ACCI, PNI and FAR will be analysed by univariate and multivariate logistic regression analyses. Besides, a predictive model will be established according to associated risk factors, and the receiver operating characteristic curve will be used to further evaluate the accuracy of the predictive model.

ETHICS AND DISSEMINATION: The study has been approved by the Medical Ethics Committee of Hebei General Hospital (approval number 2022021) and will intend to be published in peer-reviewed journals.

TRIAL REGISTRATION NUMBER: Chinese Clinical Trial Registry (ChiCTR2200057126).