Risk factors for postoperative cognitive dysfunction and the predictive model in elderly patients undergoing lumbar surgery under general anesthesia / 中华麻醉学杂志

ABSTRACT

Objective:To identify the risk factors for postoperative cognitive dysfunction (POCD) and develop the prediction model in elderly patients undergoing lumbar surgery under general anesthesia.Methods:The elderly patients undergoing elective lumbar surgery under general anesthesia in our hospital from July 2021 to July 2022 were enrolled. Cognitive function was assessed at 7 days after surgery using Mini-Mental State Examination and Montreal Cognitive Assessment. When the decrease in both scales≥ 1 standard deviation, the patients were considered as having POCD. The patients were divided into POCD group and non-POCD group according to whether POCD developed. The propensity score matching was used to balance the confounding bias between two groups. The multivariate logistic regression analysis was used to identify the risk factors for POCD. The prediction model was constructed, and a nomogram was drawn for visualization of the model. The receiver operating characteristic curve, calibration plot and decision curve analysis (DCA) were drawn to evaluate the differentiation, consistency and clinical validity of the model, respectively.Results:A total of 159 patients were enrolled in this study, and the incidence of POCD was 31.4%. There were statistically significant differences in the ratio of intraoperative blood transfusion, cumulative time of hypotension, total infusion volume and operation time between two groups ( n=32 each) after propensity score matching ( P<0.05). The results of multivariate logistic regression showed that age, educational levels, diabetes mellitus, previous two or more operations under general anesthesia, APTT and cumulative time of hypotension were independent risk factors for POCD in elderly patients undergoing lumbar surgery under general anesthesia ( P<0.05). A model was developed based on the risk factors mentioned above LogitP=-15.878+ 0.263 × Age (years) - 0.122 × Educational Level (years)+ 1.601 × Diabetes Mellitus+ 1.468 × History of General Anesthesia for 2 or more times+ 0.608 × Cumulative Time of Hypotension(min) - 0.140 × APTT (s). The area under the receiver operating characteristic curve was 0.930 (95% CI 0.887-0.973), the sensitivity was 0.920, specificity was 0.798 and Youden index was 0.718. After visualizing the model via nomogram, the model was verified by Hosmer-Lemeshow test, P=0.403, C index was 0.930, and corrected C index was 0.914. Conclusions:Age, educational levels, diabetes mellitus, previous multiple operations under general anesthesia, APTT and cumulative time of hypotension are independent risk factors for POCD in elderly patients undergoing lumbar surgery under general anesthesia, and the established risk prediction model can effectively predict the occurrence of POCD in elderly patients undergoing lumbar surgery under general anesthesia.