Accuracy of cerebrospinal fluid Aβ-42 to tau level ratio in predicting postoperative cognitive dysfunction in elderly patients / 中华麻醉学杂志

ABSTRACT

Objective To evaluate the accuracy of cerebrospinal fluid (CSF) amyloid beta 42 (Aβ-42) to tau level ratio (Aβ-42/tau) in predicting postoperative cognitive dysfunction (POCD) in elderly patients.Methods Eighty ASA physical status Ⅱ or Ⅲ patients of both sexes,aged 65-85 yr,undergoing elective total hip or knee replacement under combined spinal-epidural anesthesia,were enrolled in the study.Epidural catheter was placed at T3,4 interspace,and after a catheter was successfully placed into the subarachnoid space,CSF 2 ml was obtained to measure Aβ-42 and tau levels (unitspg/ml),and the ratio between them was calculated.Neuropsychological tests were performed at 1 day before surgery and 1 week after surgery.The Z score was used to identity POCD.The cut-off value for POCD and nonPOCD patients was determined by using ROC curve.Results Thirty-two patients were diagnosed with POCD,and the incidence was 40％.The Aβ-42/tau was 2.6±0.3 and 1.7±0.4 in non-POCD and POCD groups,respectively,and the ratio was significantly lower in POCD group than in non-POCD group.The sensitivity of CSF Aβ-42/tau in predicting POCD was 91.7％,the specificity was 81.2％,and Youden index was 0.7.ROC curves revealed that the cut-off value for POCD and non-POCD patients was 2.0.Conclusion CSF Aβ-42/tau can accurately predict the occurrence of POCD in elderly patients.