5. Blood samples and plasma testing
A preoperative sample and a postoperative sample were taken from the cubital vein. The preoperative sampling time was upon admission, and the postoperative sampling time was 2 days after the operation. Immediately after the collection of these samples, they were promptly subjected to centrifugation. Fresh plasma samples were used to measure NSE levels, whereas samples stored at − 80°C were used to measure plasma S-100β levels until batch evaluation. An enzyme-linked immunosorbent assay (ELISA) detection kit was utilized to measure the levels of NSE and S-100β. The specific method is based on previous research in our lab.