MAPT and delirium: Our results showed the CSF levels of Aβ40 and Aβ42 in POD patients were significantly lower than those in non-POD patients, whereas the CSF levels of P-tau and T-tau in patients with delirium were significantly higher than those in patients without delirium, which suggested that P-tau and T-tau were risk factors of POD and Aβ40 and Aβ42 were protective factors.