Bilateral Bispectral Index, Asymmetries and Post-operative Delirium

Values of the study variables will be extract in these specific moments (considering a delay of thirty seconds between the in vivo phenomenon and the instrument): (t1) BIS probe application (t2) 60" before GA administration (t3) 60" after myoresolution (t4) intubation (t5) surgical incision (t6) end of ipnosis (t7) 10 minutes after extubation. Daily follow-up for the first five post-operative days is performed in order to verify the onset of POD and a telephone follow-up at thirty and ninety post-operative days in order to verify the onset of POD / POCD. CAM scale will be used for the diagnosis of POD; while for the diagnosis of POCD, 6-CIT test will be used, the EQ50 test in the case of tracheostomized patients.