Day 1 plasma NfL levels were higher in patients who then spent two or more days in delirium or deep sedation (n=123) compared with patients who spent only one or no days in delirium or deep sedation (n=18), mean 37.8 pg/ml (standard deviation 32.6) compared with 96.5 pg/ml (SD 106.1) p-value 0.002 (Table 2). Here, NEFL is linked to delirium.