SAMPLE SIZE AND DATA ANALYSIS The primary outcome (occurrence of delirium) is expected to be distributed normally. Although evidence to prevent delirium is scarce, an absolute reduction of 13% incidence has been reported previously after an intervention. The estimated delirium incidence according to literature is 25%. The hypothesis is that by using a continuous FICB administered very early in the clinical course in the ED, the incidence can be decreased from 25 to 12%. Superiority of the FICB versus usual care will be tested using the Chi Square Test. In order to detect a clinically relevant between-group-difference of 13% decrease in incidence, a significance level of 0.05 and 80% power will be used. For this analysis, each group will have 154 patients. When accounting for 10% loss to follow-up after three months, a total study population of 340 will be needed.