Using the bolus-infusion method, high drug levels can be quickly obtained to rapidly bring break-through agitation under control, while the moving background rate provides lower level of sedation for comfort. When break-through agitation is frequent and causing concern, it is useful to increase the bolus dose. This is achieved by doubling the Fentanyl concentration to 20 g / ml. Modelling of patient agitation response has shown higher bolus doses control agitation better and reduce the total amount of drug needed. Therefore if agitation management is becoming difficult, consider using a double strength Fentanyl infusion early.