ABSTRACT
Dexmedetomidine (DEX) is a sedative used for monitored anesthesia care (MAC). DEX has been used frequently for MAC because of its less respiratory depressant effect We used DEX in four patients with severe complications who needed surgery under MAC. We started MAC with continuous infusion of 0.5-0.9 µtg - kg(-1) . hr(-1) of DEX, without initial loading dose, combined with regional anesthesia, and gradually either increased or decreased continuous infusion according to Ramsay sedation scale (RSS). The simulated plasma concentrations of DEX were calculated by AnestAs- sistTM PK . PD(-1). All patients were well sedated and operations were completed safely, although simulated plasma concentrations of DEX were low. Remarkable cardiovascular responses and respiratory depression were not observed. Our study indicated that the usage of DEX without initial loading dose combined with regional anesthesia could be an option for patients with severe complications undergoing MAC.