BACKGROUNDClinical study indicated that infusion of dexmedetomidine without loading dose intraoperative provided smooth and haemodynamically stable emergence, and improved quality of recovery with fewer postoperative side effects and analgesic requirements 9 . The objective is to determine remifentanil-propofol combined with dexmedetomidine during general anesthesia would decrease the incidence and severity of postoperative emergence agitation, anxiety and depression, and without effect on the cognitive dysfunction in elder patients.METHODS120 elder patients scheduled for ureteroscopic holmium laser lithotripsy were randomly allocated to PR group administered the normal saline, and PRD group administered dexmedetomidine 0.4 µg.Kg -1 .h -1 intravenously after induction of anesthesia, and stopped 30 minutes before the end of surgery. The primary outcome was the scores of richmond agitation sedation, mini mental state examination, state-trait anxiety inventory, zung self-Rating depression scale, and the arabic numeral memory. The secondary outcome was the duration of surgery, and time to spontaneous respiration, recovery and extubation.RESULTSThe dosage of propofol and remifentanil decreased more significantly in PRD group ( P< 0.001). The RASS scores in the PRD group was significantly lower than in PR group at t 1-3 ( P< 0.001). The MMSE scores were lower at T 1 - 2 in two groups ( P< 0.001). Compared to PR group, the ZSDS scores and STAI scores at T 1 - 2 were lower in PRD group ( P <0.005). The recalled arabic numbers were lower at T 2 in PR group ( P< 0.001).CONCLUSIONDexmedetomidine administration could reduce both the dosage of remifentanil and propofol during surgery, and the incidence and severity of postoperative emergence agitation, anxiety and depression in elderly patients.Trial registrationthe Chinese Clinical Trial Registry, ChiCTR1900021254, Registered 3 February 2019, http://www.chictr.org.cn/ChiCTR1900021254.