ObjectiveTo evaluate the application of dexmedetomidine for moderate sedation in patients undergoing endoscopic ultrasonography.MethodsPatients who were planned to undergo endoscopic ultrasonography in West China Hospital of Sichuan University from February to June 2019 were randomly divided into dexmedetomidine group (trial group) and propofol group (control group). The basic conditions, success rate of endoscopic ultrasound diagnosis and treatment, sedation-related adverse events, implementation of airway management, postoperative comfort evaluation and endoscopic physician satisfaction score of the two groups were compared.ResultsA total of 120 patients were eventually enrolled, 60 in each group. There was no significant difference in the basic conditions of the two groups (P>0.05). The success rate of endoscopic ultrasound diagnosis and treatment in two groups were 100%. There was no significant difference in the incidence of bucking, apnea and bradycardia between the two groups (P>0.05). The incidence of hypotension (15.0% vs. 31.7%), hypoxemia (6.7% vs.20.0%) in the trial group was lower than those in the control group, the differences were statistically significant (P<0.05). The proportion of patients in the trial group who performed airway management was lower than that in the control group (1.7% vs. 28.3%), and the difference was statistically significant (P<0.05). There was no significant difference in postoperative pain score, the first time to get out of bed and postoperative 15-item quality of recovery questionnaire score between the two groups (P>0.05). The incidence of nausea and vomiting at 6 hours after operation (48.3% vs. 3.3%) and 24 hours after operation (10.0% vs. 0.0%) and the time required for recovery of gastrointestinal function ［(201.4±178.4) vs. (148.5±75.7) min］ in the trial group were higher than those in the control group (P<0.05). The median (the lower and upper quartile) of comfort score of patients and satisfaction score of endoscopic physicians were 8 (6, 10) and 8 (7, 9) in the trial group, respectively, and were 10 (9, 10) and 9 (8, 10) in the control group, with statistically significant differences (P<0.05).ConclusionModerate sedation with dexmedetomidine could provide good sedative and analgesic effects in endoscopic ultrasonography. It has little effect on respiration and blood pressure, but the incidence of postoperative nausea and vomiting were higher than deep sedation with propofol. And patient comfort and endoscopic physician satisfaction also need to be improved.