BACKGROUND Desaturation is a common complication of endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA). Dexmedetomidine (DEX), a commonly used sedative in intensive care, is associated with less respiratory depression compared with other sedatives.

OBJECTIVE We compared DEX with midazolam (MDZ) when used as a sedative during EBUS-TBNA.

DESIGN A randomised, parallel, double-blinded trial.

SETTING A university-affiliated teaching hospital between June 2014 and July 2015.

PATIENTS A total of 102 patients who underwent EBUS-TBNA were randomly allocated to two groups (48 DEX group, 54 MDZ group).

INTERVENTIONS DEX group received 0.25 to 0.75 μg kg-1 h-1 (start with 0.5 μg kg-1 h-1, modulated in three steps from 0.25 to 0.75 μg kg-1 h-1) of DEX after a loading dose of 0.25 μg kg-1 h-1 for 10 min to maintain a Ramsay Sedation Scale (RSS) of 3 to 5. If the patient was agitated, 1 mg of MDZ bolus was used as a rescue drug. Patients in the MDZ group initially received 0.05 mg kg-1 of MDZ as a bolus. For maintenance and rescue, 1 mg of MDZ bolus was used.

MAIN OUTCOME MEASURES The primary outcome was the presence of oxygen desaturation. Secondary outcomes were level of sedation (Ramsay Sedation Scale score), cough score, sedation and procedure satisfaction score.

RESULTS The baseline characteristics of the patients, duration of EBUS-TBNA procedures and the use of rescue MDZ were not different between the groups. There was no significant difference in desaturation events between the DEX and MDZ groups (56.3 and 68.5%, respectively; P = 0.20). The level of sedation and the sedation satisfaction scores were similar between the two groups. However, cough score was significantly lower in the DEX group (41.9 vs. 53.4; P = 0.02).

CONCLUSION The use of DEX during EBUS-TBNA was not superior to MDZ in terms of oxygen desaturation.

TRIAL REGISTRATION Clinicaltrials.gov identifier: NCT02157818.