Abstract

Remimazolam is a new short-acting gamma aminobutyric acid type A receptor agonist with minimal impact on cardiorespiratory suppression. However, the potential benefits of remimazolam . propofol in elderly patients undergoing colonoscopy are unknown. This was a multicentre, double-blinded randomized controlled trial. Elderly individuals, (65-85) y of age scheduled to undergo elective colonoscopy were randomized at a 1:1 ratio to receive sedation with either remimazolam at a rate of 5 mg/min or propofol at a rate of 50 mg/min at 1 min after a bolus injection of 0.05 mg fentanyl. When the Modified Observer’s Assessment of Alertness/ Sedation score reached ≤1, infusion was stopped and colonoscopy started. Modified Observer’s Assessment of Alertness/Sedation was maintained at ≤3 throughout the procedure. The primary outcome was the rate of hypotension (defined as systolic blood pressure at ≤90 mmHg or ≤70 % of the baseline) anytime during the procedure, as calculated in the intent-to-treat population. A total of 400 (201 women and 199 men, (71.0±5.0) y of age) were enrolled (200 per group). The rate of hypotension was 41.5 % (83/200) in the remimazolam group and 64.5 % (129/200) in the propofol group (p<0.001). The remimazolam group also had lower rate of bradycardia, as defined by heart rate ≤50 per minute (21.0 % . 42.5%, p<0.001) and respiratory depression, as defined by respiratory rate <8 per minute and/or saturation of peripheral oxygen <90 % (2.0 % . 6.0 %, p=0.029). For use to maintain adequate level of sedation in elderly patients undergoing colonoscopy, remimazolam infusion was associated with lower rate of hypotension as well as other measures indicative of cardiorespiratory inhibition than propofol.