Capnography-detected respiratory depression during procedural sedation with remimazolam versus propofol: a randomised trial

Remimazolam, a novel ultra-short-acting benzodiazepine, has gained attention for its favourable safety profile, particularly its reduced risk of respiratory depression compared to propofol during procedural sedation. However, previous studies have primarily relied on visual assessment or pulse oximetry, which may underestimate the incidence of respiratory compromise. In this prospective randomized controlled trial, we compared the respiratory effects of remimazolam and propofol using continuous capnography monitoring, a more sensitive method for detecting hypoventilation and apnoea. Seventy adult patients undergoing procedural sedation were randomly assigned to receive either remimazolam with remifentanil or propofol with remifentanil. The primary outcome was the frequency of respiratory depression events during sedation. The median [IQR] number of respiratory depression episodes was comparable between the remimazolam and propofol groups (2 [1-3] vs. 2 [1-5], p = 0.44). Respiratory polygraphy showed no significant difference in sleep apnoea severity between groups. However, the propofol group experienced more frequent hypotensive episodes and greater blood pressure reductions. These results suggest that remimazolam does not significantly reduce the incidence of respiratory depression compared to propofol under continuous capnographic monitoring, but it may offer advantages in haemodynamic stability. Our findings support the consideration of remimazolam as a safer alternative in patients at risk of hypotension during procedural sedation.Trial registration: Clinical Trial Registry of Korea on December 2, 2021 (KCT0006797, https//cris.nih.go.kr principal investigator Suk Young Lee).