Comparison of effects of remimazolam and propofol on mask ventilation during general anaesthesia induction: A randomised controlled trial.

BACKGROUND

Benzodiazepines facilitate mask ventilation due to their airway relaxant properties. Remimazolam, an ultra-short-acting benzodiazepine, may offer advantages during anaesthesia induction. This study evaluated the difficulty of mask ventilation between remimazolam and propofol during the induction of general anaesthesia.

METHODS

Seventy-six adult patients scheduled for elective surgery under general anaesthesia were randomised into propofol and remimazolam groups. In the propofol group, general anaesthesia was induced with target-controlled infusion of propofol at an effect-site concentration of 4 µg/mL. In the remimazolam group, continuous infusion of remimazolam was performed at 12 mg/kg/h. The primary outcome was mask ventilation difficulty assessed by the Warters scale. Secondary outcomes included time to achieve loss of consciousness (LOC) and mean blood pressure during induction.

RESULTS

The remimazolam group exhibited significantly lower Warters score compared to the propofol group (0.0 [0.0-0.8] vs. 1.0 [0.0-3.0], P = 0.002). The occurrence of mask ventilation difficulties requiring more than one airway device during anaesthetic induction was also significantly lower in the remimazolam group than in the propofol group (odds ratio [95% confidence interval], 0.23 [0.08-0.68]; P = 0.006). Mean blood pressure immediately after LOC was higher in the remimazolam group (P = 0.037), although the incidence of hypotension after induction was comparable between groups. The time required to achieve LOC was longer in the remimazolam group (P < 0.001).

CONCLUSION

Compared to propofol, remimazolam induction was associated with easier mask ventilation and more stable blood pressure after LOC, despite a longer time to achieve LOC.

REGISTRATION: University Hospital Medical Information Network Clinical Trials Registry (registration number: UMIN000053553; registration date: 7 February 2024; registration URL: https://center6.umin.ac.jp/cgi-bin/ctr_e/ctr_view_reg.cgi?recptno=R000061086).