Abstract / Summary
Abstract Background: The comparative cerebral hemodynamic effects of remimazolam and propofol during anesthesia induction are poorly characterized. We explored these effects using continuous transcranial color-coded duplex sonography. Methods: In this single-center, randomised, open-label, blinded-endpoint exploratory trial, 52 adults (ASA I–II, 18–65 years) scheduled for major abdominal surgery were randomised to induction with remimazolam 0.3 mg/kg (n = 26) or propofol 2 mg/kg (n = 26). The primary outcome was the adjusted between-group difference in middle cerebral artery mean flow velocity (MCAvm) from baseline to 1, 3, 5, and 10 min after intubation (T1–T4), analysed with a linear mixed-effects model (baseline MCAvm as covariate, group-by-time interaction) under a treatment-policy strategy. The full analysis set comprised the 44 participants with retrievable data (remimazolam 20, propofol 24). Secondary and exploratory outcomes were not adjusted for multiplicity. Trial registration: NCT07303985. Results: MCAvm decreased from baseline by approximately 12 cm/s in both groups. Adjusted between-group differences (remimazolam minus propofol) were +3.88 (95% CI −3.21 to 10.97), +0.63 (−6.46 to 7.72), −1.37 (−8.57 to 5.83), and −1.09 (−8.38 to 6.21) cm/s at T1–T4 (group-by-time interaction p = 0.206). A post-hoc equivalence analysis (margin ±10 cm/s) yielded a 90% CI of −6.26 to 6.36 cm/s for the baseline-to-T4 change difference. Mean arterial pressure and estimated effective cerebral perfusion pressure were nominally higher with remimazolam at T1 only. Conclusions: No significant between-group difference in MCAvm was detected in this small exploratory sample; the study was underpowered for differences smaller than approximately 10.5 cm/s. Findings are hypothesis-generating and require confirmation in adequately powered trials.