Early Postintubation Hemodynamic Changes Following Remimazolam or Propofol Induction With Simultaneous Bolus Remifentanil in Total Hip Arthroplasty: A Retrospective Observational Study

Background Early postintubation hypotension is a clinically relevant concern during anesthesia induction. During induction, whether remimazolam provides a hemodynamic advantage over propofol remains unclear. Here, we aimed to compare postintubation hypotension between remimazolam-based and propofol-based anesthesia induction. Methods In this single-center retrospective study, we included patients undergoing elective total hip arthroplasty. Anesthesia was induced using a standardized simultaneous-bolus protocol with remifentanil 3 μg/kg and either remimazolam 0.2 mg/kg or propofol 1.0 mg/kg. The primary outcome was the occurrence of at least one one-minute epoch with a mean arterial pressure (MAP) <65 mmHg within five minutes of postintubation. Sensitivity outcomes were defined using a MAP threshold of <60 mmHg, a decrease in MAP of ≥30% from preinduction MAP, and a 0-3 min postintubation window. Secondary outcomes included percentage change in MAP from hypnotic administration to five minutes postintubation; MAP trajectories, systolic blood pressure, diastolic blood pressure, heart rate, and bispectral index; minimum MAP during induction; time-weighted average MAP below 65 mmHg; maximum increase in systolic blood pressure; and vasopressor use. Analyses were performed using cases with sufficient induction time-series data to reconstruct the predefined time points. Results Of the 190 screened cases, 59 were included in the analysis: 33 in the remimazolam group and 26 in the propofol group. Early postintubation hypotension occurred in 19 patients (57.6%) in the remimazolam group and 14 patients (53.8%) in the propofol group. No significant between-group difference was observed in the primary outcome, and sensitivity analyses yielded concordant findings. In the exploratory multivariable logistic regression analysis, hypnotic agent selection was not significantly associated with hypotension. Older age and lower preinduction MAP were associated with a higher risk of hypotension. No significant between-group differences in secondary outcomes were noted. No refractory or life-threatening hypotension was observed. Conclusions Under a standardized simultaneous-bolus induction protocol with remifentanil, no significant difference in early postintubation hypotension was observed between patients receiving remimazolam and those receiving propofol. Older age and lower preinduction MAP were associated with hypotension, whereas hypnotic agent selection was not. Clinically relevant differences and selection bias cannot be excluded owing to the small analyzable cohort, wide confidence intervals, nonrandom hypnotic selection, and the exclusion of many screened cases because of insufficient induction records for analysis.