Remimazolam-Remifentanil versus Propofol-Remifentanil for Spontaneous Ventilation During Fiberoptic Bronchoscopy: A Randomized Controlled Trial.

Objective: Optimizing sedation to minimize respiratory depression during fiberoptic bronchoscopy (FOB) presents an ongoing challenge. This trial compared the safety and efficacy of remimazolam-remifentanil versus propofol-remifentanil for maintaining spontaneous ventilation in patients undergoing FOB.

Methods: This pre-registered randomized controlled trial enrolled 103 consecutive candidates for FOB (April 2023 to April 2024). After excluding 10 ineligible participants, 93 were enrolled in a two-phase study. In the initial dose-determination phase, 21 participants underwent dose escalation to establish the induction dose of remimazolam (0.35 mg/kg) using the modified Dixon's method. Subsequently, 72 participants were randomly assigned in a 1:1 ratio to remimazolam-remifentanil group (Group R-R) or propofol-remifentanil group (Group P-R) (n = 36 each). Remifentanil was administered by target-controlled infusion (3.0 ng/mL plasma concentration) in both groups. Group R-R received remimazolam 0.35 mg/kg, while Group P-R received propofol 2.0 mg/kg after remifentanil loading. Standardized supplemental doses were administered for inadequate sedation (Modified Observer's Assessment of Alertness/Sedation score >1 or Bispectral index >75). The primary endpoint was the incidence of respiratory depression, defined as SpO₂ <95% or a respiratory rate <8 breaths/min. Secondary outcomes included procedure completion, movement or cough-related interruptions, hemodynamic stability, adverse events, procedural time, and satisfaction ratings from both bronchoscopists and participants.

Results: Group R-R demonstrated a significantly lower incidence of respiratory depression (11.1% vs. 33.3%; P = 0.045) and of hypotension requiring vasopressors (16.7% vs. 41.7%; P = 0.020). However, transient involuntary movements (25.0% vs. 8.3%; P = 0.111) and cough (38.9% vs. 22.2%; P = 0.125) were numerically more frequent in Group R-R, though not statistically significant. All procedures were completed successfully without discontinuation. Hypertension, arrhythmias, procedural times, and satisfaction scores were comparable between groups (all P > 0.05).

Conclusions: Compared to propofol-remifentanil, remimazolam-remifentanil provides effective moderate sedation for FOB with superior respiratory safety and reduced hypotension requiring vasopressors, despite a numerically higher incidence of transient movement and cough. It thus represents a promising alternative for maintaining spontaneous ventilation during FOB.