The ED50 and ED95 of remifentanil for suppressing intubation-related hemodynamic responses during remimazolam-based induction in elderly patients were 0.85 and 0.97 µg/kg, respectively.
The ED50 of remifentanil combined with remimazolam (0.3 mg/kg) for suppressing intubation-induced stress responses in elderly patients was 0.85 µg/kg.
The ED95 of remifentanil combined with remimazolam (0.3 mg/kg) for suppressing intubation-induced stress responses in elderly patients was 0.97 µg/kg.
Positive hemodynamic responders showed elevated blood pressure at 30 seconds to 1 minute post-intubation compared to non-responders.
The incidence of hypotension following the remimazolam-remifentanil induction regimen was low in elderly patients.
Transient BIS elevations occurred in over half of patients during intubation, but no intraoperative awareness was reported.
This research suggests that when elderly patients (aged 60 and older) receive a combination of two anesthetic drugs — remimazolam (a sedative) and remifentanil (a short-acting opioid painkiller) — a relatively modest dose of remifentanil is sufficient to prevent dangerous spikes in blood pressure and heart rate that can occur when a breathing tube is inserted during surgery. Specifically, the study found that approximately 0.85 µg/kg of remifentanil was enough to suppress these stress responses in half of patients, and about 0.97 µg/kg was sufficient for 95% of patients, suggesting a narrow effective dose range. Importantly, this dose regimen appeared to be reasonably safe in this vulnerable population: rates of low blood pressure (hypotension) were relatively low at 14–20%, and while more than half of patients showed brief increases in brain activity monitoring readings during tube insertion, none experienced awareness during their procedure. The differences between patients whose blood pressure responded to intubation and those who did not were mainly seen in blood pressure readings in the first minute after tube insertion, while measures of heart pumping function and blood vessel resistance were similar between groups. This research matters because elderly patients are at higher risk from both the stress of intubation and from anesthetic side effects like low blood pressure. Finding the right dose of remifentanil to use alongside remimazolam could help anesthesiologists better balance keeping elderly patients hemodynamically stable during this critical period of surgery, though the authors note this was an exploratory study with a small sample size and further research is needed to confirm these findings.
Ma Y, Huang J, Zhou H, Zhou J, Zheng Q, Xu Z, et al.. (2026). The Effective Dose of Remifentanil Combined with Remimazolam in Inhibiting Tracheal Intubation Responses in Elderly Patients: An Up-Down Dose-Finding Study.. Clinical interventions in aging. https://doi.org/10.2147/CIA.S608528