Age-Stratified Median Effective Dose of a Continuous Remimazolam Maintenance Infusion for Moderate Sedation During Spinal Anesthesia: A Prospective Up-and-Down Dose-Finding Study.
- 1Department of Anesthesiology and Pain Medicine, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-Ro 43-Gil, Songpa-Gu, Seoul 05505, Republic of Korea.
- 2Department of Anesthesiology and Pain Medicine, Seoul Medical Center, 156 Sinnae-Ro, Jungnang-Gu, Seoul 02053, Republic of Korea.
Abstract
Background and Objectives: Remimazolam is an ultra-short-acting benzodiazepine suitable for continuous infusion; however, evidence regarding its maintenance infusion rate for moderate sedation during spinal anesthesia across age strata is limited. We aimed to estimate and compare the continuous maintenance median effective dose (ED₅₀) of remimazolam across three prospectively defined age groups. Materials and Methods: In this prospective, single-center dose-finding study (ClinicalTrials.gov NCT05379777), 60 patients undergoing lower-extremity orthopedic surgery under spinal anesthesia were stratified into Group A (<60 years), Group B (60-74 years), and Group C (≥75 years) (n = 20 each). After a loading infusion (1.0 mg/kg/h) to achieve moderate sedation (Modified Observer's Assessment of Alertness/Sedation [mOAA/S] score ≤ 3), maintenance rates were assigned using Dixon's up-and-down method; success was defined as maintaining mOAA/S ≤ 3 until the end of surgery without dose titration. The maintenance ED₅₀ was estimated using centered isotonic regression with 90% confidence intervals (CIs). Safety outcomes were evaluated in all patients. Results: Sedation was maintained at the assigned rate in 13, 13, and 14 patients in Groups A, B, and C, respectively, and all failures were managed by upward titration. The maintenance ED₅₀ was 0.238 (90% CI, 0.152-0.336), 0.233 (90% CI, 0.170-0.301), and 0.178 (90% CI, 0.092-0.245) mg/kg/h in Groups A, B, and C, respectively; the CIs overlapped, and no statistically significant difference was observed. Hypotension requiring vasopressors occurred in 25.0% and respiratory depression requiring airway management in 23.3% of patients, without significant intergroup differences; no patient had peripheral oxygen saturation < 90% or required flumazenil. Conclusions: The maintenance ED₅₀ of remimazolam for moderate sedation during spinal anesthesia was numerically lower in patients aged ≥75 years, without a statistically significant difference among age groups. A conservative initial maintenance rate may be considered in this age group; this hypothesis-generating suggestion requires confirmation in adequately powered studies.
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BibTeX
@article{park2026agestratified,
title = {{Age-Stratified Median Effective Dose of a Continuous Remimazolam Maintenance Infusion for Moderate Sedation During Spinal Anesthesia: A Prospective Up-and-Down Dose-Finding Study.}},
author = {Se-Ung Park and Yeon Ju Kim and Min Chul Yang and Chan-Hye Park and Hyungtae Kim and Ha-Jung Kim and Won Uk Koh},
journal = {Medicina (Kaunas, Lithuania)},
year = {2026},
month = oct,
doi = {10.3390/medicina62101937},
url = {https://europepmc.org/article/MED/42942468},
note = {CC BY},
}
RIS
TY - JOUR
TI - Age-Stratified Median Effective Dose of a Continuous Remimazolam Maintenance Infusion for Moderate Sedation During Spinal Anesthesia: A Prospective Up-and-Down Dose-Finding Study.
AU - Se-Ung Park
AU - Yeon Ju Kim
AU - Min Chul Yang
AU - Chan-Hye Park
AU - Hyungtae Kim
AU - Ha-Jung Kim
AU - Won Uk Koh
PY - 2026
DA - 2026/10/08
JO - Medicina (Kaunas, Lithuania)
DO - 10.3390/medicina62101937
UR - https://europepmc.org/article/MED/42942468
AB - Background and Objectives: Remimazolam is an ultra-short-acting benzodiazepine suitable for continuous infusion; however, evidence regarding its maintenance infusion rate for moderate sedation during spinal anesthesia across age strata is limited. We aimed to estimate and compare the continuous maintenance median effective dose (ED₅₀) of remimazolam across three prospectively defined age groups. Materials and Methods: In this prospective, single-center dose-finding study (ClinicalTrials.gov NCT05379777), 60 patients undergoing lower-extremity orthopedic surgery under spinal anesthesia were stratified into Group A (<60 years), Group B (60-74 years), and Group C (≥75 years) (n = 20 each). After a loading infusion (1.0 mg/kg/h) to achieve moderate sedation (Modified Observer's Assessment of Alertness/Sedation [mOAA/S] score ≤ 3), maintenance rates were assigned using Dixon's up-and-down method; success was defined as maintaining mOAA/S ≤ 3 until the end of surgery without dose titration. The maintenance ED₅₀ was estimated using centered isotonic regression with 90% confidence intervals (CIs). Safety outcomes were evaluated in all patients. Results: Sedation was maintained at the assigned rate in 13, 13, and 14 patients in Groups A, B, and C, respectively, and all failures were managed by upward titration. The maintenance ED₅₀ was 0.238 (90% CI, 0.152-0.336), 0.233 (90% CI, 0.170-0.301), and 0.178 (90% CI, 0.092-0.245) mg/kg/h in Groups A, B, and C, respectively; the CIs overlapped, and no statistically significant difference was observed. Hypotension requiring vasopressors occurred in 25.0% and respiratory depression requiring airway management in 23.3% of patients, without significant intergroup differences; no patient had peripheral oxygen saturation < 90% or required flumazenil. Conclusions: The maintenance ED₅₀ of remimazolam for moderate sedation during spinal anesthesia was numerically lower in patients aged ≥75 years, without a statistically significant difference among age groups. A conservative initial maintenance rate may be considered in this age group; this hypothesis-generating suggestion requires confirmation in adequately powered studies.
SN - 1010-660X
SN - 1648-9144
ER -