This study aimed to determine the median effective dose (ED50) of remimazolam for loss of consciousness (LOC) in elderly and frail elderly patients using the Dixon up-and-down method, while utilizing a novel Respiratory Volume Monitor (RVM) to detect subclinical respiratory depression.
The physiological decline associated with frailty in elderly patients presents significant challenges for anesthesia induction. Remimazolam tosilate, an ultra-short-acting benzodiazepine, offers a promising safety profile, yet its optimal dosing in frail populations remains undefined. This prospective, up-and-down sequential allocation trial was conducted at the Second Hospital of Hebei Medical University. 58 patients aged ≥65 years undergoing elective surgery were stratified into two groups: an Elderly Group (Clinical Frailty Scale \[CFS\] \< 5) and a Frail Elderly Group (CFS ≥ 5). The initial remimazolam induction dose was set at 0.15 mg/kg for the elderly group and 0.13 mg/kg for the frail group, with dose adjustments based on the previous patient's response. A non-invasive RVM was employed to continuously monitor Tidal Volume (VT) and detect early hypoventilation.
Study Type
INTERVENTIONAL
Allocation
NON_RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
58
The initial induction dose was set at 0.15 mg/kg administered as a single intravenous bolus over 30 seconds. The dose adjustment gradient for consecutive patients was 0.02 mg/kg based on the Dixon up-and-down method.
The initial induction dose was set at 0.13 mg/kg administered as a single intravenous bolus over 30 seconds. The dose adjustment gradient for consecutive patients was 0.01 mg/kg based on the Dixon up-and-down method.
Second Hospital of Hebei Medical University
Shijiazhuang, Hebei, China
Sedation Success (Loss of Consciousness)
Defined as the achievement of Loss of Consciousness (LOC) confirmed by loss of eyelash reflex, no response to verbal commands, Ramsay Sedation Score ≥ 5, and MOAA/S score \< 1.
Time frame: up to 2 minutes
Median Effective Dose (ED50) of Remimazolam
The ED50 calculated via probit analysis based on the Dixon up-and-down sequential allocation method.
Time frame: Perioperative/Periprocedural
Changes in Tidal Volume (VT)
Continuous assessment of spontaneous Tidal Volume (VT) utilizing a non-invasive Respiratory Volume Monitor (RVM) to evaluate subclinical respiratory depression.
Time frame: Baseline, 30 seconds, 60 seconds, 90 seconds, and up to 120 seconds post-administration
Mean Arterial Pressure (MAP)
Changes in Mean Arterial Pressure (MAP) during the induction period, measured in mmHg.
Time frame: Baseline and up to 2 minutes post-administration
Heart Rate (HR)
Changes in Heart Rate (HR) during the induction period, measured in beats per minute.
Time frame: Baseline and up to 2 minutes post-administration
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