Median Effective Dose of Remimazolam for Sedation in Elderly Patients

Study Overview
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Brief Summary
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Currently used drugs for monitored general anesthesia include propofol, midazolam, and dexmedetomidine. Each drug has different advantages and disadvantages. Remimazolam causes a relatively small decrease in blood pressure, and it has no injection pain. In addition, remimazolam has a very short onset time, and even after the continuous infusion, the onset of remimazolam is fast, and even after continuous injection, the effect disappeared very quickly due to the short context-sensitive half time. And through continuous infusion, the patient's depth of anesthesia can be maintained constant. In addition, the short duration of action and the ability to quickly reverse the effect of flumazenil suggest that remimazolam can be used effectively under general anesthesia as well as under general anesthesia. Remimazolam can be used as a continuous infusion for general anesthesia. However, it has also been reported to be used for sedation by continuous infusion or divided intravenous infusion. However, the effective maintenance dose of remimazolam for sedation without mechanical ventilation has not been established. In addition, age might be an important factor for determining the appropriate dose of remimazolam. In this study, we aim to identify the median effective dose of remimazolam for maintaining sedation in elderly patients undergoing lower limb surgery under spinal anesthesia.

Official Title
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Median Effective Dose of Remimazolam for Sedation in Elderly Patients Undergoing Lower Limb Surgery Under Spinal Anesthesia

Conditions
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Sedative

Intervention / Treatment
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* Drug: Remimazolam


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: age: equal or older than 20 years ASA PS: 1-3 patients who are scheduled to undergo lower limb surgery under spinal anesthesia with sedation using remimazolam Exclusion Criteria: Patients who refuse to participate in this study Patients with hypersensitivity to benzodiazepine or flumazenil Patients with severe renal/hepatic disease Patients with drug/alcohol abuse Patients who take antidepressants, anticonvulsants, psychoactive drugs chronically Patients with difficulty in communication Patients with severe obstructive sleep apnea or other airway problems Patients contraindicated to regional anesthesia Patients judged to be inappropriate for this study

Ages Eligible for Study
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Minimum Age: 20 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Supportive Care
Allocation: Non-Randomized
Intervention Model: Single Group Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: young-old group<br>a group of patients who are 60 to 74 years old | Drug: Remimazolam<br>* A loading dose of remimazolam is 1mg/kg/hr. When sedation is achieved, the dose of remimazolam is adjusted to the assigned dose. The maintenance dose of remimazolam begins at 1.0mg/kg/hr. When the maintenance is not successful during the surgery, the maintenance dose will be increased by 0.1-0.2mg/kg/hr in the next patient. When the maintenance is successful, the dose will be decreased by 0.1-0.2mg/kg/hr. (maximal dose: 2mg/kg/hr)<br>|
| Active Comparator: old-old group<br>a group of patients who are equal or older than 75 years | Drug: Remimazolam<br>* A loading dose of remimazolam is 1mg/kg/hr. When sedation is achieved, the dose of remimazolam is adjusted to the assigned dose. The maintenance dose of remimazolam begins at 1.0mg/kg/hr. When the maintenance is not successful during the surgery, the maintenance dose will be increased by 0.1-0.2mg/kg/hr in the next patient. When the maintenance is successful, the dose will be decreased by 0.1-0.2mg/kg/hr. (maximal dose: 2mg/kg/hr)<br>|
| Active Comparator: young adult group<br>a group of patients who are 20-59 years old | Drug: Remimazolam<br>* A loading dose of remimazolam is 1mg/kg/hr. When sedation is achieved, the dose of remimazolam is adjusted to the assigned dose. The maintenance dose of remimazolam begins at 1.0mg/kg/hr. When the maintenance is not successful during the surgery, the maintenance dose will be increased by 0.1-0.2mg/kg/hr in the next patient. When the maintenance is successful, the dose will be decreased by 0.1-0.2mg/kg/hr. (maximal dose: 2mg/kg/hr)<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| success or failure of sedation maintenance | MOAA/S score of 3 or less (MOAA/S: Modified Observer's Alertness/Sedation scale) Awake (5) - Unresponsive (0) | throughout the surgery | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| respiratory depression | respiratory rate equal or less than 6 time per minute | throughout the surgery |