Safety Study of Dexmedetomidine in Elderly Under General Anesthesia

Study Overview
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Brief Summary
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The purpose of this study is to find out appropriate dose range of dexmedetomidine to provide the elderly patients satisfactory sedation and analgesia with stable hemodynamics during perioperative period of hip replacement under general anesthesia.

Detailed Description
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All patients will be screened to determine eligibility for study entry, and the patients who meet the eligibility requirements will be informed about the study and potential risks. After giving written informed consent, the patients will be randomized into different doses of dexmedetomidine groups and the comparative groups in a same ratio.

Official Title
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Effects of Dexmedetomidine at Different Doses on Hemodynamics and Recovery Quality in Elderly Patients Undergoing Hip Replacement Surgery Under General Anesthesia

Conditions
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Hip Fractures, Hip Disease

Intervention / Treatment
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* Drug: Dexmedetomidine
* Drug: Normal saline
* Drug: Midazolam


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: age ≥65yr, American Society of Anesthesiologists (ASA) physical status scale grade I-III, ready for HP; body weight between 45 and 75kg, body mass index (BMI) between 18 and 24kg/m2; the health conditions generally well according to medical history, physical examination, and laboratory tests; no signs of difficult intubation; no history of dementia and mental problems; normal cognitive function, ability to understand and comply with study procedures. Exclusion Criteria: Age <65 yr or >90 yr; BMI greater than 24 kg/m2; ASA grade higher than III; Heart failure, severe arrhythmias, severe bradycardia (heart rate less than 40 beats/min), atrioventricular block of degree 2 or above, sick sinus syndrome, systolic blood pressure (SBP) ≥180 or <90 mmHg, diastolic blood pressure (DBP) ≥110 or <60 mmHg; Severe liver or kidney dysfunction, severe infection, and other pathological conditions that interfere with study results. Dementia, cerebrovascular accidents within 3 months, mental illness, epilepsy, and other adverse events that interfere with study results. Patients with the conditions that block communication and preoperative assessment, such as serious hearing or visual impairment; History of chronic analgesic use, long-term psychotropic medication use, alcohol or drug addiction.

Ages Eligible for Study
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Minimum Age: 65 Years
Maximum Age: 90 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: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Group D0.25, Group D0.5, Group D0.75<br>Dexmedetomidine will be administered at different initial loading doses (0.25/0.5/0.75 μg/kg within 15min) following same maintained dosage ( 0.5μg/kg/h) in Group D0.25/D0.5/D0.75. | Drug: Dexmedetomidine<br>* In dexmedetomidine groups, patients will be pumped 0.1ml/kg of dexmedetomidine (contained dexmedetomidine 0.25/0.5/0.75µg/kg in Group D0.25/D0.5/D0.75) for 15min before anesthesia induction, following continuous infusion at the rate of 0.125ml/kg/h until the end of operation.<br>* Other names: Dex;|
| Placebo Comparator: Group NS, Group MD<br>In Group NS, patients will be pumped 0.1ml/kg of normal saline for 15min before anesthesia induction, following continuous infusion at the rate of 0.125ml/kg/h until the end of operation. In Group MD, patients will be administrated with midazolam 0.03mg/kg at the beginning of anesthesia induction. | Drug: Normal saline<br>* normal saline<br>* Other names: physiological saline;Drug: Midazolam<br>* midazolam<br>* Other names: Dormicum;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes of baseline blood pressure | Changes of baseline blood pressure in each group, including systolic blood pressure, diastolic blood pressure and mean arterial pressure | Through the whole perioperative period, an average of 10 hours | 
| Changes of baseline heart rate | Changes of baseline heart rate in each group | Through the whole perioperative period, an average of 10 hours | 
| Numbers of elderly patients with hypotension | Hypotension is defined as systolic blood pressure <90 mmHg or mean arterial pressure below >20% of basal values. | Through the whole perioperative period, an average of 10 hours | 
| Numbers of elderly patients with bradycardia | Bradycardia is defined as heart rate <50 beats/min or below >20% of basal values. | Through the whole perioperative period, an average of 10 hours | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Sedation changes after general anesthesia using Richmond agitation-sedation scale | Sedation changes after general anesthesia using Richmond agitation-sedation scale(-5 to +4, 0 means awake and quiet) in each group | before general anesthesia, up to 2 hours after general anesthesia | 
| Pain changes after general anesthesia using visual analogue scale | Pain changes after general anesthesia using visual analogue scale(0 to 10,higher scores mean a worse outcome) in each group | before general anesthesia, up to 2 hours after general anesthesia | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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General anesthesia, Dexmedetomidine, Elderly, Hemodynamics, Hip replacement