Effects of Different Doses of Dexmedetomidine on Postoperative Cognitive Dysfunction in Elderly Hypertensive Patients

Study Overview
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Brief Summary
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The purpose of this study is to identify the effects of different doses of dexmedetomidine on postoperative cognitive dysfunction in elderly hypertensive patients

Official Title
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Effects of Different Doses of Dexmedetomidine on Postoperative Cognitive Dysfunction in Elderly Hypertensive Patients-A Single Center,Randomized, Double-blinded,Controlled Study

Conditions
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Postoperative Cognitive Dysfunction

Intervention / Treatment
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* Drug: dexmedetomidine
* Drug: dexmedetomidine
* Drug: normal saline
* Drug: midazolam,fentanyl,etomidate,Cisatracurium besylate
* Drug: cisatracurium besylate,propofol,remifentanil,sevoflurane


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Written informed consent Elective gastrointestinal surgery American Society of Anesthesiologists class II to III Aged between 65 and 80 years old Weight between 45 and 75 kilogram,Body Mass Index between 19 and 24 kg.m-2 With primary hypertension reaching or more than 1 year Normal cognitive function,mini-mental state examination more than 27 Exclusion Criteria: Severe arrhythmia,atrioventricular block and secondary hypertension Liver and kidney dysfunction,pulmonary disease,endocrine disease Suspected or confirmed difficult airway Any disease or pathologic change will interfere study result Inability to exchange with serious visual and hearing impairment Long term use of sedative-hypnotic drugs and antidepressant drug Addicted to alcohol, tobacco or drug Neuromuscular disease Suspected of malignant hyperthermia Allergic to investigational products or with other contraindication Participated in other study within 30 days

Ages Eligible for Study
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Minimum Age: 65 Years
Maximum Age: 80 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: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Group A, dexmedetomidine , 0.3µg.kg-1.h-1<br>Continuous pump infusion dexmedetomidine with loading dose at 0.8µg.kg-1 over 10 minutes,followed Continuous pump infusion dexmedetomidine at 0.3µg.kg-1.h-1 until 30 minutes before end of operation | Drug: dexmedetomidine<br>* Experimental: Group A, Continuous pump infusion dexmedetomidine with loading dose at 0.8µg.kg-1 over 10 minutes,followed continuous pump infusion dexmedetomidine at 0.3µg.kg-1.h-1 until 30 minutes before end of operation<br>Drug: midazolam,fentanyl,etomidate,Cisatracurium besylate<br>* Anesthesia induction : 0.05 mg.kg-1 midazolam,4 5μg.kg-1 fentanyl,1.0 1.5mg.kg-1etomidate and 0.15 mg.kg-1Cisatracurium besylate<br>Drug: cisatracurium besylate,propofol,remifentanil,sevoflurane<br>* Maintenance of anesthesia :Continuous pump infusion 0.05 0.1mg.kg-1.h-1cisatracurium besylate,4 8mg.kg-1.h-1propofol,0.1 0.2μg.kg-1.min-1 remifentanil and sevoflurane inhalation with 0.6% 1.0%<br>|
| Experimental: Group B,dexmedetomidine , 0.5µg.kg-1.h-1<br>Continuous pump infusion dexmedetomidine with loading dose at 0.8µg.kg-1 over 10 minutes,followed continuous pump infusion dexmedetomidine at 0.5µg.kg-1.h-1 until 30 minutes before end of operation | Drug: dexmedetomidine<br>* Group B, Continuous pump infusion dexmedetomidine with loading dose at 0.8µg.kg-1 over 10 minutes,followed continuous pump infusion dexmedetomidine at 0.5µg.kg-1.h-1 until 30 minutes before end of operation<br>Drug: midazolam,fentanyl,etomidate,Cisatracurium besylate<br>* Anesthesia induction : 0.05 mg.kg-1 midazolam,4 5μg.kg-1 fentanyl,1.0 1.5mg.kg-1etomidate and 0.15 mg.kg-1Cisatracurium besylate<br>Drug: cisatracurium besylate,propofol,remifentanil,sevoflurane<br>* Maintenance of anesthesia :Continuous pump infusion 0.05 0.1mg.kg-1.h-1cisatracurium besylate,4 8mg.kg-1.h-1propofol,0.1 0.2μg.kg-1.min-1 remifentanil and sevoflurane inhalation with 0.6% 1.0%<br>|
| Placebo Comparator: Group C ,normal saline<br>Normal saline infusion will be given with the same infusion volume as group A and B | Drug: normal saline<br>* Group C , Normal saline infusion will be given with the same infusion volume as group A and B<br>Drug: midazolam,fentanyl,etomidate,Cisatracurium besylate<br>* Anesthesia induction : 0.05 mg.kg-1 midazolam,4 5μg.kg-1 fentanyl,1.0 1.5mg.kg-1etomidate and 0.15 mg.kg-1Cisatracurium besylate<br>Drug: cisatracurium besylate,propofol,remifentanil,sevoflurane<br>* Maintenance of anesthesia :Continuous pump infusion 0.05 0.1mg.kg-1.h-1cisatracurium besylate,4 8mg.kg-1.h-1propofol,0.1 0.2μg.kg-1.min-1 remifentanil and sevoflurane inhalation with 0.6% 1.0%<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change from baseline to postoperation in cognitive function | Mini-mental State Examination | One day before operation,third day after operation,sixth day after operaion | 
| Change from baseline to postoperation in recent memory | Rey Auditory Verbal Learning Test | One day before operation,third day after operation,sixth day after operation | 
| Change from baseline to postoperation in visual space and directional force | Trail Making Test A,Trail Making Test B | One day before operation,third day after operation,sixth day after operaion | 
| Change from baseline to postoperation in attention | Digit Span Test | One day before operation,third day after operation,sixth day after operaion | 
| Change from baseline to postoperation in pain scores | Visual analog scales | One day before operation,third day after operation,sixth day after operation | 
| Change from baseline to postoperation in depression scale | Beck Depression Inventory | One day before operation,third day after operation,sixth day after operation | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The duration of operation |  | From begining of cutting skin to the end of skin closure,an expected average of 3 hours | 
| The blood volume during the operation |  | From begining of cutting skin to the end of skin closure,an expected average of 3 hours | 
| The urine volume during operation |  | From begining of cutting skin to the end of skin closure,an expected average of 3 hours | 
| The dose of drugs used during operation | The dose of ephedrine, urapidil, atropine used during operation | From begining of cutting skin to the end of skin closure,an expected average of 3 hours | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Dexmedetomidine,postoperative cognitive dysfunction