Mechanism of Cardiac and Cerebral Function Injury Caused by Intraoperative Limb Ischemia-reperfusion

Study Overview
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Brief Summary
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As a simple auxiliary tool for lower extremity orthopedic surgery, tourniquet can effectively reduce intraoperative bleeding and ensure the clarity of the operative field, effectively shorten the operation time and improve the operation efficiency. The extensive use of tourniquets in lower extremity surgery will not only cause local paralysis, pain and other complications, but also bring about postoperative complications such as large drainage volume and deep vein thrombosis. Recent studies have found that tourniquet induced ischemia-reperfusion injury not only affects the local tissue structure and function of skeletal muscle, but also causes reperfusion injury in distant organs (such as heart, lung and brain). Therefore, improving tourniquet ischemia-reperfusion injury after knee replacement is of great significance to improve the quality of life of patients during the perioperative period. Therefore, the aim of this study was to investigate the effects of dexmedetomidine and tourniquet pretreatment on myocardial injury and brain injury caused by lower extremity ischemia-reperfusion.

Official Title
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Mechanism of Cardiac and Cerebral Function Injury in Patients With Coronary Heart Disease Caused by Intraoperative Limb Ischemia-reperfusion and Perioperative Organ Function Protection Strategy

Conditions
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Ischemic Reperfusion Injury

Intervention / Treatment
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* Drug: Dexmedetomidine
* Drug: 0.9% Sodium chloride
* Device: Tourniquet(Early)
* Device: Tourniquet(Late)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients undergoing TKA under general anesthesia Voluntarily sign the informed consent ASA Grade I to III BMI 18-28 kg/m2 Exclusion Criteria: Congenital heart disease or history of cardiac surgery, heart conduction disease, frequent ventricular/atrial premature beats, atrial fibrillation and other serious arrhythmias Severe liver disease and kidney disease Temporary and permanent pacemaker implantation Patients with serious central nervous system diseases or serious mental disorders Recent history of sedation, antidepressant or opioid use Body mass index >35kg/m2 Participants in other clinical trials within 1 month prior to study enrollment.

Ages Eligible for Study
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Minimum Age: 60 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: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Sham Comparator: C group<br>Before induction of anesthesia, general anesthesia was performed after ultrasound-guided femoral nerve block | Drug: 0.9% Sodium chloride<br>* Whether apply DEX or not<br>* Other names: NS;|
| Experimental: DEX group<br>Before induction of anesthesia, general anesthesia was performed after ultrasound-guided femoral nerve block. Dexmedetomidine 0.8μg/kg was pumped intravenously for 10min 15min before induction of anesthesia, and then continued to be infused at 0.5μg/ (kg·h) until 30min before the end of surgery | Drug: Dexmedetomidine<br>* Whether apply DEX or not<br>* Other names: DEX;|
| Experimental: ERIPC group<br>Before induction of anesthesia, ultrasound-guided femoral nerve block was performed, and then general anesthesia was performed. After induction of anesthesia, orthopedic tourniquet was tied and inflated to 200 mmHg(1 mmHg=0.133 kPa) for 5 min and deflated for 5 min, and three cycles were repeated | Device: Tourniquet(Early)<br>* Timing of tourniquet application<br>|
| Experimental: LRIPC group<br>An orthopedic pressure tourniquet was placed on the lower extremity 24 h before surgery and inflated to 200 mmHg for 5 min and deflated for 5 min. Three cycles were repeated | Device: Tourniquet(Late)<br>* Timing of tourniquet application<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| SOD | Superoxide dismutase | Baseline to day2 | 
| MDA | Malonaldehyde | Baseline to day2 | 
| IL-6 | Interleukin- 6 | Baseline to day2 | 
| TNF-α | Tumor necrosis factor-α | Baseline to day2 | 
| hs-Tn | High sensitive troponin | Baseline to day2 | 
| BDNF | Brain-derived neurotrophic factor | Baseline to day2 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| HRV | HeartRateVariability | Baseline to day2 | 
| PRR | Pulse Repetition Rate | Baseline to day2 | 
| BP | Blood Pressure（both systolic and diastolic blood pressure will be measured） | Baseline to day2 | 
| SpO2 | Peripheral capillary oxygen saturation | Baseline to day2 | 
| VAS | Visual Analogue Scale/Score(Draw a 10cm horizontal line on the paper. One end of the horizontal line is 0, indicating no pain; the other end is 10, indicating severe pain; the middle part indicates pain. Different degrees of pain. Let the patient draw a mark on the horizontal line according to his own feelings to indicate the degree of pain.) | Baseline to day2 | 
| MMSE | Mini-mental State Examination（The scale includes the following seven aspects: time orientation, place orientation, instant recall, attention and computational power, delayed memory, language, and whether to answer correctly or not. The test scores are closely related to the educational level. The normal threshold is more than 20 points, and the junior high school and above are more than 24 points） | Baseline to day2 |