Comparison of Dexmedetomidine and Remifentanil Infusion During CABG

Study Overview
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Brief Summary
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We are trying to investigate whether intraoperative dexmedetomidine infusion could decrease the incidence of intraoperative hypokalemia and arrhythmia, and myocardial injury in patients undergoing off-pump coronary artery bypass graft, and trying compare these effects with those of remifentanil infusion.

Detailed Description
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Alpha2-adrenergic agonist, dexmedetomidine, is recently used for sedation, analgesia or adjuvant to general anesthesia. Postsynaptic activation of alpha2 adrenoceptors in the central nervous system (CNS) inhibits sympathetic activity and thus can decrease blood pressure and heart rate. The blockade of sympathetic activity decrease the neuroendocrine stress response and may decrease the incidence of hypokalemia. The hypokalemia can increase the incidence of arrythmia, especially in cardiac patients. We postulated that dexmedetomidine could decrease the neuroendocrine stress response, thus decrease arrhythmia during cardiac surgery. Furthermore, dexmedetomidine have been reported to have cardioprotective effect with previous animal studies. Therefore, the aim of the present study is to investigate whether the intraoperative dexmedetomidine infusion can reduce the incidence of hypokalemia and arrythmia, and myocardial injury in subjects undergoing off-pump coronary artery bypass graft. We are also trying to compare these effects with those of remifentanil infusion.

Official Title
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The Comparison of Serum Potassium Concentration, Antiarrhythmic Effect, and Myocardial Protective Effect Between Dexmedetomidine and Remifentanil Infusion in Patients Undergoing Coronary Artery Bypass Surgery

Conditions
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Coronary Artery Bypass Graft, Hypokalemia, Cardiac Arrhythmia, Dexmedetomidine, Remifentanil

Intervention / Treatment
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* Drug: Dexmedetomidine infusion
* Drug: Remifentanil infusion


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Those undergoing off-pump coronary artery bypass graft during March, 2012   February, 2013 in Samsung Medical Center Age between 20 and 70 yrs old Exclusion Criteria: Any patients with plasma aldosterone, or glucocorticoid disorder including primary hyperaldosteronism, renovascular hypertension, rennin-secreting tumor, salt-wasting renal disease, Cushing syndrome Patients with recent exogenous steroid administration or previous diuretics therapy

Ages Eligible for Study
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Minimum Age: 20 Years
Maximum Age: 70 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

Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Dexmedetomidine group<br>Dexmedetomidine infusion 0.2 mcg/kg/hr during anesthetic induction 0.3 - 0.7 mcg/kg/hr during the surgery | Drug: Dexmedetomidine infusion<br>* Dexmedetomidine infusion 0.2 mcg/kg/hr during anesthetic induction 0.3 - 0.7 mcg/kg/hr during the surgery<br>* Other names: Dexmedetomidine;|
| Active Comparator: Remifentanil group<br>Remifentanil infusion 0.05 - 0.3 mcg/kg/min during the anesthetic induction and surgery | Drug: Remifentanil infusion<br>* Remifentanil infusion 0.05 - 0.3 mcg/kg/min during the anesthetic induction and surgery<br>* Other names: Remifentanil;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| serum potassium concentration | serum potassium concentration at the day before anesthetic induction | at 24 hour before anesthetic induction | 
| serum potassium concentration | 1 minutes before anesthetic induction (etomidate injection) | 1 minutes before anesthetic induction | 
| serum potassium concentration | serum potassium concentration 20 minutes after start of anesthetic induction (at the end of anesthetic induction) | 20 minutes after start of anesthetic induction | 
| serum potassium concentration | serum potassium concentration at 2 hour after anesthetic induction (after mammary artery dissection and graft formation) | 2 hour after the start of anesthetic induction | 
| serum potassium concentration | serum potassium concentration at 3 hour after end of anesthetic induction (after the anastomosis of coronary graft) | 3 hour after start of anesthetic induction | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| arterial blood gas analysis results | arterial blood gas analysis results | 24 hour, 1 min before anesthetic induction, 20 min, 2 and 3 hour after the start of anesthetic induction | 
| incidence of hypokalemia | incidence of hypokalemia (serum K < 3.5) incidence of hypokalemia (serum K < 4.5) | 24 hour, 1 min before anesthetic induction, 20 min, 2 and 3 hour after the start of anesthetic induction | 
| hemodynamic parameters | hemodynamic parameters (blood pressure, heart rate, central venous pressure, cardiac output, SvO2) | 24 hour, 1 min before anesthetic induction, 20 min, 2 and 3 hour after the start of anesthetic induction | 
| inotropics, vasopressor requirement | inotropics, vasopressor requirement | 24 hour, 1 min before anesthetic induction, 20 min, 2 and 3 hour after the start of anesthetic induction | 
| Myocardial injury marker | serum concentration of CK-MB, Troponin (i)as a marker for myocaridial injury | 2, 24, 48 hour after the end of surgery | 
| Left ventricular function | left ventricular function determined by Tei index, ejection fraction of preoperative, intraoperative, postoperative echocardiography | 72 hour before, during (immediate after grafting), 72 hour after surgery | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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coronary artery bypass graft, hypokalemia, cardiac arrhythmia, dexmedetomidine, remifentanil