Dexmedetomidinine in the Prevention of Postoperative Delirium in the Intensive Care Unit After Cardiac Surgery

Inclusion Criteria: * patients undergoing open heart surgery with the use of cardiopulmonary bypass (including coronary artery bypass grafting, valve repair/replacement, and combined) * left ventricular ejection fraction (LVEF) \>40%. Exclusion Criteria: * preoperative atrial fibrillation * previous history of interventionally treated arrhythmias * second and third degree atrioventricular block * bradycardia with heart rate ≤50/min * pacemaker * renal or hepatic insufficiency * emergency procedures * history of serious mental illness, delirium, and severe dementia