“…However, most patients undergoing CABG, experience different levels of pain, usually caused by many sources including sternotomy or leg incisions, tissue retraction and dissection during surgery and chest tube insertion after the surgery ( 8 - 11 ). Besides, the nature of CABG surgery requires admission and hospitalization of patients in Intensive Care Unit (ICU), which due to inability of patients in this ward to report pain due to mechanical ventilation, concomitant use of sedatives, or as a consequence of loss of consciousness, pain control may be precluded frequently ( 12 , 13 ). Postoperative pain in these patients affects not only patients’ operative outcomes, well-being and satisfaction from medical care, but also development of tachycardia, hyperventilation, hypoxemia, insomnia, agitation, myocardial ischemia and delirium, which lead to poor wound healing and increased mortality and morbidity rates, which in turn may impact the operative outcomes ( 8 , 13 , 14 ).…”