Evaluation of the Effect of intravenous paracetamol on perioperative pain in coronary artery bypass graft surgery

INTERVENTION: In paracetamol group 15 minutes before induction of anesthesia 1 g intravenous paracetamol in 50 cc normal saline solution was infused to the patient within 15 minutes. Next dose of paracetamol was 1 g which was infused intravenously over 15 minutes within 6‐4 hours after the first dose, so that the injection time was during the last 20 minutes of surgery. Then subsequent doses of paracetamol, every 6 hours for 3 days was injected in intensive care at a rate of 1 g. In the control group at all stages of paracetamol injection instead of paracetamol equal volume of normal saline was used. CONDITION: Perioperative pain in coronary artery bypass graft surgery PRIMARY OUTCOME: Preemptive administration of paracetamol and continue to be administered in the postoperative treatment with prescription of opioids drugs will improved quality of pain control after coronary artery bypass surgery. SECONDARY OUTCOME: 1‐ the potency is not enough to reduce the need for narcotics and sedatives drugs and eliminate their side effects.; 2‐ no additional liver damages; 3‐ Hemodynamic stability INCLUSION CRITERIA: Inclusion criteria for the study were: undergoing elective surgery CABG, the individual agreement to participate in the study, age 40 to 70 years, not having liver failure (Serum bilirubin greater than 1.8 mg per deciliter and aspartate and alanine aminotransfraz more than 1.5 times of the upper limit of normal), not having renal failure (serum creatinine greater than 2 mg per deciliter), not addictive to opioid drugs and psychotropic substances, and having cardiac ejection fraction greater than 30%.,