The Addition of a Tramadol Infusion to Morphine Patient-Controlled Analgesia after Coronary Artery Bypass Graft

Background: Patient-controlled analgesia (PCA) has been advocated as superior to conventional controlled analgesia with less risk to patients in cardiac surgery. In this double-blinded, randomized controlled trial, we tested whether the addition of Tramadol to morphine for patient-controlled analgesia (PCA) resulted in improved analgesia efficacy and smaller morphine requirements compared with morphine PCA alone after Coronary Artery Bypass Graft (CABG) surgery in adults. Methods: Seventy patients who were randomly allocated into two groups underwent anesthesia by Total IV anesthesia, midazolam, fentanyl and atracurim and, in end of surgery each group received morphine sulfat 0.2 mg/kg after arrived in ICU, morphin PCA was started with demand (bolus) dose 1mg, lockout interval 10 minutes. The Tramadol group after separated from cardiopulmonary bypass received an intra operative initial loading dose of Tramadol (1mg/kg) and a postoperative infusion of Tramadol at 0.2 mg• kg-1• h-1. The control group received an intra operative equivalent volume of normal saline and a postoperative saline infusion (placebo). The demographic data of both groups were the same. Post-operative data were recorded in the cardiac intensive care unit at 30 min, 1 h, 2 h, 4 h, 12 h and 24 h after extubation by the same anesthesiologist, who had no knowledge of the groups, and the side-effects were also evaluated. Results: Postoperatively, Tramadol was associated with improved subjective analgesic efficacy (P = 0.031) and there was significantly less PCA morphine use in the Tramadol group (P = 0.023). No differences between the groups were found with regard to nausea dizziness, itching, antiemetic use, sedation, or quality of recovery (all P > 0.05). Conclusions:We conclude that a Tramadol infusion combined with PCA morphine improves analgesia and reduces morphine requirements after cardiac surgery compared with morphine PCA alone.