The effects of single-dose tramadol on post-operative pain and morphine requirements after coronary artery bypass surgery

Aim: To investigate the effects of a single dose of tramadol administered prior to extubation on post-operative pain and morphine consumption after coronary artery bypass surgery. Methods: Patients were randomized post-operatively into two groups (group T, n=30; group P, n=30). The technique of anaesthesia was standardized for all patients. The patients in group T received intravenous tramadol, 1 mg/kg, and the patients in group P received 2 ml of saline 0.9%, both approximately 1 h before extubation. After extubation, all patients were allowed to use the morphine patient-controlled analgesia (PCA) device for 24 h post-operatively. 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 anaesthesiologist, who had no knowledge of the groups, and the side-effects were also evaluated. Results: In group P, the visual analogue scale (VAS) scores were found to be higher 30 min (P < 0.01), 1 h (P < 0.01), 2 h (P < 0.01) and 4 h (P < 0.05) after extubation. The patient comfort scores were higher in group T 30 min (P < 0.01), 1 h (P < 0.05), 2 h (P < 0.01) and 4 h (P < 0.01) after extubation. The total morphine consumption was higher in group P at all evaluation times (P < 0.01), and the numbers of PCA demands and boluses were also higher in group P (P < 0.01). Conclusions: The study demonstrated that a single dose of tramadol administered prior to extubation following coronary artery bypass surgery is associated with a decrease of up to 25% in morphine consumption, a decrease in the VAS scores and an improvement in patient comfort within the first 4 h post-operatively.