Introduction: It has been shown that patients who have undergone noncardiac surgery had decreased postoperative pain and needed less opioid treatment when given magnesium sulphate (MgSO4) [1,2]. We investigated the possible effects of postoperative MgSO4 infusion on pain management following coronary artery bypass graft surgery (CABG).
Method: After approval of the Ethics Committee and informed consent, 50 patients undergoing elective CABG, who were classified as ASA III, and had preoperative EF > 40% were selected. The patients were prospectively randomized to group I (n = 25) as control and to group II (n = 25) given MgSO4 (15 mg kg−1 h−1). Anaesthesia and cardiopulmonary bypass were standardized. Before surgery, detailed information was given to all of the patients about using patient controlled analgesia (PCA). In the intensive care unit, continuous morphine infusion (0.07 mgkg−1 h−1) was started by PCA (Abbott Medical). The apparatus was set up to a dose of 0.005 mg kg−1 h−1 with a 10 minute-locked time. We evaluated pain scores just after and at 2, 6 and 12 hours after extubation by the Visual Analog Scale (VAS). The number of analgesia requests by the patient, granted requests and the amount of total morphine were also recorded at the same time intervals. Student's t-test and two-way ANOVA were used for statistical analysis. All variables were expressed as mean ± sd. P < 0.05 was considered significant.
Results: Results are summarized in the following tables.
The amount of total morphine and frequency of PCA use were less in the magnesium group than the control group. However these differences were not statistically significant.
Discussion: We suggest that magnesium therapy for postoperative analgesia could be a useful option.
1 Tramer MR, Schneider J, Marti RA. Role of magnesium sulfate in postoperative analgesia. Anesthesiology
2 Wilder Smith CH, Knopfli R, et al. Perioperative magnesium infusion and postoperative pain. Acta Anaesthesiol Scand