The effects of perioperative low-dose magnesium sulfate infusion on postoperative pain in lumbar surgery

This paper aimed at evaluating the effect of low-dose perioperative magnesium sulfate (MgSO4) on postoperative pain in lumbar surgery. Sixty adult patients were included in this randomized controlled double-blind study. After intubation, an infusion of MgSO4 (10 mg/kg/h) and isotonic saline 0.9% (10 mg/kg/h) were administered in groups M and C, respectively. Heart rate and mean arterial pressure were recorded before and during surgery. Serum magnesium levels were recorded before and after the surgery. Perioperative remifentanil consumption and extubation time were recorded. In the post anesthesia care room (PACU), Agitation-sedation with Richmond Agitation-Sedation Scale (RASS), the pain was evaluated with Visual Analogue Scale (VAS) and recorded at the baseline, at 5th, 10th, 15th and 30th minutes. Patients were transferred to surgical ward with intravenous patient-controlled analgesia (PCA) for postoperative analgesia and received diclofenac sodium for rescue analgesia if VAS >4. Postoperative VAS scores at 2nd, 4th, 6th and 24th hours, opioid consumption after 4 and 24 hours and rescue analgesic consumption for postoperative 24 h were recorded. In the PACU, RASS scores were statistically lower in group M than in group C (p = 0.001), and VAS scores were statistically lower at all measurement times in group M than in group C. In the surgical ward, VAS Scores were statistically lower in Group M at the 6th and 24th hours than in group C (p = 0.015, p = 0.009, respectively). The need for post-operative rescue analgesic was statistically lower in Group M (p < 0.001). The side effect incidence of both groups was similar. Our findings suggest that perioperative low-dose (10 mg/kg/h) MgSO4 infusion reduces early post-op agitation, VAS scores and the need for analgesics up to 24 hours postoperatively. Low dose MgSO4 infusion can be effectively applied for pain management in patients undergoing lumbar surgery.