Effects of epidural magnesium sulphate on intraoperative sufentanil and postoperative analgesic requirements in thoracic surgery patients

Abstract

Introduction. Thoracic surgery is associated with high levels of pain. Magnesium has antinociceptive effects in animal and human models of pain. Objectives. The aim of this randomized prospective study was to assess the effects of continuous epidural magnesium infusion during thoracic surgery on intraoperative sufentanil consumption and postoperative analgesic requirements during the first 48 hours after surgery. Materials and methods. Seventy patients were randomized into two groups of 35 patients: Group 1 (magnesium group) received an epidural with 10% magnesium sulfate (MgSO4) along with anesthetic drugs (midazolam, propofol, rocuronium, sufentanil, levobupivacain), and group 2 (control group) received an epidural with 0.9% sodium chloride (NaCl) solution along with anesthetic drugs intraoperatively. Postoperatively, group 1 patients were administered the 10% magnesium sulfate epidural in addition to a local anesthetic and opioid, whereas group 2 patients were administered the local anesthetic and opioid alone. Primary outcomes of the study were to determine the cumulative doses of intraoperatively administered sufentanil and cumulative doses of sufentanil and levobupivacaine administered during the first 48 h postoperatively. Secondary outcomes were a visual analog scale (VAS) score for rest and movement every 4 hours, level of sedation, cardiovascular, respiratory and neurological complications, incidence of postoperative shivering, nausea and vomiting and global patient satisfaction. Results. The cumulative sufentanil dose required intraoperatively was significantly lower in the magnesium group: 43.00 μg vs 56.3 μg (p = 0.001). VAS scores measured every 4 hours at rest and movement during the first 48 hours postoperatively, cumulative analgesic consumption, incidence of shivering, nausea and vomiting were significantly lower in the magnesium group. The global satisfaction score was significantly higher in the magnesium group (4.3 vs 3.7; p = 0.005). Conclusion. The addition of magnesium in the epidural mixture of sufentanil and levobupivacaine led to more efficient intraoperative and postoperative analgesia, lower sufentanil and levobupivacaine consumption, lower incidence of postoperative shivering, nausea and vomiting. Epidural with magnesium appears to be a useful adjunct to anesthetic drugs, which can exert positive effects on the course and outcome of thoracic surgery patients.