Effects of magnesium sulfate on remifentanil requirements for achieving hemodynamic stability during laparoscopy assisted distal gastrectomy

ABSTRACT

BACKGROUND: Magnesium is known to reduce the requirement of analgesic agents by blocking calcium channels that exist at the neuronal and neuromuscular junctions. However, former studies have shown inconsistent results regarding this concept. Therefore, we investigated the effects of magnesium on remifentanil requirements for achieving hemodynamic stabilization in patients undergoing laparoscopic gastrectomy. METHODS: Laparoscopic gastrectomy patients (n = 30) were randomly divided into two groups. Group M received 50 mg/kg of magnesium sulfate for 15 minutes prior to the induction of anesthesia. Then, 20 mg/kg/h of magnesium was administered during the operation time. Group N was administered the same amount of saline. Anesthesia was maintained with intravenous propofol and remifentanil injection. Vecuronium (0.1 mg/kg) was administered before intubation, and an additional 0.02 mg/kg was administered if a T1 twitch response was observed during surgery. Anesthetic time was standardized to provide an appropriate comparison of all patients. During 100 minutes, total anesthetic requirements and anesthetic requirements at every 10 minutes were analyzed. Postoperative pain was controlled with a patient controlled analgesia device. RESULTS: The remifentanil and vecuronium requirements during 100 minutes were significantly lower in Group M. There was no significant difference in propofol requirements between the two groups. No significant difference was observed in mean arterial pressure and heart rate. Postoperative VAS, PONV, or shivering also did not show any difference between the two groups. CONCLUSIONS: Magnesium reduced remifentanil and vecuronium requirements but not propofol requirements. Magnesium seems to have antinociceptic properties and reduces remifentanil requirements.