Evaluation the effect of intraoperative administration of magnesium sulfate on post operative pain of patient undergoing general anesthesia for inguinal hernioraphy

Objective: comparison of postoperative pain score in administration of magnesium sulfate with normal saline in patients undergoing general anesthesia for inguinal hernioraphy Design: Double blind clinical trial Setting: Patients were divided into two groups randomly: A(Magnesium sulphate) and B(Isotonic saline). Anesthesia was induced in both groups equally using Fentanyl 2 microgramms per kilogram, Midazolam 0.03 milligramms per kilogram, Sodium thiopental 5 milligramms per kilogram and Atracorium 0.5 milligramms per kilogram and was maintained with Propofol infusion (50 to 150 microgram per kilogram per minute). Morphine 0.1 milligramms per kilogram was administered in both groups half hour before the end of surgery. Inclusion criteria: patients with ASA 1 or 2 ; the patients without history of drug abuse ; without sensitivity to magnesium , opioids and analgesics ; any hepatic, renal, cardiovascular, neuromascular or neurological disorder ; not to use calcium channel blockers Exclusion criteria: patients with preoperative hemodynamic instability ; preoperative respiratory distress ; preoperative nausea and vomiting or any important adverse effects; patients with magnesium infusion time less than one hour and more than 3 hours. Intervention: Group A (Magnesium) received magnesium sulphate 40 miligram per kilogram and then 15 miligram per kilogram per hour infusion during the operation until the 20 min after the end of surgery and B (Isotonic saline) received the same volume of isotonic saline over the same period. Main outcomes: Pain score by VAS and Mepiridine consumption at 30 min, 2, 4, 6, 12 and 24 hours after discontinue the infusion, any adverse effects were evaluated.

Vice Chancellor for research of Ahvaz Jondishapour University of Medical Science