بررسی تاثیر سولفات منیزیوم در بی‌دردی پس از جراحی ترمیم فتق اینگوینال

Background: Magnesium Sulfate (MgSO4) has been used as a pharmacologic agent in different situations for many years in the treatment of tachyarrhythmias, myocardial ischemia, preeclampsia, and tocolysis among others. The analgesic effect of MgSO4 for postoperative pain has been used since the 1990s. Postoperative pain is one of the most common complications in the perioperative period and can result in serious consequences in different organs if left untreated. Inguinal herniorrhaphy is among the most common surgeries and is almost always accompanied by severe pain. The object of this study is to determine the effect of a pre-induction infusion of MgSO4 on the reduction of postsurgical pain after herniorrhaphy. Methods: This double-blind, randomized clinical trial included 105 ASA class I and class II herniorrhaphy patients at Shariati Hospital in years 2004 and 2005. For statistical analysis, the 2 and T tests were used. The patients were divided into three groups based on block randomization. Patients in the following groups received: Group A, 200 ml of normal saline infusion (placebo) Group B, 25 mg/kg MgSO4 in 200 ml of normal saline Group C, 50 mg/kg MgSO4 in 200 ml of normal saline. All groups were infused twenty minutes before induction of anesthesia using identical methods and dosage in all three groups. Heart rate and mean arterial pressure (MAP) at pre- and postintubation and so at skin incision time were charted. Visual analog scale (VAS) pain score, nausea, vomiting and the amount of morphine used before recovery room discharge and in six, twelve and twenty-four hours after recovery discharge was recorded.Results: The average age for the different groups was as follows: Group A: 33.6, Group B: 37.37, Group C: 32.74. Nausea and vomiting between the case and control groups were not statistically different (60% vs. 71.4%, p=0.0499), nor was the amount of Morphine used. On recovery room discharge, the VAS scores were 8.1, 7.2, and 5.5 for the first, second and third groups, respectively (P<0.001). However, no statistical significance was found for the VAS scores six hours after recovery room discharge. Conclusion: The results in this study show that pre-induction with MgSO4 has no remarkable effect on decreasing postoperative pain or morphine use for inguinal herniorrhaphy.