Effect of Prescription of Magnesium Sulfate to have Controlled Hypotension during Septorhinoplasty
Introduction: Controlled hypotension is a technique to decrease intra-operative bleeding. Magnesium sulfate would be a compatible choice for this target.
Aim: This study was conducted to evaluate effect of magnesium sulfate on controlling blood pressure during septorhinoplasty.
Materials and methods: In this double-blind randomized clinical trial study, 60 patients aged 18-50 years with ASA class I and II, underwent septorhinoplasty. They were randomly divided into two groups: magnesium sulfate (M) and control (C). In Group M, diluted magnesium sulfate (50%) (40 mg/kg in 100 ml of normal saline) was infused intravenously in 10 minutes, prior to the induction of general anesthesia then followed by 15 mg/kg/hr administration during surgery. In Group C, same volume of normal saline 0.9% was infused. Anesthesia was conducted through intravenous infusion of propofol (50 μg/kg/min) and remifentanil (0.1 μg/kg/min) for all. The mean arterial pressure was maintained 60-65 mm Hg mm Hg by injection of nitroglycerine (25-50 μg/min), if needed. Data was analyzed considering significant p<0.05.
Results: Most of participants were female (55 persons-91.7%). Mean length of surgery was 72.2 ± 14.8 min. Over 76% of controls (23 patients) needed to nitroglycerin infusion, while to none of magnesium receivers, nitroglycerin was delivered (p=0.001). Although, mean heart rate was different significantly between two groups prior to anesthesia induction (p=0.002), but its changes between two groups were not obvious at any other time of measurements. The incidence of pain feeling also was significantly lower in magnesium receivers in recovery room. There was no significant difference in amount of bleeding and surgeon satisfaction between groups.
Conclusion: Magnesium sulfate seems to be effective in inducing hypotension and accompanied with lower postoperative pain.