Magnesium Sulfate versus Nitroglycerin in Controlled Hypotensive Anesthesia in Middle Ear Surgeries

Background: Controlled hypotension is required for middle ear surgeries to achieve a bloodless operative field and improve its quality, both magnesium sulfate and nitroglycerine used to produce deliberate hypotension.  Aim of the work: This study aimed to compare the efficacy of magnesium sulfate and nitroglycerin in inducing controlled hypotensive anesthesia as a primary outcome and using propranolol if tachycardia occurred as a secondary outcome, in middle ear surgeries. Patients and Methods:The study was carried out on 40 adults’ patients were randomly classified into two equal groups, twenty patients each: Group [M]: Received an intravenous [IV] bolus of magnesium sulfate 30 mg/ kg in 100 ml saline over 10 min followed by infusion of 10 mg/kg/h. Group [N]: Received nitroglycerin IV infusion 0.5-10 mcg/kg/min. Propranolol 1- 2.5 mg IV had been given to both groups if there was tachycardia. Results: Both drugs induced hypotension with statistically significant difference in systolic and mean blood pressure [BP] and there was highly significant increase in heart rate [HR] in nitroglycerin more than magnesium sulfate and high doses of propranolol were administrated in nitroglycerine group. Postoperative pain was significantly increased in nitroglycerin than magnesium sulfate groups which had more analgesic effect. Conclusion: Both drugs induced hypotension. However, magnesium sulfate was better as it provided optimum surgical field, less tachycardia, need less dose of propranolol with less post-operative pain in comparison to nitroglycerin