Effect Of Two Doses Of Magnesium Sulfate On Hemodynamic Stability During Induction And Orotracheal Intubation In Adult Diabetic Patients

Patients and Methods: After approval of the ethical committee in Beni Suef University (Egypt), a written informed consent will be obtained from 50 ASA II males and females patients aged 40-65 years old, with controlled type II diabetes mellitus planned for elective surgery under general anesthesia requiring orotracheal intubation. Patients will be excluded from the study if they had history of type I diabetes mellitus, hypertension, cardiac disease, hypomagnesemia or hypermagenesmia , a known allergy to the study drugs, neuromuscular, liver and renal diseases ,suspected or history of difficult intubation, prolonged intubation longer than 30 secs or more than one attempt required, BMI >30 . Patients undergoing cardiac and neurosurgical procedures will be also excluded. All patients will be prepared preoperatively by taking history, examination, routine investigations. On arrival to the operating theatre, 18 G intravenous cannula will be inserted and IV crystalloid fluids will be infused ,the monitor will be attached to the patients to take preoperative readings of heart rate, non-invasive arterial blood pressure,SpO2 The patients will be randomly divided using closed envelope technique for randomization to one of two groups: M 30 group ( n = 25): will receive magnesium sulfate 30 mg/kg added to 100 ml of normal saline over 15 minutes before induction of general anesthesia M 50 ( n =25): will receive magnesium sulfate 50 mg/kg added to 100 ml of normal saline over 15 minutes before induction of general anesthesia General anesthesia will be induced after preoxygenation for 3- 5 minute with 100% oxygen by facemask, then induction of anesthesia in all patients will be with the use of i.v. propofol 2 mg/ kg slowly, fentanyl 2 micogram/ kg, atracurium (0.5mg/kg) and will be ventilated manually with sevoflorane 2 volume % ,oxygen 100% via a face mask then oral cuffed endotracheal tube will be inserted by expert anesthesiologist. Hypotension (systolic blood pressure less than 90 mmHg) will be treated with volume replacement and ephedrine as indicated. Persistent hypertension (systolic blood pressure more than 160 mmHg lasting more than one minute) will be treated with IV nitroglycerin. Tachycardia (heart rate more than 120 beats/min) will be treated with IV boluses of esmolol. Bradycardia (heart rate less than 50 beats/minute) will be treated with 0.5 mg atropine IV. At the end of surgery, neuromuscular blockade will be reversed with IV neostigmine 0.04mg/kg and atropine 0.02 mg/kg, the trachea will be extubated when the patient respond to commands, all patients will be transferred to PACU, where they receive oxygen via face mask 3-4 L/min and will be monitored. The following parameters will be evaluated and recorded by senior anesthesiologist unaware of the study protocol: 1. Demographic data: age, sex, weight, height. 2. The systolic , diastolic , mean arterial blood pressure and heart rate will be measured and recorded:a- Before the administration of the study drug at baseline b-after induction of anesthesia c –at 1,5,10 minutes following tracheal intubation and before skin incision.