The study is a double-blinded, experimental and clinical trial. It will be accomplished after inform consent, on 102 cases, between 35-55 years old. All patients have undergone abdominal hysterectomy under general anesthesia. Sampling will be done from January 2014 to January 2015.
Cases with same inclusion criterion, will put in three different groups(1-2-3) with Random-Block method. In this respect, cases will be divided into three groups(1, 2, 3), and a pocket will be allocated to them. Patients will be received one of the pockets by one of the colleagues who do not know about contents.
The groups arrang in this manner:
1)Will receive bolus Mg-sulphate(50%)(50mg/kg) during 15 minutes, before the induction.
2)Will receive 50mg/kg ,bolus of Mg-sulphate(during 15 minutes) before the induction and then 15 mg/kg/hr continuously.
3) Will receive just 100 ml of Normal saline.
Injections will be performed by colleagues blindly. Monitoring should be performed with ECG, sphygmomanometer, pulse-oxymetery and nerve-stimulator.
After 6 hours fasting, induction will be exerted with sodium thiopental, succynil-choline and Fentanyl. Then maintenance should be accomplished with Isoflurane,O2,/N2O, Atracurium and incremental doses of Fentanyl. Patients will be reversed with Neostigmine and Atropine.All cases will be monitored according to PR(pulse rate),BP(blood pressure) throughout 24 hours. Pain score will be recorded with Visual Analogue Scale(VAS), 1-6-18-24 hours after the surgery. With VAS more than 4;Pethidine with dose of 0.5 mg/kg will be recommended.
The time interval between the end of surgery and the first dose of Pethidine will be accounted as Analgesic Time.