Dexmedetomidine for Cesarean Section

The dexmedetomidine groups (n = 20 ) will receive i.v. infusion of 0.5 μg/kg of solution containing 5 µg/mL of dexmedetomidine, at 10 min after the level of anesthesia completed. Followed with 0.1ml/kg/hr continuous infusion until the closure of the abdominal.The placebo and the dexmedetomidine solutions will be looked identical and their infusions will be continued until skin closure.

The placebo group (n = 20) will pumped in the same volume of saline 0.9% as calculated by patients' weight in 10 min, then will receive an i.v. infusion of 0.1 mL/kg/h saline 0.9%, until the closure of the abdominal. The placebo and the dexmedetomidine solutions will be looked identical and their infusions will be continued until skin closure.