Hemodynamic and Cardiac Effects of Dexmedetomidine Versus Fentanyl by Intravenous Infusion as Adjuncts to General Anesthesia in Patients Undergoing Major Abdominal Cancer Surgeries.

Patients will receive Fentanyl loading dose of 1 µg/kg over 10 minutes, followed by an infusion of 0.5-1 µg/kg/h.

Patients will receive Dexmedetomidine loading dose of 0.5 µg/kg over 10 minutes, followed by an infusion of 0.3-0.9 µg/kg/h.