Fluid management has a great influence on patient's morbidity, mortality and on the overall outcome.Goal directed therapy was proved by multiple studies to be a goal therapy in maintaining a stable hemodynamic state. Nevertheless, as the population worldwide is aging, elderly presenting for surgery are also increasing. This population is known for the multiple comorbidities and physiological changes which makes them prone to dehydration and hypotension. That's when we are going to use either Norepinephrine in one group or Phenylephrine in the other and compare the effects of both vasopressors.