Subsequent anaesthesia will be maintained in all the patients in both the groups with isoflurane inhalation to maintain BIS values between 40-60 or end-tidal isoflurane of 1-MAC. Patients will be mechanically ventilated with 50% oxygen-air mixture and minute ventilation will be adjusted to achieve normocapnia till sternotomy. Vasoactive drug phenylephrine 100ug/ml will be prepared and boluses (1-2 ug/kg) given to all patients to maintain MAP > 60 mmHg (stable haemodynamics) on CPB. Normothermic CPB will be carried in all cases. Hematocrit of > 24% will be maintained in all patients on CPB. Total dose of phenylephrine received before and on bypass will be recorded in both the groups. Anesthesia and hemodynamics on cardiopulmonary bypass (CPB) will be maintained with isoflurane in oxygen-air mixture connected to the CPB machine and anesthesia post CPB period will be maintained with isoflurane in oxygen-air mixture. All patients will receive fentanyl 1ug/kg atleast 5-minutes before sternal closure.