Trial to Compare Different Strategies of Mean Arterial Pressure Management During Cardiopulmonary By-pass

"The patients enrolled to elective cardiac surgeries will be evaluated during a pre-operative outpatient visit and widely informed about the chance to participate in the study. When patients undergo to the elective surgery general anaesthesia is administered and CPB is installed. The nominal flow for each patient will be 2,4 l/min/m2.~To keep the MAP values around those corresponding to the randomized group, vasodilator (if MAP overcomes the assigned MAP value) or vasoconstrictor drugs will be used (if MAP value is lower than the assigned group). The following drugs will be used: nitroglicerine at incremental dose of 0,01 mcg/kg/min for a vasodilator effect and norepinephrine at incremental dose of 0,01 mcg/kg/min for a vasoconstrictor effect"