 This controlled, randomized, double-blind study will aim at confirming the efficiency as well as the security of Milrinone, used in inhalation, to diminish the degree of pulmonary hypertension before the cardiopulmonary bypass ECC circulation. In addition, the pharmacokinetic and echo graphic repercussions of administering the medication will be analysed. At the present time, there is no data on the pharmacokinetics of the medication when its administered through inhalation. For this reason, we would like to study the serous rate of the medication in the minutes following its administration through inhalation. 