Hemodynamic Effect of Norepinephrine Versus Vasopressin on the Pulmonary Circulation in Cardiac Surgery Patients:

The specific aims of our study are to compare 1) the relative increase in the mPAP with the same unit increase in MAP adjusted for baseline and 2) RV function assessed by GLS, between VP and NE in patients with normal and increased pulmonary artery pressure, who require vasopressor support during cardiac surgery. We hypothesize that the use of vasopressin compared with norepinephrine induces a lower mPAP-to-MAP ratio, in cardiac surgical patients with and without pulmonary hypertension who require intraoperative vasopressor support. Second, we will test the hypothesis that vasopressin is associated with improved right ventricular global longitudinal strain compared to norepinephrine in patients requiring vasopressor support during cardiac surgery.