Objective:Postoperative pulmonary hypertension increases the mortality risk in cardiac surgery. We have used central venous prostaglandin E1(PGE1) and left atrial norepinephrine (NE) infusion to wean from cardiopulmonary bypass (CPB) patients with refractory postoperative pulmonary hypertension.Design:Observational, nonrandomized study.Setting:Department of Cardiac Surgery in a university hospital.Patients:We studied 10 nonconsecutive American Society of Anesthesiologists III and New York Heart Association class III-IV patients with postoperative pulmonary hypertension and low cardiac output syndrome preventing separation from CPB.Interventions:Patients received right atrial PGE1(31.5 ± 6.26 ng/kg/min) and left atrial NE (0.11 ± 0.02 μg/kg/min) infusion. Hemodynamic data were obtained before CPB (T0), after CPB under maximal inotropes and vasodilator infusion (T1), 10 mins (T2) and 12 hrs (T3) after PGE1and NE infusion, and 48 hrs after withdrawal of PGE1and NE (T4).Measurements and Main Results:All patients were successfully weaned from CPB and survived. The biatrial infusion of PGE1and NE caused a dramatic reduction in mean pulmonary artery pressure (from 42.8 ± 5.1 mm Hg at T1 to 28.5 ± 2.6 mm Hg at T2 and 20.5 ± 2.0 mm Hg at T4), pulmonary vascular resistance index (from 1158 ± 269 dyne·sec/cm5·m2at T1 to 501 ± 99 dyne·sec/cm5·m2at T2 and 246 ± 50 dyne·sec/cm5·m2at T4), and pulmonary-to-systemic vascular resistance index ratio (from 0.61 ± 0.17 at T1 to 0.20 ± 0.04 at T2 and 0.11 ± 0.03 at T4). Cardiac index increased from 1.7 ± 0.2 L/min/m2at T1 to 2.3 ± 0.2 L/min/m2at T2 and 2.9 ± 0.1 L/min/m2at T4.Conclusions:In patients with refractory postoperative pulmonary hypertension, the combined administration of low-dose PGE1in the right atrium and NE in the left atrium is an effective means to wean patients from cardiopulmonary bypass.