Acute pulmonary hypertension with life-threatening right heart failure may complicate the postoperative course following cardiothoracic surgery. Both inhaled nitric oxide and inhaled iloprost, a stable analogue of prostacyclin, have been used frequently for this purpose in acute pulmonary hypertension of various origins. We present a case of a patient with acute pulmonary hypertension and severely impaired gas exchange following pulmonary thrombo-endarterectomy. Therapy with one inhaled vasodilator alone did not satisfactorily abort a postoperative pulmonary hypertensive crisis and low-output syndrome due to right heart failure. Combined inhaled nitric oxide and inhaled iloprost, however, showed additive effects. Hence, the combination of both drugs may be reasonable in cases where the standard therapy fails. The effect has been demonstrated by means of continuous blood gas monitoring.