Pulmonary artery (PA) end-diastolic pressure is used as an estimate of PA wedge pressure. We evaluated contrast enhanced pulmonary regurgitant signals in the assessment of PA end-diastolic pressure in 24 patients in a critical care unit. Right atrial pressure was estimated by the percent decrease of the inferior vena caval diameter with inspiration. Weak or absent pulmonary regurgitant signals were enhanced by sonicated albumin (Albunex) in 23 patients (96%). The Doppler-determined PA end-diastolic pressure (the sum of the pulmonary regurgitant pressure gradient at end-diastole and the right atrial pressure) was significantly correlated with the catheter-determined PA end-diastolic pressure (y = 0.85x + 1.72, r = 0.93). Compared with invasive hemodynamic monitoring, the contrast-enhanced Doppler technique using Albunex is effective for measuring PA end-diastolic pressure, even in critically ill patients.