Pulmonary capillary wedge pressure or PCWP (also called the pulmonary wedge pressure or PWP, or pulmonary artery occlusion pressure or PAOP) is the pressure measured by wedging a pulmonary catheter with an inflated balloon into a small pulmonary arlerial branch.> Because of the large compliance of the pulmonary circulation, it provides an indirect measure of the left atrial pressure.> For example, it is considered the gold standard for determining the cause of acute pulmonary edema; this is likely to be present at a PCWP of >20mmHg.> It has also been used to diagnose severity of left ventricular failure and mitral stenosisCalculating PCWP is also important in diagnosis of acute respiratory distress syndrome (ARDS).Physiological pressure: 6-12 mm Hg.">