PCWP is important to measure when evaluating pulmonary hypertension. PCWP is also useful in evaluating blood volume status when fluids are administered during hypotensive shock. Given here is the Pulmonary Capillary Wedge Pressure (PCWP) formula to estimate the left atrial pressure (LAP) in a patient. It is advisable to measure PCWP to diagnose the severity of left ventricular failure and to quantify the degree of mitral valve stenosis in order to avoid severe issues.