Write about Pulmonary Capillary Wedge Pressure here.

• Measured by passing a special balloon-tipped catheter (e.g. Swan-Ganz) via a central vein through the right side of the heart to the pulmonary artery

• The balloon of the catheter is then inflated and is carried forward in the blood flow until it wedges in a pulmonary capillary

• The measurement of pulmonary capillary wedge pressure reflects LEFT atrial pressure and in ARDS it is < or = 18 mmHg, whereas in Cardiogenic pulmonary oedema it is elevated.