A Chest drainage system is a surgical drain that is inserted through the chest wall and into the pleural space or the mediastinum to remove clinically undesired substances such as air, excess fluid, blood, chyle or pus from the intrathoracic space. An intrapleural chest tube is also known as a Bülau drain or an intercostal catheter (ICC) and can either be a thin, flexible silicone tube, or a larger, semi-rigid, fenestrated plastic tube, which often involves a flutter valve or underwater seal.