A medical instrument used to drain accumulations of fluid in the pleural space, a condition called pleural effusion. A chest tube is inserted through a small incision in the chest wall. The tube is then connected to a suction device to aid in draining the fluid and re-expanding the lungs. When bleeding occurs in the pleural space between the chest wall and the lungs, a condition called hemothorax, a chest tube may be inserted through the chest wall to drain the blood. The tube is left in place after the draining to aid the lung in expanding again. Chest tubes may also be inserted to drain pus that may accumulate in the pleural space as the result of severe pneumonia.