The pleural space is the area between the lung and the chest wall. If air, blood, or fluid gets into this space, it can be a problem. This air, fluid, or blood can cause one or both lungs to collapse, which makes breathing difficult. A chest tube can drain the pleural space. This tube is soft and flexible. Your child may need a chest tube to prevent his or her lung from collapsing. Or he or she may need it to allow the lung to expand after collapsing.