A chest tube is a flexible plastic tube that is inserted through the chest wall and into the pleural space or mediastinum. It is used to remove air in the case of pneumothorax or fluid such as in the case of pleural effusion, blood, chyle, or pus when empyema occurs from the intrathoracic space. It is also known as a Bülau drain or an intercostal catheter. Insertion of chest tubes is widely performed by radiologists, pulmonary physicians and thoracic surgeons. Large catheters or small catheters are used based on each situation that the medical doctor encounters. In the current review we will focus on the chest drain systems that are in use.
Pressure around the lungs is lower than atmospheric pressure outside the body. The aims for an adequate chest drainage system to be fulfilled are: (I) remove fluid & air as promptly as possible; (II) prevent drained air & fluid from returning to the pleural space, restore negative pressure in the pleural space to re-expand the lung. Thus, a drainage device must: (I) allow air and fluid to leave the chest; (II) contain a one-way valve to prevent air & fluid returning to the chest; (III) have design so that the device is below the level of the chest tube for gravity drainage. An underwater seal chest drainage system is used to restore proper air pressure to the lungs, re-inflate a collapsed lung as well as remove blood and other fluids. The system is a two-chambered or three-chambered plastic unit with vertical columns bringing measurements marked in milliliters. The thoracic drainage devices cover a wide range and have evolved considerably since their introduction. The basic design principle of these systems has been the avoidance of air entrance in the pleural cavity during the various phases of the respiratory cycle and continuous drainage of air and fluid from the pleural cavity. A key issue in the successful treatment of patients is the understanding of how these systems function. The application and development was based on the original one-bottle system. The understanding of this principal system introduces us to the mechanism of function.