A chest tube, also known as a thoracostomy tube, is a flexible plastic device inserted into the chest cavity, specifically the pleural space. This area is the thin space between the lung and the chest wall. The primary function of this device is to drain excess air, fluid, or blood that has accumulated in this space. The observation of tidaling is common and expected when a chest tube is functioning correctly.
Why Chest Tubes Are Necessary
The pleural space maintains negative pressure, which is necessary for the lungs to fully inflate and deflate with each breath. Certain medical conditions or traumatic injuries can disrupt this balance, causing air or fluid to build up and compress the lung. For instance, a pneumothorax occurs when air leaks into this space, causing a collapsed lung. A hemothorax involves the accumulation of blood, while a pleural effusion is a general term for excess fluid buildup. Inserting a chest tube continuously removes the unwanted substance, which helps restore the necessary negative pressure and allows the compressed lung to re-expand and resume normal function.
What Exactly Is Tidaling?
Tidaling is a normal observation in a functioning chest tube drainage system. It is defined as the rhythmic rise and fall of the fluid level within the water seal chamber of the drainage unit. This movement reflects the continuous changes in pressure inside the chest cavity as a person breathes. During spontaneous inhalation, the pressure within the pleural space becomes more negative, pulling the water level upward. The level then drops during exhalation as chest pressure temporarily increases. This back-and-forth movement confirms that the tube remains open and properly positioned within the pleural space. The presence of tidaling indicates that the chest tube is patent.
Interpreting Changes in Tidaling
The observation of tidaling serves as a dynamic indicator of the patient’s condition and the tube’s patency. A change in the expected pattern of fluctuation warrants closer attention. The complete cessation of tidaling is a significant clinical event that has two main interpretations.
Cessation Due to Lung Re-expansion
Ideally, cessation means that the lung has fully re-expanded and sealed off the air or fluid leak. In this case, the pressure changes of breathing are no longer transmitted through the tube.
Cessation Due to Obstruction
Conversely, the absence of tidaling can signal a dangerous mechanical problem with the system itself. This includes an obstruction, such as a kinked or clamped tube, or a clot blocking the drainage holes. The lack of fluctuation in this scenario means the tube is no longer functioning to drain the pleural space, which can lead to a rapid deterioration of the patient’s condition.
Tidaling vs. Air Leaks
It is important to distinguish tidaling from bubbling, which is another type of movement observed in the water seal chamber. Tidaling is a smooth, wave-like fluctuation of the water column, reflecting the patient’s breathing cycle. An air leak, however, is signaled by the appearance of bubbling in the water seal chamber.
Types of Bubbling
Continuous bubbling suggests a persistent leak of air from the chest into the system or a leak within the drainage system connections. Intermittent bubbling that occurs only with coughing or deep breathing is expected, particularly when the chest tube is draining a pneumothorax. As the lung heals, air leaks should progressively diminish, and the patient’s breathing will eventually cease to cause any bubbling.