A chest tube is a medical device used to drain air or fluid from the space surrounding the lungs. Bubbling in the drainage system is a common observation that can cause concern. Understanding what this bubbling signifies is important for proper patient care and to differentiate between normal processes and potential complications.
What a Chest Tube Does
The chest cavity contains the lungs, which are encased in a double-layered membrane called the pleura. The narrow space between these layers, known as the pleural space, typically contains a small amount of lubricating fluid. This fluid allows the lungs to expand and contract smoothly during breathing. When air, excess fluid, or blood accumulates in this space, it can exert pressure on the lung, potentially causing it to collapse and impairing breathing.
A chest tube, also called a thoracic catheter or intercostal drain, is surgically inserted into the pleural space. Its function is to remove unwanted substances like air (pneumothorax), fluid (pleural effusion), or blood (hemothorax), re-establishing normal negative pressure. The tube connects to a closed drainage system, typically including a collection chamber, a water seal chamber, and sometimes a suction control chamber.
How Bubbling Occurs in a Chest Tube
Bubbling in a chest tube system specifically occurs within the water seal chamber. This chamber contains sterile water and acts as a one-way valve, allowing air to exit the pleural space while preventing outside air from re-entering the chest. When air from the pleural space passes through the water in this chamber, it creates bubbles.
The pattern of bubbling provides clues about the air’s origin and flow. Intermittent bubbling typically corresponds with the patient’s breathing, often appearing during exhalation or coughing. This suggests that air is actively leaving the pleural space through the tube as intrathoracic pressure changes. Conversely, continuous bubbling indicates a more constant flow of air through the water seal.
When Bubbling is Expected
Bubbling in the water seal chamber can be a normal and expected sign in several scenarios. Following the insertion of a chest tube for a pneumothorax, intermittent bubbling is common as the air initially trapped in the pleural space is evacuated. This type of bubbling often increases with deep breaths or coughing, reflecting the movement of air from the lung through the tube. As the lung re-expands and the air leak resolves, this intermittent bubbling should gradually decrease over time.
If the chest tube system is connected to suction, continuous gentle bubbling in the suction control chamber is also a normal finding. This indicates that the suction mechanism is actively working and applying the prescribed negative pressure to the drainage system. It is important to distinguish this from continuous bubbling in the water seal chamber, which has different implications.
When Bubbling is a Concern
While some bubbling is normal, certain patterns or the absence of expected bubbling can indicate a problem. New or increased continuous bubbling in the water seal chamber, especially if previously intermittent or absent, often signals a new or worsening air leak from the patient’s lung. It could also indicate a leak within the chest tube system, such as a loose connection or a crack in the tubing.
Conversely, if bubbling suddenly stops when previously present and expected, it warrants attention. This could mean the tube is kinked, a clot has formed, or the lung has fully re-expanded and the air leak has sealed. If the lung has not fully re-expanded, a sudden cessation of bubbling could signify an obstruction.
Vigorous or excessive bubbling in the water seal chamber may suggest a large air leak or an issue with the suction level being too high, which can lead to rapid evaporation of water. If any concerning changes in bubbling, drainage, or the patient’s condition are observed, notify a healthcare professional immediately. Patients or caregivers should never attempt to manipulate or fix the tube or system independently.