A chest tube is a medical device used to drain unwanted air or fluid from the space surrounding the lungs, known as the pleural space. This procedure helps the lung re-expand and function properly. Sometimes, a complication called an “air leak” can develop, where air escapes from the lung or the chest tube system.
What a Chest Tube Does and What an Air Leak Is
The lungs are encased by a double-layered membrane called the pleura. Between these layers lies the pleural space, which normally contains a small amount of lubricating fluid. This fluid helps maintain a negative pressure that keeps the lung expanded against the chest wall.
When air or fluid abnormally collects in this pleural space, it can disrupt the negative pressure, causing the lung to collapse. A chest tube, a flexible plastic tube, is inserted through the chest wall into this space to remove the excess air, blood, or fluid. This drainage helps restore normal negative pressure, allowing the lung to re-expand.
An “air leak” refers to the abnormal escape of air. This air can originate from the lung itself, moving into the pleural space, or it can enter the system from outside the body. Once air escapes into the pleural space, the chest tube system then drains it, and its presence is often indicated by bubbling within the drainage unit.
Why Air Leaks Occur
Air leaks can develop for several reasons, often related to the underlying lung condition or issues with the chest tube system. A common cause is a persistent leak from the lung tissue itself. This can happen after lung surgery, where air continues to escape from the surgical site, or following a traumatic injury to the lung, such as a puncture. This communication allows air to continuously flow out.
Another reason for air leaks involves problems with the chest tube system. The tube might become slightly dislodged from the chest wall, creating a path for outside air to enter the pleural space. Alternatively, a crack in the tubing, a loose connection between different parts of the drainage system, or an issue with the drainage unit itself can allow air to leak into the system. These external leaks compromise the closed system.
The original condition that necessitated chest tube placement, such as a collapsed lung (pneumothorax), might not be fully resolved or could worsen. If the lung continues to leak air, perhaps due to ongoing lung disease or barotrauma from mechanical ventilation, an air leak will persist. A new or worsening pneumothorax can also lead to continued air leakage from the lung into the pleural space, preventing full lung re-expansion.
How Air Leaks Are Identified and Managed
Medical professionals primarily identify an air leak by observing the chest drainage system. The most common sign is continuous or intermittent bubbling in the water-seal chamber of the chest drainage unit. The pattern of bubbling offers clues: continuous bubbling throughout the respiratory cycle might suggest a larger leak, while intermittent bubbling, particularly with coughing or exhaling, could indicate a smaller leak.
Beyond visible bubbling, other indicators include changes in the patient’s breathing or vital signs. Healthcare providers also assess for subcutaneous emphysema, a crackling sensation under the skin, indicating air has leaked into the tissues around the chest tube insertion site. If an air leak is suspected, a chest X-ray may be performed to assess lung re-expansion and tube position.
Management of air leaks involves careful monitoring of the leak’s size and persistence. Healthcare providers systematically troubleshoot the chest tube system to rule out external issues. This involves checking all connections for tightness, inspecting the tubing for any cracks or kinks, and ensuring the drainage unit is intact. Briefly clamping the tube at different points can help pinpoint if the leak is coming from the patient or the drainage system.
Small air leaks often resolve on their own as the underlying lung injury heals, and conservative management is sufficient. Placing the chest tube to a water seal, without active suction, is sometimes preferred to allow the lung to seal naturally. However, if the leak persists or is large, further medical evaluation or intervention may be necessary. This could involve adjusting the level of suction applied to the chest tube or, for prolonged and significant leaks, more invasive procedures like surgical repair to seal the source of the air leak.