A pleural effusion occurs when excess fluid accumulates in the pleural space, the thin area between the lung and the inner chest wall. Normally, this space contains only a small amount of lubricating fluid. Disease or injury can cause a buildup that compresses the lung, leading to difficulty breathing. To alleviate this pressure and allow the lung to re-expand, a flexible, sterile chest tube is inserted into the pleural space. The tube remains until the underlying issue resolves and the fluid has been adequately drained.
Function of the Drainage System
The chest tube connects to a closed drainage system designed to restore the natural negative pressure of the pleural space, which keeps the lungs inflated. The drainage unit typically consists of three chambers: a collection chamber, a water seal chamber, and a suction control chamber.
The collection chamber gathers and measures the fluid draining from the chest cavity. The water seal chamber acts as a one-way valve, allowing air or fluid to leave the chest while preventing outside air from re-entering the pleural space. This seal is achieved by placing the tube end under a column of water, which also allows for monitoring air leaks.
The final chamber controls the level of suction applied, often connected to a wall vacuum unit to assist in pulling fluid out and promoting lung re-expansion. The goal of this entire system is to maintain a vacuum environment, ensuring the lung remains fully expanded as the fluid is removed.
Clinical Milestones for Removal
The decision to remove a chest tube relies on achieving specific, objective clinical milestones rather than a set time frame. These criteria confirm the patient no longer requires drainage assistance and that the lung has fully recovered. The main objective is confirming the resolution of fluid accumulation and the integrity of the lung tissue.
Fluid Output
The volume of fluid draining into the collection chamber is a primary metric. Physicians typically require the daily drainage output to fall to a minimal, stable threshold, often less than 200 milliliters over a 24-hour period. While some protocols allow for removal up to 300 mL per day, 200 mL is a common target for uninfected fluid.
The fluid’s appearance is also monitored closely; it must become less bloody, serous, or purulent, indicating the acute process is resolving. High drainage volume suggests ongoing internal bleeding or an unresolved condition, preventing safe tube removal. A low, non-bloody output over a full day confirms the body can handle the remaining fluid.
Air Leak Status
The absence of a persistent air leak is a mandatory requirement before tube removal. An air leak occurs when air escapes from the lung tissue into the pleural space, visualized as bubbling in the water seal chamber. The leak must completely resolve, often for a minimum of 24 hours, ensuring the lung surface has healed.
Before removal, the chest tube is sometimes placed on a simple water seal—with suction discontinued—to test for occult air leaks. If the lung holds its expansion and no air bubbles are seen after this trial, the pleural space is confirmed sealed. Removing the tube with an active air leak risks a new lung collapse.
Imaging Confirmation
Final confirmation of lung status is made using medical imaging, typically a chest X-ray or bedside ultrasound. Imaging is performed after drainage output has stabilized and the air leak has ceased. The X-ray must show that the lung is fully, or at least adequately, re-expanded and remains in contact with the chest wall.
The imaging also confirms the tube is positioned correctly and that the pleural space is clear of significant residual fluid or air pockets. In some modern protocols, ultrasound is used to confirm “lung sliding,” which is a sign that the two layers of the pleura are moving against each other, indicating a full seal and expansion. This visual confirmation is the final step in the clinical decision-making process.
The Removal Procedure and Recovery
Once the criteria are met, the physical removal procedure is performed with careful attention to pain management and technique. The patient is often pre-medicated with pain relief about 30 minutes before the procedure, as the tugging sensation of removal can be uncomfortable. The physician will cut the sutures holding the tube in place and prepare the insertion site.
The patient is instructed to perform a specific breathing maneuver, usually the Valsalva maneuver, which involves taking a deep breath and bearing down or holding the breath. This technique temporarily increases the pressure inside the chest cavity, which prevents outside air from rushing back into the pleural space as the tube is quickly and smoothly withdrawn. Immediately upon removal, a sterile, airtight occlusive dressing is placed over the incision site to prevent air entry.
Following removal, the patient is monitored closely for any signs of respiratory distress, such as increasing shortness of breath or changes in vital signs. A final confirmation chest X-ray is typically ordered within a few hours to ensure that the lung has remained fully expanded after the tube’s removal. The incision site is kept covered for about 48 hours to allow the small opening to seal completely.