A chest tube (thoracostomy tube) is a flexible catheter inserted into the pleural space (between the lung and chest wall). Its primary function is to drain unwanted air, fluid, or blood, allowing the collapsed or compressed lung to re-expand and function normally. Chest tubes are necessary for conditions like pneumothorax (collapsed lung) or hemothorax (blood in the chest cavity). Since the tube is connected to a closed drainage system designed to maintain negative pressure, a critical safety question arises during patient transport: should the tube be clamped?
The Standard Protocol: Why Clamping is Avoided During Patient Movement
The general rule in chest tube management is that the tube connected to a closed drainage system must remain open and unclamped during patient transport. The system is designed to allow continuous one-way flow out of the chest cavity, and clamping immediately defeats this mechanism. The danger of cutting off the exit route for air or fluid accumulation outweighs any convenience clamping might offer during movement.
A chest tube maintains the negative pressure required for lung expansion. When a patient has a persistent air leak, the tube must be free to let that air escape. Therefore, the standard procedure involves keeping the chest tube connected to its drainage system and transporting it alongside the patient. This ensures the therapeutic process of draining the pleural space continues without interruption.
Understanding the Critical Risks of Clamping
Inappropriate clamping of a chest tube carries a life-threatening risk: the development of a tension pneumothorax. A pneumothorax occurs when air leaks into the pleural space, and the chest tube is placed to provide an exit route for this air.
If the tube is clamped while the patient is still leaking air from the lung, the air continues to accumulate in the chest cavity with nowhere to go. This rapid buildup of positive pressure within the pleural space defines a tension pneumothorax.
The increasing pressure compresses the lung and pushes the heart and major blood vessels to the opposite side of the chest, known as a mediastinal shift. This shift severely impairs the heart’s ability to fill with blood, leading to a sudden drop in blood pressure and circulatory collapse. This complication can occur very rapidly, making clamping a patient with a known or suspected air leak extremely dangerous.
Necessary Exceptions for Brief Clamping
While routine clamping is strictly avoided, a few specific clinical exceptions allow temporary clamping under direct medical supervision.
One exception is when medical staff need to momentarily check for the source of a large air leak within the system itself. By clamping the tube briefly at various points, they can isolate whether the leak is coming from the patient’s chest or a faulty connection in the drainage system.
Another accepted exception is the brief period required to change a full chest drainage system to a new one. This involves clamping the tube for a few seconds to prevent air from entering the chest while the old and new canisters are swapped.
Clamping is also performed as a “trial” before the tube is completely removed. This is a period of observation, not transport, and is done only after the air leak has resolved and drainage volume is minimal. In all these cases, the clamping is temporary, intentional, and part of a closely monitored procedure.
Essential Steps for Safe Patient Transport
Since clamping is avoided, safe patient transport focuses on managing the drainage system correctly. The first step is ensuring the entire drainage system remains secured and upright throughout the movement. Tipping the canister can disrupt the water seal, which prevents air from re-entering the pleural space.
The drainage system must always be kept well below the level of the patient’s chest, typically on the floor or in a designated carrier. This positioning relies on gravity to facilitate the drainage of fluid and air, preventing fluid from siphoning back into the patient’s chest.
If the patient was connected to wall suction, the tubing is typically disconnected for transport. The system is then placed on a water seal or air vent mode, allowing air or fluid to escape through the water seal chamber.
During transport, medical personnel must continuously observe the water seal chamber for “tidaling.” This fluctuation of the water level with the patient’s breathing confirms that the tube remains patent. The patient’s respiratory status is monitored closely, and any signs of distress or rapid, excessive bubbling must be immediately reported.