Situation: A 22-year-old tall, thin man who smokes is admitted to the surgical ward with a right primary spontaneous pneumothorax. Six hours ago a chest tube was inserted and connected to a three-chamber drainage system with wet suction set at 20 cm H2O. While he is being turned, the chest tube separates from the drainage tubing at the connector, and the end of the drainage tubing drops to the floor. He is breathing without distress, and his oxygen saturation is 97%. A bottle of sterile water and a new drainage unit, still in its sealed package, are at the bedside. What should the nurse do FIRST?

All four actions are needed, but air can enter the pleural space through the open chest tube with every breath, so sealing it comes first. Submerging the tube end 2 to 3 cm in sterile water creates an immediate water seal; the nurse then connects a new drainage unit (the fallen tubing is contaminated), assesses him, and informs the physician. Because he is stable, assessment can follow the few seconds needed to seal the tube.

What the situation means
A chest tube that separates from the drainage tubing is no longer a closed system. In a patient with pneumothorax, the tube communicates directly with the pleural space. Once the connector opens to room air, atmospheric air can be pulled into the pleural cavity during inspiration, which can rapidly convert a small or resolving pneumothorax into a larger one. The immediate priority is therefore to re-establish a barrier between the pleural space and the atmosphere. Because the patient is breathing without distress and has an oxygen saturation of 97%, there is a brief window to intervene before clinical deterioration occurs.

The first action is to submerge the open end of the chest tube 2 to 3 cm below the surface of sterile water. This creates a temporary water seal. Water allows air to escape from the pleural space during expiration but prevents room air from entering during inspiration. The depth matters: too shallow a submersion may break the seal with movement, while too deep a submersion increases resistance to air drainage and can impair lung re-expansion.

Watch out! The drainage tubing that fell to the floor is contaminated and must not be reconnected to the patient. The new drainage unit should be opened and connected after the temporary water seal is in place. Reconnecting contaminated tubing first would introduce a direct pathway for pathogens into the pleural space, increasing the risk of empyema.

Why the other actions come later
Reporting to the physician is necessary, but it does not stop air from entering the pleural space. The physician cannot intervene faster than the nurse can place the tube under water at the bedside. Assessment of breath sounds and chest expansion is also important, but it takes longer and does not address the open system. In a stable patient, assessment can safely follow the few seconds required to create the water seal. Connecting the tube to the new drainage unit is the definitive step, but it requires opening the package and preparing the system; during that time the tube would remain open to air.

How the water seal works
A three-chamber drainage system includes a collection chamber, a water-seal chamber, and a suction control chamber. The water seal is the mechanism that permits one-way flow: air leaves the pleural space but cannot return. When the chest tube is disconnected, that one-way mechanism is lost. Submerging the tube end in sterile water restores the same principle using only a bottle and water. The water level should be maintained at 2 to 3 cm because this provides enough resistance to prevent air entry while still allowing air to bubble out during expiration.

Intermittent bubbling in the water seal during expiration is expected when a pneumothorax is resolving; continuous bubbling suggests an air leak. After the temporary seal is established, the nurse should observe for bubbling and then connect the new drainage unit, assess the patient, and notify the physician. The patient’s tall, thin body habitus and smoking history are consistent with the underlying risk for spontaneous pneumothorax, but they do not change the immediate priority of sealing the open tube.

Key point! The sequence is seal first, then replace the contaminated system, then assess and report. Air entry through an open chest tube can occur with every breath, so even a few seconds of delay increases the risk of recurrent or worsening pneumothorax during hospitalization.