In chest tube drainage, movement of the water seal chamber during respiration is expected to be

• A. Completely still
• B. Only in the upright position
• C. Random and jagged
• D. Up and down with respiration

Answer: (D)

In a chest tube with a water-seal chamber, rhythmic movement of the water level with breathing (tidaling) shows the system is patent and the pleural space is communicating with the atmosphere. As the patient breathes in, intrapleural pressure becomes more negative and the water level typically rises; as they exhale, it falls. This up-and-down change occurs with each breath and can be seen in any patient position. If the chamber were completely still, that could indicate a blockage or disconnection and would require assessment. Random, jagged movement doesn’t align with the smooth, regular pattern of breathing. So, the expected finding is movement up and down with respiration.