Which sign on the water-seal chamber suggests the chest tube is functioning and air is moving with respiration?

• A. Tidaling
• B. No bubbling
• C. Constant continuous drainage
• D. No air movement

Answer: (A)

The main idea is that the water-seal chamber should show a rise and fall with breathing. This up-and-down movement means air is moving through the chest tube as the person inhales and exhales, so the pleural space is still communicating with the atmosphere and the system is patent. This movement, called tidaling, is the best sign that the chest tube is functioning and air is moving with respiration. If the seal shows no tidaling, it could indicate an obstruction, a fully evacuated pleural space, or other issues, which is why tidaling is the key indicator. Continuous drainage or no air movement alone don’t specifically prove respiration-driven airflow through the seal.