What do bubbles in the water seal chamber indicate?

• A. A normal water seal function
• B. A chest tube kink or blockage
• C. An air leak
• D. A clogged suction line

Answer: (C)

Bubbles in the water-seal chamber mean air is escaping from the pleural space into the chest-tube system. The water seal is designed to prevent air from flowing back into the chest, so continuous bubbling indicates an air leak somewhere in the system, often from the lung injury or a loose/sealed connection. It’s not a sign of normal water-seal function, which would show little or no bubbling. A kinked or blocked chest tube would usually reduce or stop bubbling and impair drainage, while a clogged suction line would affect the suction-control chamber rather than the water seal.