How is an air leak identified in a chest-tube system?

• A. No bubbling at all.
• B. Bubbling only during expiration.
• C. Bubbles in the collection chamber only.
• D. Continuous bubbling in the water-seal chamber during both inspiration and expiration.

Answer: (D)

Continuous bubbling in the water-seal chamber during both inspiration and expiration shows an air leak in the chest-tube system. The water-seal chamber is designed to permit air to escape from the pleural space but not to let room air back in; normally, bubbling is limited and related to specific breathing phases or short coughing episodes. If bubbling occurs constantly in both phases, air is entering the system somewhere along the tubing or at the insertion site, indicating a leak. This prompts checking and securing all connections, inspecting the tube for cracks, and ensuring the dressing and system are intact so the seal remains closed to atmosphere. The other patterns—no bubbling, bubbling only during expiration, or bubbling only in the collection chamber—do not reflect a persistent system leak in the water-seal portion.