Chest Tube Water-Seal Bubbling: Air Leak or Normal?

Respiratory · Question from the ATI RN Medical-Surgical 2023 Proctored Exam study set

Correct answer: B. A system air leak

Why this is the answer

Continuous bubbling in the water-seal chamber (as opposed to gentle bubbling only with breathing/coughing) means air is entering the system somewhere it shouldn't — from a loose connection, an insertion-site problem, or a crack in the tubing. Normal operation (A) is wrong because normal water-seal activity is "tidaling" — fluid rising and falling with respiration — not continuous bubbling. Lung re-expansion (C) is actually shown by tidaling slowing down or stopping as the lung fills the pleural space again, the opposite of what continuous bubbling suggests. Suction being too high (D) is a separate issue that affects the suction control chamber, not bubbling in the water-seal chamber.

The bigger concept

Chest tube troubleshooting comes down to knowing which chamber tells you what: the water-seal chamber reflects air leaks and lung re-expansion (via tidaling), while the suction control chamber reflects how much negative pressure is being applied. Mixing these up is a common exam trap.

Related Respiratory practice questions

• When Chest Tube Drainage Signals a Problem
• The Gold-Standard Test for a Pulmonary Embolism
• Interpreting an ABG in a COPD Exacerbation
• What a V/Q Scan Actually Measures
• Chest Tube 'Tidaling' in the Water-Seal Chamber

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