When is suction particularly indicated?

• A. When there is persistent air leak or incomplete lung expansion; suction helps remove air and promote re-expansion.
• B. When the lung is fully expanded and no air leak.
• C. Only during placement.
• D. Never used.

Answer: (A)

Suction is used when the chest tube needs help removing air from the pleural space to allow the lung to re-expand. The negative pressure drawn through the tube accelerates evacuation of air in cases where there is a persistent air leak or the lung has not fully inflated after placement. By pulling air out, the pneumothorax shrinks and the lung can reoccupy its space, improving ventilation and oxygenation.

If the lung is already fully expanded and there is no ongoing air leak, there’s no benefit to applying suction; it can cause unnecessary negative pressure, discomfort, and potential tissue irritation. In that situation, keeping the drainage on a gravity water-seal is usually sufficient until the leak resolves and expansion remains stable.