What is the purpose of taping the chest-tube insertion dressing on three sides?

• A. To create a completely airtight seal.
• B. To secure the tube without any air passage.
• C. To allow air to escape while preventing retreat of air into the pleural space.
• D. To prevent skin irritation.

Answer: (C)

The key idea is that the chest-tube dressing is kept on three sides to form a one-way valve. This setup lets air escape from the pleural space through the chest tube when intrapleural pressure rises (during exhalation or coughing) but prevents air from rushing back into the space during inspiration. That one-way flow helps keep the pneumothorax from re-forming while still allowing drainage. It’s not about creating an airtight seal or about preventing skin irritation—the main purpose is to vent air outward while blocking re-entry.