For a penetrating chest wound, why is an occlusive dressing taped on three sides?

• A. To completely seal to prevent any air from escaping.
• B. To immobilize the chest wall.
• C. To prevent air entry during inhalation while allowing air to escape during exhalation, reducing tension pneumothorax risk.
• D. To keep the dressing dry.

Answer: (C)

Penetrating chest wounds risk air entering the pleural space and causing a pneumothorax. If the wound were sealed on all sides, any air that enters could be trapped, increasing pressure and potentially leading to a tension pneumothorax. Taping the occlusive dressing on three sides creates a one-way valve: it prevents air from entering during inhalation but allows air to escape during exhalation. This venting reduces intrapleural pressure buildup while still protecting the wound from contamination. It’s a balance between sealing the wound and preventing dangerous air accumulation.