Three-sided occlusive dressing is used to:

• A. To allow air to escape but prevent air entry
• B. To prevent any air flow
• C. To seal completely
• D. To collect fluids

Answer: (A)

For chest wounds, the goal is to vent any air that has entered the chest while preventing more air from coming in, to reduce the risk of a tension pneumothorax. A three-sided occlusive dressing seals three sides around the wound and leaves the fourth edge open as a vent. This setup acts like a one-way valve: air can escape from the chest as the patient exhales, but air is not easily drawn back in during inhalation. It’s not meant to seal completely or to primarily collect fluids; its purpose is to prevent air from accumulating in the chest while still allowing a way for it to escape.