# Answers

### What is tension pneumothorax?

As a tension pneumothorax develops, air enters the chest cavity through the wound with every inspiration, but doesn’t leave with expiration and is trapped, so every breath adds more air to the air space inside the rib cage and outside the lung, and the pressure inside the chest builds up and causes the lung to collapse. Injured lung tissue acts as a one-way valve, trapping more and more air between the lung and the chest wall. Pressure builds up and compresses both lungs and the heart.

### How should you treat an open chest wound?

Treat open chest wounds by applying a vented chest seal completely over the wound during expiration.

### What should you do if you suspect a casualty has a tension pneumothorax?

If a chest seal is in place, burp the seal. If there is no improvement after burping the seal perform a needle decompression of the chest.