Which of the following should be avoided when treating a chest wound?

When treating a chest wound, exposing the wound to air is something that should be avoided because it can lead to a significant risk known as a tension pneumothorax. An open chest wound can allow air to enter the pleural cavity, disrupting normal respiratory mechanics and leading to collapsed lung(s).

By using an airtight seal, not only can you prevent air from entering the pleural space, but you can also help stabilize the injury and allow for better management of the casualty's breathing. Applying direct pressure is also an important action, particularly for any bleeding that may accompany the wound, and keeping the casualty calm is essential as it can help alleviate anxiety and prevent increased respiratory distress. Thus, the best course of action is to keep the wound sealed to promote stabilization and minimize complications.