In cases of tension pneumothorax, what occurs in the pleural space?

• A. Fluid accumulation.
• B. Air escapes through the lung.
• C. Air pressure increases.
• D. Blood enters the pleural cavity.

Answer: (C)

In cases of tension pneumothorax, the pleural space experiences an increase in air pressure. This condition occurs when air enters the pleural cavity and cannot escape, often due to a one-way valve effect from a ruptured lung or chest wall injury. As more air enters the pleural space, it creates a buildup of pressure that compresses the lungs on the affected side, making it difficult for the patient to breathe adequately. This increased pressure can also shift the mediastinum, pushing the heart and other structures toward the opposite side, which can lead to cardiovascular compromise. Thus, the fundamental change in the pleural space during tension pneumothorax is the progressive increase in air pressure, which is critical to recognize for effective emergency management.