Tension pneumothorax is defined as what condition?

• A. When air enters but does not leave the space around the lungs (pleural space)
• B. Air accumulates in the subcutaneous tissue
• C. Infection of pleural space
• D. Air leaves the pleural space into the lungs

Answer: (A)

Tension pneumothorax occurs when air enters the pleural space and cannot escape, creating a continuous buildup of pressure. This rising pressure collapses the affected lung and pushes the mediastinal structures toward the opposite side, which can impede venous return to the heart and lead to life-threatening respiratory and circulatory compromise. The option describing air entering the pleural space and not leaving matches this mechanism exactly.

Other scenarios describe different problems: air in subcutaneous tissue is subcutaneous emphysema; infection of the pleural space is empyema; and air moving out of the pleural space into the lung would relieve pressure rather than cause the pressure buildup characteristic of a tension pneumothorax. In practice, tension pneumothorax is a medical emergency requiring immediate intervention.