New York State Basic Emergency Medical Technician (EMT-B) Practice Exam

What defines a tension pneumothorax?

1. Air trapped in the chest cavity

2. Fluid buildup in the lungs

3. Partial collapse of the lung

4. Excess air escaping from the pleural space

The correct answer is: Air trapped in the chest cavity

A tension pneumothorax is specifically characterized by air being trapped in the chest cavity that cannot escape. This occurs when air enters the pleural space and creates increasing pressure, leading to a shift in the mediastinum and potentially compromising vital structures such as the heart and large blood vessels. The trapped air prevents the lung on that side from fully expanding, causing respiratory distress and a decrease in oxygenation. In contrast, fluid buildup in the lungs indicates conditions such as pulmonary edema or pleural effusion, which are distinct from a tension pneumothorax. A partial collapse of the lung, usually referred to as atelectasis, does not involve the progressive pressure build-up that defines tension pneumothorax. Excess air escaping from the pleural space is not an accurate description, as a tension pneumothorax is defined by excessive air accumulating rather than escaping. Thus, the defining feature of a tension pneumothorax is indeed the accumulation of air that exerts pressure within the chest cavity.