PADI Divemaster Certification Practice Exam

What condition is characterized by air overexpanding in the lungs and accumulating in the center of the chest?

1. Mediastinal emphysema

2. Barotrauma

3. Pneumothorax

4. Decompression sickness

The correct answer is: Mediastinal emphysema

Mediastinal emphysema is characterized by the presence of air in the mediastinum, the central compartment of the thoracic cavity. This condition can occur when air escapes from the lungs due to trauma or barotrauma, which is a result of pressure changes. In the context of diving, as a diver ascends, if air from the lungs expands rapidly, it can find its way through ruptures in the airways or alveoli, leading to the accumulation of air in the mediastinum. This condition is significant because the presence of air in this area can compress vital structures such as the heart and major blood vessels, potentially leading to serious complications. Understanding mediastinal emphysema is crucial for divers, as it informs safe diving practices and highlights the importance of maintaining proper ascension rates to prevent lung overexpansion injuries.