Mediastinal Emphysema Causes includes which?

• A. Drinking water
• B. Exhaustion
• C. Breath holding during ascent
• D. Cold exposure

Answer: (C)

Mediastinal emphysema happens when air escapes from the lung into the mediastinum because the alveolar walls rupture under pressure changes. In diving, holding your breath during ascent creates a situation where the air inside the lungs expands as pressure drops. If that air isn’t exhaled, the expanding gas can rupture alveoli, and air can track into the mediastinum, producing mediastinal emphysema. That makes breath holding during ascent the best answer.

Drinking water, exhaustion, or cold exposure don’t directly cause alveolar rupture or air trapping in the mediastinum, so they’re not typical causes of this condition.