What might an observer notice in a diver with mediastinal emphysema?

A diver with mediastinal emphysema can present with swelling or inflation of the neck due to the accumulation of air in the mediastinal space. This occurs as air escapes from the lungs or the tracheobronchial tree during or after a dive, potentially as a result of barotrauma or improper equalization techniques. The presence of air in the mediastinum can create pressure that causes noticeable swelling in the neck area.

In addition to this visible sign, diverting attention toward other symptoms can help in understanding the complication better. Although breathing patterns could be affected due to the accompanying respiratory distress, the most striking and observable characteristic is the neck swelling, which is a direct physical manifestation of the underlying condition. The accumulation of air can also lead to other complications but the immediate observation that might be most apparent to an observer during a dive-related incident is the swelling in the neck region.