Treatment of such an injury usually involves a chest puncture to release the trapped air. In some cases, recompression is also necessary. Mediastinal and Subcutaneous Emphysema Mediastinal Emphysema and Subcutaneous Emphysema are both due to air being forced into tissues outside of the lungs. Mediastinal Emphysema is the movement of air into the tissues around the heart, the major blood vessel and the trachea. With ascent, the trapped gas expands and can cause impaired venous return.
Symptoms are usually pain under the sternum and shortness of breath.
Subcutaneous Emphysema is caused by air being forced into the tissue beneath the skin of the neck. Mild cases show symptoms of only a feeling of fullness in the neck. More severe cases can present with a crackling of the skin to the touch. Treatment is usually recommended as oxygen therapy, as the oxygen will speed absorption of the subcutaneous air. Ear Problems Difficulties with the ear resulting directly as a result of pressure changes while diving are common.