A complete collapse of the lung which occurs when air enters but does not leave the space around the lungs (pleural space). It is a potentially life-threatening condition which can lead to dangerously low oxygen levels, shock, or death. See also pneumothorax .

Causes, incidence, and risk factors

Any condition that leads to pneumothorax can cause a tension pneumothorax. (See pneumothorax.) In an uncomplicated pneumothorax, air can enter and leave the pleural space easily. In tension pneumothorax, however, air enters the pleural space with each breath and becomes trapped there. As the amount of trapped air accumulates, pressure builds up in the chest. The lung collapses on that side and may push the important structures in the center of the chest (such as the heart, major blood vessels, and airways) towards the unaffected side of the chest. The shift may cause compression of the opposite lung and may affect the flow of blood returning to the heart. This situation can lead to low blood pressure, shock, and death. Tension pneumothorax is a life-threatening emergency.

Signs and tests

Physical examination may show decreased breath sounds when listening to the chest with a stethoscope. Structures in the mediastinum (center of the chest) may appear shifted. Subcutaneous emphysema (air trapped in the subcutaneous tissue of the chest wall) may be present, causing a spongy feeling when the chest is felt with the hands ( palpation ). In general, if a health care provider suspects tension pneumothorax, treatment should start before diagnostic tests are done. Nonetheless, some tests may help confirm the diagnosis if there is doubt or to assess the severity of the situation: Tests used in the diagnosis of tension pneumothorax include:

Treatment

The objective of treatment is to remove the air from the pleural space, allowing the lung to re-expand. In an emergency, a small needle (such as a standard intravenous needle) may be placed into the chest cavity through the ribs to relieve the excessive pressure. The definitive treatment is a chest tube, a large plastic tube that is inserted through the chest wall between the ribs to remove the air completely. The chest tube is attached to a vacuum bottle that slowly and continuously removes air from the chest cavity. This allows the lung to re-expand. As the lung heals and stops leaking air, the vacuum is turned down and then the chest tube is removed. Hospitalization is required for proper care of the chest tube and because several days may be required before the affected lung re-expands. Surgery may be indicated for recurrent episodes or if the lung does not re-expand after 5 days with a chest tube in place.

Expectations (prognosis)

Up to 50% of patients with spontaneous pneumothorax experience recurrence. There are no long-term complications following successful therapy.

Complications

Calling your health care provider

Go to the emergency room or call the local emergency number (such as 911) if symptoms of this disorder are present.

Prevention

Use precautions to avoid chest trauma. Many cases are not preventable.