Open pneumothorax—also called an open or sucking chest wound—results when atmospheric air (positive pressure) flows directly into the pleural cavity (negative pressure). As the air pressure in the pleural cavity becomes positive, the lung collapses on the affected side, resulting in substantially decreased total lung capacity, vital capacity, and lung compliance. The resulting ventilation-perfusion imbalances lead to hypoxia. Types of open pneumothorax include penetrating pneumothorax and traumatic pneumothorax.

Closed pneumothorax occurs when air enters the pleural space from within the lung, causing increased pleural pressure and preventing lung expansion during normal inspiration. Closed pneumothorax may be called traumatic pneumothorax when blunt chest trauma causes lung tissue to rupture, which results in air leakage.

Spontaneous pneumothorax, another type of closed pneumothorax, is more common in males than in females. It’s common in older patients with chronic pulmonary disease, but it may occur in healthy, tall, young adults. In the latter, the cause is usually the rupture of an air-filled bleb or blister on the surface of the lung, which allows air to move from airways to the pleural cavity. Both types of closed pneumothorax can result in a collapsed lung with hypoxia and decreased total lung capacity, vital capacity, and lung
compliance. The total amount of lung collapse can range from 5% to 95%.

In tension pneumothorax, air in the pleural space is under higher pressure than air in adjacent lung and vascular structures. The air can’t escape, and the accumulating pressure causes the lung to collapse. As air continues to accumulate and intrapleural pressures rise, the mediastinum shifts away from the affected side and decreases venous return. This forces the heart, trachea, esophagus, and great vessels to the unaffected side, compressing the heart and the contralateral lung. Without immediate treatment, this emergency can rapidly become fatal.

Extensive pneumothorax can lead to fatal pulmonary and circulatory impairment.

The patient history reveals sudden, sharp, pleuritic pain. The patient may report that chest movement, breathing, and coughing exacerbate the pain. He may also report shortness of breath.

Inspection typically reveals asymmetrical chest wall movement with overexpansion and rigidity on the affected side. The patient may appear cyanotic. In tension pneumothorax, he may have distended neck veins, tracheal deviation, and pallor, and may exhibit anxiety. (Test results may confirm increased central venous pressure.)

Palpation may reveal crackling beneath the skin, indicating subcutaneous emphysema (air in tissues) and decreased vocal fremitus. In tension pneumothorax, palpation may disclose tracheal deviation away from the affected side and a weak and rapid pulse. Percussion may demonstrate hyperresonance on the affected side, and auscultation may disclose decreased or absent breath sounds over the collapsed lung. The patient may be hypotensive with tension pneumothorax. Spontaneous pneumothorax that releases only a small amount of air into the pleural space may cause no signs and symptoms.