112 224 Definition Accumulation of air or gas in the pleural cavity, resulting in lung collapse or displacement of the heart within the thoracic cavity. Hemothorax, or the collection of blood within the pleural cavity, can result. It can occur spontaneously in the course of pulmonary disease or it might follow trauma to or perforation of the chest wall, resulting in either a closed or open pneumothorax. Spontaneous pneumothorax: Collection of air or gas in the thoracic cavity that causes the lung to collapse, usually in the absence of a traumatic injury to the chest or lung. Usually, the rupture of a small bullae causes the collapse. Secondary causes include COPD, lung cancer, tumors, tuberculosis, cystic fibrosis, or a history of pneumothorax. Open pneumothorax: Collapsed lung due to penetrating wounds of the chest wall that per- mit persistent communication between the outside and intrapleural space, allowing air to enter the intrapleural space. This is often referred to as a “sucking” chest wound. The chest wall may become airtight after penetration (closed) or air may continue to enter the in- trapleural space. Tension pneumothorax: Pressure increase during the respiratory cycle as a result of a wound or flap of tissue that acts as a one-way valve: air can enter, but not leave, the intrapleural space. The rising pressure causes a mediastinal shift to the opposite side that may severely compromise pulmonary and cardiac function. Characteristics Depending on the type of pneumothorax, symptoms can range from mild disturbance to se- vere dyspnea, shock, and life-threatening respiratory failure and circulatory collapse. Sudden sharp chest pain, dyspnea, and occasionally a dry, hacking cough may occur at onset. Breath sounds may be diminished to markedly depressed or absent on the affected side. Symptoms tend to be less severe in a slowly developing pneumothorax and usually subside as accommodation to the altered physiologic state occurs. Chest X-ray will show air without peripheral lung markings. In open pneumothorax, a sucking sound on inspiration and expi- ration may be present, as well as an open chest wound. In small closed traumatic and spon- taneous pneumothoraces the air is reabsorbed in a few days to 2 to 4 weeks, often with no special treatment. A tension pneumothorax is a medical emergency requiring immediate removal of air from the intrapleural space. Symptoms include hypotension, tachycardia, tracheal deviation, jugular venous distention, unilateral decreased or absent breath sounds, diminished chest wall motion on affected side, tympany on percussion, and subcutaneous emphysema. Policy Initiate immediate emergency transportation to the hospital and stabilize the employee in the occupational health unit until transfer is complete. Pneumothorax Guideline continues on next page