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Pneumothorax is defined as air in the pleural space and is commonly seen after thoracic surgery. Pneumomediastinum is defined as air in the mediastinum and is quite rare. Despite their differences, the principles used to treat these two conditions are similar. Successful management requires a thorough understanding of the thoracic anatomy and pathophysiologic mechanisms that cause these conditions. Pneumothorax may signal a life-threatening condition, and pneumomediastinum may be a sign of an innocuous problem that requires no treatment. This chapter provides an overview of the incidence, causes, pathophysiology, symptoms, radiologic signs, diagnostic evaluation, and most importantly, the techniques for treatment of both pneumothorax and pneumomediastinum.
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Pneumothorax is a collection of air or gas in the pleural space. It is classified into three subtypes: spontaneous, traumatic, and iatrogenic pneumothorax (Table 128-1). A spontaneous pneumothorax is a collection of air or gas in the chest that causes the lung to collapse. It can be further classified as primary (i.e., collapse of lung for no apparent reason) or secondary (i.e., collapse of the lung secondary to underlying pulmonary pathology), as detailed in Table 128-2. The incidence of all types of pneumothoraces is greater in men than in women. For primary pneumothorax, the incidence is 7.4 per 100,000 per year in men and 1.2 per 100,000 in women. Similarly, the incidence of secondary pneumothorax is 6.3 per 100,000 population per year in men and 2.0 per 100,000 in women. More specifically, the incidence is greatest in tall, thin young males.1,2
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A tension pneumothorax occurs as a result of a pulmonary parenchymal or bronchial injury that acts as a one-way valve, permitting air to enter the pleural space but not escape. This causes a decrease in venous return and leads to hemodynamic compromise owing to low preload. Iatrogenic pneumothorax occurs as a consequence of inadvertent puncture of the lung during an invasive procedure.
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The lung has an inherent tendency to collapse and the chest wall to expand. Hence the pressure in the pleural space is always negative in relation ...