Pneumothoraces are categorized as simple, open, or tension pneumothorax. The principal physiologic changes are hypoxemia due to reduced vital capacity, alveolar hypoventilation, and impaired venous return secondary to increased intrathoracic pressure.

Simple pneumothorax can result from both blunt and penetrating chest trauma. It is defined as the presence of air in the pleural space without an open chest wound or evidence of tension pneumothorax. Diagnosis can be made radiographically, by chest radiography or computed tomography, although in many trauma situations, the patient's condition precludes obtaining conventional imaging. In such cases, diagnosis can be made by lung ultrasound. The lack of pleural sliding, lung pulse, and vertical artifacts over the anterior chest wall, coupled with the presence of a lung point, are highly sensitive and specific findings for pneumothorax. Recent studies have demonstrated that using lung ultrasound can be a faster and more sensitive test than a supine anterior-posterior chest radiography. Definitive treatment is the placement of a chest tube or pleural pigtail if the patient is experiencing cardiopulmonary instability, and/or if the pneumothorax is sizable, that is greater than 10% of the pleural cavity. Of note, pigtail catheters have been shown to be equally as effective as chest tubes with decreased complications.

Open pneumothorax is the result of an open wound in the thoracic cavity that favors constant entrainment of air through the wound. Treatment entails placing an occlusive dressing on three sides over the wound, to create a "flutter valve" and allow egress of air but not entrainment of air, followed by chest tube placement.

Tension pneumothorax is the rapid buildup of air within the pleural space that cannot escape, causing an acute rise in airway pressures with resulting mediastinal shift and obstructive shock. Management is immediate decompression of the thoracic cavity by needle thoracentesis or finger thoracostomy followed by chest tube insertion.

References

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