CLINICAL PEARLS AND PITFALLS Pneumothorax is one of the most common injuries seen in thoracic trauma The unstable patient with suspected tension pneumothorax requires emergent needle decompression, even before radiologic evaluation, followed by tube thoracostomy The stable pediatric patient with suspected thoracic trauma may be assessed by chest radiography and bedside ultrasound (US) Computed tomography (CT) imaging may not be required Tube thoracostomy is recommended for patients with pneumothoraces that are large, associated with respiratory compromise, or when air transport is required Positive pressure ventilation by itself is not an indication for tube thoracostomy in patients with a small pneumothorax detected on CT only Hemothorax can lead to both respiratory and circulatory compromise, as a large volume of blood can be lost into the pleural space Treatment of hemothorax includes tube thoracostomy and support of circulation with both crystalloid products and blood transfusion as needed Current Evidence Pneumothorax is the second most commonly encountered injury in blunt thoracic trauma and the most common in penetrating thoracic trauma Air within the pleural cavity can arise from penetration of the chest wall, disruption of the lung parenchyma, a tear of the tracheobronchial structures, or esophageal rupture Hemothorax is much more common in penetrating than blunt thoracic trauma In blunt thoracic trauma, a hemothorax can occur from rib fractures lacerating the lung, pulmonary parenchymal injuries unrelated to rib fractures, lacerations of the chest wall vessels, or disruption of the vascular structures in the mediastinum or hilum The most common cause of a hemothorax is injury to the intercostal or internal mammary arteries, whereas injury to the lung or great vessels is less common but more significant Intraperitoneal hemorrhage may lead to a hemothorax if associated with disruption of the diaphragm Air and fluid within the pleural space more easily shift the mediastinum in children, compromising venous return and cardiac output to a greater extent than