(See also Overview of Thoracic Trauma.)
The usual cause of hemothorax is laceration of the lung, intercostal vessel, or an internal mammary artery. It can result from penetrating or blunt trauma. Hemothorax is often accompanied by pneumothorax (hemopneumothorax).
Hemorrhage volume ranges from minimal to massive. Massive hemothorax is most often defined as rapid accumulation of ≥ 1000 mL of blood. Shock is common.
Patients with large hemorrhage volume are often dyspneic and have decreased breath sounds and dullness to percussion (often difficult to appreciate during initial evaluation of patients with multiple injuries). Findings may be unremarkable in patients with smaller hemothoraces.
Patients with signs of hypovolemia (eg, tachycardia, hypotension) are given IV crystalloid and sometimes blood transfusion (see Intravenous Fluid Resuscitation).
If blood volume is sufficient to be visible on chest x-ray (usually requiring about 500 mL), or if pneumothorax is present, a large-caliber (eg, 32 to 38 Fr) chest tube is inserted in the 5th or 6th intercostal space in the midaxillary line. Tube drainage improves ventilation, decreases risk of clotted hemothorax (which can lead to empyema or fibrothorax), and facilitates assessment of ongoing blood loss and diaphragmatic integrity. Blood collected via tube thoracostomy can be autotransfused, decreasing the requirement for crystalloid and exogenous blood.
Urgent thoracotomy is indicated in either of the following situations: