Clinical meaning
Hemothorax is the accumulation of blood in the pleural space, most commonly from trauma (rib fractures lacerating intercostal or internal mammary arteries, lung parenchymal injury, or great vessel injury). Non-traumatic causes include malignancy, pulmonary embolism with infarction, coagulopathy/anticoagulation, ruptured aortic aneurysm, and spontaneous hemopneumothorax. The pleural space can hold 2-3 liters of blood — massive hemothorax (> 1500 mL or > 200 mL/hr for 2-4 hours) constitutes a surgical emergency. A retained hemothorax that is not evacuated within 72 hours becomes organized as fibrin deposits trap blood, forming a fibrous peel (fibrothorax) that restricts lung expansion and may become infected (empyema). The decision between chest tube drainage alone versus surgical intervention (VATS or thoracotomy) depends on the initial output and ongoing drainage rate.
Diagnosis & workup
Diagnostics & workup: - CXR upright: meniscus sign at costophrenic angle (300 mL detectable); large hemothorax: complete opacification of hemithorax with mediastinal shift - FAST exam (eFAST): detection of pleural fluid in trauma setting; cannot reliably distinguish blood from other fluids - CT chest with contrast: quantifies hemothorax, identifies source of bleeding, associated injuries (rib fractures, pulmonary contusion, aortic injury) - Pleural fluid analysis: hematocrit > 50% of peripheral blood hematocrit defines hemothorax (vs bloody effusion) - Chest tube output: initial drainage volume and ongoing rate determine management - Massive hemothorax criteria: > 1500 mL initial drainage OR > 200 mL/hr for 2-4 consecutive hours → surgical exploration - Serial hemoglobin and hemodynamic monitoring: trending Hgb drop and hemodynamic instability indicate ongoing hemorrhage - CXR post-chest tube: assess adequacy of drainage, residual hemothorax, lung re-expansion