Hemothorax refers to the accumulation of blood in the pleural cavity, and when it coexists with pneumothorax, it is termed hemopneumothorax. The primary sources of bleeding in hemothorax include the heart, major thoracic blood vessels and their branches, the chest wall, lung tissue, diaphragm, and pericardial vessels. The presence of hemothorax not only affects circulatory function due to the loss of blood volume but also compresses the lungs, reducing respiratory surface area and impairing respiratory function. Hemothorax can shift the mediastinum, compress the healthy lung, and obstruct venous return to the heart. When a large volume of blood rapidly accumulates in the pleural cavity and exceeds the defibrination capacity of the lungs, pericardium, and diaphragm, coagulation occurs, leading to coagulating hemothorax. Over time, organized blood clots form fibrous plaques that restrict the movement of the lungs and chest wall, further impairing respiratory function. Bacteria introduced through wounds or lung ruptures can proliferate rapidly in the accumulated blood, resulting in infective hemothorax, which may progress to pyohemothorax. Persistent massive bleeding into the pleural cavity is referred to as progressive hemothorax. In some cases, delayed onset hemothorax can occur when displaced rib fragments puncture intercostal vessels or when clots detach from ruptured vessels, resulting in a late accumulation of blood in the pleural cavity.
Clinical Manifestations
The clinical manifestations of hemothorax depend on the volume of bleeding, the rate of bleeding, and the patient's physical condition. In adult patients, hemothorax with a volume ≤500 mL is classified as mild, 500–1,000 mL as moderate, and >1,000 mL as massive. Patients may present with varying degrees of hypovolemic shock, characterized by pallor, a rapid and weak pulse, reduced blood pressure, and poor peripheral perfusion. Other signs include rapid breathing, fullness of the intercostal spaces, tracheal deviation toward the healthy side, dullness on percussion, and diminished breath sounds on the affected side. Chest X-rays or CT scans typically reveal signs of pleural effusion. The diagnosis is confirmed by thoracentesis, which reveals blood in the pleural cavity.
Progressive hemothorax may be indicated by the following:
- Persistent tachycardia and hypotension, or unstable blood pressure despite fluid resuscitation.
- Closed thoracic drainage yields >200 mL of blood per hour for three consecutive hours.
- Progressive decreases in hemoglobin levels, red blood cell count, and hematocrit, with the hemoglobin concentration and red blood cell count of the drained blood closely matching peripheral blood and coagulating rapidly.
Infective hemothorax should be suspected in patients presenting with:
- Systemic signs of infection, such as chills and high fever.
- Cloudy or particulate material in aspirated pleural blood (1 mL of pleural blood mixed with 5 mL of distilled water appears turbid or contains floccules, suggesting infection); noninfected pleural blood remains uniformly pink and transparent.
- Increased white blood cell count in pleural fluid relative to peripheral blood. Infections disturb the normal red-to-white blood cell ratio of 500:1, with ratios of 100:1 indicative of infective hemothorax.
- Smear and bacterial culture from the pleural fluid identifying pathogens, which guide the selection of effective antibiotics.
Management
Non-progressive hemothorax with a small amount of blood in the pleural cavity can be managed with thoracentesis to remove the accumulated blood. Moderate to large hemothorax, or cases where the hemothorax persists with the risk of coagulating or infective hemothorax, requires aggressive management with closed thoracic drainage to promote lung re-expansion and improve respiratory function. Antibiotics are used to prevent infections. Progressive hemothorax necessitates timely thoracotomy for exploration. Coagulating hemothorax should be treated surgically as soon as the patient stabilizes, to clear blood clots and remove fibrous membranes formed from organized blood. Thoracotomy within 2–3 days post-injury is often optimal, as delaying surgery significantly complicates the removal of fibrin membranes adhering to the lung surface.
Infective hemothorax requires improvement in pleural drainage and the removal of infected blood and pus. If drainage proves insufficient or if lung re-expansion remains incomplete, early surgery is indicated to evacuate the infected blood and excise any purulent fibrous membranes. Video-assisted thoracoscopic surgery (VATS) is commonly employed for both coagulating and infective hemothorax due to its minimal invasiveness, high efficacy, and shorter hospitalization time.