bubble_chart Overview

The presence of blood in the pleural cavity is called hemothorax, and when both blood and air are present, it is called hemopneumothorax. Hemothorax is common in cases of chest trauma. Bleeding can originate from intercostal vessels, internal thoracic vessels, lung lacerations, or injuries to the heart and major thoracic vessels. The amount of blood in the hemothorax depends on the size of the vascular rupture, the blood pressure, and the duration of bleeding. Most lung tissue bleeding is caused by rib fractures puncturing the pleura and lung. Due to the small size of the ruptured vessels and the low pressure in the pulmonary circulation, the bleeding site is often sealed by clots and stops on its own, usually resulting in a small amount of bleeding. Rupture of intercostal arteries or internal thoracic arteries, due to the high pressure in the systemic circulation, is less likely to stop on its own and results in more significant bleeding. Rupture of the heart or major thoracic vessels such as the aorta and its branches, the superior and inferior vena cava, and the pulmonary arteries and veins, leads to massive bleeding, severe injury, and patients often die from shock due to massive blood loss in a short period of time.

bubble_chart Pathological Changes

Hemothorax in the pleural cavity first causes compression and collapse of the ipsilateral lung. A massive hemothorax can also shift the mediastinum toward the healthy side, leading to collapse of the contralateral lung. Significant blood loss and compression of the mediastinum and lungs can result in respiratory difficulties and circulatory dysfunction, with severe cases presenting symptoms of shock. The compression of the lungs and mediastinum is even more severe in cases of hemopneumothorax. Blood accumulates in the pleural cavity, and the continuous movement of the lungs, diaphragm, and heart helps to remove fibrin, generally delaying blood coagulation. However, sometimes blood coagulates shortly after bleeding. Extensive trauma to the lung and chest wall tissues, as well as hemothorax accompanied by liver, spleen, or diaphragm rupture, often leads to early blood coagulation. In cases of uninfected hemothorax, after blood coagulation, the fibrin and blood clots attached to the pleura gradually organize, forming fibrous tissue that covers and constricts the lungs and chest wall, limiting chest wall movement, compressing lung tissue, and impairing gas exchange. The fibrous tissue layer on the pleura can reach several millimeters in thickness, a condition known as fibrothorax.

Blood is an excellent medium for bacterial growth. If hemothorax is not promptly treated, bacteria entering from wounds in the chest wall or internal organs can easily lead to pleural cavity infection, resulting in empyema.

bubble_chart Clinical Manifestations

The clinical manifestations of hemothorax vary depending on the amount of bleeding, the rate of bleeding, the condition of intrathoracic organ injuries, and the constitution of the patient. Rib fractures complicated by a small amount of hemothorax generally result in less blood loss and do not present obvious clinical symptoms. In cases where the bleeding is substantial, exceeding 1000ml, and the bleeding rate is rapid, symptoms of hypovolemic shock such as pale complexion, rapid and weak pulse, rapid breathing, and decreased blood pressure may appear, along with respiratory difficulties and hypoxia due to the compression of the lungs and mediastinum by a large amount of blood in the pleural cavity. A small hemothorax often shows no abnormal signs. A large hemothorax may present with the trachea and heart shifting to the healthy side, fullness of the intercostal spaces on the injured side, and dullness on percussion. In cases of hemopneumothorax, the upper chest may show tympanic resonance, while the lower chest shows dullness. Breath sounds may be weakened or absent. Patients with hemothorax caused by lung lacerations often have hemoptysis. A small amount of blood retained in the costophrenic sinus may be difficult to detect on chest X-rays, or the costophrenic angle may disappear. A larger amount of hemothorax will show increased density on the injured side of the chest, which is more clearly visible on lateral decubitus chest films. A large hemothorax will show a large area of dense fluid shadow and signs of mediastinal shift. In cases of hemopneumothorax, a fluid level will be visible. Diagnosis can be confirmed by aspirating blood from the pleural cavity. After aspiration, the pleural effusion may decrease and then increase again. If the blood in the pleural cavity coagulates and aspiration fails to withdraw blood or only a small amount of blood is withdrawn, but shock symptoms worsen or X-ray shows an increase in pleural effusion; or if the pleural drainage exceeds 200ml per hour and persists for more than 2 hours after pleural drainage, these indicate ongoing bleeding that requires timely treatment.

Pleural effusion can cause low-grade fever, but if symptoms of suppurative infection such as shivering, high fever, and increased white blood cell count appear, aspiration should be performed for bacterial smear and culture tests.

If hemothorax evolves into fibrothorax, and the affected area is large, it may lead to collapse of the affected chest, weakened respiratory movement, shift of the trachea and mediastinum to the affected side, and reduced lung ventilation. X-ray examination will show dense shadows caused by fibrous plaques.

bubble_chart Treatment Measures

A small amount of hemothorax, such as that commonly associated with rib fractures, can be rapidly absorbed without leaving any sequelae and does not require special treatment. For moderate or larger amounts of hemothorax (less than 1000ml), if the bleeding has stopped on its own and the patient's condition is stable, a thoracentesis can be performed to remove as much accumulated blood as possible, or intercostal drainage can be done to promote lung expansion, improve respiratory function, and prevent the complication of empyema. After each thoracentesis, antibiotics can be injected into the pleural cavity, and blood transfusion or fluid replacement can be administered as necessary to correct hypovolemia.

In cases of progressive bleeding in the pleural cavity, where the hemothorax has clotted and cannot be removed, or in cases of open chest wall injuries or ruptured thoracic organs, a thoracotomy should be performed after initiating anti-shock treatments such as blood transfusion and fluid replacement. The goal is to remove blood clots and accumulated blood and to identify the source of bleeding. For bleeding from intercostal or internal thoracic vessels, ligation should be performed at both the proximal and distal ends of the vessel rupture. Most lung lacerations can be sutured to stop bleeding, but if the laceration is extensive and the tissue injury is severe, a partial lung resection may be necessary. Injuries to thoracic organs are generally severe and require urgent treatment. For coagulated hemothorax, fibrinolytic enzymes such as streptokinase (100,000 U) or streptodornase (25,000 U) can be injected into the pleural cavity, but due to significant side effects, high cost, and unsatisfactory efficacy, this method is now less commonly used.

If hemothorax is complicated by pleural infection, it should be treated as empyema.

Organized hemothorax or fibrothorax should be treated with thoracotomy 2-3 weeks after the injury, once the fibrous layer of the pleura has formed. The goal is to peel off the fibrous tissue layer from the chest wall and lung surface to increase chest wall mobility, expand lung tissue, and improve respiratory function. Performing the surgery too early, before the fibrous layer has formed, makes it difficult to peel off in one piece. Performing the surgery too late may result in tight adhesions between the fibrous layer and lung tissue, leading to more bleeding and multiple lung tissue injuries during the peeling process. Postoperative pleural drainage is necessary.