Ideally, the pleural cavity can contain up to 2500-3000 ml of fluid: from this, it is understandable how hemothorax can constitute a significant source of blood loss. If blood accumulates in the pleural cavity, the circulating blood volumeis reduced: this “shift” of blood is considered much more serious than a possible collapse of the lung induced by hemothorax. The video below, although in English, gives a very good idea of how a hemothorax forms following displaced rib fractures , and what its consequences are on respiratory mechanics.
Causes And Risk Factors
Contrary to what one might believe, not all forms of hemothorax are the expression of perforating trauma. Two types of hemothorax have therefore been identified:
- Traumatic hemothorax: it is the most recurrent variant, typical consequence of closed traumas ( contusions , chest compression, fractures, dislocations) or perforating wounds (penetrating injuries and piercing wounds, generally associated with lesions of the lung parenchyma ). Sometimes, incorrect placement of a central venous catheter can cause hemothorax. When air and bloody pleural fluid accumulate in the pleural cavity, it is called hemopneumothorax .
- Non-traumatic hemothorax: the effusion of blood into the pleural cavity does not depend on injuries or trauma. This variant is mainly related to alterations in blood pressure levels , pulmonary cysts, blood coagulation defects , hemopathies, bullous emphysema , pulmonary infarction, ruptured aneurysm , tuberculosis and tumors (e.g. pleural cancer ).
|Traumatic hemothorax||Non-traumatic hemothorax|
+ lesions of the lung parenchyma
The symptom picture caused by hemothorax differs more or less significantly based on the triggering factor. NON-traumatic hemothorax is always accompanied by chest pain , breathing difficulties , tachycardia and pallor (these last three signs are characteristic of an anemic state). The traumatic variant is characterized by a much more complex picture, in which signs and symptoms of different nature coexist. Generally speaking, the most recurring symptoms are:
- alteration of blood pressure values
- mood swings/irritability
- lung collapse
- tracheal deviation in correspondence with the healthy hemithorax (half of the thorax).
- subcutaneous emphysema
- severe chest pain
- shortness of breath
- cold, clammy skin
- reduction of breath sound in the affected hemithorax
Hemothorax is suspected in the presence of pleural effusion with reddish veins. When the fluid from the pleural effusion appears bloody, it is essential to proceed with the measurement of the hematocrit value of the pleural fluid . Suspicion of hemothorax is confirmed when the hematocrit is >50% of peripheral blood. In such circumstances, immediate chest drainage is required. Chest radiography,
CT and exploratory thoracentesis are other possible diagnostic strategies used to confirm or not hemothorax . By reading the tests, it is possible to verify the extent and nature of the spill.
A hemothorax visible on radiological examination justifies the instillation of a drain.
The main objectives of therapy for hemothorax are, first and foremost, the arrest of bleeding and the reintegration of blood volume. Prevention of relapses and complications, as well as re-expansion of the lung in a short time are other fundamental principles that must be achieved as soon as possible.
In case of massive hemothorax, the option of a blood transfusion should be considered: in such circumstances, constant monitoring of the patient is recommended. For hemothoraxes with spillage equal to or greater than 1500 ml, emergency thoracotomy is conceivable: this practice frees the pleural cavity, stops the bleeding and allows re-expansion of the lung. Clearly, emergency surgery for hemothorax must be performed with a view to also preventing possible complications, such as empyema and fibrothorax.