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Emergency And Acute Medicine – Hemothorax
Basics And Description
Hemothorax is the accumulation of blood within the intrapleural space, most commonly following blunt or penetrating chest trauma, though nontraumatic causes exist. Bleeding usually results from disruption of chest wall tissues, pleura, or intrathoracic vessels, leading to decreased vital capacity, hypoxia, and respiratory compromise. Significant intravascular blood loss may cause hemodynamic instability and hemorrhagic shock. Massive hemothorax can increase intrathoracic pressure, impair venous return, and reduce cardiac output. In blunt trauma, hemothorax is rarely isolated and is frequently associated with pneumothorax, extrathoracic injuries, and pulmonary contusion. Large collections may release anticoagulant substances, promoting continued bleeding. Untreated hemothorax can progress to empyema or fibrothorax due to pleural adhesions and lung trapping.
Etiology
Traumatic causes include injury to major thoracic vessels such as intercostal arteries, internal mammary arteries, pulmonary vessels, the aorta, vena cava, and the heart. Lung parenchymal injuries may also cause bleeding, which often stops spontaneously because of low pulmonary pressures and high thromboplastin levels, and are frequently associated with pneumothorax. Nontraumatic or spontaneous hemothorax is rare and should prompt evaluation for coagulation disorders, malignancy, vascular catastrophes such as aortic dissection or ruptured aneurysm, pulmonary embolism with infarction, tuberculosis, bullous emphysema, pulmonary arteriovenous malformations, or lobar sequestration. Hemothorax may also occur from torn pleural adhesions during spontaneous pneumothorax or following tube thoracostomy.
Diagnosis – Signs And Symptoms
Small hemothoraces, generally less than 400 mL, may cause minimal or no changes in vital signs or physical examination. Large hemothoraces, typically exceeding 1,000 mL, present with restlessness, anxiety, pallor, pleuritic chest pain, hemoptysis, dyspnea, and air hunger. Signs of hemorrhagic shock appear when blood loss reaches or exceeds 30% of circulating volume, including tachycardia, tachypnea, and hypotension. In cases with slow or insidious onset, such as malignancy-related hemothorax, dyspnea is often the predominant symptom without acute hemodynamic compromise.
History
Important historical features include recent blunt or penetrating chest trauma, rib fractures, flail chest, or delayed onset of symptoms hours to days after injury. Delayed hemothorax may result from rupture of chest wall hematomas or intercostal vessel injury from rib fracture movement. Additional history includes known malignancy, metastatic disease, or recent thoracic procedures such as thoracentesis or chest tube placement.
Physical Examination
Vital signs may reveal hypoxia, tachypnea, tachycardia, or hypotension depending on severity. Jugular venous distention may be present with increased intrathoracic pressure, and tracheal deviation can occur in massive collections. Chest inspection may show asymmetric expansion, deformity, contusions, abrasions, or paradoxical movement. Palpation may elicit rib tenderness, crepitus, or subcutaneous emphysema, while percussion typically reveals dullness over the affected hemithorax. Auscultation demonstrates decreased or absent breath sounds, best appreciated in the upright patient.
Essential Workup
Chest radiography is the primary diagnostic study. In stable patients, an upright posteroanterior film is ideal and can detect pleural fluid volumes greater than 200–300 mL, seen as meniscus formation or blunting of the costophrenic angle. In supine trauma patients, up to 1,000 mL of blood may be missed, appearing only as diffuse haziness of the hemithorax. Associated injuries such as pneumothorax, rib fractures, pulmonary contusions, or mediastinal widening should be assessed.
Diagnostic Tests And Interpretation
Laboratory evaluation includes hematocrit monitoring for trends, type and cross-match, pulse oximetry, and arterial blood gas analysis when indicated. Pleural fluid hematocrit exceeding 50% of peripheral blood hematocrit confirms hemothorax. Ultrasound, particularly extended FAST, is highly sensitive for detecting intrapleural fluid in trained hands. Computed tomography is useful for identifying small hemothoraces not visible on chest radiographs and for evaluating associated injuries.
Differential Diagnosis
Hemopneumothorax, pneumothorax, pulmonary contusion, pleural effusion, and empyema or pneumonia.
Treatment – Prehospital Care
Initial management includes assessment of vital signs and oxygen saturation, supplemental oxygen, intravenous access, and fluid resuscitation for hypotension. Clinical differentiation between hemothorax and pneumothorax may be difficult; subcutaneous emphysema suggests pneumothorax, while dullness to percussion favors hemothorax. In unstable patients with suspected tension pneumothorax, needle thoracostomy should be performed immediately.
Initial Stabilization And Therapy
Airway, breathing, and circulation are prioritized. Endotracheal intubation is indicated for impending respiratory failure. High-flow oxygen, two large-bore intravenous lines, and rapid fluid resuscitation are initiated. If chest tube equipment is not immediately available in an unstable patient, needle thoracostomy should not be delayed. Patients should be positioned upright when possible.
Emergency Department Treatment And Procedures
Definitive management involves evacuation of blood from the pleural space via tube thoracostomy. A large-bore chest tube, typically 36–40 French, is inserted in the 4th or 5th intercostal space at the mid-axillary line, directed posteriorly and superiorly, and connected to underwater seal drainage with suction. Post-procedure chest radiography confirms placement and lung re-expansion. Autotransfusion should be considered when available. Indications for operative thoracotomy include initial chest tube output greater than 20 mL/kg in children or approximately 1,000 mL in adults, persistent bleeding exceeding 7 mL/kg/hr or 200 mL/hr for four hours, enlarging hemothorax, refractory hypotension, or clinical deterioration after initial response. Emergency department thoracotomy may be indicated in select cases of penetrating trauma with recent arrest or profound shock, and rarely in blunt trauma under specialized circumstances.
Medications
Local anesthetics are used for chest tube placement in awake patients. Procedural sedation and analgesia with agents such as fentanyl and midazolam may be administered in stable patients. Additional sedatives may be used as clinically appropriate.
Follow-Up And Disposition
Patients requiring tube thoracostomy should be admitted to a trauma, cardiothoracic, or surgical service experienced in chest tube management. Small, isolated hemothoraces detected incidentally may be observed for 4–6 hours and discharged if asymptomatic, normoxic, and without evidence of ongoing bleeding. Asymptomatic blunt chest trauma patients with normal initial radiographs do not require repeat imaging prior to discharge.
Key Clinical Insights And Common Pitfalls
The pleural cavity can hold more than 4 liters of blood, allowing massive hemorrhage without external bleeding. In supine patients, physical findings may be subtle due to posterior blood distribution. Hemothorax may be misread as pneumonia in the absence of trauma history. Concurrent diaphragmatic injury raises concern for intra-abdominal bleeding. Early preparation for autotransfusion is important, as the greatest blood loss often occurs at initial chest tube placement. Improper chest tube positioning, especially too anterior or superior, can impair drainage; all fenestrations must lie within the thoracic cavity. Prophylactic antibiotics with chest tube placement do not reduce pneumonia or empyema risk.
Basics And Description
Hemothorax is the accumulation of blood within the intrapleural space, most commonly following blunt or penetrating chest trauma, though nontraumatic causes exist. Bleeding usually results from disruption of chest wall tissues, pleura, or intrathoracic vessels, leading to decreased vital capacity, hypoxia, and respiratory compromise. Significant intravascular blood loss may cause hemodynamic instability and hemorrhagic shock. Massive hemothorax can increase intrathoracic pressure, impair venous return, and reduce cardiac output. In blunt trauma, hemothorax is rarely isolated and is frequently associated with pneumothorax, extrathoracic injuries, and pulmonary contusion. Large collections may release anticoagulant substances, promoting continued bleeding. Untreated hemothorax can progress to empyema or fibrothorax due to pleural adhesions and lung trapping.
Etiology
Traumatic causes include injury to major thoracic vessels such as intercostal arteries, internal mammary arteries, pulmonary vessels, the aorta, vena cava, and the heart. Lung parenchymal injuries may also cause bleeding, which often stops spontaneously because of low pulmonary pressures and high thromboplastin levels, and are frequently associated with pneumothorax. Nontraumatic or spontaneous hemothorax is rare and should prompt evaluation for coagulation disorders, malignancy, vascular catastrophes such as aortic dissection or ruptured aneurysm, pulmonary embolism with infarction, tuberculosis, bullous emphysema, pulmonary arteriovenous malformations, or lobar sequestration. Hemothorax may also occur from torn pleural adhesions during spontaneous pneumothorax or following tube thoracostomy.
Diagnosis – Signs And Symptoms
Small hemothoraces, generally less than 400 mL, may cause minimal or no changes in vital signs or physical examination. Large hemothoraces, typically exceeding 1,000 mL, present with restlessness, anxiety, pallor, pleuritic chest pain, hemoptysis, dyspnea, and air hunger. Signs of hemorrhagic shock appear when blood loss reaches or exceeds 30% of circulating volume, including tachycardia, tachypnea, and hypotension. In cases with slow or insidious onset, such as malignancy-related hemothorax, dyspnea is often the predominant symptom without acute hemodynamic compromise.
History
Important historical features include recent blunt or penetrating chest trauma, rib fractures, flail chest, or delayed onset of symptoms hours to days after injury. Delayed hemothorax may result from rupture of chest wall hematomas or intercostal vessel injury from rib fracture movement. Additional history includes known malignancy, metastatic disease, or recent thoracic procedures such as thoracentesis or chest tube placement.
Physical Examination
Vital signs may reveal hypoxia, tachypnea, tachycardia, or hypotension depending on severity. Jugular venous distention may be present with increased intrathoracic pressure, and tracheal deviation can occur in massive collections. Chest inspection may show asymmetric expansion, deformity, contusions, abrasions, or paradoxical movement. Palpation may elicit rib tenderness, crepitus, or subcutaneous emphysema, while percussion typically reveals dullness over the affected hemithorax. Auscultation demonstrates decreased or absent breath sounds, best appreciated in the upright patient.
Essential Workup
Chest radiography is the primary diagnostic study. In stable patients, an upright posteroanterior film is ideal and can detect pleural fluid volumes greater than 200–300 mL, seen as meniscus formation or blunting of the costophrenic angle. In supine trauma patients, up to 1,000 mL of blood may be missed, appearing only as diffuse haziness of the hemithorax. Associated injuries such as pneumothorax, rib fractures, pulmonary contusions, or mediastinal widening should be assessed.
Diagnostic Tests And Interpretation
Laboratory evaluation includes hematocrit monitoring for trends, type and cross-match, pulse oximetry, and arterial blood gas analysis when indicated. Pleural fluid hematocrit exceeding 50% of peripheral blood hematocrit confirms hemothorax. Ultrasound, particularly extended FAST, is highly sensitive for detecting intrapleural fluid in trained hands. Computed tomography is useful for identifying small hemothoraces not visible on chest radiographs and for evaluating associated injuries.
Differential Diagnosis
Hemopneumothorax, pneumothorax, pulmonary contusion, pleural effusion, and empyema or pneumonia.
Treatment – Prehospital Care
Initial management includes assessment of vital signs and oxygen saturation, supplemental oxygen, intravenous access, and fluid resuscitation for hypotension. Clinical differentiation between hemothorax and pneumothorax may be difficult; subcutaneous emphysema suggests pneumothorax, while dullness to percussion favors hemothorax. In unstable patients with suspected tension pneumothorax, needle thoracostomy should be performed immediately.
Initial Stabilization And Therapy
Airway, breathing, and circulation are prioritized. Endotracheal intubation is indicated for impending respiratory failure. High-flow oxygen, two large-bore intravenous lines, and rapid fluid resuscitation are initiated. If chest tube equipment is not immediately available in an unstable patient, needle thoracostomy should not be delayed. Patients should be positioned upright when possible.
Emergency Department Treatment And Procedures
Definitive management involves evacuation of blood from the pleural space via tube thoracostomy. A large-bore chest tube, typically 36–40 French, is inserted in the 4th or 5th intercostal space at the mid-axillary line, directed posteriorly and superiorly, and connected to underwater seal drainage with suction. Post-procedure chest radiography confirms placement and lung re-expansion. Autotransfusion should be considered when available. Indications for operative thoracotomy include initial chest tube output greater than 20 mL/kg in children or approximately 1,000 mL in adults, persistent bleeding exceeding 7 mL/kg/hr or 200 mL/hr for four hours, enlarging hemothorax, refractory hypotension, or clinical deterioration after initial response. Emergency department thoracotomy may be indicated in select cases of penetrating trauma with recent arrest or profound shock, and rarely in blunt trauma under specialized circumstances.
Medications
Local anesthetics are used for chest tube placement in awake patients. Procedural sedation and analgesia with agents such as fentanyl and midazolam may be administered in stable patients. Additional sedatives may be used as clinically appropriate.
Follow-Up And Disposition
Patients requiring tube thoracostomy should be admitted to a trauma, cardiothoracic, or surgical service experienced in chest tube management. Small, isolated hemothoraces detected incidentally may be observed for 4–6 hours and discharged if asymptomatic, normoxic, and without evidence of ongoing bleeding. Asymptomatic blunt chest trauma patients with normal initial radiographs do not require repeat imaging prior to discharge.
Key Clinical Insights And Common Pitfalls
The pleural cavity can hold more than 4 liters of blood, allowing massive hemorrhage without external bleeding. In supine patients, physical findings may be subtle due to posterior blood distribution. Hemothorax may be misread as pneumonia in the absence of trauma history. Concurrent diaphragmatic injury raises concern for intra-abdominal bleeding. Early preparation for autotransfusion is important, as the greatest blood loss often occurs at initial chest tube placement. Improper chest tube positioning, especially too anterior or superior, can impair drainage; all fenestrations must lie within the thoracic cavity. Prophylactic antibiotics with chest tube placement do not reduce pneumonia or empyema risk.
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