Overview

Definition

A hemothorax is defined as a collection of fluid with a hematocrit of at least 50% accumulated in the potential space between the parietal and visceral pleura Pleura The pleura is a serous membrane that lines the walls of the thoracic cavity and the surface of the lungs. This structure of mesodermal origin covers both lungs, the mediastinum, the thoracic surface of the diaphragm, and the inner part of the thoracic cage. The pleura is divided into a visceral pleura and parietal pleura. Pleura of the lungs Lungs Lungs are the main organs of the respiratory system. Lungs are paired viscera located in the thoracic cavity and are composed of spongy tissue. The primary function of the lungs is to oxygenate blood and eliminate CO2. Lungs.

Epidemiology

• In the United States, an estimated 300,000 cases are reported annually.
• Associated with chest trauma and particularly motor vehicle accidents
• Chest trauma seen in 60% of polytrauma

Etiology

The source of blood may be the chest wall Chest wall The chest wall consists of skin, fat, muscles, bones, and cartilage. The bony structure of the chest wall is composed of the ribs, sternum, and thoracic vertebrae. The chest wall serves as armor for the vital intrathoracic organs and provides the stability necessary for the movement of the shoulders and arms. Chest Wall, lung parenchyma, heart, or great vessels from either traumatic or non-traumatic causes.

Traumatic causes:

• Lung parenchymal injury:
  • Most common cause
  • More commonly small (< 10%)
  • Often self-limited
• Arterial injury:
  • Intercostal artery injury (most common)
  • Internal mammary artery injury
  • Great large vessels (rare, but life threatening)
• Iatrogenic:
  • Central venous catheter Central Venous Catheter Central venous catheters are IV lines placed into the large central veins for monitoring of central venous pressure (CVP), prolonged drug administration, or administration of parenteral nutrition. The most common sites of insertion are the internal jugular and subclavian veins. Central Venous Catheter: Technique placement
  • Thoracostomy tube placement

Non-traumatic causes:

• Malignancy
• Anticoagulant medications
• Coagulopathies
• Aortic dissection Aortic dissection Aortic dissection occurs due to shearing stress from pulsatile pressure causing a tear in the tunica intima of the aortic wall. This tear allows blood to flow into the media, creating a "false lumen." Aortic dissection is most commonly caused by uncontrolled hypertension. Aortic Dissection or aneurysm Aneurysm An aneurysm is a bulging, weakened area of a blood vessel that causes an abnormal widening of its diameter > 1.5 times the size of the native vessel. Aneurysms occur more often in arteries than in veins and are at risk of dissection and rupture, which can be life-threatening. Extremity and Visceral Aneurysms
• Tuberculosis Tuberculosis Tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis complex bacteria. The bacteria usually attack the lungs but can also damage other parts of the body. Approximately 30% of people around the world are infected with this pathogen, with the majority harboring a latent infection. Tuberculosis spreads through the air when a person with active pulmonary infection coughs or sneezes. Tuberculosis and necrotizing infections

Pathophysiology

Hemodynamic component:

Large volume loss (each hemothorax can contain up to 40% of total circulating blood volume) into the pleura Pleura The pleura is a serous membrane that lines the walls of the thoracic cavity and the surface of the lungs. This structure of mesodermal origin covers both lungs, the mediastinum, the thoracic surface of the diaphragm, and the inner part of the thoracic cage. The pleura is divided into a visceral pleura and parietal pleura. Pleura can lead to decreased cardiac function due to:

• Decreased preload by constricting the vena cava
• Increased restriction of movement of the cardiac wall
• Increased hydrostatic pressure leading to pulmonary hypertension Pulmonary Hypertension Pulmonary hypertension (PH) or pulmonary arterial hypertension (PAH) is characterized by elevated pulmonary arterial pressure, which can lead to chronic progressive right heart failure. Pulmonary hypertension is grouped into 5 categories based on etiology, which include primary PAH, and PH due to cardiac disease, lung or hypoxic disease, chronic thromboembolic disease, and multifactorial or unclear etiologies. Pulmonary Hypertension

Respiratory component:

Blood collecting in the pleura Pleura The pleura is a serous membrane that lines the walls of the thoracic cavity and the surface of the lungs. This structure of mesodermal origin covers both lungs, the mediastinum, the thoracic surface of the diaphragm, and the inner part of the thoracic cage. The pleura is divided into a visceral pleura and parietal pleura. Pleura decreases the lung’s functional vital capacity by:

• Causing hypoventilation (decreased tidal volume)
• Creating ventilation/perfusion (V/Q) mismatch
• Leading to anatomic shunting

Clinical Presentation

Symptoms

• Shortness of breath
• Chest pain

Signs

• Ipsilateral absent or ↓ breath sounds
• Tracheal deviation
• Dullness on percussion
• Crepitus
• Signs of hemorrhagic shock Shock Shock is a life-threatening condition associated with impaired circulation that results in tissue hypoxia. The different types of shock are based on the underlying cause: distributive (↑ cardiac output (CO), ↓ systemic vascular resistance (SVR)), cardiogenic (↓ CO, ↑ SVR), hypovolemic (↓ CO, ↑ SVR), obstructive (↓ CO), and mixed. Types of Shock in large hemothoraces:
  • Hypotension
  • Tachycardia
  • Tachypnea
  • ↓ Jugular venous pressure

Diagnosis

Diagnosis is established by utilizing history, physical, and appropriate imaging. In cases of trauma, use of the primary survey is paramount to rapid diagnosis and treatment.

Imaging

• Chest X-ray: best initial diagnostic study
  • Upright imaging shows layering of blood.
  • Supine imaging shows haziness or opacity (whiteout).
  • May also show free air if a pneumothorax Pneumothorax A pneumothorax is a life-threatening condition in which air collects in the pleural space, causing partial or full collapse of the lung. A pneumothorax can be traumatic or spontaneous. Patients present with a sudden onset of sharp chest pain, dyspnea, and diminished breath sounds on exam. Pneumothorax is present
• Ultrasound of the lungs Lungs Lungs are the main organs of the respiratory system. Lungs are paired viscera located in the thoracic cavity and are composed of spongy tissue. The primary function of the lungs is to oxygenate blood and eliminate CO2. Lungs (thorax sonography):
  • Part of the Extended Focused Assessment with Sonography for Trauma (eFAST) exam
  • Able to be obtained quickly
  • Can show complex fluid in the pleural cavity
  • More sensitive than a chest X-ray in detecting a hemothorax, but is technician dependent
• Chest computed tomography (CT)—definitive imaging choice:
  • Should only be obtained if the patient is stable 
  • CT can show other associated pathology.
  • CT angiogram can show the source of bleeding.

Management and Complications

Management

• Airway, breathing, and circulation (ABC) assessment → administer 100% oxygen → establish intravenous (IV) access
• Stabilize the patient (fluid resuscitation and blood transfusion as necessary).
• Reverse anticoagulants Anticoagulants Anticoagulants are drugs that retard or interrupt the coagulation cascade. The primary classes of available anticoagulants include heparins, vitamin K-dependent antagonists (e.g., warfarin), direct thrombin inhibitors, and factor Xa inhibitors. Anticoagulants, if necessary.
• Provide analgesia appropriate to the level of the patient’s pain.
• Insert a chest tube (thoracostomy) for large hemothoraces or in an unstable patient:
  • Chest tube inserted on the midaxillary line at the 5th intercostal space
  • Used to drain the hemothorax
  • Monitor output of the hemothorax.
• Surgical intervention (thoracotomy) is indicated when:
  • Evacuating > 1,500 mL of blood directly after inserting a chest tube
  • Continued high output → collecting of > 1 L (1,000 mL) of blood over 4 hours or > 200 mL/hour for 3 consecutive hours

Complications

• Impaired ventilation on the affected side:
  • Leads to respiratory distress
  • May require intubation
• Empyema:
  • Retained blood collection develops a bacterial infection.
  • 5% of cases
• Fibrothorax:
  • Formation of scar tissues within the lungs Lungs Lungs are the main organs of the respiratory system. Lungs are paired viscera located in the thoracic cavity and are composed of spongy tissue. The primary function of the lungs is to oxygenate blood and eliminate CO2. Lungs due to blood irritation
  • 1% of cases

Differential Diagnosis

• Pneumothorax: abnormal collection of air in the pleural space due to laceration of the lungs Lungs Lungs are the main organs of the respiratory system. Lungs are paired viscera located in the thoracic cavity and are composed of spongy tissue. The primary function of the lungs is to oxygenate blood and eliminate CO2. Lungs. Types of pneumothorax Pneumothorax A pneumothorax is a life-threatening condition in which air collects in the pleural space, causing partial or full collapse of the lung. A pneumothorax can be traumatic or spontaneous. Patients present with a sudden onset of sharp chest pain, dyspnea, and diminished breath sounds on exam. Pneumothorax include spontaneous pneumothorax Pneumothorax A pneumothorax is a life-threatening condition in which air collects in the pleural space, causing partial or full collapse of the lung. A pneumothorax can be traumatic or spontaneous. Patients present with a sudden onset of sharp chest pain, dyspnea, and diminished breath sounds on exam. Pneumothorax and traumatic pneumothorax Pneumothorax A pneumothorax is a life-threatening condition in which air collects in the pleural space, causing partial or full collapse of the lung. A pneumothorax can be traumatic or spontaneous. Patients present with a sudden onset of sharp chest pain, dyspnea, and diminished breath sounds on exam. Pneumothorax. Patients have dyspnea Dyspnea Dyspnea is the subjective sensation of breathing discomfort. Dyspnea is a normal manifestation of heavy physical or psychological exertion, but also may be caused by underlying conditions (both pulmonary and extrapulmonary). Dyspnea, chest pain Chest Pain Chest pain is one of the most common and challenging complaints that may present in an inpatient and outpatient setting. The differential diagnosis of chest pain is large and includes cardiac, gastrointestinal, pulmonary, musculoskeletal, and psychiatric etiologies. Chest Pain, decreased breath sounds, and hyper-resonance on percussion. Treatment includes needle decompression and chest tube placement.
• Pleural effusion Pleural Effusion Pleural effusion refers to the accumulation of fluid between the layers of the parietal and visceral pleura. Common causes of this condition include infection, malignancy, autoimmune disorders, or volume overload. Clinical manifestations include chest pain, cough, and dyspnea. Pleural Effusion: accumulation of fluid in the pleural cavity. Can be caused by many conditions, including infection, malignancy, and heart failure. Symptoms include chest pain Chest Pain Chest pain is one of the most common and challenging complaints that may present in an inpatient and outpatient setting. The differential diagnosis of chest pain is large and includes cardiac, gastrointestinal, pulmonary, musculoskeletal, and psychiatric etiologies. Chest Pain, dyspnea Dyspnea Dyspnea is the subjective sensation of breathing discomfort. Dyspnea is a normal manifestation of heavy physical or psychological exertion, but also may be caused by underlying conditions (both pulmonary and extrapulmonary). Dyspnea, and orthopnea. Diagnosis is by imaging, and pleural fluid analysis helps determine the etiology. Management is dependent on the underlying condition and severity, but may include monitoring, thoracentesis, chest tube placement, or surgery.
• Atelectasis Atelectasis Atelectasis is the partial or complete collapse of a part of the lung. Atelectasis is almost always a secondary phenomenon from conditions causing bronchial obstruction, external compression, surfactant deficiency, or scarring. Atelectasis: condition characterized by the collapse of alveoli, and eventually, lobar lung collapse and complete obstruction. Patients present with respiratory distress ( dyspnea Dyspnea Dyspnea is the subjective sensation of breathing discomfort. Dyspnea is a normal manifestation of heavy physical or psychological exertion, but also may be caused by underlying conditions (both pulmonary and extrapulmonary). Dyspnea, tachypnea, tachycardia) and hypoxemia. Physical examination of the lungs Lungs Lungs are the main organs of the respiratory system. Lungs are paired viscera located in the thoracic cavity and are composed of spongy tissue. The primary function of the lungs is to oxygenate blood and eliminate CO2. Lungs reveals dullness to percussion and decreased breath sounds. Chest X-ray shows lung opacification. Management is aimed at ventilatory support. 
• Pulmonary embolism Pulmonary Embolism Pulmonary embolism (PE) is a potentially fatal condition that occurs as a result of intraluminal obstruction of the main pulmonary artery or its branches. The causative factors include thrombi, air, amniotic fluid, and fat. In PE, gas exchange is impaired due to the decreased return of deoxygenated blood to the lungs. Pulmonary Embolism (PE): obstruction of pulmonary arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries, most often due to thrombus migration from the deep venous system. Signs and symptoms include pleuritic chest pain Chest Pain Chest pain is one of the most common and challenging complaints that may present in an inpatient and outpatient setting. The differential diagnosis of chest pain is large and includes cardiac, gastrointestinal, pulmonary, musculoskeletal, and psychiatric etiologies. Chest Pain, dyspnea Dyspnea Dyspnea is the subjective sensation of breathing discomfort. Dyspnea is a normal manifestation of heavy physical or psychological exertion, but also may be caused by underlying conditions (both pulmonary and extrapulmonary). Dyspnea, tachypnea, and tachycardia. Severe cases are life threatening. Chest CT with angiography is the primary method of diagnosis. Management includes oxygenation, anticoagulation, and thrombolytic therapy for unstable patients.