Thoracic Trauma

Overview

Emphasis in thoracic trauma is on proper airway and breathing (since injury can be to the airway structures themselves). Patients with thoracic trauma should be put on 100% O2 via NRB mask (not nasal cannulas) since hypoxia is an independent risk factor for mortality in chest trauma. Open injury can be caused by penetrating trauma (knife, gunshot) while closed injury commonly occurs following blunt trauma, blasts and deceleration injury (RTA is the most common cause)

85% of thoracic trauma can be treated with a simple tube thoracostomy. Thoracic injuries account for 25% of deaths from trauma, and 2/3 of these deaths occur in hospital. Half of of patients who die from multiple injury have significant thoracic injury.

Life-threatening thoracic injuries on primary survey

• Causes of shock in chest trauma
  • Blood loss (damage to great vessels)
  • Increased intrapleural pressure (tension pneumothorax causing mediastinal shift which reflects on the heart)
  • Vascular disruption
  • Myocardial dysfunction
  • Cardiac tamponade
• How does chest pain increase the risk for atelectasis and pneumonia?
  • Chest pain causes more frequent, shallow breaths.
  • Less deep breaths → Greater risk for atelectasis and pneumonia (lungs aren’t aerated well from apices to bases. Big concern in older patients)
  • Need good pulmonary toilet
• General life-threatening chest injuries
  • Pneumothorax (tension, open)
  • Hemothorax (more concerning if massive)
  • Pulmonary contusion (may co-exist with flail chest)
  • Tracheobronchial injury
  • Blunt cardiac injury
  • Traumatic Aortic injury
  • Traumatic Diaphragmatic injury
  • Traversing mediastinal injury
• Potentially life-threatening chest injuries
  • Traversing chest wound
  • Tracheobronchial tree injury
  • Oesophageal injury
  • Severe injury

Tension pneumothorax

Tension pneumothorax is the disruption of lung tissue causing progressive accumulation of air in the pleural space.

• Pathophysiology
  • Rib fractures → punctures pleura → accumulation of air in pleural space without outside communication → increased pressure causes mediastinal shift and reflects back on the heart → reduced venous return → decreased cardiac output.
  • Can lead to bullae.
  • Can develop from the retroperitoneum
• Key Signs and Symptoms
  • Jugular Venous Distension (Due to acute CHF)
  • Absent breath sounds on the affected side
  • Hyperresonant percussion on the affected side
  • Dyspnea
• Signs and symptoms
  • Chest pain and Dyspnea: Sudden, severe, and/or stabbing, ipsilateral , pleuritic
  • Hemodynamic instability: tachycardia, hypotension, pulsus paradoxus,
  • Inspection: JVD, Penetrating chest wound, Severe acute respiratory distress, cyanosis, restlessness, diaphoresis, reduced chest expansion on the ipsilateral side
  • Palpation: decreased fremitus on the ipsilateral side, subcutaneous emphysema (crepitus), tracheal deviation
  • Auscultation: Reduced or absent breath sounds
  • Percussion: Hyperresonant percussion
• P-THORAX
  • Pleuritic pain
  • Tracheal deviation
  • Hyperresonance
  • Onset sudden
  • Reduced breath sound and dyspnea
  • Absent fremitus
  • X-ray shows collapse, mediastinal shift
• Investigations
  • Chest X-ray: loss of vascular markings, mediastinal shift to the unaffected side
• Treatment
  • Emergent chest decompression (relieves shock) ****followed by **chest-tube placement (**keeps air out)

Emergent chest decompression

Open Pneumothorax (Sucking Chest Wound)

An open pneumothorax is due to chest wall defect causing accumulation of air in the pleural space with resulting equilibration of atmospheric and hemi-intrathoracic pressure. Lungs expand only by the development of a negative hemi-intrathoracic pressure. In pneumothorax, the lung is collapsed and cannot exchange oxygen. Physical exam findings may be normal if the pneumothorax is < 25%. ATLS recommends chest tube placement for traumatic pneumothorax. Some pneumothorax can be managed with observation or aspiration (except when the patient is scheduled to receive general anaesthesia or positive pressure ventilation). Moderate (20 – 40%) and large (>40%) pneumothoraces are associated with persistent symptoms that cause physical limitation and require a chest tube. Pneumothoraces are typically reabsorbed at a rate of 1% per day.

• Key signs and symptoms
  • Dyspnea
  • Absent lung sounds on the affected side
  • Hyper-resonance to percussion on the affected side
• Difference between open pneumothorax and tension pneumothorax
  • There is no compression of the heart or vena cava in open pneumothorax since it does not trap pressure in the hemithorax (the pressure is only equilibrated with the outside)
  • Thus might not have JVD or shock
• Investigations
  • eFAST: highly sensitive
  • Chest X-ray
• Treatment
  • Sterile gauze and three-sided taping of wound (to allow air to get out. Tape on 4 sides and convert it to tension pneumothorax)
  • Tube thoracostomy
  • Definitive Wound closure (with debridement)
  • Video-assisted thoracoscopy (VATS) if there is persistent air leak on post-injury day 3

Tracheobronchial disruption

Uncommon but devastating and life-threatening. Injury to the upper/mid-upper airway. Caused by crush injury or MVA. 80% of patients die before receiving medical attention. Stabilize by intubating the patient

• Signs and symptoms
  • Respiratory distress/failure
  • Hypoxia
  • Hemoptysis
  • Subcutaneous emphysema of the upper chest (more specific)
• Investigations
  • CXR if stable: Pneumomediastinum, Subcutaneous air
  • Tracheobronchoscopy (most accurate)
• Treatment
  • Definitive surgical correction

Hemothorax

Hemothorax is the accumulation of blood in the pleural space. It arises from trauma which damages the chest wall, lung parenchyma, or other vascular structures. Commonly occurs with penetrating chest trauma. They should be drained by a chest tube regardless of their size to reduce the risk of empyema.

• Signs and symptoms
  • Respiratory distress
  • Tachypnoea
  • Hypoxia
  • Hypotension w/narrow pulse pressure
  • Dull to percussion in dependent areas on the affected side
• Investigations
  • Chest X-ray (upright lateral and AP when stable): cannot distinguish between hmothorax and pleural effusion on Chest X-ray
    • Opacity (possible if fluid > 200-300mL)
    • Blunting of costophrenic angle
    • Tracheal deviation (mediastinal shift)
• Treatment
  • Tube thoracostomy immediately when a haemothorax is suspected
  • Ensure hemodynamic stability (Group and Cross Match and O negative blood on hand)
  • Video Assisted Thoracoscopy (VATS) if there is persistent or retained hemothorax following chest tube placement
  • Intrapleural thrombolytic therapy (streptokinase, urokinase or tPA) for loculated hemothorax
  • Open thoracostomy if indicated
• Complications of hemothorax
  • Pleural empyema (clot infection)
  • Fibrothorax
  • Trapped lung (clot prevent lung from expanding)

Tube thoracostomy (Chest Tube)

Chest tube placement is a critical surgical procedure that is often life-saving when done urgently. Antibiotic prophylaxis should be given to all penetrating trauma patients before chest tube placement (consideration can be given before placing a tube in patients with blunt chest trauma)

• Complications of chest tube placement
  • Neurovascular injury
  • Lung laceration
  • Empyema thoracis (due to introduction of bacteria, retained hemothorax, or penetrating trauma)
  • Re-expansion of pulmonary edema (after rapid lung re-expansion)
  • Hemorrhage
  • Tube malposition, blockage, or accidental removal
  • Subcutaneous emphysema
  • Tension pneunmothorax if the tube is not working correctly

Open thoracostomy

• Indications for open thoracostomy
  • ≥ 1,500 ml from initial tube drainage
  • ≥ 200ml/hr drained for 4 continuous hour
  • Multiple transfusions required
  • Patient decompensates after initial stabilization

Rib Fracture

Rib fractures are the most common injury sustained during blunt trauma to the chest. Usually associated with motor vehicle accidents. Fractures of ribs 5 – 10 are most commonly reported. Fracture of the lower ribs (11 – 12) are uncommon since they are short and less exposed. These are associated with injuries to the underlying viscera i.e. spleen, liver and diaphragm. Upper thoracic rib fractures (1 – 5) are also uncommon since they are protected by the pectoral girdle. They are seen in high-velocity injury and can be associated with blunt aortic injury (6%) and blunt cerebrovascular injury.

There is a high incidence of rib fractures in the elderly due to loss of chest wall compliance (due to ossification of costal cartilage and osteoprorosis).

• Signs and symptoms
  • Exquisite chest pain on inspiration
  • Localised tenderness
  • Local crepitations
  • Dyspnea
  • Shallow rapid breaths (tachypnea, due to pain)
  • Features of hemothorax, pneumothorax, or flail chest may be present
• Investigations
  • Chest X-ray: confirm diagnosis in acute setting. Callus appears 3 – 6 weeks after injury
• Treatment
  • Focused on preventing complications (atelectasis and pneumonia) by maintaining good ventilatory function
  • Pain management: Acetaminophen, NSAIDs, Opiates (can cause respiratory depression), Intercostal nerve block (best, bupivacaine > lidocaine)
  • Incentive spirometry, deep breathing exercises and coughing to reduce secretions
  • Rib fractures alone and healthy w/mild-moderate pain – send home with instruction
  • Severe injuries OR concomitant injuries OR respiratory illnesses (COPD) – admit for observation
• Indications for advanced monitoring or admission to the ICU
  • More than 4 rib fractures
  • Age > 65 years old
• Complications of rib fracture
  • Atelectasis → Retained secretions → Pneumonia
  • Flail chest
  • Pulmonary contusion
  • Pneumothorax
  • Hemothorax

Sternal Fracture

Sternal fractures are uncommon and occur secondary to blunt trauma and deceleration injuries of the anterior chest.

• Investigations
  • Lateral chest X-ray: gold standard
  • Sagittal CT scan of the chest
• Treatment
  • Internal fixation: for isolated injuries. For analgesia and cosmesis.
• Complications of sternal fractures
  • Aortic disruption
  • Cardiac contusion
  • Pericardial effusion

Pulmonary contusion

Pulmonary contusion is injury to the lung parenchyma causing oedema and bleeding .“Bruise of the lung”. More trauma = more contusion = less lung for respiratory exchange. Localized and appears after a while following trauma. Presents as hypoxia in a patient who was previously doing better. Develops within the first 24 hours. Diagnosed days later (up to 48 hours). Resolves after 1 week. If contusions are seen on the initial Chest X-ray they are likely severe. There should be a low threshold for intubation and the patient should be closely monitored. The contusion itself cannot be removed. Fluids should be used cautiously since fluid overload can worsen the oedema.

NOT DUE TO PENETRATING LACERATION OF THE LUNG PARENCHYMA. Most common injury in blunt chest trauma. 30-75% of all blunt chest trauma develop a pulmonary contusion.

• Signs and symptoms
  • Hypoxia and hypoxemia (worsening after fluid administration)
  • Dyspnea and tachypnea
  • Tachycardia
  • Chest pain
• Investigation
  • Chest X-ray: get another chest X-ray within 6 hours of injury
    • Patchy infiltrates (associated with edema)
    • Local infiltrates (consolidation)
    • Diffuse opacity (white out) – can occur in young patients without rib fracture
• Treatment
  • Admit
  • Monitor ABGs
  • Intubate → Mechanical ventilation (if respiratory distress with severe hypoxia develops). Supplemental oxygen and initial PEEP of 10 – 15 mmHg (PEEP limits damage from contusion by tamponading small bleeding vessels)
  • Chest physiotherapy
  • Judicious use of fluids: careful to avoid overload. Use colloids and diuretics if fluids are necessary
  • Serial CXRs to monitor resolution
• Who to admit in case of pulmonary contusion
  • Elderly
  • Sick
  • Multiple trauma
  • Concurrent respiratory illness (COPD)
  • Severe contusion
• Differentials
  • Pneumothorax (ipsilateral reduced breath sounds)
• Complications of pulmonary complications
  • ARDS
  • Pneumonia

Flail Chest

A flail chest is the loss of bony contiguity of a portion of the chest wall interfering with normal expansion. Usually 2 fractures per rib (segmental) within 3-4 contiguous ribs. Commonly due to blunt force trauma, which results in multiple local rib fractures.

• Signs and symptoms
  • Paradoxical chest movement (25%, by no means a sine qua non – absolutely essential)
  • Respiratory distress
  • Hypoxia
• Investigation
  • CXR: Multiple rib fractures
• Treatment
  • 100% O2 NRB
  • Pain control (opiates PCA) to allow normal breathing. Pain control meds are used for pain control and not for sedation. Use contracts (make sure the patient also uses an incentive spirometer)
  • Chest physiotherapy
  • Follow up CXR – for pulmonary contusion and widened mediastinum
  • Restrict fluids, use colloids, diuretics to maintain euvolemia -for concurrent contusion
  • Serial ABGs
  • Spiral CT chest
  • Mechanical intubation with bilateral chest tubes (prophylaxis for pneumothorax)
• Indications for mechanical intubation in flail chest
  • Marked hypoxia
  • Hypercapnia
  • Inadequate breathing

Diaphragmatic Rupture

The diaphragm commonly ruptures at the left side due to blunt trauma (as liver protects right side). Penetrating thoracoabdominal injury between the nipples and costal margins anteriorly (below the 5th ICS) and tips of the scapulae and costal margin posteriorly are likely to cause diaphragmatic injury. Blunt trauma usually involves restrained car passengers (seat belt compression causing burst injury). Nasogastric tube + Contrast CT shows a significantly raised hemidiaphragm . The patient usually has difficulty breathing.

• Signs and symptoms
  • Difficulty breathing
• Investigations
  • Chest X-ray:
    • Raised left hemidiaphragm
    • Nasogastric tube passes through the hiatus then into the left chest
  • Thoracoabdominal CT scan
  • Laparoscopy or thoracoscopy: to rule out diaphragmatic injury in penettrating thoracoabdominal injuries
• Treatment
  • Surgical repair (non-emergent): can wait 12 – 24 hours to assess for clinical evidence of bowel injury before deciding between laparoscopy or laparotomy

Cardiac Tamponade

In cardiac tamponade, there is elevated intrapericardial pressure from a pericardial effusion causing compression of the heart (right ventricle). Need not be large fluid. Rapid small effusion can cause tamponade symptoms

• Beck’s triad
  • Raised JVP
  • Decreased arterial pressure
  • Muffled heart sounds
• Other signs and symptoms
  • Tachycardia, Pulsus paradoxus
  • Pallor, cold sweats
  • Left Ventricular Failure
  • Symptoms of RHF
  • Obstructive shock, cardiac arrest (presenting as pulseless electrical activity)
• Cardiac tamponade has all features of pneumothorax except…
  • Breath sounds are present
  • Chest expands symmetrically
• Investigations
  • 2D echocardiography (subxiphoid window)
• EKG findings
  • Sinus tachycardia
  • Low amplitude (QRS) waves
  • Electrical alternans (consecutive QRS complexes that alternate in height when the heart swings in fluid)
  • Pulseless electrical activity (PEA) = Cardiac arrest
• Treatment
  • Pericardiocentesis done at 45 degrees to the xiphoid process
  • Pericardial window
  • Sternotomy or thoracotomy (for severe wounds depending on the patient’s condition)

Blunt Aortic Injury (Aortic Rupture)

Here the aorta breaks. Commonly in the aortic isthmus, distal to the exit of the left-subclavian vein.

It is the second most common cause of trauma after head injury. 85% of deaths occur at the scene. 80-85% of tears occur distal to the left subclavian artery where the ligamentum arteriosum is attached to the aorta. 10-15% occur at the diaphragmatic hiatus while 5-10% occur at the ascending aorta.

• Pathophysiology
  • Acceleration-Deceleration (Driving) tears ligamentum arteriosum → Bleeding and lethal profound hypotension needing urgent cardiothoracic intervention
• Investigations
  • Chest X-ray: mediastinal widening
  • Dynamic, spiral thoracic CT: excellent sceening test. ‘Gated’ imaging adds accuracy to the CT scan e.g. each image is taken at the QRS peak to avoid motion artefact
  • Aortography or CT angiogram: if there is clear widening of the mediastinum on CXR or positive CT scan findings
• Chest X-ray findings
  • Mediastinal widening
  • Abnormal aortic contour
  • Tracheal deviation
  • Nasogastric tube shift
  • Left apical pleural cap
  • Thickening of the left or right paraspinal stripe
  • Depression of the left main bronchus
  • Obliteration of the aorticopulmonary window
  • Left pulmonary hilar hematoma or hemothorax
• Treatment
  • Antihypertensive therapy with a short acting beta blocker (esmolol): goal HR < 80 bpm and MAP 60 – 70 mmHg
  • Surgical repair