Thoracic Trauma: Blunt and Penetrating Injuries

Thoracic Trauma

• Thoracic trauma accounts for 20-25% of traumatic deaths worldwide
• Male and female distributions are equal, with a peak incidence in the 20-30 age group
• Mechanisms of injury: penetrating, blunt, and transfixing
  • Penetrating: high velocity (gunshot wounds) and low velocity (stab wounds)
  • Blunt: direct (assault and blast), indirect (falls, MVA, crush injuries, and shearing forces)
  • Transfixing

Pediatric and Geriatric Thorax

• Pediatric thorax: more cartilage, absorbs forces, and has a higher incidence of respiratory failure
• Geriatric thorax: calcification and osteoporosis, more fractures

Acceleration-Deceleration Injuries

• Shearing, tearing, and traction forces on structures with varying degrees of fixation
• Aorta, heart, and esophagus are susceptible to injury

Initial Evaluation

• Goal: prompt identification of life-threatening injuries
• Physiological causes of death: tissue hypoxia, hypercarbia, metabolic acidosis
• ATLS primary survey: airway, breathing, circulation
• Secondary survey: systematic evaluation with imaging

Traumatic Rib Fractures

• Sternal fractures: 4%, transverse, in the upper or mid-portions
• Associated injuries: myocardium, scapula, and clavicle
• Mortality: 10%

Pleura

• Traumatic pneumothorax: may be missed initially, erect CXR must exclude during 2nd survey
• Haemothorax: associated with penetrating or blunt chest trauma with bony injury

Lung Injury

• Clinical: haemoptysis, pneumothorax, haemothorax
• Management: severity of injury, ICD, and chest physiotherapy
• Surgery: suture, wedge resection, pulmonary tractotomy, lobectomy, and pneumonectomy

Pulmonary Contusion

• Blunt trauma, high-energy impact, and potential lethality
• Clinical features: subsequent respiratory failure, slow progression
• Diagnosis: CXR/CT chest
• Management: supportive, oxygen, analgesia, pulmonary toilet, intubation (significant hypoxia, pre-existing conditions)

Tracheobronchial Tree Injuries

• Central airways, common after blunt injury, high-energy impact
• Mechanism: forceful AP compression, high airway pressure, and rapid deceleration injury
• Site: cervical trachea most common
• Clinical features: missed in >30% of patients, high suspicion in mediastinal emphysema, subcutaneous emphysema, pneumothorax, and haemoptysis

Esophageal Injuries

• Rare, blunt trauma, and penetrating (stab or trans-mediastinal gunshot injury)
• Clinical features: pneumothorax, haemothorax without rib fractures, lower sternum or epigastric pain
• Investigations: combination of clinical suspicion, CXR, water-soluble contrast swallow, oesophagogram, and oesophagoscopy
• Management: surgical repair or resection with delayed reconstruction

Diaphragmatic Injuries

• Often occult, easily missed, and detected on the left
• Marker of severe thoracoabdominal trauma
• Clinical features: with or without signs of bowel obstruction, drainage of peritoneal content via chest drain
• Investigations: CXR, swallow and follow-through, contrast-enhanced CT scan
• Management: surgical repair = thoracotomy vs. thoraco-abdominal incision vs. laparotomy, laparoscopy

Cardiac Injuries

• Penetrating and blunt cardiac injuries
• Pathology: patchy areas of muscle necrosis, hemorrhagic infiltrate, rupture of small vessels
• Clinical features: cardiac tamponade, arrhythmias, and heart failure
• Investigations: ECG, cardiac enzymes, formal ECHO/TEE

Surgery

• Elective or urgent, depending on the severity of injury
• Myocardial rupture: simple cardiorrhaphy, pledgetted sutured
• Mitral valve: repair/replacement
• Tricuspid: repair
• IVS: traumatic VSD-closure

Great Vessel Injuries

• Aorta most commonly injured in severe blunt or penetrating trauma
• 85-95% mortality, typically patients survive the initial injury insult
• Mechanisms: acceleration-deceleration, shearing forces, and direct luminal compression
• Site: isthmus, near ligamentum arteriosum
• Clinical features: death on the scene, rapid exsanguination, expanding thoracic inlet hematoma, bruit, hypotension, pulse deficit