Paediatric Thoracic Trauma

Introduction

• Only 10% penetrating injury (RCH)
• Mortality as high as 30% for serious chest trauma (RCH)
• Multiple body region injury is almost universal in paediatric blunt chest trauma
  • Head 46%
  • Lower extremity 32%
  • Abdominopelvic 30%
• Most common injuries are pulmonary contusions, rib fractures and haemopneumothorax

• Differences to adults
  • Small target
  • Narrow airway prone to obstruction
  • Anterior larynx makes for difficult intubation
  • Increased surface area and risk of hypothermia
  • Prone to rapid desaturation
  • Increased pliability of ribs makes fracture less common and contusion more common
  • Hypotension is a late sign of shock
  • Mobile mediastinum makes serious airway/great vessel injury less likely but also predisposes to ventilatory and cardiovascular compromise due to mediastinal shift

Mechanisms

• Infants/toddlers
  • 60-80% blunt trauma
  • MVA in >50%
  • Falls
  • Child abuse
• School-age
  • MVA and bicycles
  • Sporting
• Adolescence
  • Penetrating trauma incidence rises with increase in mortality
  • MVA
  • Drug and alcohol complications

Initial approach

• ABCDE
• CXR
• OGT to decompress stomach to aid ventilation
• FAST should occur early if available including pericardium
• CT used selectively
  • High impact trauma
  • Multiple injuries present or suspected
  • Severe head injury (high likelihood of severe chest injury also)

Indications for operative intervention

• Great vessel injury
• Pericardial tamponade
• Large haemothoraces
• Tracheobronchial injuries
• Oesophageal injury
• Diaphragmatic lacerations
• Open pneumothorax with major chest wall defect
• Penetrating chest trauma that crosses the mediastinum

Rib fractures

• Age 0-3: Rib fractures = NAI in 70%
  • Consider bone scan
• Multiple rib fractures increase risk of severe intrathoracic injury, multiple injuries and mortality
• Fracture of first rib suggests high force and associated great vessel/tracheal injury
• If stable, admit for close observation as late deterioration can occur due to associated pulmonary contusions (almost universally present)

Pulmonary contusion

• Can have no signs externally
• 50% of CXR showing contusion also show fractured ribs and/or haemopneumothoraces
• 90% have some changes on initial CXR
• Management
  • Maintain SpO2 >94%
  • Pain relief
  • Avoid excessive IV fluids
  • Respiratory physiotherapy
• Complications
  • ARDS and pneumonia

Pneumothorax

• Occur in 1/3 of children with significant thoracic trauma
• CT > USS > CXR in sensitivity
• Small, isolated pneumothorax in stable patient
  • Unlikely to require NIV or transport
  • Can consider observation, supplemental O2 and analgesia in HDU (as may still convert to tension PTX)
• Most others will require chest drain
  • If symptomatic, >20% on CXR needs drain

Chest drain sizing

• Newborn – 8-12Fr
• Infant – 14-20Fr
• Child – 20-28Fr
• Adolescent 28-32Fr
  • = 4x ETT size

Tension pneumothorax

• Always consider differential including haemothorax, pericardial tamponade, pulmonary contusion, right main stem intubation and gastric distension
• 16G cannula to 2^nd ICS then chest tube via lateral approach
• 10-20% chance of causing a pneumothorax if thoracocentesis is performed and child does not have a PTX
  • Must follow-up with CXR

Open pneumothorax

• If >2/3 tracheal diameter, air preferentially enters sucking chest wound
• 3-sided occlusive dressing, chest drain away from wound and then occlude 4^th side of dressing
• Consider mechanical ventilation if ongoing respiratory distress

Pulmonary lacerations

• Usually penetrating trauma but blunt injuries, especially with rib fractures, can lead to this
• Usually result in haemothorax (may be massive) and pneumothorax
• Rarely complicated by air embolism
  • Often after initiation of positive pressure ventilation with sudden haemodynamic deterioration +- neurological signs
  • DDx includes tension PTX, pericardial tamponade or massive haemothorax
• If air embolism is thought to have occurred:
  • 100% oxygen therapy and reduce ventilation pressures
  • Emergency thoracotomy with clamping of hilum on affected side and aspiration of ventricular air has been life saving in the past

Haemothorax

• Clinically relevant haemothoraces occur in 15% of blunt trauma
• Each hemithorax can hold 40% of child’s blood volume
• Chest drain indicated
  • Lateral approach aimed posteriorly
  • Drainage of massive haemothorax may lead to further bleeding due to loss of tamponade effect
  • Prophylactic antibiotics are recommended (Cameron) based on adult literature showing reduced infection rate even in closed traumatic haemothoraces requiring drainage
• Indications for thoracotomy
  • Initial drainage >15mL/kg
  • Continued bleeding >1-2mL/kg/hr
  • Increasing bleeding rate
  • Significant residual haemothorax post-tube drainage
• Complications
  • Empyema

Tracheobronchial injuries

• Uncommon, high mortality
• Usually occur near main stem bronchi (unless penetrating trauma)
• Presentation
  • Respiratory distress
  • Subcutaneous emphysema
  • Pneumomediastinum
  • PTX
  • Haemoptysis
  • Ongoing air leak and failed lung expansion after Rx for PTX
• Treatment
  • Second chest tube and urgent cardiothoracic surgical review
  • CT and/or bronchoscopy may be necessary to delineate injury (CXR often difficult to interpret in setting of massive subcutaneous emphysema

Aortic transection

• Aortic transection
  • 80% occur at aortic isthmus just distal to origin of left subclavian
  • Most rapidly fatal at scene
  • If considered, need CT aortogram +- TOE to confirm and subsequent surgery
  • Beta-blockers may be started pre-operatively to reduce wall stress
  • CXR signs of aortic injury
    • Widened mediastinum (ratio >0.25)
    • Loss of aortic knob contour
    • Depression of left mainstem bronchus
    • Deviation of trachea to the right
    • Deviation of oesophagus to the right
    • Left pleural cap
    • Left haemothorax
    • Upper rib fractures

Cardiac injuries

• Myocardial contusion may manifest as arrhythmia, unexplained tachycardia and/or hypotension
• A normal ECG has high negative predictive value for clinically significant complications in suspected myocardial contusion
• Echo useful in assessing suspected clinically significant contusion in unexplained hypotension, tachycardia, arrhythmia or new murmur
• Ongoing ECG monitoring not required if none of these criteria met
• Treatment in suspicious cases
  • Cardiac monitoring in ICU, f/u troponin and echo

Cardiac tamponade

• Shock, narrow pulse pressure, distended neck veins, soft heart sounds, raised JVP
• Consider in unexplained refractory shock
• Confirm by POCUS
• Treatment
  • Urgent surgical referral
  • Needle pericardiocentesis if surgeons not available, but open surgical drainage is safer and more reliable
  • If arrests, emergency thoracotomy

Commotio cordis

• Phenomenon of sudden cardiac arrest following direct blow to chest is well documented in children

Penetrating cardiac trauma

• May result in exsanguination or pericardial haemorrhage/tamponade
• If stable, urgent surgery
• If deterioration, urgent pericardiocentesis can be considered
• If peri-arrest/arrest with vital signs at scene and short transit time to hospital, emergency thoracotomy indicated

Diaphragmatic injury

• Associated intra-abdominal injury is common
• Usually forceful blunt trauma to abdomen with rise in intra-abdominal pressure
• Suspect in crushing injury to abdomen
• Tear usually on the left
• Diagnosis is difficult unless CXR shows clear herniated stomach/bowel or NG tube curling into thorax
• Often diagnosis made at laparotomy for other injuries
• CT scanning may miss small tears
• MRI may have a role in diagnosis of small defects

Oesophageal injury

• Only seen in penetrating trauma and high index of suspicion is required
  • Exception is severe blow to upper abdomen, resulting in forceful ejection of stomach contents causing linear tear in lower oesophagus (Borehaave syndrome)
• Easy to miss with serious morbidity/mortality
• Mediastinal air on CXR is first clue
• Over hours, subsequent sepsis with pleural effusions and mediastinitis ensues
• Suspicion requires urgent oesophagoscopy, Gastrograffin study or both and if confirmed, broad-spectrum antibiotics and surgery

Traumatic asphyxia

• ‘Run over’ injury
• Prolonged, severe compression of chest, resulting in obstruction of venous return
• Leads to extravasation of blood into tissues and massive oedema
• Diagnosis
  • Petechiae over upper chest/arms/face
  • Bulging eyes
  • Subconjunctival haemorrhages
  • Motor or sensory deficits may be present
• Supportive care + Treat underlying injuries as identified and thoracic surgeon for definitive care

Last Updated on October 13, 2021 by Andrew Crofton