Traumatic pneumothorax

Background

• Present in 25% of patients with chest trauma

Types

1. Open
   • Communication between pleural space and atmospheric pressure (sucking chest wound)
2. Closed
3. Occult
   • Positive pressure ventilation (e.g. intubation) can convert an occult pneumothorax to a tension pneumothorax

Clinical Features

• Rib fracture and penetrating trauma most common causes
• Isolated pneumothorax does not cause severe symptoms until >40% of hemithorax is occupied

Differential Diagnosis

Pneumothorax Types

• Tension pneumothorax
• Spontaneous pneumothorax
  • Catamenial pneumothorax
• Traumatic pneumothorax
  • Iatrogenic pneumothorax

Thoracic Trauma

• Airway/Pulmonary
  • Bronchial injury
  • Diaphragmatic trauma
  • Hemothorax
  • Pneumomediastinum
  • Pulmonary contusion
  • Tracheal injury
  • Trachobronchial injury
  • Traumatic pneumothorax
    • Tension pneumothorax
• Cardiac/Vascular
  • Cardiac injury
    • Blunt cardiac injury
      • Cardiac contusion
      • Commotio cordis
    • Penetrating cardiac injury
    • Cardiac tamponade
  • Traumatic aortic transection
• Musculoskeletal
  • Clavicle fracture
    • Clavicle fracture (peds)
  • Rib fracture
    • Flail chest
  • Scapular fracture
  • Scapulothoracic dissociation
  • Sternoclavicular dislocation
  • Sternum fracture
  • Thoracic and lumbar fractures and dislocations
• Other
  • Esophageal injury or Perforation
  • Pneumomediastinum
  • Pneumopericardium
  • Traumatic asphyxia

Evaluation

• Occult pneumothorax after a stab wound may be delayed for up to 6 hours
  • If patient decompensates, obtain repeat imaging

Clinically Stable

Defined as having all of the following:

• Resp rate < 24
• Heart rate 60-120 beats per minute
• Normal BP
• SaO2 >90% on room air and patient can speak in whole sentences

Workup

• CXR
  • Displaced visceral pleural line without lung markings between pleural line and chest wall
  • Upright is best
    • Expiratory films DO NOT improve accuracy
    • Lateral decubitus films with suspected side up do increase sensitivity. Good approach in pediatrics to avoid CT
  • Supine CXR = deep sulcus sign
• CT Chest
  • Very sensitive and specific

Lung ultrasound of pneumothorax

• No lung sliding seen (not specific for pneumothorax)
• May also identify "lung point": distinct point where you no longer see lung sliding (pathognomonic)
• Absence of lung sliding WITHOUT lung point could represent apnea or right mainstem intubation
• Evaluate other intercostal spaces because pneumothorax may only be seen in least dependent area of thorax
  • NO comet tail artifact
  • Bar Code appearance/"Stratosphere" sign on M-mode (absence of "seashore" waves)
• Ultrasound has greater sensitivity than chest x-ray for pneumothorax in trauma patients

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Estimating Pneumothorax Size

Measuring pneumothoraxes. Line A = lung apex to cupola. Line B = interpleural distance.

• On a conventional, upright posterior-anterior chest radiograph:
  • Very small: <1 cm interpleural distance (confined to upper 1/3 of chest) OR only seen on CT
  • Small: ≤3cm lung apex to cupola (chest wall apex) on CXR
  • Large: >3cm lung apex to cupola (chest wall apex) on CXR

3cm apex to cupola measurement is roughly equivalent to 2cm interpleural distance (at the level of the hilum)

Both roughly correlate with a 50% pneumothorax by volume

Management

Supplemental oxygen with non-rebreather for all

Tension pneumothorax

• Immediate needle thoracostomy followed by chest tube

Open pneumothorax

• Cover wound with three-sided dressing
  • Make sure to avoid complete occlusion (may convert injury to a tension pneumothorax)

Closed traumatic pneumothorax

• Tube thoracostomy indicated if:
  • Cannot be observed closely
  • Requires intubation
  • Will be transported by air or over a long distance
• Observation if:
  • Very small AND does not require mechanical ventilation
  • Unchanged on repeat CXR in 6 hours
• Decision to intubate
  • Intubation can lead to positive pressure which may worsen a stable traumatic pneumothorax
  • If patient stable, preferable to just perform thoracostomy
  • If GCS < 8 or patient having difficulty, they should be intubated

Adult Chest Tube Sizes

Chest Tube Size	Type of Patient	Underlying Causes
Small (8-14 Fr)	Most spontaneous pneumothorax (primary and secondary) Most iatrogenic pneumothorax	Alveolar-pleural fistulae (small air leak) Iatrogenic air
Medium (20-28 Fr)	Traumatic pneumothorax Traumatic hemothorax ("any acute hemothorax visible on chest radiograph") Pneumothorax on mechanical ventilation Non-traumatic tension pneumothorax Malignant effusion	Trauma/bleeding (hemothorax/hemopneumothorax) Bronchial-pleural fistulae (large air leak) Malignant fluid
Large (36-40 Fr)	Empyema	Thick pus

Disposition

Admit

Special Instructions

Flying

• Can consider flying 2 weeks after full resolution of traumatic pneumothroax

Complications

• Reexpansion pulmonary edema

See Also

• Pneumothorax (main)
• Thoracic Trauma
• Hemothorax