Cardiothoracic Surgery: Spontaneous Pneumothorax (PTX)

Definition

• Definition: Gas within the Pleural Space without Any External Event
• Types:
  • Primary: No Underlying Clinical Lung Disease
  • Secondary: From Underlying Clinical Lung Disease

Risk Factors

• Male (3-6x Higher)
• Smoking
• Age:
  • Primary – Generally Younger (10-30 Years)
  • Secondary – Generally Older (> 55 Years)
• Family History
• Profession (Airline Pilot or Scuba-Diver)
• Marfan Syndrome
• Homocystinuria
• Thoracic Endometriosis
• Malnutrition
• *Classic Patient with Primary Spontaneous Pneumothorax: Healthy, Thin, Tall, Young Male

Association with COVID

• Uncommon Complication
  • Incidence of Spontaneous PTX: 0.66%
  • Incidence of Cystic Changes in the Lung: 10%
• Predominant Risk Factor: Mechanical Ventilation
• Pathophysiology:
  • Cytokine Storm – Hyperactive and Dysregulated Immune Response Causes a Hyperinflammatory form of ARDS
  • Thrombosis & Microangiopathy
  • Pneumatocele May Be Due to Diffuse Alveolar Damage & Necrosis of Airway Walls

Causes

• Almost All are Due to Rupture of Subpleural Bleb/Bullae
  • Cause of Both Primary & Secondary Disease
  • Most Common Site: Right Upper Lobe Apex
  • *See Cardiothoracic Surgery: Pulmonary Cystic Lesions
• Secondary Associations:
  • COPD/Emphysema – Most Common Cause of SSP (50-70%)
    • Risk Correlates to Severity of Disease
  • Interstitial Lung Disease
  • Malignancy
  • Tuberculosis (TB)
  • Sarcoidosis
  • Cystic Fibrosis
  • Catamenial Pneumothorax
    • Pneumothorax Associated with Menstruation
    • Due to Thoracic Endometriosis
  • Necrotizing Pneumonia

Diagnosis

• Initial Imaging: Chest X-Ray (CXR)
• Size:
  • Small: ≤ 3 cm at Apex or ≤ 2 cm at Hilum
  • Large: > 3 cm at Apex or > 2 cm at Hilum

Treatment

• Stable:
  • Small: Observation with Supplemental Oxygen
    • Resolves at 1% Per Day without Treatment
    • Supplemental Oxygen: 6 L/Minute for 6 Hours
      • Increases Rate of Reabsorption Up to Six-Fold
      • Avoid Positive Pressure – Risk for Worsening
  • Large: Catheter Aspiration or Chest Tube
    • *Some Propose Conservative Management Even for Moderate-Large Size PTX if Asymptomatic (Debated)
• Unstable: Chest Tube
  • Smaller Diameter (≤ 14 Fr) Generally Preferred
  • Generally Placed to Water-Seal Initially
    • Consider Adding Suction (-10 to -20 cm H2O) if Fails
  • Consider Needle Thoracostomy if Chest Tube Placement Will Cause Delay

Complications

• Persistent Air Leak
  • Air Leak > 4-5 Days
  • Cerfolio Classification:
    • Grade 1 (FE): During Forced Expiration Only (Cough)
    • Grade 2 (E): Only During Expiration
    • Grade 3 (I): Only During Inspiration
    • Grade 4 (C): Continuous During Both Inspiration & Expiration
  • Treatment: Surgery (VATS Thoracoscopy, Resection & Mechanical Pleurodesis)
    • If No Blebs are Seen – Still Preform an Apical Resection
• Recurrent Pneumothorax
  • Risk: 50-60%
• Tension Pneumothorax