General Principles

• Pneumothorax may occur spontaneously or as a result of trauma.
• Primary spontaneous pneumothorax occurs without obvious underlying lung disease.
• Secondary spontaneous pneumothorax results from underlying parenchymal lung disease including COPD and emphysema, interstitial lung disease, necrotizing lung infections, Pneumocystis jirovecii pneumonia, tuberculosis, and cystic fibrosis.
• Traumatic pneumothorax occurs as a result of penetrating or blunt chest trauma.
• Iatrogenic pneumothorax occurs after thoracentesis, central line placement, transbronchial biopsy, transthoracic needle biopsy, or barotrauma from mechanical ventilation and resuscitation.
• Tension pneumothorax results from continued accumulation of air in the chest that is sufficient to shift mediastinal structures and impede venous return to the heart. This results in abnormal gas exchange, hypotension, and ultimately, cardiovascular collapse.
  • The causes include barotrauma due to mechanical ventilation, a chest wound that allows ingress but not egress of air, or a defect in the visceral pleura that behaves in the same way (“ball valve” effect).
  • Suspect tension pneumothorax when a patient experiences hypotension and respiratory distress on mechanical ventilation or after any procedure in which the thorax is violated.