What are the causes of tension pneumothorax (collapsed lung due to air in the chest cavity)?

Causes of Tension Pneumothorax

Tension pneumothorax develops when air enters the pleural space through a one-way valve mechanism but cannot escape, creating progressive pressure buildup that impairs venous return and cardiac output—this occurs most commonly from traumatic chest wall injuries, positive pressure ventilation complications, iatrogenic procedures, and underlying lung disease. 1

Traumatic Causes

Penetrating Trauma

• Open chest wounds from penetrating trauma (stab wounds, gunshot wounds, blast injuries) create direct communication between the external environment and pleural space 2
• High-velocity rifle wounds, shotgun wounds, and blast injuries create larger chest wall defects with greater risk of tension development 2
• Smaller wounds from handgun injuries and most rifle wounds typically do not create sufficient air leak to cause tension physiology 2

Blunt Trauma

• Massive blunt chest trauma can cause lung parenchymal injury with air leak into the pleural space 2
• Rib fractures may puncture the lung, creating the valve mechanism necessary for tension development 1

Iatrogenic Causes

Central Line Placement

• Failed or complicated central venous catheterization attempts, particularly subclavian vein access, can puncture the lung apex 3
• Even unsuccessful attempts from the previous day can result in delayed tension pneumothorax development during subsequent procedures 3

Positive Pressure Ventilation

• Mechanical ventilation is the most common precipitant of tension pneumothorax in hospitalized patients 2
• High peak airway pressures from positive-pressure ventilation can convert a simple pneumothorax into tension pneumothorax 2
• An undetected small pneumothorax without symptoms can rapidly progress to tension under positive pressure ventilation during general anesthesia 3
• Patients on non-invasive ventilation who suddenly deteriorate are at high risk 1

Procedural Complications

• Thoracentesis, pleural biopsy, and other invasive chest procedures can cause iatrogenic pneumothorax that progresses to tension 1

Medical Conditions

Severe Asthma Exacerbation

• Tension pneumothorax is a rare but life-threatening complication of severe asthma 2
• Air trapping from severe bronchospasm combined with high intrathoracic pressures creates the mechanism for tension development 2
• Although usually occurring in mechanically ventilated asthma patients, spontaneously breathing patients can develop tension pneumothorax 2
• Breath stacking with limited exhalation ability leads to progressive pressure buildup 2

Underlying Lung Disease

• Cystic fibrosis patients have particularly high risk, with 40% developing contralateral pneumothoraces and median survival of only 30 months after pneumothorax occurrence 1
• Chronic obstructive pulmonary disease (COPD) with bullous disease predisposes to spontaneous pneumothorax that can progress to tension 4
• Tuberculosis and other cavitary lung diseases create structural defects allowing air leak 4

Spontaneous Pneumothorax

• Primary spontaneous pneumothorax in young, tall, thin males (often smokers) can rarely develop tension physiology 4
• Family history increases risk of spontaneous pneumothorax 4
• True tension physiology in spontaneously breathing patients without positive pressure ventilation is extremely rare 5, 6

Mechanism-Specific Considerations

The One-Way Valve

• Air enters the pleural space during inspiration when intrathoracic pressure is negative but cannot escape during expiration, creating progressive accumulation 1
• Tension development is NOT dependent on pneumothorax size—even small pneumothoraces can become immediately life-threatening 1

Positive Pressure Ventilation Changes the Dynamics

• Positive pressure ventilation exacerbates any existing air leak, dramatically accelerating the progression from simple to tension pneumothorax 5
• The time to severe physiological impact is much shorter in ventilated patients compared to spontaneously breathing patients 5
• All patients on positive pressure ventilation with pneumothorax require tube thoracostomy, as positive pressure maintains the air leak 1

Critical Clinical Context

Improper Wound Management

• Improper use of occlusive dressings on open chest wounds can create iatrogenic tension pneumothorax by preventing air from exiting through the chest wound 2
• This is why monitoring for worsening breathing after dressing placement is essential, with immediate loosening or removal if breathing deteriorates 2

Intraoperative Development

• Tension pneumothorax during one-lung ventilation can occur in the dependent lung, particularly during bronchial anastomosis procedures 7
• Unrecognized pneumothorax from previous procedures can manifest as tension only after anesthetic induction and positive pressure ventilation begins 3