What is pneumothorax?

Pneumothorax: Definition, Types, and Management

Pneumothorax is defined as the abnormal presence of air in the pleural space—that is, between the lung and the chest wall—resulting in partial or complete collapse of the lung. 1 This condition can cause significant respiratory distress and, in severe cases, can be life-threatening if not promptly identified and treated.

Types of Pneumothorax

Pneumothoraces can be classified into several categories:

1. Primary Spontaneous Pneumothorax (PSP)

   • Occurs in otherwise healthy people without clinically apparent underlying lung disease
   • Most common in young adults
   • Despite the absence of clinical lung disease, subpleural blebs and bullae are found in up to 90% of cases at thoracoscopy 1
   • Strong association with smoking (lifetime risk in smoking men may be as high as 12% vs 0.1% in non-smokers) 1

2. Secondary Spontaneous Pneumothorax (SSP)

   • Occurs in patients with underlying lung disease (commonly COPD, cystic fibrosis)
   • Generally more serious than primary pneumothorax
   • Higher morbidity and mortality rates
   • Patients over 50 years with smoking history may be classified as SSP 1

3. Tension Pneumothorax

   • Occurs when intrapleural pressure exceeds atmospheric pressure throughout the respiratory cycle
   • Results from a one-way valve mechanism allowing air to enter but not exit the pleural space
   • Medical emergency requiring immediate decompression
   • Clinical presentation includes severe respiratory distress, cyanosis, tachycardia, and hypotension 1

4. Iatrogenic Pneumothorax

   • Caused by medical procedures (transthoracic needle aspiration, subclavian vessel puncture, thoracocentesis, etc.)
   • Accounts for a significant proportion of all pneumothoraces 1

5. Traumatic Pneumothorax

   • Results from chest trauma (not covered extensively in the guidelines)

Clinical Presentation

Symptoms vary based on the size of the pneumothorax and underlying lung function:

• Chest pain (typically sharp and may be pleuritic)
• Shortness of breath/dyspnea (severity correlates with collapse size) 2
• Tachypnea
• Decreased breath sounds on the affected side
• Hypoxemia (particularly in secondary pneumothorax)
• In tension pneumothorax: rapid deterioration with labored respiration, cyanosis, sweating, tachycardia, and hypotension 1

Diagnosis

Diagnosis is primarily based on:

1. Clinical suspicion based on symptoms and physical examination

2. Chest radiography (standard upright PA film)

   • Expiratory films are not recommended for routine diagnosis 1
   • Size can be determined by measuring the distance from lung apex to ipsilateral thoracic cupola 1

3. CT scanning may be used in complex cases or for surgical planning

   • Can detect blebs/bullae in up to 80% of primary pneumothorax cases 1

Management

Management depends on the type, size, and clinical stability of the patient:

Primary Spontaneous Pneumothorax

1. Small, asymptomatic pneumothorax:

   • Conservative management with observation
   • High-flow oxygen (accelerates air reabsorption)
   • Follow-up chest radiograph after 2 weeks 1

2. Symptomatic or large pneumothorax:

   • Simple aspiration is the first-line treatment
     • Using a cannula (≥16F and at least 3cm long) in the second intercostal space, mid-clavicular line 1
     • Discontinue if resistance felt, excessive coughing occurs, or >2.5L aspirated 1
   • If aspiration fails, proceed to chest tube drainage

Secondary Spontaneous Pneumothorax

1. All symptomatic cases:

   • Require intervention due to poor respiratory reserve
   • Intercostal tube drainage is recommended
   • Hospitalization is generally required 1

2. Small, minimally symptomatic:

   • May be observed with close monitoring
   • Supplemental oxygen
   • Low threshold for intervention if clinical deterioration

Tension Pneumothorax

1. Immediate decompression with a cannula of adequate length (≥4.5cm) in the second intercostal space, mid-clavicular line 1
2. Followed by formal chest tube placement
3. High-flow oxygen

Chest Tube Management

• Tube size:

  • Small-bore catheter (≤14F) for most primary pneumothoraces
  • 16F-22F for secondary pneumothoraces
  • 24F-28F for anticipated large air leaks or patients requiring positive-pressure ventilation 1

• Drainage system:

  • Water seal device with or without suction
  • Heimlich valve (one-way valve) for ambulatory management in selected cases 1

• Removal criteria:

  • Full lung re-expansion
  • No air leak for 24 hours
  • Confirm with chest radiograph 1

Persistent Air Leak and Recurrence Prevention

For persistent air leak (>48-72 hours) or recurrent pneumothorax:

1. Chemical pleurodesis through chest tube
2. Surgical intervention:
   • Partial pleurectomy (95% success rate in preventing recurrence) 1
   • Pleural abrasion
   • Talc pleurodesis
   • Video-assisted thoracoscopic surgery (VATS) is preferred over open thoracotomy

Special Considerations

Cystic Fibrosis

• Early aggressive treatment recommended
• Higher risk of contralateral pneumothorax (up to 40%)
• Surgical intervention should be considered after first episode 1

Post-Resolution Care

• Avoid air travel until complete radiographic resolution
• Permanently avoid diving after pneumothorax unless bilateral surgical pleurectomy performed 1
• Strongly encourage smoking cessation (critical for preventing recurrence) 1
• Follow-up in chest clinic within 7-10 days 1

Common Pitfalls and Caveats

1. Missed diagnosis of tension pneumothorax, particularly in ICU settings or in patients on mechanical ventilation 1

2. Inadequate cannula length for emergency decompression (should be ≥4.5cm as chest wall thickness exceeds 3cm in 57% of patients) 1

3. Inappropriate chest tube positioning leading to treatment failure (upper lobe leaks are common, proper tube placement is critical) 1

4. Failure to recognize secondary pneumothorax in older patients or those with subtle signs of underlying lung disease

5. Premature chest tube removal before complete resolution of air leak

6. Inadequate patient education regarding activity restrictions and follow-up care

By understanding the pathophysiology, clinical presentation, and management principles of pneumothorax, clinicians can provide timely and effective care to minimize morbidity and mortality associated with this condition.