What size chest tube (French) is recommended for pneumothorax, and when to use a moderate-sized versus small chest tube?

Chest Tube Size Selection for Pneumothorax Management

Small-bore chest tubes (10-14F) should be used as the initial treatment for most pneumothoraces, with moderate-sized tubes (16-22F) reserved for specific situations with large air leaks or when small tubes fail. 1

Initial Chest Tube Size Selection Algorithm

For Spontaneous Pneumothorax:

• Small-bore tubes (≤14F) are recommended as first-line therapy for:

  • Most spontaneous pneumothoraces in non-ventilated patients 1, 2
  • Clinically stable patients with large pneumothoraces 1
  • Primary spontaneous pneumothorax regardless of size 1

• Moderate-sized tubes (16-22F) should be considered for:

  • Clinically unstable patients with large pneumothoraces 1
  • Cases with persistent air leaks after small tube failure 1
  • Secondary spontaneous pneumothorax with significant underlying lung disease 1

Factors Favoring Larger Tube Selection:

• Presence of pleural fluid along with pneumothorax 1
• Large air leak exceeding capacity of smaller tubes 1
• Mechanically ventilated patients 3, 4
• Hemopneumothorax requiring drainage of blood 4

Evidence Supporting Small-Bore Tubes

The British Thoracic Society guidelines strongly recommend small-bore tubes (10-14F) as initial management, stating: "There is no evidence that large tubes (20–24F) are any better than small tubes (10–14F) in the management of pneumothoraces" 1. Studies have shown primary success rates of 84-97% using small-bore drains (7-9F) 1.

The American College of Chest Physicians consensus statement also supports using small-bore catheters (≤14F) or moderate-sized tubes (16-22F) for clinically stable patients with large pneumothoraces 1.

When to Consider Moderate-Sized Tubes

Despite the preference for small-bore tubes, moderate-sized tubes (16-22F) may be necessary in specific situations:

1. When a small tube fails to adequately drain the pneumothorax 1
2. For unstable patients with large pneumothoraces 1
3. When there is a very large air leak 5
4. When there is concurrent hemothorax requiring blood drainage 4

Practical Considerations

• Small-bore tubes can be inserted using the Seldinger technique, which is less traumatic 5, 2
• Moderate-sized tubes may require blunt dissection technique 2
• Both tube sizes can be connected to either a Heimlich valve or water seal device 1
• Chest tubes should never be clamped if they are bubbling due to risk of tension pneumothorax 5

Common Pitfalls to Avoid

1. Using unnecessarily large tubes: The traditional belief that larger tubes are more effective has been disproven by multiple studies 1, 6, 7
2. Trocar technique: This should be avoided in favor of blunt dissection or Seldinger technique 2
3. Immediate application of suction: Suction should not be applied directly after tube insertion but can be added after 48 hours for persistent air leak 1
4. Inadequate follow-up: Pneumothoraces failing to respond within 48 hours should be referred to a respiratory specialist 1

Recent evidence from trauma settings suggests that even for traumatic pneumothoraces, tube size (comparing 28-32F vs. 36-40F) did not significantly impact clinical outcomes including drainage efficacy, complications, or patient-reported pain 7.

For most pneumothorax cases, starting with a small-bore tube (10-14F) and escalating to a moderate-sized tube (16-22F) only if necessary represents the most evidence-based approach to minimize patient discomfort while maintaining effective treatment.