In a patient with persistent pneumothorax, is replacing the old, smaller intercostal chest drain (ICD) with a new, larger bore ICD safer than using a different type of ICD?

Management of Persistent Pneumothorax: Chest Drain Selection

For persistent pneumothorax, replacing a small intercostal chest drain (ICD) with a larger bore ICD is safer and more effective than using a different type of ICD when there is a large air leak that exceeds the capacity of the smaller tube. 1

Indications for Replacing with a Larger Bore ICD

When managing persistent pneumothorax, the decision to replace a smaller chest tube with a larger one should be based on:

• Persistent air leak: If air leak continues beyond 48 hours with a small-bore tube 1, 2
• Large volume air leak: When the volume of air leak exceeds the capacity of the smaller tube 1
• Presence of pleural fluid: Combined air and fluid drainage requirements 1
• Failure of lung re-expansion: Despite adequate positioning and patency of smaller tube 2

Evidence for Chest Tube Size Selection

The British Thoracic Society guidelines provide clear recommendations on chest tube sizing:

• Small tubes (10-14 F) are generally recommended for initial management of pneumothoraces 1
• Primary success rates of 84-97% have been recorded using small-bore drains (7-9 F) 1
• There is no evidence that large tubes (20-24 F) are inherently better than small tubes for initial management 1
• However, replacement with a larger tube may become necessary specifically when there is a persistent air leak 1

Safety Considerations

When dealing with persistent pneumothorax, safety concerns include:

• Surgical emphysema risk: A small tube with a very large air leak may potentially cause surgical emphysema, which can lead to respiratory compromise 1
• Complications: The 2020 study showed no significant difference in major complications between small-bore and large-bore tubes 3
• Patient comfort: Small-bore ICCs are associated with less pain and better patient tolerance 3
• Dwell time: Small-bore ICCs had shorter dwell time (5±4 days) compared to large-bore ICTs (8±6 days) 3

Management Algorithm for Persistent Pneumothorax

1. Initial assessment (48-hour mark):

   • If pneumothorax persists after 48 hours with a small-bore tube, refer to a respiratory physician 1, 2
   • Evaluate for air leak volume and lung expansion on chest radiograph

2. Decision point:

   • If air leak is large and exceeds small tube capacity → Replace with larger bore tube (20-24 F) 1
   • If tube is malpositioned, kinked, or blocked → Reposition or replace with similar sized tube
   • If no evidence of large air leak but persistent pneumothorax → Consider adding suction

3. When replacing with larger tube:

   • Use aseptic technique to minimize infection risk (empyema rates 1-6%) 1
   • Position in 5th intercostal space in midaxillary line 4
   • Consider high volume, low pressure suction (-10 to -20 cm H₂O) 1, 2

4. Post-replacement monitoring:

   • Monitor for complications including surgical emphysema, tube blockage, and infection 2
   • Patients requiring suction should be managed on lung units with specialist experience 1

Important Caveats

• Surgical referral should be considered if air leak persists beyond 5-7 days despite appropriate chest tube management 2
• The risk of complications is higher in patients with persistent air leaks, including pneumonia (13.3% vs 4.9%) and prolonged hospital stays (14.2 vs 7.1 days) 2
• While small-bore tubes are effective for initial management, the presence of a very large leak is a specific indication where larger tubes may be necessary 1

Recent meta-analyses suggest that small-bore pigtail catheters have similar success rates (79.84% vs 82.87%) to large-bore chest tubes for initial treatment, but this does not specifically address replacement in persistent pneumothorax cases 5.