What is the approach to applying negative suction pressure in a patient with a non-expanding pneumothorax?

Approach to Negative Suction Pressure for Non-Expanding Pneumothorax

For non-expanding pneumothoraces, apply negative suction pressure of -10 to -20 cm H₂O only after 48 hours of standard chest tube drainage, using a high volume, low pressure system such as a Vernon-Thompson pump or regulated wall suction. 1

Initial Management Before Considering Suction

1. Begin with standard chest tube insertion:

   • Use small-bore drains (≤14F) for initial management 2
   • Connect to underwater seal without initial suction
   • Confirm tube position with chest radiograph
   • Administer supplemental oxygen to aid reabsorption

2. Monitor for lung re-expansion:

   • Allow 48 hours for spontaneous resolution with standard drainage before applying suction
   • Assess for air leak and lung expansion with serial chest radiographs

When and How to Apply Negative Suction

Timing of Suction Application

• Apply suction only after 48 hours if the pneumothorax is slow to re-expand 1
• Early application of suction (before 48 hours) may precipitate re-expansion pulmonary oedema, especially in primary pneumothoraces that have been present for several days 1

Suction Parameters

• Use -10 to -20 cm H₂O negative pressure 1
• Utilize high volume, low pressure systems only 1
• Avoid high pressure systems (both high and low volume) as they can cause:
  • Air stealing
  • Hypoxemia
  • Perpetuation of persistent air leaks 1

Monitoring During Suction

• Place patient in an area with specialized nursing experience 1
• Monitor for complications including:
  • Subcutaneous emphysema
  • Re-expansion pulmonary edema
  • Hemodynamic instability

Persistent Non-Expansion and Air Leaks

Surgical Referral Timeline

• For patients without pre-existing lung disease: Refer for surgical evaluation after 5-7 days of persistent air leak 1
• For patients with underlying lung disease, large persistent air leak, or failure of lung to re-expand: Consider earlier referral (2-4 days) 1

Alternative Management Options

• Chemical pleurodesis can be considered for patients unwilling or unable to undergo surgery 1, 2

  • Should only be performed by respiratory specialists
  • Can be performed through smaller tubes or indwelling catheter systems
  • Preferred agents include talc or doxycycline

• Surgical options for persistent non-expansion:

  • Video-assisted thoracoscopic surgery (VATS) with staple bullectomy and pleural symphysis
  • Open thoracotomy and pleurectomy (lowest recurrence rate for difficult cases) 1, 2

Cautions and Pitfalls

• Never clamp a bubbling chest tube due to risk of converting simple pneumothorax to tension pneumothorax 2
• Maintain drainage system below chest level at all times 2
• Be aware that positive pressure ventilation can convert a small pneumothorax into a tension pneumothorax 3
• In spontaneously breathing patients, the rate of deterioration with tension pneumothorax is less rapid compared to ventilated patients 4

Special Considerations

• High negative pressure suction (-150 mmHg) may be used for managing subcutaneous emphysema, but not for the pneumothorax itself 5
• While some older studies report success with intermittent negative pressure aspiration for chronic pneumothorax 6, current guidelines recommend continuous low pressure suction
• Recent research (2024) suggests that negative pleural suction may not significantly reduce the duration of intercostal drainage in trauma patients compared to conventional underwater seal drainage 7

By following this structured approach to applying negative suction pressure for non-expanding pneumothoraces, clinicians can optimize outcomes while minimizing complications.