Can a water seal (water seal drainage system) have suction applied in a chest tube (thoracostomy tube) system?

Water Seal Drainage Systems Can Have Suction Applied in Chest Tube Management

Yes, water seal drainage systems can have suction applied to chest tubes, and this is often necessary when the lung fails to re-expand with water seal alone. 1, 2

Basic Principles of Chest Tube Drainage Systems

A water seal drainage system is designed to:

• Allow unidirectional flow of air or fluid out of the pleural space
• Prevent air from re-entering the pleural cavity
• Provide visual indication of air leaks through bubbling

The standard setup includes:

• A chest tube inserted into the pleural space
• Connection to an underwater seal bottle/device
• A side vent that either allows air escape or connects to suction

Water Seal vs. Suction: Clinical Decision Algorithm

Initial Management

1. Start with water seal alone (good consensus) 1

   • Connect the chest tube to a unidirectional flow drainage system
   • Maintain the drainage system below the level of the patient's chest at all times
   • Monitor for lung re-expansion and resolution of pneumothorax

2. Apply suction when indicated 1, 2

   • If the lung fails to re-expand quickly with water seal alone
   • For large pneumothoraces with significant air leaks
   • When patients require positive-pressure ventilation

Suction Parameters

• Apply via the underwater seal at a pressure of 5-10 cm H2O 1
• Low pressure reduces the risk of drain blockage from debris

Special Considerations

Pneumothorax Size and Air Leak Volume

• Small pneumothorax with minimal air leak: Water seal alone is usually sufficient 1, 3
• Large pneumothorax (>8 cm) with significant air leak: Higher likelihood of requiring suction 3
• Air leak ≥4/7 on leak meter: Higher risk of pneumothorax development when on water seal alone 4

Patient-Specific Factors

• Mechanically ventilated patients: More likely to benefit from suction 2
• Post-pulmonary resection: Evidence suggests water seal may be superior for resolving air leaks unless the pneumothorax is large 3, 4
• Trauma patients: Suction may reduce duration of chest tube treatment and hospital stay 5

Important Safety Considerations

Never clamp a bubbling chest tube

• Can lead to potentially fatal tension pneumothorax 1
• A clamped drain should be immediately unclamped if the patient develops breathlessness or chest pain

Temporary Disconnection from Suction

• Brief disconnection from suction (e.g., for radiographs or mobilization) is acceptable 1
• Ensure proper instructions are given to maintain the underwater seal bottle below chest level

Evidence Quality and Consensus

The recommendation to start with water seal and apply suction if needed has good consensus among experts 1. However, there are some contradictions in the literature:

• Some studies show water seal is superior for resolving air leaks after pulmonary resection 4
• Other studies suggest suction may reduce chest tube duration and hospital stay in trauma patients 5

The highest quality evidence supports a graduated approach: start with water seal and progress to suction if the lung fails to re-expand or if the pneumothorax is large with significant air leak 1, 2.

Common Pitfalls to Avoid

1. Applying excessive suction pressure (>10 cm H2O)
2. Clamping a chest tube with an active air leak
3. Failing to recognize when water seal alone is insufficient
4. Not keeping the drainage system below the level of the patient's chest
5. Overlooking the development of subcutaneous emphysema, which may indicate inadequate drainage

By following these evidence-based guidelines, clinicians can optimize chest tube management to improve patient outcomes while minimizing complications.