How do I diagnose an air leak in a chest tube (thoracostomy tube)?

Diagnosing Air Leaks in Chest Tubes

Air leaks in chest tubes can be diagnosed by observing continuous bubbling in the water seal chamber of the drainage system, which indicates air escaping from the pleural space. 1

How to Identify an Air Leak

Visual Assessment of the Drainage System

• Look for bubbling in the water seal chamber of the chest drainage system:

  • Continuous bubbling indicates an ongoing air leak from the pleural space
  • Bubbling that occurs only during expiration or coughing suggests a smaller air leak
  • No bubbling suggests absence of air leak 2, 1

• Check for respiratory swing in the fluid level within the chest tube:

  • Presence of swing confirms the tube is in the pleural space
  • Absence of swing may indicate tube blockage or malposition 2

Digital Monitoring Systems

• Modern digital drainage systems provide objective measurement of air leak:
  • Quantify air leak flow in mL/min
  • Display trends over time
  • Allow for more objective assessment than traditional visual inspection 3
  • Facilitate earlier chest tube removal decisions with greater confidence 3

Distinguishing True Air Leaks from System Leaks

True Air Leaks (from patient)

• Bubbling persists despite tube manipulation
• Bubbling increases with coughing or Valsalva maneuver
• Respiratory swing is present in the water seal chamber

System Leaks (from drainage apparatus)

• Check all connections between the chest tube and drainage system
• Ensure all connections are tight and secure
• Apply water or soap solution to connections - bubbles will form at leak sites
• Replace the drainage system if connections are intact but leaking persists

Important Precautions

Never Clamp a Bubbling Chest Tube

• A bubbling chest tube should never be clamped as this can convert a simple pneumothorax into a life-threatening tension pneumothorax 2, 1
• If a chest tube is clamped and the patient develops breathlessness or chest pain, immediately unclamp the tube 1

Proper Drainage System Management

• Always keep the drainage system below the level of the patient's chest
• Ensure the system remains upright to maintain the water seal
• Monitor for kinks or obstructions in the tubing
• When transporting patients, briefly disconnecting from suction is acceptable, but maintain the underwater seal position below chest level 1

Management Decisions Based on Air Leak Assessment

• Persistent air leak (>4-5 days):

  • Consider surgical evaluation for possible bronchopleural fistula 2
  • May require video-assisted thoracoscopic surgery (VATS) 1

• Resolving air leak:

  • Discontinue suction and observe on water seal
  • If no recurrence of air leak, chest tube can be removed after confirming lung expansion on chest radiograph 2, 1

• No air leak with expanded lung:

  • Chest tube can be removed after confirming on chest radiograph 2
  • 53% of experts recommend against clamping trials before removal 2

Conclusion

Proper assessment of air leaks in chest tubes is critical for patient management decisions. The most reliable method is direct observation of bubbling in the water seal chamber, with digital monitoring systems offering more objective assessment. Never clamp a bubbling chest tube, as this can lead to life-threatening complications.