How to diagnose an air leak in an InterCostal Drainage (ICD) tube?

How to Diagnose an Air Leak in an Intercostal Drainage (ICD) Tube

The definitive sign of an air leak is continuous or intermittent bubbling in the underwater seal chamber of the chest tube drainage system. 1

Visual Assessment of the Drainage System

The primary diagnostic method involves direct observation of the chest tube drainage system:

• Continuous bubbling in the underwater seal indicates an ongoing visceral pleural air leak, meaning air is actively escaping from the lung into the pleural space 1
• Intermittent bubbling (occurring only with respiration) suggests a smaller air leak that manifests during certain phases of breathing 1
• Respiratory swing (oscillation of fluid level with breathing) confirms proper tube positioning and patency in the pleural cavity, but does not itself indicate an air leak 1

Systematic Approach to Air Leak Detection

Step 1: Confirm the Drainage System is Functioning

• Ensure the chest tube is connected to a unidirectional flow drainage system positioned below the level of the patient's chest at all times 1
• Check for tube kinking, especially with small soft drains in mobile patients, as this is the most common cause of apparent drainage cessation 1
• If drainage suddenly stops, flush with normal saline to check for obstruction 1

Step 2: Characterize the Air Leak Pattern

• Timing: Note whether bubbling is continuous (larger leak) or intermittent with respiration (smaller leak) 1
• Duration: An air leak persisting beyond 48 hours warrants referral to a respiratory physician 2
• Persistence: An air leak lasting beyond 4 days is defined as a persistent air leak and should prompt consideration for surgical evaluation 1, 3

Step 3: Use Advanced Monitoring When Available

• Digital drainage systems provide objective measurements of air flow rate and pleural pressure, allowing precise quantification of air leak severity 4, 5
• These systems can distinguish between a true active air leak (characterized by high differential pleural pressure due to increased mean expiratory pressure >1 cm H₂O) and a "pleural space effect" (high differential pressure due to lower mean inspiratory pressure <20 cm H₂O) 5

Critical Safety Considerations

• NEVER clamp a bubbling chest tube as this can cause tension pneumothorax, a potentially fatal complication 1, 3, 6
• Patients with chest tubes should be managed on specialized wards by staff trained in chest tube management 1
• If suction is required for persistent air leak after 48 hours, use high volume, low pressure systems (−10 to −20 cm H₂O) 2

Clinical Decision Points

At 48 hours: If air leak persists or pneumothorax fails to re-expand, refer to respiratory physician for complex drain management decisions 2

At 4 days: Consider surgical evaluation if air leak continues beyond this timeframe 1, 3

Before removal: Confirm absence of bubbling for at least 24 hours and complete lung re-expansion on chest radiograph 6