How should physicians assess an intercostal drain (ICD) for pneumothorax?

Assessment of Intercostal Drain for Pneumothorax

Physicians should assess an intercostal drain by checking for bubbling in the underwater seal, confirming respiratory swing in the fluid level, verifying tube position on chest radiograph, and monitoring for signs of malfunction including subcutaneous emphysema or persistent air leak. 1

Primary Assessment Parameters

Bubbling Status

• A bubbling chest tube indicates an ongoing air leak and should never be clamped, as this could convert a simple pneumothorax into a life-threatening tension pneumothorax 2, 1, 3
• A non-bubbling tube generally indicates lung re-expansion, though it should still not routinely be clamped 2, 1
• Absence of bubbling may also indicate tube malposition, kinking, or blockage rather than successful treatment 4

Respiratory Swing Assessment

• Respiratory swing in the fluid level of the chest tube is the most useful indicator of tube patency and confirms proper position in the pleural cavity 1
• Loss of respiratory swing suggests tube blockage, malposition, or complete lung re-expansion 1
• This should be assessed at every clinical evaluation of the patient 1

Radiographic Confirmation

• A chest radiograph must be performed after insertion to check tube position and ensure no iatrogenic pneumothorax has developed 1
• Serial chest radiographs should be obtained to assess lung re-expansion 2
• If the lung remains collapsed after 48 hours despite proper tube function, referral to a respiratory physician is indicated 1

Physical Examination Findings

Signs of Tube Malfunction

• Watch for development of subcutaneous emphysema, which may indicate a malpositioned, kinked, blocked, or inappropriately clamped tube 1
• Increasing breathlessness in a patient with a chest drain warrants immediate assessment 2, 1, 3
• If a patient with a clamped drain (which should be rare) develops breathlessness or subcutaneous emphysema, the drain must be immediately unclamped and medical advice sought 2, 1, 3

Drainage System Integrity

• All chest tubes must be connected to a unidirectional flow drainage system (underwater seal bottle) kept below the level of the patient's chest at all times 1
• The underwater seal bottle should have a side vent for air escape or connection to suction 1
• Verify the system remains a closed circuit without breaks in sterility 1

Troubleshooting Non-Functioning Drains

Common Causes of Failure

• Tube displacement or withdrawal from the pleural cavity 2, 4
• Kinking of the catheter 2, 4
• Blockage from clot or debris 4
• Air leaking around the drain site 2
• Large persistent air leak overwhelming drainage capacity 2

Management Approach

• If failure to aspirate is suspected due to catheter withdrawal or kinking, another attempt at aspiration or repositioning should be considered before inserting an additional drain 2, 4
• Active chest tube clearance methods can be used to prevent occlusion without breaking the sterile field 1
• Stripping or breaking the sterile field of chest tubes to remove clot is not recommended 1
• In cases of prolonged air leaks, wall suction should be considered to create a closed system 1

Timing of Specialist Referral

• Pneumothoraces that fail to respond within 48 hours to treatment should be referred to a respiratory physician 1
• Persistent air leak exceeding 48 hours duration warrants specialist consultation 1
• If clamping is being considered (which should be exceptional), this must only occur under supervision of a respiratory physician or thoracic surgeon in a specialist ward with experienced nursing staff 2, 1, 3

Critical Safety Considerations

• Full aseptic technique must be maintained during any manipulation of the chest drainage system to prevent infection (empyema rates 1-6%) 2, 1, 3
• The drainage system must remain upright and below chest level at all times 1
• Never use substantial force or trocars during insertion, as this risks damage to intrathoracic structures 1
• Ensure adequate analgesia with intrapleural local anesthetic (20-25 ml of 1% lignocaine) given as a bolus and at eight-hourly intervals, which significantly reduces pain without affecting blood gases 2, 1, 3