How is the drain rate chosen and monitored for a chest drain in pleural effusion, what does swinging indicate, and when should the chest drain be removed?

Management of Chest Drains for Pleural Effusion

Chest drains for pleural effusion should be removed when there is no ongoing air leak and fluid drainage is less than 300 mL/24 hours, with monitoring of respiratory swing as an indicator of drain patency. 1, 2

Drain Rate Selection and Monitoring

Initial Drainage Rate

• Initial fluid removal should be limited to 10 mL/kg body weight, after which the drain should be clamped for 1 hour to prevent re-expansion pulmonary edema (RPO) 1
• In adults and larger children/adolescents, no more than 1.5 liters should be drained at one time, or drainage should be slowed to about 500 mL/hour 1
• Care must be taken when clamping to ensure no air leak has developed during insertion, as this risks tension pneumothorax 1

Ongoing Monitoring

• Daily assessment of drainage volume, color, consistency, and presence of respiratory swing should be documented 1, 2
• The underwater seal bottle must remain below the patient's chest level at all times to prevent backflow 1, 2
• If suction is used, it should be maintained at 5-10 cm H₂O pressure via the underwater seal 1

Understanding Respiratory Swing

Respiratory swing (or "swinging") refers to the fluctuation of fluid level in the underwater seal bottle that corresponds with the patient's breathing:

• During inspiration, the fluid level rises as negative intrapleural pressure is transmitted through the drain
• During expiration, the fluid level falls
• Presence of swing indicates drain patency and proper function 2
• Absence of swing may indicate drain blockage, kinking, or complete resolution of the pleural collection

Management of Drain Complications

Blocked Drains

• When fluid drainage suddenly stops, check for obstruction (blockage or kinking) 1
• Flush the drain with normal saline (10 mL is typically adequate for small-bore drains) 2
• If blockage persists despite flushing, imaging (ultrasound or CT) should be considered to check drain position and assess remaining fluid 2

Air Leaks

• Continuous bubbling in the underwater seal indicates ongoing air leak from the lung 2
• A bubbling chest drain should never be clamped due to risk of tension pneumothorax 1
• If a drain is clamped, it should be immediately unclamped if the patient complains of breathlessness or chest pain 1

Chest Drain Removal Criteria

The decision to remove a chest drain should be based on:

1. Resolution of air leak: No bubbling in the underwater seal for pneumothorax cases 1, 2

2. Minimal fluid drainage:

   • Less than 300 mL/24 hours is considered safe for removal 1
   • Some studies show equivalent outcomes with removal at <300 mL/24h compared to waiting for <100 mL/24h, with significantly decreased drainage times (44 vs. 67 hours) and hospital stay (5 vs. 6 days) 1
   • More conservative approaches wait for drainage <150 mL/day 1
   • Some centers safely remove drains when serous fluid drainage is <500 mL/day 1

3. Radiographic improvement: Chest radiograph showing resolution of the pleural effusion 2

4. Clinical improvement: Resolution of symptoms that prompted drain insertion 2

Important Considerations and Pitfalls

• Patients with chest drains should be managed on specialized wards by staff trained in chest drain management 1, 2
• Routine use of chest drains for all pleural effusions leads to avoidable drain insertions in a large proportion of cases (up to 45.4%) and causes unnecessary complications 3
• Major complications occur in approximately 21.5% of chest drain procedures, including pneumothorax requiring intervention (2.1%), bleeding (0.7%), and organ puncture or drain misplacement (2%) 3
• Patient education about drain care and movement restrictions is essential to prevent accidental removal 2
• Brief disconnection from suction for activities like radiographs or mobilization is acceptable, provided the underwater seal bottle remains below chest level 1

By following these guidelines for drain rate selection, monitoring, and removal criteria, clinicians can optimize patient outcomes while minimizing complications associated with chest drain management for pleural effusions.