What is the protocol for treating pleural infection using saline irrigation?

Protocol for Saline Irrigation in Pleural Infection

Saline irrigation should be used for treating pleural infection when intrapleural TPA and DNase therapy or surgery is not suitable, using 250 mL of saline three times daily for 3 days. 1

Indications for Saline Irrigation

• Primary indication: Pleural infection where initial chest tube drainage has ceased but leaves a residual pleural collection
• Specifically indicated when:
  • TPA and DNase therapy is contraindicated (e.g., bleeding risk)
  • Patient is not a surgical candidate
  • Standard drainage measures have failed

Pre-Irrigation Assessment

• Confirm pleural infection diagnosis:
  • Pleural fluid pH ≤7.2 indicates high risk of complicated parapneumonic effusion (CPPE) or pleural infection
  • Pleural fluid LDH >900 IU/L
  • Low pleural fluid glucose (<3.3 mmol/L)
  • Positive pleural fluid cultures
  • Purulent pleural fluid
• Ensure proper chest tube placement (14F or smaller) under ultrasound guidance

Saline Irrigation Protocol

1. Preparation:

   • Use sterile normal saline (0.9% sodium chloride)
   • Warm to body temperature (37°C)
   • Prepare 250 mL aliquots for each irrigation session

2. Administration Schedule:

   • Frequency: Three times daily
   • Duration: 3 consecutive days
   • Total treatments: 9 irrigation sessions

3. Irrigation Procedure:

   • Instill 250 mL of saline into the pleural space via chest tube
   • Allow saline to dwell in pleural space for 3 hours
   • Open drainage for 1 hour to allow complete evacuation
   • Repeat cycle every 4 hours, three times daily 2

4. Concurrent Management:

   • Continue appropriate antibiotic therapy based on culture results or empiric coverage
   • Maintain chest tube patency between irrigations
   • Monitor drainage output and characteristics
   • Provide adequate analgesia to ensure patient comfort during the procedure

Monitoring During Treatment

• Daily assessment of:

  • Volume of fluid drained
  • Character of drainage fluid
  • Patient's temperature and vital signs
  • White blood cell count
  • C-reactive protein levels
  • Clinical symptoms (pain, dyspnea)

• Imaging:

  • Chest radiograph before starting irrigation and after completion
  • Consider CT scan before and after to assess percentage reduction in pleural collection volume 3

Efficacy Assessment

• Primary outcome measure: Percentage reduction in pleural collection volume on CT imaging
  • Target: >30% reduction in pleural fluid volume by day 3 3
• Secondary outcome measures:
  • Resolution of fever
  • Reduction in inflammatory markers
  • Improved clinical status
  • Avoidance of surgical referral

Complications and Management

• Potential complications:

  • Pain during instillation (manage with appropriate analgesia)
  • Chest tube blockage (flush with small volume of saline)
  • Fluid leakage around chest tube site (secure dressing)
  • Infection at insertion site (local wound care)

• No serious complications have been documented with saline irrigation 3

Treatment Completion

• Complete the full 3-day course (9 irrigation sessions)
• Consider chest tube removal when:
  • Drainage output <50-70 mL/24 hours
  • Resolution of sepsis (normalization of temperature, WBC)
  • Radiographic improvement of pleural collection

Follow-up

• Clinical review 1-2 weeks after discharge
• Repeat chest imaging to confirm resolution
• Continue antibiotics for at least 14 days total, adjusting based on clinical response

Evidence and Efficacy

Saline irrigation has been shown to:

• Significantly reduce pleural collection volume compared to standard care (32.3% vs 15.3% reduction) 3
• Significantly reduce referrals for surgery (OR 7.1,95% CI 1.23-41.0) 3
• Potentially reduce hospital stay compared to conventional treatments 2

Cautions

• Ensure chest tube is properly positioned before starting irrigation
• Monitor for fluid overload in patients with cardiac or renal impairment
• Discontinue if patient experiences significant discomfort or clinical deterioration
• Consider alternative therapies (TPA/DNase or surgery) if no improvement after 3 days

This protocol is based on the British Thoracic Society guideline for pleural disease (2023), which conditionally recommends saline irrigation for pleural infection when TPA/DNase therapy or surgery is not suitable 1.