Bronchopleural Fistula (BPF)

1. Definition

Bronchopleural fistula (BPF) is an abnormal communication between the bronchial tree and the pleural space, leading to persistent air leak.

👉 It results in:

  • Continuous air leak
  • Failure of lung expansion
  • Pneumothorax or hydropneumothorax
  • Severe ventilatory difficulty in ICU patients

It is one of the most serious complications after thoracic surgery and in mechanically ventilated patients.


2. Classification

A. Based on Anatomy

Type

Description

Central BPF

Communication between main bronchus or lobar bronchus and pleural space

Peripheral BPF

Fistula between distal bronchioles/alveoli and pleura (also called alveolopleural fistula)


B. Based on Timing (Post-surgical)

Type

Time After Surgery

Usual Cause

Early

< 7 days

Technical failure of stump closure

Intermediate

7–30 days

Infection, stump necrosis

Late

> 30 days

Tumor recurrence, chronic infection


3. Etiology

A. Postoperative (Most Common)

Most common cause: post-pneumonectomy

High-risk procedures:

  • Pneumonectomy
  • Lobectomy
  • Sleeve resection

Risk factors:

  • Right-sided pneumonectomy (shorter bronchial stump)
  • Diabetes
  • Malnutrition
  • Prolonged mechanical ventilation
  • Steroids
  • Preoperative radiation
  • Infection


B. Infectious Causes

  • Necrotizing pneumonia
  • Lung abscess
  • Tuberculosis
  • Fungal infections


C. Mechanical Ventilation

  • High airway pressures
  • Barotrauma
  • ARDS


D. Trauma

  • Blunt chest trauma
  • Penetrating injury


E. Malignancy

  • Bronchogenic carcinoma eroding bronchus
  • Post-radiation necrosis


4. Pathophysiology

Stepwise Mechanism:

  1. Bronchial stump breakdown
  2. Communication with pleural cavity
  3. Air leak into pleural space
  4. Loss of negative pleural pressure
  5. Lung collapse
  6. Hypoxemia
  7. Ventilator failure (if intubated)


In Mechanically Ventilated Patients:

  • Positive pressure forces air preferentially through fistula
  • Tidal volume lost into pleural cavity
  • Hypercapnia develops
  • Refractory hypoxemia
  • Difficulty maintaining PEEP


5. Clinical Features

A. Spontaneously Breathing Patient

  • Sudden dyspnea
  • Persistent pneumothorax
  • Failure of lung re-expansion
  • Fever (if empyema develops)


B. Ventilated ICU Patient

Classic findings:

  • Sudden large air leak in chest tube
  • Bubbling in underwater seal
  • Drop in delivered tidal volume
  • Hypercapnia
  • Increasing FiOâ‚‚ requirement
  • Difficulty maintaining PEEP

In post-pneumonectomy:

  • Sudden expectoration of serosanguinous fluid
  • Mediastinal shift
  • Subcutaneous emphysema


6. Diagnosis

A. Chest X-ray

Findings:

  • Persistent pneumothorax
  • Air-fluid level
  • Non-expanding lung
  • Post-pneumonectomy cavity with new air-fluid level


B. CT Thorax (Gold Standard Imaging)

  • Visualizes fistulous tract
  • Air in pleural cavity
  • Stump dehiscence


C. Bronchoscopy (Diagnostic + Therapeutic)

Direct visualization:

  • Bronchial stump defect
  • Air bubbling
  • Necrotic tissue


D. Ventilator Clues (ICU High Yield)

  • Delivered VT ≠ Exhaled VT
  • Sudden ETCOâ‚‚ drop
  • Persistent air leak > 5–7 days


7. Complications

  • Empyema
  • Sepsis
  • ARDS
  • Respiratory failure
  • Tension pneumothorax
  • Death (high mortality after pneumonectomy)

Mortality:

  • Post-pneumonectomy BPF: 25–70%


8. Management

A. Initial Stabilization (ICU Protocol)

  1. 100% oxygen
  2. Chest tube drainage
  3. Broad-spectrum antibiotics
  4. Optimize nutrition
  5. Treat sepsis

Postural drainage can be initiated after specimens have been obtained, as long as a patient can expectorate, the chest cavity and chest tube drainage is less than 30 mL per day, and simultaneous pleural irrigation is performed.

B. Ventilator Strategy 

Goal:Reduce airflow across fistula

Strategy:

Parameter

Recommendation

Tidal volume

4–6 mL/kg

PEEP

Minimal required

Plateau pressure

< 28 cm Hâ‚‚O

Respiratory rate

Lower

Permissive hypercapnia

Allowed

Avoid:

  • High PEEP
  • High inspiratory pressures

The large air leak via BPF can also result in auto-triggering the ventilator, leading to severe hyperventilation and inappropriately large doses of sedatives and neuromuscular blockers administered to reduce spontaneous respiration.

Advanced Ventilation Strategies

  1. Independent lung ventilation/differential lung ventilation
    • Double lumen tube
    • Ventilate healthy lung separately
  1. High-frequency jet ventilation (HFJV)
    • Reduces airway pressure swings
  1. ECMO
    • VV-ECMO as bridge


C. Bronchoscopic Management

Suitable for small (<5 mm) fistulas.

Options:

  • Endobronchial valves
  • Glue (cyanoacrylate)
  • Fibrin sealant
  • Coils
  • Stents


D. Surgical Management

Indications:

  • Large fistula
  • Failed conservative therapy
  • Sepsis
  • Post-pneumonectomy BPF

Procedures:

  • Stump re-closure
  • Muscle flap reinforcement
  • Thoracoplasty
  • Open window thoracostomy (Eloesser flap)


9. Prevention (Post-Thoracic Surgery)

  • Short bronchial stump
  • Buttressing with intercostal muscle flap
  • Avoid excessive cautery
  • Infection control
  • Glycemic control