Introduction
Bronchopleural fistula is a pathological communication between the bronchial tree and the pleural membrane. It may be caused by lung neoplasm, necrotizing pneumonia, empyema, blunt, penetrating trauma to the lung tissues, or as a complication of surgical procedures. Out of which, lung resection is the most common cause of bronchopleural fistula. It is usually seen one week to three months post-lobectomy or pneumonectomy.
What Are the Types of Bronchopleural Fistula?
Bronchopleural fistula is of two types:
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Central bronchopleural fistula.
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Peripheral bronchopleural fistula.
Central bronchopleural fistula can be defined as the communication between the pleura and the trachea or lobar bronchus. It can be seen in the early postoperative period. It can be easily diagnosed with bronchoscopy or after a large air leak.
Peripheral bronchopleural fistula can be defined as the communication between the pleura and the airway distal to the segmental bronchi or the lung parenchyma. It can be seen when there is an air leak, prolonged pneumothorax with air-fluid levels within pleural effusion or empyema, history of a chest drainage tube into the thorax, gas-producing bacteria, or aspiration pneumonia due to backflow of pus into the bronchial tree.
Another classification of Bronchopleural fistula is based on the time of onset:
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Early-onset.
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Late-onset.
The early onset of bronchopleural fistula can be defined as the fistula occurring within one month of the surgery.
The late-onset of bronchopleural fistula can be defined as the fistula occurring one month after the surgery. It is typically associated with patient-related factors and coexists with empyema. It usually involves a more complex and long-term treatment approach.
What Are the Risk Factors Associated With the Bronchopleural Fistula?
The most common risk factors associated with bronchopleural fistula can be classified as
Patient-Related Factors:
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Age over sixty years.
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More common in males than females.
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Radiation therapy.
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Smoking.
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Patients on immunosuppressive agents.
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Diabetes mellitus patient.
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Post-operative mechanical ventilation patient.
Surgeon-Related Factors:
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Poorly secured knots.
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Stapler misfiring.
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Increased anastomotic tension.
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Extensive mediastinal lymphadenectomy and peribronchial dissection.
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Long bronchial stump.
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Non-coverage of bronchial stumps with viable tissue.
What Are the Signs and Symptoms of Bronchopleural Fistula?
The most common signs and symptoms of bronchopleural fistula are
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Fever.
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Persistent cough with purulent sputum production.
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Night sweats.
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Chills.
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Expectorations.
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Muscle wasting.
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Dullness to percussion on the affected side.
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Respiratory symptoms may worsen if the patient lies on the contralateral side of the fistula.
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Pooling of the infected contents of the pleural cavity to the contralateral lung can be seen, usually resulting in pneumonia or acute respiratory distress syndrome.
What Are the Diagnostic Tests to Be Carried Out?
The diagnostic tests that can be carried out are:
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Regular Complete Blood Count: It will reveal a marked increase in white blood cells. Also, systemic inflammatory mediators may be seen.
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Chest X-Ray: It may reveal a steady increase in intrapleural air. There may be an intrapleural air-pleural fluid collection which can result in hydropneumothorax. Changes in the gas fluid level can be observed. A decrease in the air-fluid level exceeding two cm can be appreciated.
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Computed Tomography: It is considered the gold standard diagnostic tool for bronchopleural fistula. It may reveal pneumothorax, hydropneumothorax, and pneumomediastinum. It may also help diagnose the underlying pulmonary pathology and fistulous communication.
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Radioaerosol Scanning: It can identify the bronchopleural fistula by visualization of the radioactive isotopes in the pleural cavity. The most common radioactive tracers used in the scanning are technetium 99m labeled diethylenetriamine pentaacetate, xenon 133, and single photon emission tomography using radiolabeled aerosol inhalation. Although it is a non-invasive diagnostic procedure, it is not a practical and easy-to-use method with no additional benefit for underlying lung disease.
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Bronchoscopy: A characteristic feature that may be revealed is the presence of air-fluid leakage and air bubbling originating in the bronchial stump. The fistulous patency may not be appreciated.
What Is the Management of Bronchopleural Fistula?
Bronchopleural fistula management involves managing life-threatening situations such as sepsis, tension pneumothorax, and respiratory failure. To decrease the risk of pneumonia and respiratory failure, it is important to protect the contralateral healthy lung from aspiration of the pleural fluid. Therefore, a chest tube must be applied to ensure the drainage of the pleural cavity. Also, broad-spectrum antibiotic coverage should be initiated immediately.
Early bronchopleural fistulas are mostly associated with failure in surgical management. The best treatment approach may require surgical repair of the bronchial stump.
Late bronchopleural fistulas are mostly associated with the poor medical condition of the patient. In such cases, surgical approaches are contraindicated, and a more conservative approach is required, like drainage and reduction of the pleural space, pleural irrigation, antibiotic coverage, and nutritional supplementation.
Several surgical procedures can be used to treat bronchopleural fistulas, such as:
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Video-Assisted Thoracoscopic Surgery (VATS): is a useful method to drain and debride the infected pleural content with surgical instruments. Small fistulas of less than three mm can be managed with fibrin glue.
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Thoracostomy: In the case of empyema, drainage of the pleural space becomes essential to control the septic status of the patient. The procedure involves segmental resection of two to three ribs with the creation of a skin flap, marsupialization of the cavity, and a thoracostomy window is obtained, and effective drainage is ensured. Later the wound is packed with gauze and moistened with normal saline.
Large bronchopleural fistulas can cause a loss in the tidal volume, aspiration of the infected pleural content, and respiratory distress. Therefore, the bronchial defect must be managed with a transpleural approach. The fistula must be identified, and aggressive dissection and devascularization of the proximal bronchus must be avoided because of the increased risk of repair failure and recurrence rate. Staplers may be used if there is a sufficient length in the bronchial stump to repair. After repair, the stump must be bolstered with well-vascularized tissue such as a diaphragmatic flap.
Conclusion
Bronchopleural fistulas are mostly associated with high mortality and morbidity. Multiple options can be used for these patients. The best treatment is to prevent the disease. Robust surgical technique and bronchial stump coverage are the major steps in treating bronchopleural fistula.
