130: Management of Acute Bronchopleural Fistula

There are two types of communications that can develop between the lung parenchyma and the pleural space. Communications that develop in the peripheral lung, typically beyond the cartilaginous airways, are commonly referred to as peripheral air leaks. Peripheral communications generally demonstrate respiratory (phasic) variation in the magnitude of the air leak and will heal with time. In contrast, a communication with the cartilaginous airways is referred to as a bronchopleural fistula (BPF). BPFs are associated with a relatively larger communication. Negative-pressure external drainage usually demonstrates a continuous (nonphasic) air leak. Acute BPF, or communications with proximal airways, frequently require therapeutic intervention.

The etiology of acute BPF may be classified as infectious, malignant, traumatic, iatrogenic, and idiopathic (Table 130-1). The most common types of BPFs are associated with the complications of pulmonary resections. The surgical techniques for managing these problems are described in Chapter 82. The medical management of nonmalignant BPF is discussed in Chapter 127. This chapter summarizes the acute management options for benign BPF.

The acute surgical management of BPF depends not only on the etiology but also on the clinical presentation. In general, the main tenets of therapy are (1) the treatment of any systemic infection, (2) drainage of any infected fluid, (3) reexpansion of the lung to eliminate residual pleural space, and (4) treatment of the underlying cause. Specific management is discussed according to etiology.

Nonresectional Benign BPF

The most common nonsurgical etiology for BPF is infection. BPF may be a complicating factor in necrotizing pneumonia or a lung abscess. A variety of bacterial, mycobacterial, and fungal infections have been implicated in benign BPF. Clues to the development of a lung abscess with proximal airway communication include an intractable cough, fever, weight loss, and failure to thrive.¹ Clinical presentation may range from a productive cough to frank sepsis. A pneumothorax may be present as well; however, the presence of intrapleural air does not distinguish between a proximal and peripheral communication. Regardless of the site of communication, the initial management involves the drainage of the pleural space with a chest tube, broad-spectrum antibiotics to treat the underlying infection, and chest physiotherapy to aid drainage. Culture of the drainage fluid permits targeted antibiotic therapy. Surgical intervention is rarely indicated.

Malignant BPF is generally the result of the necrosis associated with large tumors in the chest. These may be primary lung carcinomas or metastatic cancers such as sarcomas. Patients may experience shortness of breath as a result of a pneumothorax. Management includes insertion of a chest tube to treat the pneumothorax and bronchoscopy to evaluate the proximal airways. Depending on the stage and location of the tumor, resection may be an option, but usually malignant BPF is associated with advanced disease.

Both penetrating and blunt chest trauma may result in a BPF. Laceration of the peripheral pulmonary parenchyma can be frequently managed by chest tube drainage alone. Failure to reexpand the lung after insertion of chest tubes, particularly in the presence of a continuous (nonphasic) air leak, is an indication for bronchoscopy and possible surgery. Injury to the proximal airway may necessitate thoracotomy with primary repair.

An air leak may be associated with radiation therapy, rupture of bullae, or positive-pressure ventilation. The accumulation of intrapleural air is an indication for insertion of a chest tube. A small leak that rapidly resolves does not require further intervention. A large or continuous air leak may require bronchoscopy to evaluate the proximal airways. In patients on mechanical ventilation for acute respiratory distress syndrome, a number of treatment options have been suggested, including jet ventilation and conventional ventilatory settings.²

Postresectional Benign BPF

Incidence

With improved surgical technique and understanding of bronchial healing, the incidence of BPF after pulmonary resection has decreased dramatically over the past several decades.³ The incidence of BPF ranges from 1.5% to 11.1% after pneumonectomy and 1.5% to 2% after lobectomy. Mortality from BPF has been reported to range from 25% to 71% in the literature.

Risk Factors

Based on univariate and multivariate analyses, several variables have been associated with an increased risk of developing BPF. These factors include advanced age, previous chemotherapy and radiation, postoperative mechanical ventilation, pneumonectomy, and right-sided procedures. Algar et al.⁴ studied 242 patients who underwent pneumonectomy for lung cancer. The incidence of BPF was 5.4%. Univariate analysis identified chronic obstructive pulmonary disease, hyperglycemia, hypoalbuminemia, previous steroid use, poor predicted postoperative forced expiratory volume in 1 second (ppo FEV₁), long bronchial stumps, and mechanical ventilation as risk factors. Multiple logistic regression modeling identified bronchial stump coverage, bronchus length, the side of the procedure, ppo FEV₁, chronic obstructive pulmonary disease, and mechanical ventilation as variables influencing the development of BPF.

In a study of 767 patients undergoing lobectomy, 12 (1.6%) developed BPF. Five of twelve (41.7%) died as a result of the BPF. Multivariate analysis identified squamous cell carcinoma, preoperative chemotherapy, lower lobectomy, and middle/lower lobectomy as risk factors for BPF.⁵

Clinical Presentation

The clinical presentation of a patient with a postresectional BPF may range from subtle symptoms of dry cough to fulminant sepsis. BPFs occur most commonly 8 to 12 days postoperatively,⁶ although they can be apparent by the first or second postoperative day to several years later.⁷

After pneumonectomy, the pleural space will fill with fluid. A decrease in the fluid level in the postoperative period should raise suspicion for a BPF. Some patients will complain of a dry, nonproductive, persistent cough. Other patients will produce rust-colored sputum reflecting old blood from the postpneumonectomy space. The development of pulmonary consolidation and infiltrate on the contralateral side is also consistent with aspiration of pleural fluid into the remaining lung and should raise the suspicion of a BPF. Symptoms of failure to thrive (e.g., malaise, weight loss, and decreased energy) may be the only complaints of a patient with a BPF. Finally, signs and symptoms of sepsis due to empyema also may be present.

Diagnosis

In a patient with suspected BPF after pneumonectomy, the first step is to rule out empyema by thoracentesis under sterile conditions. Patient positioning is crucial to avoid contamination of the “good” lung. If a stat Gram stain on the pleural fluid is positive or the fluid is grossly suspicious for infection, a chest tube should be inserted immediately to drain the postpneumonectomy space and prevent contamination of the contralateral lung. Broad-spectrum antibiotics should be started until culture and sensitivity results are available.

The patient then should be taken to the OR, where a bronchoscopy should be performed. The bronchial stump should be examined for good apposition of the cartilaginous and membranous walls. A defect may or may not be visible. The length of the bronchial stump also should be noted. If a defect is not identified, there are several maneuvers that can help to identify a fistula. First, saline can be inserted, submerging the staple or suture line. Then air can be inserted via the chest tube in the pleural space and the staple or suture line observed for air bubbling. Others have described instillation of tracer dyes, such as methylene blue, through the bronchoscopy and detection in the chest tube, indicating a BPF.

CT scanning may have a role in the diagnosis and certainly in the evaluation of a peripheral BPF.⁸ A ventilation/perfusion scan also may be a helpful noninvasive test, especially in a patient with subacute presentation of failure to thrive.

Treatment

The choice of management depends on the timing and presentation. A BPF diagnosed within the first 48 hours following lobectomy or pneumonectomy is caused by a technical error. The bronchial stump generally should be revised unless very small and amenable to endoscopic treatment. Endoscopic treatment with the use of fibrin glue, cyanoacrylate glue, cellulose, Gelfoam, silver nitrate, and coils has been reported with varying degrees of success. Stents also have been used with some success. For BPF diagnosed beyond 48 hours, traditional teaching has advocated drainage alone. Once the pleural space infection has resolved, the bronchial stump should heal. Wright et al.³ have suggested that all BPFs occurring within 1 month with minimal pleural contamination should be revised. Most would recommend buttress of the stump with pericardium, thymic fat pad, omentum, or muscle flap. The use of omentum is thought to enhance vascularity and provide fibroblasts to aid in healing. Other options include thoracoplasty and Clagett window. These procedures are discussed in Chapter 82. The application of vacuum-assisted closure (VAC) as an alternative to open window sterilization has recently been reported and was noted to reduce both hospital stay and costs in a patient with acute postpneumonectomy empyema complicated by BPF.⁹

Acute BPF remains a difficult problem to manage. Optimal therapy depends on specific cause and clinical presentation. Early detection and diagnosis are crucial for successful treatment and satisfactory outcome.

The authors wish to acknowledge Aneil A. Mujoomdar who contributed to this chapter in the first edition.

Postpneumonectomy BPFs are notably life-threatening in two settings: (1) prior to diagnosis and (2) during positive-pressure ventilation. The unrecognized fistula may only produce brown-colored sputum prior to sudden and life-threatening contamination of the contralateral lung. The potential for contralateral pneumonia is the reason that the cavity must be drained urgently. Also, a large proximal fistula will decompress the airways and preclude effective positive-pressure ventilation. General anesthesia can be used, but with either spontaneous ventilation or an occlusive packing (e.g., mineral oil-soaked gauze) in the pneumonectomy space.