Bronchopleural fistula (BPF) occurs in 1.5% to 7% of patients after pneumonectomy. BPFs can have devastating consequences, with mortality of 25% to 71% and prolonged hospital stays involving multiple procedures for survivors.^1,2 Presentation may be acute or delayed: The majority of patients present within 3 months postoperatively, most of whom do so within the first 12 days after surgery.^2,3 Late-onset BPF can be more difficult to diagnose and generally is seen in the setting of empyema. The basic principles of successful BPF management include protection of the remaining lung, control of sepsis, debridement of necrotic tissue, closure of the fistula reinforced with vascularized tissue, and obliteration of the pleural space.

Risk factors for the development of BPF after pneumonectomy include anatomic, technical, and patient factors (Table 82-1).^4,5 Right pneumonectomy is associated with a fourfold to fivefold higher incidence of BPF than left pneumonectomy, likely related to anatomic differences between the right and left mainstem bronchi.⁶ A right pneumonectomy stump has minimal mediastinal coverage of the bronchial stump compared with a left-sided stump, which retracts underneath the aorta into the mediastinum when properly fashioned (Fig. 82-1). The right mainstem bronchus is also oriented much more vertically than the left, which permits secretions to pool in the bronchial stump. Finally, the vascular supply to the left mainstem bronchus is augmented by direct vascular branches as the bronchus passes behind the aorta. The blood supply on the right travels from the trachea via local branches in the subcarinal space, which are often disrupted by dissection and lymph node removal.

Technical factors related to BPF formation include devascularization of the bronchial stump by excessive dissection; a long bronchial stump with increased pooling of secretions and risk of secondary infection that leads to stump breakdown; stump closure with suture instead of staples; and closure under tension, as in the case of a thickened bronchial wall at the point of closure.^4,7 Closure under tension also can be implicated in a predominance of right-sided BPFs because the diameter of the right mainstem bronchus at the point of transection generally is larger than the left. Although excessive bronchial dissection increases the risk of BPF, mediastinal lymphadenectomy has not been shown to increase the risk of BPF.⁸

The primary patient factor associated with BPF is postoperative mechanical ventilation. The overall BPF incidence in a series of 256 patients was 3.1%, which increased to 19.3% in patients requiring postoperative ventilation.⁹ Prolonged high airway pressures likely create trauma at the level of the stump that impairs healing. The need for postoperative mechanical ventilation also may explain the association between BPF and severe chronic obstructive pulmonary disease, as well as low forced expiratory volume in 1 second (FEV₁) and the diffusion capacity of the lung to carbon monoxide (D_LCO). Other patient factors include those that impair wound healing, such as preoperative radiation therapy (>45 Gy), poor nutritional status, and prolonged corticosteroid use. Local infectious processes such as tuberculosis or the presence of empyema also increase the risk of BPF.

Coverage of the bronchial stump may reduce the incidence in patients at an increased risk for developing BPF after pneumonectomy.⁴ Bronchial stump coverage with an intercostal muscle flap was associated with a reduction in the incidence of BPF from 8.8% to 0% in a randomized trial involving diabetic patients.¹⁰ Coverage is likely especially important on the right side, where the stump is exposed in the pneumonectomy space. Many groups routinely cover all right-sided stumps, covering left-sided stumps only for patients with increased risk. Coverage can be provided by using a variety of local and distant tissues as vascularized flaps that are tacked over the bronchial stump. Tissues used routinely include pericardial fat pad and intercostal muscle flaps. If these tissues are inadequate, or if the patient is thought to be at extraordinary risk of stump complications, larger muscle or omental flaps are used.

BPF should be suspected in patients who develop fever, empyema, aspiration pneumonia, an excessively productive cough, or an increasing air leak or amount of pleural air after lung resection. Many patients present early with a fulminant course, including expectoration of large amounts of serous or seropurulent fluid, respiratory distress, and sepsis. Appearance of these symptoms should raise the index of suspicion and be followed by a quick and accurate diagnosis before there is overwhelming aspiration of pleural fluid into the remaining lung. This presentation is most common in large fistulas with abundant drainage of pleural fluid into the tracheobronchial tree. Small fistulas more commonly present with productive cough with serous or purulent sputum, fever, hemoptysis, or subcutaneous emphysema. Findings on chest radiograph suggestive of BPF include progressive subcutaneous or mediastinal emphysema, development of a new air–fluid level in a previously opacified pneumonectomy space, a 2-cm drop in an existing air–fluid level with shift of the mediastinum away from the pneumonectomy space, or new development of multiple air–fluid levels. Late-onset BPF often presents with nonspecific symptoms, including low-grade fever, anorexia, fatigue, and weight loss similar to late postpneumonectomy empyema. Proving the presence of a fistula in these patients can be more problematic because the connection is often small and not identified by bronchoscopy. Nuclear medicine techniques have been used to confirm the presence of radiolabeled inhaled gas in the postpneumonectomy space.

Whether the diagnosis is apparent clinically or radiographically or suggested by advanced testing, all patients should undergo diagnostic bronchoscopy. A large fistula generally can be visualized. Fistulas smaller than 1 to 2 mm may be difficult to identify. Perhaps more important, bronchoscopy provides information about the length of the remaining bronchial stump and the condition of the tissue at the level of the stump that can be helpful in planning definitive repair. In addition, pulmonary toilet can be optimized by aspirating any fluid or secretions in the remaining lung.

Draining the Pleural Space

Acute management focuses on controlling life-threatening conditions, including postural drainage with the affected lung positioned down in cases of airway flooding, early thorough pleural drainage to prevent sepsis and aspiration pneumonia, and appropriate antibiotic therapy. Adequate nutrition is also paramount to a favorable outcome.

Drainage can be performed at the bedside with a tube thoracostomy under local anesthesia placed to either balanced drainage system or water seal but not suction. Immediate drainage is especially important for patients who present with large fistulas in which a significant volume of pleural contents is draining into the airways, potentially flooding the contralateral lung. Care must be taken to place the tube above the level of the previous thoracotomy incision because the diaphragm will be elevated as part of the normal thoracic remodeling that occurs after pneumonectomy. In addition, the patient should be in the supine position when the thoracostomy tube is placed. Lateral positioning places the remaining lung in a dependent position and encourages further aspiration. Once the tube is in place, further positional maneuvers to prevent aspiration include maintaining the patient in as close to an upright position as possible and rotating the patient such that the pneumonectomy side is down.

Once the urgent situation is controlled and the patient is started on appropriate parenteral antibiotics, the remaining pleural debris and necrotic tissue are removed. Debridement can be accomplished by means of an open thoracic window or thoracotomy. The selection of technique depends on the patient’s overall condition. At this stage, debilitated or critically ill patients may tolerate a major thoracic procedure poorly, especially a prolonged procedure involving muscle flaps or other approaches used to definitively address the fistula. These patients often benefit from a period of treatment with a simple open window thoracostomy to permit control of sepsis and nutritional support followed by delayed definitive closure.

Technique for Open Window Thoracostomy

Open window thoracostomy allows open drainage of an infected intrathoracic space by using a U-shaped incision over the most dependent portion of the space (Fig. 82-2). Segments of one or two ribs are removed to limit the tendency of the opening to contract and close. The skin flap then is sutured directly to the parietal pleura with interrupted absorbable sutures to create an epithelialized tract, which both maintains the patency of the window and encourages healing. The window should not be placed too far posteriorly such that it is difficult for the patient to manage. Similar care is taken to avoid placing the window too far inferiorly, where it might interfere with the diaphragm. Other techniques, including placement of large-bore drainage tubes through the window as stents, also will help to maintain patency. Dressing changes with moistened gauze then are performed until the cavity is sterilized. Very small fistulas may close spontaneously once the local sepsis is eradicated. Most, however, require definitive closure. Patients in generally good condition at the time of presentation can proceed directly to simultaneous debridement of the pleural space and definitive closure.