Hemoptysis is one of the most common clinical problems for which bronchoscopy is indicated [8,9] (see Chapter 53 for a detailed discussion). Whether the patient complains of blood streaking or massive hemoptysis (expectoration of greater than 600 mL in 48 hours), bronchoscopy should be considered to localize the site of bleeding and diagnose the cause. Localization of the site of bleeding is crucial if definitive therapy, such as surgery, becomes necessary, and it is also useful to guide angiographic procedures. Bronchoscopy performed within 48 hours of the time when bleeding stops is more likely to
localize the site of bleeding (34% to 91%) compared with delayed bronchoscopy (11% to 52%) [10]. Bronchoscopy is more likely to identify a bleeding source in patients with moderate or severe hemoptysis [11]. Whenever patients have an endotracheal or tracheostomy tube in place, hemoptysis should always be evaluated, because it may indicate potentially life-threatening tracheal damage. Unless the bleeding is massive, a flexible bronchoscope, rather than a rigid bronchoscope, is the instrument of choice for evaluating hemoptysis. In the setting of massive hemoptysis, the patient is at risk for imminent decompensation and death due to asphyxiation. Stabilization of the patient, focusing on establishment of a secure airway, and timely communication with pulmonology, thoracic surgery, anesthesiology, and interventional radiology is of utmost importance. This coordinated, multidisciplinary effort should focus on rapid transfer to the operation room (OR) suite for rigid bronchoscopy. The rigid bronchoscope is ideal in this situation because it provides a secure route for ventilation, serves as a larger conduit for adequate suctioning, and can quickly isolate the lung in the case of a lateralized bleeding source. In most situations, once an adequate airway has been established and initial suctioning of excessive blood has been performed, the flexible bronchoscope can be inserted through the rigid bronchoscope to more accurately assess and localize the source of bleeding beyond the main bronchi [12].

The clinical setting influences the choice of procedure. When diffuse pulmonary infiltrates suggest sarcoidosis, carcinomatosis, or eosinophilic pneumonia, transbronchoscopic lung forceps biopsy should be considered initially because it has an extremely high yield in these situations (see Chapter 69). Transbronchial lung biopsy has a low yield for the definitive diagnosis of inorganic pneumoconiosis and pulmonary vasculitides [13]; when these disorders are suspected, surgical lung biopsy is the procedure of choice. In the case of pulmonary fibrosis and acute interstitial pneumonitis, transbronchial biopsy usually does not provide adequate tissue for a specific histologic diagnosis, although by excluding infection the procedure may provide sufficient information to guide therapy.

The ability to determine the probability of ventilator-associated pneumonia (VAP) is very limited, with a sensitivity of only 50% and a specificity of 58% [14]. Quantitative cultures obtained via bronchoscopy may thus play an important role in the diagnostic strategy. Quantitative cultures of bronchoalveolar lavage (BAL) fluid and protected specimen brush (PSB), with thresholds of 10⁴ colony-forming units (CFU) per mL and 10³ CFU per mL, respectively, are most commonly employed prior to initiation of antimicrobial therapy. Cultures of bronchial washings do not add to the diagnostic yield of quantitative BAL culture alone [15]. For a brief description of how to perform BAL and obtain PSB cultures, see the “Procedure” section, given later in the chapter.

For BAL, an evidence-based analysis of 23 prior investigations yields a sensitivity of 73% and a specificity of 82%, indicating that BAL cultures fail to diagnose VAP in almost one-fourth of all cases [16]. A similar analysis of PSB cultures indicates a very wide range of results, with a sensitivity of 33% to greater than 95% and a median of 67%, and a specificity of 50% to 100% with a median of 95% [17,18]. PSB is thus more specific than it is sensitive, and negative results may not be sufficient to exclude the presence of VAP [19]. Blind protected telescoping catheter specimens yield similar results to bronchoscopically directed PSB cultures [20,21]. It is critical to note that colony counts change very quickly with antibiotic therapy. Within 12 hours of starting antibiotic therapy, 50% of all significant bacterial species initially identified in significant numbers had colony counts reduced to below the “pathogenic” threshold level. After 48 hours of therapy, only 14% of isolates are still present above threshold values [22]. It is therefore essential to obtain quantitative cultures before starting or changing antibiotics.

Despite the greater accuracy of quantitative bronchoscopic cultures, prospective randomized trials of early invasive diagnostic strategies employing bronchoscopy and quantitative lower respiratory tract cultures for VAP have not demonstrated significant advantages in mortality or other major clinical end points [23,24] over simpler methods. The largest such trial [24] found that compared to therapy based on nonquantitative endotracheal aspirates, patients randomized to bronchoscopy with quantitative cultures had no improvement in mortality, duration of mechanical ventilation, or length of ICU or hospital stay. On the basis of these findings, routine use of bronchoscopy in immunocompetent adults with suspected VAP cannot be recommended.

When an infectious process is suspected, the diagnostic yield depends on the organism and the immune status of the patient. In immunocompetent patients, BAL has a sensitivity of 87% for detecting respiratory pathogens [19], and a negative BAL quantitative culture has a specificity of 96% in predicting sterile lung parenchyma. Numerous recent investigations have examined the utility of bronchoscopy in immunocompromised patients. Most of these investigations have found that the diagnostic yield of BAL in such patients is approximately 50% and that the results of BAL lead to a change in treatment in 17% to 38% of patients. In one prospective multicenter trial [25], BAL was the only conclusive diagnostic study in 33% of patients. Although it is difficult to distinguish respiratory decompensation caused by bronchoscopy from the natural history of the patients’ underlying disease, the same study found that 48% of patients developed deterioration in respiratory status after bronchoscopy and 27% of patients were intubated. Transbronchial biopsy may add little to the diagnostic yield of BAL in immunocompromised patients, with an incremental yield of 7% to 12% [26,27,28,29]. In some series, the major complication rate of transbronchial biopsy was greater than the diagnostic utility, including a 14% incidence of major bleeding requiring intubation [29]. BAL has a relatively poor sensitivity for detecting fungal infections in this population (40%) [26]. In AIDS patients, the sensitivity of lavage or transbronchial lung biopsy for identifying all opportunistic organisms can be as high as 87% [30,31]. Transbronchial biopsy adds significantly to the diagnostic yield in AIDS patients and may be the sole means of making a diagnosis in up to 24% of patients, including diagnoses of Pneumocystis jirovecii, Cryptococcus neoformans, Mycobacterium tuberculosis, and nonspecific interstitial pneumonitis [32]. Lavage alone may have a sensitivity of up to 97% for the diagnosis of P. jirovecii pneumonia [33]. However, because induced sputum samples can also be positive for P. jirovecii in up to 79% of cases [33], induced expectorated sputum, when available, should be evaluated first for this organism before resorting to bronchoscopy.

In patients exposed to smoke inhalation, flexible nasopharyngoscopy, laryngoscopy, and bronchoscopy are indicated to identify the anatomic level and severity of injury. Prophylactic intubation should be considered if considerable upper airway mucosal injury is noted early; acute respiratory failure is more likely in patients with mucosal changes seen at segmental or lower levels [34]. Upper airway obstruction is a life-threatening problem that usually develops during the initial 24 hours
after inhalation injury. It correlates significantly with increased size of cutaneous burns, burns of the face and neck, and rapid intravenous fluid administration, and also portends a greater mortality [35].

Patients may present with atelectasis, pulmonary contusion, hemothorax, pneumothorax, pneumomediastinum, or hemoptysis. Prompt bronchoscopic evaluation of such patients has a diagnostic yield of 53%; findings may include tracheal or bronchial laceration or transection (14%), aspirated material (6%), supraglottic tear with glottic obstruction (2%), mucus plugging (15%), and distal hemorrhage (13%) [36]. Many of these diagnoses may not be clinically evident and require surgical intervention.

Flexible bronchoscopy can identify a disrupted suture line causing bleeding and pneumothorax following surgery and an exposed endobronchial suture causing cough. In these postpneumonectomy situations, the location of dehiscence and the subsequent bronchopleural fistula (BPF) is easily identified visually via flexible bronchoscopy at the stump site. However, when the BPF occurs in the setting of acute respiratory distress syndrome (ARDS) or necrotizing pneumonia, localization at the segmental and subsegmental level can be more challenging. Readers are referred to Chapter 57, which comprehensively covers this topic.

When a nasotracheal or orotracheal tube of the proper size is in place, the balloon can be routinely deflated and the tube withdrawn over the bronchoscope to look for subglottic damage. The tube is withdrawn up through the vocal cords and over the flexible bronchoscope and glottic and supraglottic damage sought. This technique may by useful after reintubation for stridor, or when deflation of the endotracheal tube cuff does not produce a significant air leak, suggesting the potential for life-threatening upper airway obstruction when extubation takes place. The flexible bronchoscope may readily identify mechanical problems such as increased airway granulation tissue leading to airway obstruction, tracheal stenosis at pressure points along the artificial airway–tracheal interface, and tracheobronchomalacia.