Rigid Bronchoscopy

The initial bronchoscope, developed by Killian and further optimized by Chevalier Jackson, was a rigid metal tube that permitted either spontaneous or mechanical ventilation. Over the decades, rigid bronchoscopes of various lengths and sizes that are adaptable for diverse applications in children and adults have become available. Although the flexible bronchoscope has to a large extent replaced the rigid scope for most diagnostic and some therapeutic indications, rigid bronchoscopy still has vital therapeutic applications.

Both rigid and flexible modern systems are equipped with optic capabilities for airway observation alone. With the rigid scope, various types of telescopic rods, equipped with circumferential illumination, permit direct and magnified visualization (Figure 11-1). Specially designed telescopes allow viewing not only directly forward but also at oblique and lateral angles. Various diagnostic and therapeutic instruments can be inserted through the rigid scope while the patient remains ventilated. Rigid bronchoscopy allows a number of therapies such as laser photoresection, endobronchial stents, balloon dilation, electrocautery, argon beam coagulation, and cryotherapy to be performed safely and effectively. Perhaps most important, a rigid scope can be used to “core out” large bulky airway tumors and to dilate central airway strictures and areas of stenosis very effectively and efficiently. In addition, the rigid bronchoscope also can be used for the passage of a flexible scope, which may be necessary for dealing with tortuous airways or distal lesions.

Figure 11-1 A typical rigid bronchoscope (middle) with Hopkins rod rigid telescope (top) and optical biopsy forceps (bottom).

(Courtesy John Beamis, MD.)

Flexible Bronchoscopy

The flexible scope is used in most bronchoscopic procedures. Although initial flexible bronchoscopes used fiberoptic systems, most such instruments now use a charge-coupled device (CCD) camera at the tip that allows transmission of digital images to a monitor. The main advantages of flexible scopes include their ease of manipulation and greater flexibility, allowing a more complete tracheobronchial tree evaluation than with rigid bronchoscopy, and a less challenging path to expertise, permitting more rapid acquisition of skills (favorable learning curve), for use of these devices (Figure 11-2).

Figure 11-2 Flexible bronchoscope. The flexible distal tip permits easy maneuverability in all lobar and segmental bronchi.

(Courtesy Olympus Corporation of the Americas, Center Valley, Pennsylvania.)

Flexible scopes vary in size, ranging from ultrathin devices allowing for endoscopy in infants and neonates to larger, adult-sized therapeutic scopes. The working channel of the bronchoscope can be used for aspiration of secretions and to accommodate various diagnostic or therapeutic accessories. Four main diagnostic tools have been developed for use during bronchoscopy in order to obtain diagnostic material: bronchoalveolar lavage (BAL), brushings, forceps biopsy, and needle aspiration (Figure 11-3). Since the inception of bronchoscopy more than 100 years ago, these diagnostic modalities have been hampered by limited ability to ensure direct localization of pulmonary nodules, masses, infiltrates, or lymph nodes. However, recent technologic developments in navigational technology and endoscopic ultrasound imaging have improved the ability to localize these lesions, to obtain diagnostic tissue, and to prevent unnecessary surgical intervention. The use of endobronchial ultrasound probes is discussed in Chapter 12.

Figure 11-3 Bronchoscopy brushes (A), needles (B), and biopsy forceps (C) are available in various sizes and types. B, Biopsy needles shown are the standard 21 G aspiration needle (top), and needle with side port (bottom), allowing for cell collection from the side and tip of the needle. C, Biopsy forceps shown (top to bottom) are alligator-jaw, alligator-jaw with needle, elongated, and standard cup forceps.

(Courtesy Olympus Corporation of the Americas, Center Valley, Pennsylvania.)

Biopsy forceps are available in various sizes and may have smooth or serrated edges. In some models, a small central needle is present between the cups for anchoring and stabilization. Smooth cup edges also may reduce tissue trauma and the concomitant bleeding risk. Lesions not accessible to direct forceps biopsy can be approached with a bronchial brush. This device consists of a rigid central wire surrounded by bristles of various size and shape. Repeated brush movement against the adjacent tissue produces minor trauma but enables collection of cellular specimens for cytologic or microbiologic analysis. Uncontaminated specimens from the lower respiratory tract can be collected with a brush protected by an additional sheath and tip. Needles of various sizes can be used to obtain both cytologic and histologic material from transbronchial lesions (e.g., lymph nodes, mediastinal masses) or from endobronchial and submucosal lesions.

Patient Preparation and Monitoring during Bronchoscopy

All patients undergoing bronchoscopy should undergo a complete prebronchoscopy evaluation, including a medical history, physical examination, and chest imaging (Box 11-1). Although routine laboratory tests are not required, each evaluation should be individualized on the basis of patients’ underlying conditions and the diagnostic and therapeutic procedures planned.

Most flexible bronchoscopy procedures are performed after patient sedation with any of a variety of pharmacologic agents. Most frequently, a combination of a short-acting benzodiazepine (e.g., midazolam) and a narcotic agent (e.g., fentanyl) are used for bronchoscopic sedation. Local anesthesia of the upper airway, larynx, and tracheobronchial tree is achieved with inhaled or bronchoscopically instilled lidocaine. Although rigid bronchoscopy initially was performed with use of minimal anesthesia and later with the patient under general anesthesia, the recent trend has been to perform the procedure with patients either breathing spontaneously or ventilated with a jet ventilator, often under total intravenous anesthesia (TIVA) with agents such as propofol and remifentanil. With appropriate monitoring, good oxygenation and adequate ventilation can be ensured.

Success of bronchoscopy, whether diagnostic or therapeutic, depends in large part on proper preparation of the patient, including relief of anxiety, muscle relaxation, cough suppression, and adequate anesthesia. Time spent in achieving these goals will be justified in reducing the complication risk and in increasing the ease of procedural performance.

Technique

The flexible bronchoscope usually is inserted nasally, orally, or through an endotracheal tube or a tracheotomy stoma. When necessary, it also can be inserted through a rigid bronchoscope. The nasal route often is preferred because the nasal passage often provides some resistance against the scope and allows for somewhat better control during airway inspection. When the oral route is used, a “bite block” should be inserted to prevent the patient from biting and damaging the scope. Supplemental oxygen should be administered to prevent hypoxemia, which is fairly common during bronchoscopy, particularly in patients with underlying lung disease.

The bronchoscopic evaluation should begin with a thorough examination of the upper airway, as well as assessment of the integrity and function of the larynx. The vocal cords should be examined for any abnormalities, such as polyps or tumors, and evaluated for paralysis during phonation.

Once the upper airway inspection is completed, a systematic evaluation of the lower respiratory tract should be performed, beginning with an evaluation of the trachea and then all segmental bronchi. Airway integrity should be assessed including thorough evaluation of the mucosal and delineation of carinal size and shape for any abnormalities with special attention paid to changes in dynamic airway caliber during either relaxed breathing or forced expiration and coughing.

It is important to distinguish among normal anatomy, anatomic variations without clinical significance, and frankly pathologic conditions. These considerations have important implications regarding potential diagnostic and therapeutic approaches. For example, an abnormal branching of a bronchus may be of no clinical significance. On the other hand, such an abnormality could explain frequent infections caused by impaired ventilation and drainage of the affected area. Bronchoscopy is particularly useful in documenting posttraumatic or postsurgical changes in bronchial integrity, such as bronchial rupture, tracheoesophageal or bronchopleural fistulas, or anastomotic complications after reconstructive or lung transplantation surgery. Similarly, bronchoscopy can be used to document tracheal injuries occurring in critically ill patients after prolonged intubation or tracheostomy. Although tracheal injuries have decreased in incidence over the past decade, tracheal stenosis, tracheomalacia, and tracheoinnominate artery fistula are still clinically important complications that must be considered and identified. Complications specific to the use of percutaneous tracheotomy include protrusion of ruptured cartilage into the tracheal lumen and extraluminal tracheostomy tube placement.

A thorough evaluation of the mucosal surface is an important part of the bronchoscopic examination. The most common abnormality is a change in mucosal coloration, with prominent hypervascular areas seen in patients with chronic bronchitis. The presence of granulation tissue can be due to reaction to a foreign body. Inflammatory mucosal reactions, although not very characteristic, should raise the possibility of mycobacterial infection, nonspecific viral and nonviral infections, and other granulomatous diseases, such as sarcoidosis (Figure 11-4). Mucosal ulcerations are more characteristic of Wegener granulomatosis or malignancy. Loss of the usual mucosal luster and presence of a roughened surface may be early signs of an infiltrative or neoplastic process.

Figure 11-4 Endobronchial sarcoidosis. Bronchoscopy demonstrates edematous airways with a “cobblestone” appearance, often seen in endobronchial sarcoidosis.

(Courtesy Meeta Prasad, MD.)

The trachea and bronchi are surrounded by mediastinal and parenchymal structures. Developmental or pathologic changes in these organs may be noted during bronchoscopic evaluation. An enlarged goiter or thymus can compress upper airways, resulting in airflow obstruction. Lymphadenopathy may produce structural changes, including widening of the main carina caused by subcarinal involvement, and compression of other bronchi—as, for example, in the right middle lobe syndrome. Peribronchial calcified lymph nodes may erode through the bronchial wall, resulting in broncholith formation. Such lesions are potential sources of obstruction, infection, or hemoptysis.

After the bronchoscopic inspection of the airways and surrounding structures has been performed, appropriate samplings should be obtained from the abnormalities identified. Aspirated secretions can be sent for microbiology cultures to determine the offending organism in cases of infection or suspected infection. Endobronchial lesions can be sampled with cytology brushes, biopsy forceps, or needles. Bronchoscopic lung biopsy can be performed for either focal abnormalities or diffuse lung diseases (Figure 11-5). For small or focal lesions, fluoroscopy helps guide peripheral forceps placement and improves the diagnostic yield of biopsies for focal lesions. The use of fluoroscopy also may obviate the need for routine chest radiography after transbronchoscopic lung biopsy. In the case of diffuse lung disease, such as sarcoidosis, use of fluoroscopy has not been demonstrated to improve the diagnostic yield of transbronchial biopsies. Fluoroscopy is useful, however, in providing information regarding the proximity of the forceps to the pleura and in more rapidly establishing the diagnosis of complications (e.g., pneumothorax). Transbronchoscopic needle aspiration (TBNA) and biopsy (TBNB) permit sampling of peribronchial lymph nodes. These transbronchial approaches provide cost-effective diagnostic modalities with less risk and a lower complication rate than with mediastinoscopy (see Chapter 17).

Figure 11-5 The mechanism by which bronchoscopic lung biopsy is obtained. The biopsy forceps pinches off the lung tissue located between two branches of terminal bronchi.

Bronchoalveolar lavage (BAL) is a useful and generally well-tolerated bronchoscopic sampling technique (Figure 11-6). BAL is safe, even in critically ill patients, when biopsy or brushing methods are not recommended because of bleeding risk. Normal saline solution, devoid of any bacteriostatic material, is instilled into distal air spaces through the “wedged” flexible scope and then aspirated through the instrument’s suction channel or from a sterile trap. The fluid collected can be analyzed for gross appearance to detect possible alveolar hemorrhage. The fluid also may be subjected to a variety of tests, depending on the clinical circumstances: microbiologic testing, specific cytologic analysis and cell count, immunologic parameters, presence of various biochemical mediators related to pathologic processes, tissue markers, polymerase chain reaction (PCR) assay, electron microscopy, flow cytometry, and DNA probes. The diagnostic yield of BAL very much depends on specific patient characteristics, the underlying pathologic process, and technical factors.

Figure 11-6 Bronchoalveolar lavage (BAL) is performed by wedging the tip of the flexible bronchoscope in the segmental bronchus leading to the parenchymal abnormalities detected by imaging techniques. Normal saline, 100 to 150 mL, in aliquots of 10 to 50 mL, is instilled through the bronchoscope channel and suctioned back into a container for analysis.

Chronic Cough

Chronic cough remains one of the most common reasons for patients to seek medical attention. Although flexible bronchoscopy frequently is used in the evaluation of chronic cough, its role has not been clearly defined, particularly in patients without other indications for the procedure. The routine use of bronchoscopy for investigation of chronic cough has a diagnostic yield of less than 5%. When chronic cough is associated with localizing signs and symptoms, such as hemoptysis, a focal wheeze, or abnormalities on an imaging study, a specific diagnosis by bronchoscopy is much more likely. In nonsmokers with normal findings on chest imaging, the most likely causes of cough are asthma, gastroesophageal reflux disease, and rhinitis. Bronchoscopy can be considered if these etiologic entities have been effectively ruled out by a combination of empirical treatment and diagnostic testing, including the use of spirometry, bronchoprovocation tests, sinus imaging, and esophageal pH probes.

Hemoptysis

Hemoptysis is a common clinical sign and one of the most frequent indications for bronchoscopic evaluation. The most common causes of scant hemoptysis include chronic bronchitis, tuberculosis, and bronchiectasis, whereas massive hemoptysis, usually defined as bleeding greater than 200 mL in a 24-hour period, most often is due to tuberculous cavities, lung cancer, mycetomas, or lung abscess (see Chapter 24). Bronchoscopy can be of help in localizing the site and cause of bleeding. Although the timing of the procedure should be dictated by clinical circumstances, studies have shown that early bronchoscopy (within 48 hours) is more likely to demonstrate active bleeding and allow for the determination of the bleeding site. Chest imaging, with either chest radiograph or computed tomography (CT) scan, can assist in bleeding site localization and, in stable patients without massive hemoptysis, should precede bronchoscopy. In patients with a normal appearance on the chest film, the prevalence of malignancy is approximately 5%, which in most cases is visible by CT scan. The yield of bronchoscopy in patients with normal findings on CT scan is extremely low, and a conservative approach consisting of observation and serial imaging should be considered. Beyond its role as a diagnostic tool, bronchoscopy often can be used to perform various therapeutic procedures in patients experiencing hemoptysis (see further on).

Pulmonary Infections

Bronchoscopy is a useful technique in the diagnosis of pulmonary infections, allowing for the collection of respiratory samples for evaluation with special stains and culture. Respiratory samples can be collected by one or more techniques, including bronchial washing, BAL, protected specimen brushing (PSB), bronchoscopic lung biopsy, and TBNA (Table 11-1).

Table 11-1 Bronchoscopic Techniques and Applications in Respiratory Infections

Bronchoscopy is not indicated for the diagnosis of community-acquired pneumonia, which is currently treated empirically with appropriate antibiotic therapy. Bronchoscopy is likely to be useful in cases of nonresolving pneumonia, ventilator-associated pneumonia (VAP), or new infiltrates in immunocompromised patients. Nonresolving pneumonia is defined as lack of improvement or worsening of symptoms despite a minimum of 10 days of antibiotic therapy or failure of radiographic abnormalities to resolve after 2 to 3 months. The causes of nonresolving pneumonia are myriad and include inadequate antibiotic therapy, resistant or highly virulent organisms, impaired host defenses, obstructing endobronchial lesions, or a noninfectious cause. Although controversial, bronchoscopy should be considered in these patients.

Mycobacterial Infections

In cases in which pulmonary tuberculosis is suspected, the initial diagnostic evaluation should consist of serial examination of sputum for the presence of acid-fast bacilli (AFB) in stained smears. Ideally, induced sputum samples should be obtained. If sputum study results are negative and tuberculosis is still suspected, bronchoscopy with BAL and biopsy should be performed. Both induced sputum collection and bronchoscopy should be performed with appropriate infection control precautions to minimize the risk of nosocomial transmission. A bronchoscopy may cause the patient to produce sputum for several days afterwards; these specimens also should be collected and analyzed, if possible. The utility of bronchoscopy varies widely in the literature, with reported diagnostic yields of 50% to 95%. The yield in patients with miliary tuberculosis, in whom sputum smears frequently are negative, is approximately 70%. Bronchoscopy also is useful in tuberculosis manifesting as an endobronchial lesion or with mediastinal and hilar adenopathy, in which case diagnostic tissue can be obtained with TBNA (Figure 11-7). The yield of diagnostic procedures, including bronchoscopy, can be expected to improve as newer interferon release assays and nucleic acid amplification techniques are incorporated into everyday practice (see Chapter 31).

Figure 11-7 Endobronchial tuberculosis involving distal trachea and main bronchi. Image on the left was obtained before chemotherapy; the posttherapy appearance is shown in image on the right. Endobronchial tuberculosis is commonly mistaken for bronchogenic carcinoma.

Bronchogenic Carcinoma