Introduction and Historical Background
Flexible bronchoscopy (FB) is one of the prime examples of an area of pulmonary medicine transformed by technological advances. Today it has become one of the most frequently performed invasive procedures in pulmonary medicine. The use of bronchoscopy for diagnosis is covered in this chapter, and the use of bronchoscopy for therapy is covered in Chapter 23 . Diagnostic bronchoscopy can also be divided into basic procedures, those available to most facilities and with significant evidence to support their use, and advanced procedures, those available only in some centers and still undergoing investigation to determine their most appropriate uses.
Gustav Killian performed the first bronchoscopy in 1897 to extract a piece of a pork bone from the right main bronchus. From that meager beginning, the technology in bronchoscopy has advanced exponentially. In 1966 the flexible bronchoscope was introduced into clinical practice by Shigeto Ikeda. Currently this instrument is one of the most important tools for diagnosis and treatment of pulmonary diseases.
Bronchoscopy can be easily performed in an outpatient setting, under moderate sedation and local anesthesia. Compared with FB, rigid bronchoscopy is now primarily used for selective indications such as massive hemoptysis and therapeutics (see Chapter 23 ).
Indications
The indications for diagnostic FB are broad and growing ( Table 22-1 ). Nonetheless, certain conditions are not considered indications for FB. For example, FB is not indicated to evaluate patients with cough unless the cough fails to respond to conventional treatment or if there is a change in its character. Similarly, bronchoscopy is not indicated to evaluate patients with isolated pleural effusion or atelectasis, and its use to remove secretions during acute exacerbations of chronic obstructive lung disease is also considered inappropriate. FB also has little role in finding synchronous lesions in patients undergoing lung resection of a solitary pulmonary nodule suspected to be primary bronchogenic carcinoma. Absolute and relative contraindications to performing FB are presented in Table 22-2 .
| Hemoptysis |
| Wheeze and stridor: suspected stricture, upper airway obstruction |
Lung opacities of unknown cause
|
| Unexplained lung collapse |
Suspected or known bronchogenic carcinoma
|
| Mediastinal and hilar lymphadenopathy and masses |
Lung transplantation
|
| Esophageal cancer evaluation |
Endotracheal intubation
|
| Evaluation for foreign body aspiration |
Chest trauma
|
| Evaluation following burns or chemical injury to the airways |
| Unexplained superior vena cava syndrome |
| Unexplained vocal cord paralysis or hoarseness |
Suspected fistulas
|
| ABSOLUTE |
|
| RELATIVE |
|
Procedure
FB is usually performed via the oral or the nasal route. Either route provides excellent access to the lower airways. By either route, attention should also be given to the upper airway. In particular, bronchoscopy performed for the evaluation of hemoptysis or wheezing should include a careful evaluation of the upper airway, including the nasopharynx and oropharynx and vocal cords.
Sedation and Anesthesia
The need for sedation during FB remains a matter of some debate in the literature. The purpose of sedation is to improve patient comfort and add to the ease of the procedure for the bronchoscopist. Although bronchoscopy can be carried out without sedation, most are performed under moderate sedation.
Intravenous preparations of various sedatives such as diazepam, midazolam, lorazepam, morphine sulfate, fentanyl, and hydrocodone have been used either alone or in combination based on the bronchoscopist’s preference and the availability of the drug. Fentanyl has a greater analgesic potency than morphine. Hydrocodone has a greater antitussive property than codeine but less than that of morphine. Due to its rapid onset and anxiolytic and amnestic properties, midazolam is one of the most commonly used sedatives; sedation with midazolam in FB improves the patient’s comfort and decreases complaints, without causing significant hemodynamic compromise. It should be offered to the patient on a routine basis.
The combination of a benzodiazepine and an opioid has been shown to be safe and synergistic for the purposes of sedation during FB. Because the combination of benzodiazepines and opiates may cause hypoventilation, particularly in patients with preexisting respiratory failure, patients should be appropriately monitored. The combination of hydrocodone and midazolam reduces cough during FB without causing significant desaturation and improves the patient’s tolerance for the procedure.
Dexmedetomidine (Precedex, Dexdomiror) also has favorable properties of sedation, sympatholysis, analgesia, and a low risk for apnea. These properties suggest that dexmedetomidine may be useful in procedural sedation. However, it has been shown that dexmedetomidine as a sole agent is unable to provide adequate sedation for awake diagnostic FB without the need for rescue sedation in a large proportion of patients.
Dextromethorphan can also be given orally 90 minutes before the procedure to improve cough suppression during the procedure.
Interestingly, according to some surveys, 16% to 21% of physicians use deep sedation or general anesthesia for FB. Use of propofol alone is as effective and safe as combined sedation in patients undergoing FB under conscious sedation, thus representing an appealing option if timely discharge is a priority. Deep sedation with propofol for bronchoscopy has gained popularity in recent years, although concern has been raised regarding its potential ability to induce severe respiratory depression. In one prospective study the use of small boluses of propofol at short intervals with monitoring of transcutaneous carbon dioxide level was found to be safe; the authors concluded that propofol used in this manner does not cause excessive respiratory depression and represents an excellent alternative to traditional sedation agents. In another prospective study the combination of propofol and hydrocodone was safe and better for cough suppression than propofol alone in FB.
Fospropofol disodium is a water-soluble prodrug of propofol. A subset analysis was undertaken among elderly patients (≥65 years) undergoing FB; fospropofol provided safe and effective sedation, rapid time to fully alert status, and high satisfaction, which were comparable with outcomes in younger patients.
Patients with human immunodeficiency virus (HIV) infection, recipients of stem cell transplantation, lung transplant recipients for cystic fibrosis, and drug users usually require higher doses of sedatives than other patients. Additionally, because protease inhibitors used in patients with HIV infection have been shown to extend the half-life of benzodiazepines significantly, many institutions in the United States encourage the use of deep sedation in these patients instead.
Local Anesthesia
Although nerve blocks can be used to provide excellent analgesia to the airway, physicians generally rely on topical administration of local anesthetic agents. Lidocaine is the most commonly used drug for providing topical anesthesia. It offers a relatively wide margin of safety with a rapid onset and sufficient duration of action to allow completion of most bronchoscopic procedures. The gel preparation of lidocaine is preferred over the spray for nasal anesthesia. Given that sensory anesthesia is not dependent on the concentration of lidocaine, 1% is preferred because larger volumes can be instilled to cover a greater surface area of the mucosa before toxic dosages are reached. The oropharynx can be anesthetized with 2% to 4% lidocaine applied as a spray, nebulized solution, or gargles.
The vocal cords as well as the endobronchial tree are anesthetized by direct instillation of lidocaine via the working channel of the bronchoscope. The total dose of lidocaine should be limited to 8.2 mg/kg in adults, with extra caution in older adults or those with liver, renal, or cardiac impairments.
Anticholinergic agents such as atropine and glycopyrrolate have been commonly used as premedication for FB with the aim to reduce the bronchial secretions and suppress vagal overactivity. Several studies have shown that anticholinergics offer little advantage as premedications, and their use should be abondoned.
Monitoring
To ensure adequate oxygenation (oxygen saturation of >92%) and hemodynamic stability, pulse oximetry, heart rate, and blood pressure are monitored throughout the procedure. There should be intravenous access and equipment for resuscitation. Supplemental oxygen should be available. At many institutions, continuous end-tidal carbon dioxide monitoring is used to assess ventilation. All FB procedures are performed observing universal precautions. Following each procedure, the instrument is thoroughly disinfected or sterilized according to recently published consensus statements.
Basic Diagnostic Bronchoscopy
The standard procedure for FB involves a thorough examination of the entire tracheobronchial tree in a systematic fashion, from the upper airway and vocal cords to the trachea and carina, major bronchi, and the segmental bronchi in each of the five lung lobes. A through understanding of normal features can allow detection of abnormalities in anatomy (e.g., missing or duplication of bronchi), shape (e.g., narrowing or distortion), changes in the anatomy with breathing (e.g., collapse), or endobronchial mucosa (e.g., induration, friability, erythema, lesions). A bronchoscopy of a patient with a relatively normal tracheobronchial tree is shown in 
.
Examination of the upper airway can be instructive. The vocal cords may be involved with infections ( Fig. 22-1 ) or malignancy; the cords may be paralyzed as a result of interruption of the recurrent laryngeal nerve or erythematous or edematous due to gastroesophageal reflux. The trachea may be abnormal owing to either congenital or acquired conditions ( Fig. 22-2A and B ). The endobronchial mucosa exhibits characteristic changes due to infiltrative or systemic conditions (see Fig. 22-2C and D ). Endobronchial lesions may be caused by a multitude of conditions, including inflammatory, malignant, or infectious disease, or by foreign bodies ( Fig. 22-3 ). Attention should also be paid to the normal expiratory collapse of the central airway as well as to the presence of excessive dynamic airway collapse/tracheobronchomalacia.
Bronchoalveolar Lavage
Bronchoalveolar lavage (BAL) has become an important clinical and investigational tool. It is a standard diagnostic procedure in all patients with diffuse lung abnormalities of unknown cause whether an infectious, noninfectious, immunologic, or malignant cause is suspected. BAL allows the recovery of both cellular and noncellular components of the epithelial (alveolar) lining fluid and epithelial surface of the lower respiratory tract. Components of the BAL fluid represent the inflammatory and immune status of the lower respiratory tract and the alveoli ( Fig. 22-4 ). BAL, which samples the distal air spaces, differs significantly from a bronchial washing, which samples the large airways via aspiration of small amounts of instilled saline. BAL should be considered a standard procedure in the evaluation of diffuse lung diseases, suspected infection, or malignancy, especially when the bleeding risk prohibits either bronchial brushing, transbronchial biopsy (TBB), or transbronchial needle aspiration (TBNA).
For diffuse opacities, any area can be chosen for BAL; however, in such cases, either the right middle lobe or the lingula is preferred because, in a supine patient, gravity assists the recovery of a maximal amount of BAL fluid return. In the case of localized disease, lavage should be performed in the area of focal radiographic abnormality, and for maximal recovery, the patient can be positioned appropriately to improve recovery from the desired segment. “Good wedge” position usually means that the bronchoscope is advanced as far as possible without losing the view of the distal lumen. In this optimal position, a slow, manual gentle aspiration, without allowing the airway walls to collapse, tends to maximize the lavage return.
BAL has significantly improved the diagnostic workup of lung diseases, whether diffuse or localized. In pulmonary alveolar proteinosis, it has both diagnostic and therapeutic value. In an international statement on the major interstitial lung diseases, BAL is considered to be helpful in strengthening the diagnosis of sarcoidosis in the absence of a tissue diagnosis, by finding a lymphocytosis (>25%) and a CD4/CD8 ratio greater than 4. BAL may be a useful tool in the diagnosis of peripherally located primary lung cancer, with an overall diagnostic yield range of 33% to 69%, being exclusively diagnostic in 9% to 11% of cases. Numerous case reports confirm the ability of BAL to diagnose leukemia and lymphomatous pulmonary involvement as well as plasma cell dyscrasia. Finding asbestos bodies in BAL fluid may correlate with occupational exposure, yet in itself, it is not proof of an asbestos-related disease. The presence of more than 25% eosinophils in the BAL fluid confirms the diagnosis of eosinophilic lung diseases, and the presence of more than 4% CD1 + Langerhans cells confirms a diagnosis of Langerhans cell histiocytosis, albeit with low sensitivity. In chronic beryllium disease, lymphocytes from the BAL proliferate when stimulated in vitro with soluble beryllium salts, with a sensitivity and specificity approaching 100%; this lymphocyte test has become a valuable diagnostic tool for this condition and has replaced open-lung biopsy.
In patients with ventilator-associated pneumonia, a positive quantitative culture (>10 4 colony-forming units (CFU)/mL) on BAL fluid may be clinically useful with a sensitivity of 22% to 93% and a specificity of 45% to 100%, depending upon the clinical status of the patient. BAL is also a useful tool in the diagnosis of pulmonary infections in immunocompromised patients, with the reported yield as high as 93% ( Fig. 22-5 ). Thus, in certain conditions, BAL findings can be diagnostic and thereby avoid the need for either TBB or open-lung biopsy ( Table 22-3 ). In other settings, although not diagnostic, BAL can be used as an adjunct to the diagnosis when interpreted in the context of the entire clinical picture.
|
While performing BAL in an immunocompromised host and if invasive Aspergillus infection is suspected, the fluid should be submitted for galactomannan cell wall antigen detection using an enzyme immunoassay. The sensitivity and specificity of elevated galactomannan levels in BAL fluid are of value in immunocompromised patients. According to a recent meta-analysis, the sensitivity, specificity, and accuracy are reported to be 79%, 86%, and 89%, respectively. It needs to be pointed out that concomitant use of certain antibiotics such as piperacillin-tazobactam, amoxicillin, or amoxicillin-clavulanate and all fermentation products of Penicillium species may produce false-positive results. Besides, the test may also have cross reactivity with Histoplasma capsulatum cell wall antigen. Hence the results should be interpreted in the context of the total clinical picture and rechecked periodically.
The most common complications associated with BAL are fever, which can be seen in up to 30% of patients, and transient hypoxemia, which is readily handled with supplemental oxygen.
Bronchial Washings
Bronchial washings are obtained by advancing the bronchoscope into an airway, instilling 10 to 20 mL of sterile saline, and then quickly aspirating the instilled saline into a specimen trap. The utility of bronchial washings is largely for the diagnosis of airway diseases, including primary or metastatic lung carcinoma and fungal or mycobacterial infection. Of the various bronchoscopic procedures, bronchial washing is the easiest to perform but has the lowest yield (sensitivity, 27% to 90%), with a higher yield for central lesions. Bronchial washings are an inexpensive adjunct and should be collected during a diagnostic bronchoscopy when appropriate because, even though by a small percentage, they can increase the overall diagnostic yield of the procedure.
Bronchial Brushings
Bronchial brushings were analyzed for the first time in 1973 and showed highly suspicious cytologic findings in most cases with lung cancer. In general, bronchial brushings provide diagnostic material in 72% (44% to 94%) of patients with central lung cancers and 45% of patients with peripheral lesions, when obtained under fluoroscopic guidance. When bronchial brushing is combined with endobronchial biopsy (EBB) of central lesions, the diagnostic yield of FB increases to between 79% and 96%. We usually perform brushing after obtaining all the other bronchoscopy specimens to avoid bleeding or cell distortion interfering with obtaining or interpreting subsequent samples. The diameter or the length of the brush has not been shown to affect the diagnostic yield from the bronchial brushing.
Protected Specimen Brush
Protected specimen brush was first described in 1979 by Wimberley and coworkers as a technique to establish an accurate diagnosis in patients with suspected pneumonia. Brushing specimens are collected using a special brush that is enclosed within a double catheter sheath. The catheter is closed off at its distal end by a wax plug, which can be easily dislodged before obtaining the specimen. The purpose of the catheter sheath and wax plug is to prevent contamination of the brush with oropharyngeal flora that remain inside the working channel of the bronchoscope.
In patients with ventilator-associated pneumonia, the sensitivity of protected specimen brush ranges from 58% to 86% and the specificity from 71% to 100%. For now, the procedure appears to have lost popularity against empiricism for the diagnosis of ventilator-associated pneumonia; however, when it is used, quantitative cultures with a cutoff value of greater than 10 3 CFU/mL should be obtained to optimize its accuracy (see also Chapter 34 ).
Endobronchial Biopsy
EBB is an essential and technically simple tool in the diagnosis of endobronchial neoplasms as well as for inflammatory conditions such as sarcoidosis and amyloidosis. When the forceps are open, they are advanced onto the target and closed, thereby gripping the target. The forceps are briskly pulled back, taking a sample of the endobronchial lesion 2 to 4 mm in diameter. The forceps and biopsy specimen are then pulled out through the working channel, and the tissue sample is collected in saline or fixative. EBB is used for lesions directly visualized during bronchoscopy. It provides histologic specimens, whereas bronchial washing provides only cytologic samples. The reported diagnostic yield of EBB is 80% with a range of 51% to 97% depending upon the patient population. The number of biopsy specimens required for optimal diagnostic yield varies according to the suspected diagnosis. Three biopsy specimens of an endobronchial lesion suspected to be bronchogenic carcinoma can provide a diagnostic yield of over 97%. Biopsy of the surface of endobronchial tumors may be falsely negative if there is surface necrosis; in such circumstances, needle sampling deeper into the mass may be diagnostic.
Transbronchial Biopsy
TBB is the technique by which a piece of lung parenchyma is obtained by using flexible forceps positioned distally via FB. TBB specimens can be obtained blindly or with guidance by fluoroscopy, computed tomography (CT), or radial-probe endobronchial ultrasonography. In many instances TBB can obviate the need for an open-lung biopsy; however, certain diagnoses such as idiopathic pulmonary fibrosis generally require larger tissue samples than those that can be obtained bronchoscopically. TBB is diagnostically useful in 38% to 79% of patients (average sensitivity, 52%) depending upon the underlying disease. For example, in sarcoidosis, TBB has a diagnostic yield of 40% to 90%, although recent studies indicate that endobronchial ultrasonography–guided TBNA (EBUS-TBNA) of mediastinal/hilar nodes may have a greater diagnostic yield. TBB has also been shown to be diagnostic in up to 10% to 40% of cases of Langerhans cell histiocytosis, 88% to 97% in Pneumocystis jirovecii pneumonia, and 57% to 79% in lung infections caused by Mycobacterium tuberculosis. In patients suspected of having pulmonary alveolar proteinosis, its diagnostic yield has been reported to be as high as 100% ( Fig. 22-6 ).
The diagnostic yield of TBB increases with the number of biopsy specimens obtained. Usually 6 to 10 biopsy specimens are obtained under fluoroscopic guidance. However, the use of fluoroscopy is not mandatory in patients with diffuse parenchymal disease, and biopsy specimens can be obtained by assessing the proximity to the pleura as guided by the patient’s perception of chest pain. The yield of TBB for malignant peripheral lesions more than 2 cm in diameter was also reported to be 70% in a recent study, even without fluoroscopic guidance. When performed in association with bronchial brushings and TBNA, TBB adds to the diagnostic yield of FB for peripheral lung cancers.
The success of lung transplantation cannot be imagined without the contributions from FB and especially TBB. In lung transplant recipients, TBB helps in diagnosing or ruling out acute cellular rejection. It also helps establish the diagnosis of antibody-mediated rejection as well as that of chronic rejection, albeit with lower yield. To date, however, there are no gold standard findings for diagnosing rejection in the lung transplant population.
Pneumothorax and hemorrhage are the most feared complications following TBB, with an incidence of up to 5% of cases. Renal insufficiency ( blood urea nitrogen [BUN] level > 30 mg/dL [10.7 mmol/L] and creatinine level of >3 mg/dL [265 µmol/L]) and other coagulopathies are considered risk factors for bleeding following TBB. TBB can be safely performed while patients are receiving aspirin or nonsteroidal anti-inflammatory drugs; however, clopidogrel bisulfate should be withheld for at least 5 to 7 days before the procedure.
Transbronchial Needle Aspiration
TBNA is a sensitive, accurate, safe, and cost-effective technique in the diagnosis and staging of lung cancer, and it can also be applied for the diagnosis of nonmalignant diseases such as sarcoidosis ( 
). Despite proven advantages, the practice of TBNA remains underutilized. There are no absolute, specific contraindications for TBNA.
Diagnosis and staging of bronchogenic carcinoma, lymphoma, and sarcoidosis can be established using 21- or 22-gauge cytology needles. For the diagnosis of lung cancer, the reported sensitivity, specificity, and accuracy of TBNA are 60% to 90%, 98% to 100%, and 60% to 90%, respectively. For mediastinal staging, the overall sensitivity, specificity, and accuracy of TBNA are 50%, 96%, and 78%, respectively. Judicious use of TBNA can thus reduce the need for surgical staging. In the diagnosis of involvement of mediastinal or hilar lymph nodes by sarcoidosis or tuberculosis, TBNA can be useful as well ( Fig. 22-7 ). In cases with pulmonary nodules, TBNA increases the diagnostic yield of FB by 25%. TBNA can also be safely performed in mechanically ventilated patients.
The procedure of TBNA is safe, with an overall major complication rate of approximately 0.26%. Complications include damage of the working channel of the bronchoscope, fever, bacteremia, and bleeding from the puncture site ( Fig. 22-8 ). Use of CT, fluoroscopy, and ultrasonographic guidance has been shown to improve the yield of TBNA.
Endobronchial Ultrasonography
Endobronchial ultrasonography (EBUS) is a bronchoscopic technique that uses ultrasound to visualize structures within and adjacent to the airway wall. There are two types of EBUS device: radial-probe EBUS (RP-EBUS) ( Fig. 22-9A–C ) and convex-probe EBUS (CP-EBUS) ( Fig. 22-9D ).
RP-EBUS is a technique in which a small ultrasound probe (1.4 to 2.8 mm diameter, 20 MHz) is introduced into the airways through the working channel of the FB to obtain ultrasonographic images of the peribronchial tissues. Because the RP-EBUS is placed in the endobronchial tree through the working channel of the conventional bronchoscope, it precludes real-time sampling. Using a fluid-filled balloon around the probe, the structure of the airway wall can be studied as, for example, to determine the depth of tumor invasion or to assess the structure of the bronchial wall in diseases such as tracheobronchomalacia. RP-EBUS provides a 360-degree view of the peribronchial tissue with high-resolution ultrasonographic views of the tissue layers in close contact with the probe or the fluid balloon (see Fig. 22-9C ).
For obtaining samples using the RP-EBUS, the RP-EBUS is introduced via a guide sheath and is advanced into the peripheral pulmonary lesion under bronchoscopic guidance. Once the lesion is identified with ultrasonographic images, the probe is removed leaving the guide sheath in place; endobronchial accessories are inserted through the sheath to the peripheral lesion to obtain diagnostic specimens (see Fig. 22-9B and C ). Using this technique, the diagnostic yield of FB for peripheral lung lesions less than 3 cm in size has been improved to nearly 75%. During the early years of EBUS application, the radial probe was also used to guide TBNA in the diagnosis of mediastinal disease and for the staging of non–small cell carcinoma. However, because real-time guidance is not possible with the RP-EBUS, in recent years, sampling of mediastinal pathologic conditions has been carried out with CP-EBUS bronchoscope (see Fig. 22-9D ).
CP-EBUS is an endobronchial ultrasonographic technique that allows real-time imaging during sampling. A 7.5-MHz curved ultrasound transducer integrated into the distal tip of the bronchoscope delivers sound waves in a linear or longitudinal fashion encompassing a 55-degree area. The scope has an outward diameter of 6.9 mm and a 30-degree forward endoscopic oblique view. While the site is being imaged ultrasonographically, the TBNA specimen is obtained with a specially designed 21- to 22-gauge needle inserted through the working channel of the scope to obtain a cytologic examination ( 
). The procedure is performed either under moderate sedation or general anesthesia.
The primary role of CP-EBUS is in the nodal staging of non–small cell lung cancer. When mediastinal/hilar lymph nodes less than 20 mm in short axis, especially in the 4L station, need to be sampled, CP-EBUS–TBNA should be the preferred sampling method. For lesions that are paraesophageal, in the inferior mediastinum, or involve the left adrenal gland, endoscopic ultrasound-guided fine-needle aspiration may be a more appropriate initial sampling method. The combined use of EBUS-TBNA with endoscopic ultrasound-guided fine-needle aspiration has been shown to reduce the need for surgical sampling and, by accurately staging unresectable patients, to avoid “unnecessary thoracotomies.” In various reports of its value in staging for lung cancer, EBUS-TBNA has excellent sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of 95%, 100%, 100%, 90%, and 96%, respectively. Despite the cytologic nature of the EBUS-TBNA specimen, adequate tissue is easily obtained for molecular studies and genetic mutation analysis for personalized treatment for unresectable adenocarcinoma of the lung. Compared to that for conventional FB, the procedure for EBUS-TBNA takes longer and requires additional training. EBUS-TBNA is more expensive than conventional TBNA but could reduce expenses by limiting the number of more costly surgical procedures ( Table 22-4 ). In the future EBUS-TBNA may have applications in the diagnosis of airway as well as pulmonary vascular disease.
| Advantages | Disadvantages |
|---|---|
| Outpatient procedure using local anesthesia and conscious sedation. Sampling of the high mediastinal, paratracheal, and subcarinal lymph nodes possible, similar to mediastinoscopy. Also allows sampling of hilar lymph nodes. High diagnostic yield. More invasive diagnostic procedures (e.g., mediastinoscopy) are frequently rendered unnecessary. Complications are uncommon, while sampling is performed in real time. Real-time imaging permits the sampling of lymph nodes that are smaller than 10 mm in short axis and/or near major blood vessels. | Cannot image or sample para-aortic and lower paraesophageal lymph nodes. Technically challenging. Not widely available. Only small (i.e., 21- and 22-gauge) needles can be used for EBUS-guided transbronchial needle aspiration. Benign condition may require histologic specimen. |
Compared to mediastinoscopy, EBUS-TBNA was as effective in determining the pathologic lymph node state in prospective studies involving patients with potentially resectable lung cancer. The specificity and positive predictive value for both techniques was 100%, whereas the sensitivity, negative predictive value, and diagnostic accuracy were 81%, 91%, and 93%, respectively, for EBUS-TBNA and 79%, 90%, and 93%, respectively, for mediastinoscopy. These studies suggest that, when performed under general anesthesia, with rapid on-site cytologic examination, and using different needles for each lymph node station, EBUS-TBNA can replace mediastinoscopy for lymph node staging.
To determine whether an endobronchial lesion is invasive or resectable, we recommend use of RP-EBUS with a balloon sheath catheter. For sampling endobronchial lesions, EBUS-TBNA is seldom required, and EBB and conventional TBNA should be performed instead. To sample a peripheral pulmonary nodule, we suggest that RP-EBUS–guided TBB should be the first sampling procedure. RP-EBUS–guided TBB of peripheral pulmonary nodules detects malignant disease with a sensitivity and specificity of 73% and 100%, respectively. The diagnostic yield of RP-EBUS–guided TBB is also higher than that of conventional TBB.
Advanced Diagnostic Bronchoscopy
The following techniques are advancing the field of bronchoscopy using new technology either to improve imaging or to improve navigation to peripheral lesions. Their specific applications and benefit are still being determined, but they hold promise for extending the range of bronchoscopy for diagnosis of central or peripheral lesions.
Ultrathin Bronchoscopy
The ultrathin bronchoscope currently being studied has an outer diameter of 2.8 mm and an inner channel diameter of 1.2 mm and is made up mainly of fiberoptic bundles ( Fig. 22-10 ). This device has been developed to overcome the low diagnostic yield of FB for lesions less than 20 mm in diameter. Complexities of the distal airway anatomy require fluoroscopic or CT guidance to maneuver the scope to peripheral lesions. These bronchoscopes also can be used with ease in mechanically ventilated patients with small endotracheal tubes. Ultrathin bronchoscopes help in evaluating the nature and the extent of upper airway obstruction where there is a risk for completely compromising the airways with standard bronchoscopes. An ultrathin bronchoscope is also useful for defining the distal extent of an endobronchial tumor when it is causing significant airway obstruction.
