Indications

Indications for tracheobronchoscopy include the evaluation of acute or chronic respiratory symptoms such as hemoptysis, nonresolving and worsening cough, and acute or worsening subacute dyspnea that may be accompanied by wheezing or stridor, pleurisy, chest pain, fever, or other symptoms suggestive of a pulmonary process (Box 75-1). Symptoms may be accompanied by radiographic abnormalities suggesting an endobronchial lesion, extrinsic compression of the airways by a mediastinal or lung mass, or presence of an infiltrate. Patients are often also referred for evaluation of asymptomatic lung or mediastinal masses and nonresolving parenchymal lung infiltrates. Pleural effusions usually lead to evaluation of the pleural fluid; however, effusions most often have an underlying parenchymal pulmonary cause, and a nonresolving effusion without an established cause after thoracentesis or thoracoscopy should prompt an examination for endobronchial obstruction. Bronchoscopy is helpful in assessing the placement of endotracheal tubes, especially in difficult intubation cases or when double-lumen tubes are required. A flexible fiberoptic bronchoscope (FOB) can be used to guide placement of an endotracheal (ET) tube in a difficult airway; in such cases, the ET tube is prepositioned and advanced over the bronchoscope. An FOB can also be used to guide percutaneous tracheostomy. Indications for tracheobronchoscopy in children include suspected foreign body, respiratory distress secondary to tracheomalacia or bronchomalacia, and evaluation of other congenital anomalies. Depending on the findings on radiography or during a diagnostic bronchoscopy, therapeutic interventions may be performed with an FOB to maintain airway patency and improve gas exchange.^6,7

After consideration of the indication for the procedure, the next steps of planning should include the multimodality team of otolaryngologists, pulmonologists, radiologists, anesthesiologists, nurses, respiratory therapists, “backups” in thoracic surgery and interventional radiology if their services may be needed, and, not least, the patient and family for careful discussion and informed consent.

Radiology

Given the millimeter-range high-resolution and rapid multiplanar reconstruction of the airways achievable with multislice spiral computed tomography (CT) scanners, a preprocedural CT scan can help pinpoint the location and extent of disease and reduce the time spent on exploration in patients with limited cardiopulmonary reserve. A contrast-enhanced CT scan is especially useful to provide the spatial relationship between pathology and vasculature and, hence, to minimize the risk of accidental and potentially life-threatening vascular injury from interventions such as laser or mechanical débridement. Contrast-enhanced atelectatic lung parenchyma can often also indicate whether there is viable lung tissue beyond central obstruction. Three-dimensional measurements of airway stenosis length and diameter facilitate the preselection of balloons for bronchoplasty and of airway stents for maintaining patency in an obstructed airway segment. A thoracic surgeon or interventional radiologist should be consulted before the bronchoscopic investigation of massive hemoptysis, in case the bleeding source can only be identified—but not quelled—by bronchoscopic interventions.

Sedation and Airway Management

Maintaining gas exchange is critical during bronchoscopy, together with the desire of minimizing patient discomfort and anxiety. Some level of sedation, monitoring, and augmentation of oxygenation and ventilation is carried out with the assistance of an anesthesiologist or nursing personnel certified in sedation and airway management. Conscious sedation usually involves intravenous sedation with short-acting benzodiazepines (midazolam is most commonly used) or other anxiolytic agents plus a short-acting narcotic (e.g., fentanyl, meperidine, or morphine sulfate) to help suppress the cough reflex. My colleagues and I also find promethazine (Phenergan) useful in patients who are difficult to sedate or who have a strong gag reflex. The medications are given in measured, small boluses and the patient is appropriately monitored with hemodynamics, cardiac monitors, and pulse oximeters. Not yet routinely used but increasingly available is transcutaneous capnography. Deep sedation with propofol (Diprivan) provides for rapid on-and-off titration of sedation and can be very helpful in some patients who are difficult to sedate. General anesthesia with inhalational anesthetics with or without intravenous sedation provides the greatest control, but this would mandate the use of an ET tube, laryngeal mask airway (LMA) ventilation, rigid endoscopy with side-port ventilation, or a previously placed tracheostomy. It is also contingent on the presence of an anesthesiologist or a nurse anesthetist, who may not be readily available for bronchoscopies performed in endoscopy units separate from the operating rooms.

For patients undergoing bronchoscopy under conscious sedation, topical anesthetics are commonly used to reduce the amount of systemic sedative-narcotics needed to suppress cough, and also to diminish local discomfort in the nasopharynx during the passage of the bronchoscope. Lidocaine and its derivatives are most commonly used and applied topically as a gel to the nasal passage or as a spray to the posterior oropharynx. Solutions with concentrations between 1% and 4% are available, but the operator must pay attention to the total dosage applied because systemic lidocaine toxicities, including inadvertent deaths in healthy research subjects, have been reported when more than 500 to 1000 mg is delivered topically in a single session.⁸ Therefore, except for spraying to the posterior oropharynx, we limit the use of topical lidocaine injected via the operating channel of the bronchoscope onto the vocal cords and airway mucosa to less than 3 to 4 mg/kg total dosage (1% lidocaine has 10 mg of lidocaine per l mL solution). Cocaine is also a very effective topical anesthetic that has the advantage of vasoconstricting the nasal mucosa membrane; it is, however, not generally available for use in the average endoscopy suite.

Miscellaneous medications that can be used in bronchoscopy include atropine or glycopyrrolate in patients with excessive secretions. Chronic bronchitis patients with acute bronchitis and patients with preprocedural problems handling bronchial secretions may be good candidates for parasympathomimetic agents. Caution should be used because such agents can precipitate tachycardia.

Patient Positioning and Route of Bronchoscope Entry

In a patient under conscious sedation with or without a previously placed tracheostomy, a flexible bronchoscope can be introduced with the patient supine or in a sitting position. It is generally easier for the bronchoscopist to be standing at the head of the bed. If a nasal approach is chosen, a cotton swab soaked with a lidocaine solution or gel is used to determine which of the nares permits easier passage. Studies have found shorter and smaller patients to experience greater postprocedural nasal discomfort when the same-sized bronchoscope is used; hence, for such patients, an oral approach may be preferable. Conversely, because of the sharper angulation of the bronchoscope at the posterior oropharynx when introduced orally, patients tend to have a greater gag response; therefore, a more thorough application of topical anesthetics to the posterior oropharynx is recommended. Because of the risk of trauma to the teeth and the instrument being used, a properly secured bite block is mandatory in this approach. For rigid bronchoscopy, although the early pioneers performed the procedure on fully conscious patients placed in a sitting position, the procedure should be carried out with the patient supine and the neck extended. The patient is almost always fully anesthetized with paralysis to facilitate the passage of the rigid bronchoscope. The rigid bronchoscope can most easily be introduced via the oral route. The insertion and maneuvers of the rigid bronchoscope as well as the proper ventilation and anesthesia are discussed later.

Ventilation and oxygenation can be better maintained in a more upright patient under lighter sedation. With a flexible FOB, the approach is made from the front of the patient. The approach via the nares or an oral passage is similar, although the view on the monitor is inverted because of the position of the bronchoscope tip relative to the approach. Once past the vocal cords, the bronchoscope can easily be turned to regain the familiar view with the ventral or anterior surface of the body facing the top.

In patients under deep sedation or general anesthesia, either a flexible FOB or a rigid bronchoscope can be used to examine the airways. For a flexible FOB, gas exchange is maintained with either an ET tube or a laryngeal mask; the latter is usually sufficiently large such that bronchoscope size is not a factor in limiting adequate ventilation and oxygenation. Prior discussion with the anesthesiologist ensures that a sufficiently large ET tube is inserted to permit smooth passage of the bronchoscope. For therapeutic cases using bronchoscopes with a diameter of 6.0 mm or greater, an ET tube of at least 7.5 mm is needed. Additional options are (1) to perform direct suspension laryngoscopy with intermittent ventilation via an ET tube alternating with bronchoscopic examination and intervention and (2) to perform direct suspension laryngoscopy using spontaneous ventilation and passive oxygenation.

To facilitate passage of the flexible bronchoscope, water-soluble lubricants are applied to the sheath of the bronchoscope. Lubricant jelly has the disadvantage of drying rather quickly, leading to stiffness in maneuvering, especially when the scope is introduced nasally. Lidocaine jelly is a good alternative that also provides some local anesthesia. Newer compounds, such as Endo-Lube (Covidien, Mansfield, MA) provide excellent lubrication and are ideal when the bronchoscope has a tight fit through devices such as an ET tube. Its cost may be higher, and caution is necessary to prevent accidental dislodgement of the ET tube from the ventilator because the lubricant also makes the various connections between the ET tube and ventilator circuit slippery. Mineral oil should not be used if at all possible because of the potential of oil aspiration leading to a lipoid pneumonia.

Patient Discussion and Informed Consent

Well-informed and educated patients and families are more likely to be compliant with therapy. In the case of bronchoscopy, especially in patients undergoing conscious sedation, an explanation of the steps helps alleviate the anxiety over the coughing and gagging that can sometimes force premature termination of the procedure. Ancillary diagnostic and therapeutic procedures, especially on hyperemic inflamed or malignant tissue, often lead to bleeding and postprocedural hemoptysis that should taper off. Similarly, a substantial portion (25%-50%) of patients may experience transient postprocedural fever during the first 24 hours. The cause need not be infectious and may be more common after bronchoalveolar lavage (BAL), which can result in surfactant washout. Informing patients of these two possible minor complications can obviate anxious midnight calls to the physician after a procedure. Conversely, patients should also be warned about prolonged bleeding and delayed pneumothoraces that may not be detected immediately after the procedure. Persistent or high spiking fevers, hemoptysis, and worsening dyspnea should prompt the patient to immediately contact a physician, who may perform a reevaluation with radiograph, physical examination, and other laboratory tests, as indicated.

Range of Flexible Bronchoscopes and Special Features

Although there remains the tendency to subdivide bronchoscopes into “adult” and “pediatric” categories depending on their outer diameters, this distinction is arbitrary. Because bronchoscopists venture more peripherally with FOBs to sample focal lesions, and more interventional procedures via a flexible FOB are performed in the pediatric population, it makes more sense to describe the bronchoscopes and leave their judicious application to the bronchoscopist according to experience and the situational need.^3,4

All FOBs have an illumination fiberoptic bundle and imaging fiberoptics or a camera. With the exception of the very few “ultrathin” bronchoscopes, there is also a channel for suction of secretions and blood, for the passage of topical medication and fluid for washing, and for the passage of various instruments for diagnostic retrieval of tissues or for therapeutic procedures (Table 75-1). The “average” diagnostic bronchoscope has an outer diameter of 5.0 to 5.5 mm and an operating channel of 2.0 to 2.2 mm. This caliber channel admits most cytology brushes, bronchial biopsy forceps, and transbronchial aspiration needles with sheathed outer diameters between 1.8 and 2.0 mm. Smaller bronchoscopes, in the range of 3.0 to 4.0 mm at the outer diameter and correspondingly smaller channels, are usually given a “P” designation (for pediatrics), but they can, of course, be used in the adult airways when narrowing is present because of benign strictures or malignant stenosis. Newer generations of “slim” video and fiberoptic bronchoscopes have a 2.0-mm operating channel with a 4.0-mm outer diameter. The one disadvantage of these bronchoscopes is the sacrifice of a smaller image area because of fewer optical bundles.

Larger “therapeutic” bronchoscopes (often designated with a “T” in the model number) can, of course, also be used for diagnostic purposes, but the larger outer diameter can cause greater discomfort and mucosal trauma in a conscious patient and can be harder to pass through an ET or tracheostomy tube, and thus can also impair gas exchange to a greater degree. Such therapeutic bronchoscopes have outer diameters between 6.0 and 6.3 mm, with operating channel lumens between 2.6 and 3.2 mm. Certain therapeutic instruments, including larger laser fibers, larger electrocautery forceps designed for gastrointestinal endoscopes, cryotherapy probes, and expandable balloons for bronchoplasty, require these larger diameters for their use through FOBs. Prototype bronchoscopes with a 9-mm outer diameter and a 5-mm operating channel have been made, the main application of which is to provide access for therapeutic instruments to airway segments that cannot normally be reached by rigid open-tube bronchoscopes and telescopes (Fig. 75-2).

Figure 75-2. Left to right, Range of fiberoptic bronchoscopes with outer/channel diameters of 4.9/2.0 mm and 6.0/2.8 mm, and a prototype therapeutic scope with diameters 9.0/5.0 mm. Note the insulated white ceramic plate, which is necessary for safe use of electrosurgery.

At the other extreme are the ultrathin bronchoscopes, with outer diameters smaller than 3 mm. The Olympus production models fiber BF-XP40 and video BF-XP160F (Olympus America, Center Valley, PA) have outer diameters of 2.8 mm and operating channels of 1.2 mm. Special instruments (e.g., reusable cytology brush and forceps) of the proper caliber are available for tissue sampling (Fig. 75-3). Handling of these ultrathin bronchoscopes is often more challenging because their very floppy tips make steering more difficult. Suction via the narrow channels is also much more limited. Nevertheless, with practice and the use of small amounts of saline to flush open the distal airways in guiding the bronchoscope forward, the ultrathin bronchoscopes can traverse 12 to 16 generations of airways and, under fluoroscopic or CT guidance, are seen to approach the periphery of the lungs to sample focal lesions.^3,4 The passage of a 2.8-mm instrument beyond the mid-teens division of the lobular bronchiole (measured at 0.7 mm in fixed tissue) calls into question some of the accepted measurements of the adult human airways. To permit the greater distance traversed, such ultrathin bronchoscopes usually have an operating length of 60 cm, 5 cm longer than the older bronchoscopes, although the current generation of videobronchoscopes are all built with a 60-cm working length.

Figure 75-3. An “ultrathin” bronchoscope, with an outer diameter of 2.8 mm and a working channel of 1.2 mm, and a custom forceps holding up a U.S. penny and shown next to a paperclip for size comparison.

New bronchoscopes manufactured today usually have a white ceramic insulated tip; this feature permits the safe use of electrocautery instruments with reduced risk of retrograde electric shock to the bronchoscopist and damage to the bronchoscope (see Figure 75-2).

Certain bronchoscopes designed for autofluorescence imaging have built-in filter wheels that are adjustable to facilitate imaging at specific spectral frequencies. Autofluorescence bronchoscopy is briefly mentioned in a later section of this chapter.

Care of the Flexible Fiberoptic Bronchoscope

Unlike the sturdy rigid bronchoscope, the flexible FOB is much more delicate, with glass fiberoptic bundles that can be easily damaged by rough handling or accidental patient bites. Repair of bronchoscopes is costly and makes the use of the instrument temporarily unavailable. The narrow operating channel can also be damaged by a number of instruments, especially when these are too large for safe passage. The two especially vulnerable portions of the flexible FOB are the angulated entry port of the working channel and the distal tip of the bronchoscope. Incompletely retracted transbronchial needle aspiration (TBNA) needles are most frequently the culprits, tearing the channel during their introduction or retrieval by an inexperienced user. Such damages are noted during the “leak test” that should be performed after each use of the bronchoscope and before machine washing. It should also be emphasized that the tip of the bronchoscope should be kept as straight as possible during introduction and retrieval of the instruments. The same care must be exercised in the use of the entire range of diagnostic and therapeutic instruments because tears can also occur with biopsy forceps improperly opened within the channel, pushing and pulling of semirigid instruments through the flexed tip of the bronchoscope, burning on the inside of a bronchoscope channel by improper activation of electrocautery instruments, or firing of laser fibers.

There is growing focus on nosocomial infections resulting from defective endoscopes (loose valves) or from improper cleaning techniques. Thus far, outbreaks of nosocomial bacterial infections (e.g., gram-negative bacilli and Mycobacterium) are rare, and there have not been confirmed reports of viral transmission. The prevalence of such infections is very low and should not discourage the appropriate performance of bronchoscopy when it can provide important diagnostic information or can aid therapy. There are a number of accepted cleaning techniques ranging from gas sterilization (ethylene oxide) to formaldehyde-based approaches. It is under the purview of the endoscopy unit or operating room director and nursing director to develop quality control measures.

Diagnostic Fiberoptic Bronchoscopy

Endobronchial and Transbronchial Biopsy

A number of biopsy forceps are available for biopsy of bronchial mucosa or endobronchial lesions, and for transbronchial biopsy of airway and parenchyma beyond direct bronchoscopic vision (Fig. 75-4). The catheters are of various diameters and lengths, with larger “therapeutic” forceps fitted with larger forceps cups. The edges of the cups are either smooth-cutting or jagged “alligator” type. A number of the larger forceps are designed primarily as forceps for use in upper and lower gastrointestinal endoscopes, and hence their cables are much longer than the 55 to 60 cm of the bronchoscope working channel. There are additional forceps with a needle or “spike” in the center of the opened jaw near the fulcrum of the opened forceps; this spike aids in the anchoring of the forceps on mucosa, scar tissue, or tumor. These needle forceps are most useful for endobronchial biopsy, especially when the target may be along an airway wall tangential to the bronchoscope and thus cannot be easily grasped by forceps opening at a very shallow angle to the lesion. Some forceps also have an attachment for electrocautery. These may be useful for sampling or removing friable tissue that bleeds, because electrocautery can effectively provide thermal hemostasis.

Figure 75-4. Instruments for use with a flexible fiberoptic bronchoscope Top to bottom, Reusable forceps with steel wire catheter sheath (Olympus America, Center Valley, PA); disposable forceps with coated catheter (Microvasive, Boston Scientific, Natick, MA); disposable needle forceps; large electrocautery forceps, which requires a 2.8-mm channel; electrocautery snare; handle with wire attachment for electrosurgical instruments.

The technique for endobronchial biopsy is fairly straightforward. After careful positioning of the opened jaws of the forceps, the forceps is advanced toward the target lesion and is closed when the lesion is within grasp. The challenge comes when the target is small, the airways are moving in response to respiration, or the patient is agitated and coughing. The opened jaws of the forceps can further obscure the view from the bronchoscope. Under these circumstances, the resultant tug of a fairly floppy forceps catheter may yield a disappointingly small specimen. One technique to improve the accuracy and yield of the biopsy is to advance with the bronchoscope closer to the target lesion before advancing the biopsy forceps outward. With closure of the forceps cups, one should pull back gently until the forceps are almost but not fully retracted into the bronchoscope channel. The bronchoscope itself should be pulled back slowly but firmly, and the much larger instrument (bronchoscope vs. the forceps) generally helps pull out a much larger specimen.

Complications from endobronchial biopsy most often involve bleeding due to trauma. Flushing small aliquots (1-2 mL) of a topical vasoconstrictor followed by a saline “chase” of 2 to 3 mL to clear the medication out of the bronchoscope channel helps stem the bleeding. Tamponade with the tip of the bronchoscope until a clot forms may also help, but this is often less effective and risks further obscuring the view with coagulum. Oxymetazoline (Afrin) 0.05% and lidocaine with epinephrine (1 : 10,000 dilution) are two vasoconstrictors commonly used for this purpose, although oxymetazoline is preferred because it causes less tachyarrhythmia and hypertension. Airway perforation is a theoretic risk but it rarely occurs, except in severely necrotic airways already distorted and destroyed by invasive cancer. Damage to the bronchoscope is a real concern; this can occur if an inexperienced operator attempts to open the forceps while it is still within the channel, or if an incompletely closed forceps or one with a kinked set of cups is forcibly withdrawn back into the channel. When there is any doubt or if there is obvious kinking of the forceps that cannot be corrected within the airways, the entire bronchoscope must be withdrawn, and the problem fixed outside the patient’s airways.

Transbronchial biopsy uses the same instruments, although there is much less reason to use the needle forceps. This procedure is usually directed toward a focal mass lesion most often suspicious for lung carcinoma, or toward focal or diffuse infiltrates suggestive of infection, inflammatory lung processes, fibrotic lung parenchyma, or metastatic carcinoma with lymphangitic or diffuse hematogenous spread. Although it is possible to perform successful transbronchial biopsy without radiographic guidance, the yield is lower and the risk of complications increased; therefore, we prefer the availability of fluoroscopy to guide transbronchial biopsy, especially of smaller, more focal, and more peripheral lesions (Fig. 75-5).^11,13

Figure 75-5. Transbronchial biopsy of a peripheral (left upper lobe) lung mass under fluoroscopic guidance.

For more diffuse peripheral disease, whether guided by fluoroscopy or with use of a “blind” approach, the forceps are advanced slowly in a closed position until gentle resistance is felt or until the tip of the instrument is seen to approach the pleura. Because of the angulation of the segmental airway branchings and the effects of foreshortening, the advancing forceps may not appear to approach the lung periphery on the planar fluoroscope. Once resistance is felt, the forceps are retracted about 2 to 3 cm, the cups are opened, and the instrument is gently pushed forward. After firm closure, the position of the forceps is confirmed by fluoroscopy and the instrument withdrawn. In a patient under conscious sedation, especially when fluoroscopy is not available, we also ask whether there is chest wall pain, which would suggest focal pleural irritation caused by the tip of the forceps and would warn us of the increased risk of pneumothorax. The yield from transbronchial biopsy varies depending on pathology, location and size of lesion, and availability of fluoroscopy. In general, the diagnostic yield for transbronchial biopsy in malignant lesions located centrally and larger than 2 cm is about 50%, compared with only 25% in lesions smaller than 2 cm located in the peripheral one third of the lung.

Complications of TBBX are bleeding and pneumothorax. As aforementioned, performing fluoroscopy and querying for symptoms of pleurisy reduce the risk of pneumothorax to less than 10%, with overall rates of 3% to 20% reported.¹¹ Significant bleeding is not increased in patients taking aspirin and cannot be predicted by routinely ordering measurements of platelet counts and coagulation parameters. Nevertheless, in critically ill or pancytopenic patients, an attempt is made to keep the platelet counts above 50,000/µL, to correct coagulopathy if present, and to temporarily suspend anticoagulation. Bleeding, when brisk, is managed by tamponading of the bleeding subsegment with the bronchoscope tip. Depending on operator preference, suction can be applied to collapse the segmental airways to prevent further retrograde bleeding into the central airways, and lavage with room-temperature or cooled saline can be performed to slow the bleeding. There are no randomized trials to suggest efficacy of one approach over another. Needless to say, life-threatening hemorrhage from transbronchial biopsy is rare but reported.

Transbronchial Needle Aspiration

TBNA has traditionally been used to sample mediastinal lymph nodes and cysts. Initially TBNA was performed using needles on a long rigid stem introduced via a rigid bronchoscope tube; in fact, the earliest cannulation of the left atrium for measurements of left atrial pressure was performed using this TBNA approach. Diagnosis of benign mediastinal adenopathy (e.g., sarcoidosis) and malignant tissue (e.g., lymphoma, nodal metastases of bronchogenic carcinoma) can be made via rigid TBNA; however, the lymph nodes sampled are often limited to the subcarina and, possibly, the precarina because of the limited angulations achievable with rigid instruments.

The introduction and refinement of TBNA needles attached to a flexible catheter has permitted sampling, with a flexible FOB, of a larger number of lymph node regions, endobronchial lesions in the segmental and subsegmental bronchi, and peripheral, endoscopically occult lesions. The majority of the needles are made of stainless steel with calibers ranging from 22 to 19 gauge (Fig. 75-6). There remains one plastic needle with a flexible tip (Microvasive Sofcor, Boston Scientific, Natick, MA) that may be bent to facilitate passage into subsegments of the upper lobes and certain lower-lobe subsegments that are otherwise often not reachable with metal transbronchial needles because the 13- to 15-mm lengths of these rigid needles reduce the tip angulations of the flexible FOBs.

Figure 75-6. Transbronchial needles and cytology brush. Top to bottom, 18-gauge Microvasive Sofcor plastic (Boston Scientific, Natick, MA); 19/21-gauge MW 319 histology steel, 15-mm length (Bard/Mill-Rose Laboratories, Mentor, OH); 21-gauge SW121 cytology steel, 15 mm (Bard/Mill-Rose Laboratories); 22-gauge MW122/222/522 cytology steel, 13 mm (Bard/Mill-Rose Laboratories); cytology brush.

Although the flexible needles have been divided into smaller gauge (20, 21, and 22 gauge) “cytology” needles and larger gauge (19-gauge metal and 18-gauge Sofcor) “histology” needles (see Figure 75-6), the choice of the needle depends on operator experience, because the larger “histology” needles still provide tissue for cytologic examination by slide smear, and samples aspirated with smaller “cytology” needles can be spun down into a cell block and cut for histologic examination. The longer needle lengths (15 mm) of the 21-gauge and larger needles offer the advantage of greater depth penetration. However, a 19-gauge needle is more unwieldy to maneuver, takes more practice for penetration of the bronchial mucosa, and can potentially cause more trauma. It is often reserved for the sampling of larger lymph nodes suspected of harboring lymphoproliferative tissue (e.g., lymphoma, Castleman’s disease) or granulomatous diseases (e.g., sarcoid, mycobacterial, and fungal adenitis) because, with practice, a 21-gauge core sample can be retrieved.

Mediastinoscopy remains the “gold standard” for examination and sampling of mediastinal lymph nodes; however, access to the subcarina, posterior tracheal, subaortic left-paratracheal/aortopulmonary window and hilar lymph nodes is limited. TBNA via FOB has the advantage of access to a larger number of lymph node stations and of being a less invasive procedure that can be combined with the endoscopic examination of the airways plus as-needed sampling of peripheral lung disease (see Figure 75-6). Therefore, TBNA may be one of multiple procedures performed in a sequence of “one-stop” diagnosis and staging of thoracic malignancies. Certain lymph node stations are also inaccessible to TBNA via FOB; these include the paraesophageal and lateral aortopulmonary-window lymph nodes, which can be sampled by real-time endoscopic ultrasonography–guided fine-needle aspiration (FNA) via the esophagus and by anterior median sternotomy (Chamberlain procedure), respectively.

Technical Aspects

The “abnormal” lymph node has been classified radiographically as one with a short axis measuring more than 1 cm. However, thorough lymph node staging of bronchogenic carcinomas has demonstrated a diagnostic sensitivity and specificity of only about 60% to 70% with this rule applied. 18-Fluorodeoxyglucose positron emission tomography may identify metabolically abnormal lymph nodes and lung nodules even when they do not fulfill this size criterion. After identification of an accessible lymph node suspicious for harboring pathology, a TBNA needle is carefully introduced with tip retracted via the operating channel of the bronchoscope. Regardless of the location of the chosen target, it is best to pass the TBNA through the lumen with the bronchoscope in a fairly central location (i.e., the trachea or mainstem bronchi) with the tip straight or minimally angulated in order to protect the expensive equipment that can be most easily damaged by instruments at its distal flexible end. With the TBNA needle still in its protective hub, the bronchoscope is then maneuvered into a position proximal to the target lesion. After the bronchoscope is centered away from the side-walls, the needle is deployed and locked in place, as care is taken to avoid mucosal trauma that will cause bleeding and obscuration of the bronchoscopic view. The catheter tip housing the beveled metallic needle usually has a protective metal hub that helps prevent inadvertent perforation of the bronchoscope channel. During positioning for TBNA, a portion of the needle or the catheter hub should always be visible; otherwise it is possible that the exposed needle was pulled back into the distal bronchoscope tip, again risking damage. If for any reason the needle is not visible, it should be retracted into the catheter and the entire catheter should be removed from the bronchoscope and properly reset for redeployment.

The actual mucosal penetration and spearing of the mediastinal target can be performed by one of two techniques, the “stab” or the “push-jab.”¹⁰ The stabbing approach entails holding the bronchoscope in place and pushing the deployed needle catheter forcefully forward, thus traversing the bronchial mucosal into a lymph node or tumor mass. The limitation of this technique is that it is suited only for lesions that are situated directly in the line of sight of the bronchoscope; the needle will more than likely take a somewhat more oblique pathway across the bronchial mucosa, thus leaving less needle length to penetrate the lesion. In a spontaneously breathing patient, subtle airway motion can translate to missing the lesion or having the needle hang up on bronchial cartilage instead of passing through the membranous portion of the mucosa. Finally, if the bronchoscope-needle setup is positioned too far away from the bronchial mucosa point of entry, pushing the flexible TBNA catheter outside the bronchoscope channel will allow the catheter to bend and kink, further limiting its effectiveness.

For these reasons, the piggy-back “push-jab” technique is preferred. In this approach, the deployed and locked needle is kept partially withdrawn into the distal bronchoscope and the sharp needle tip is carefully directed toward a selected entry point; the membranous mucosa between cartilage rings is chosen. The bronchoscope tip can be partially flexed such that the bronchoscope and needle catheter behave as a curved needle set, with the needle anchored at about a 45-degree angle. Control of both the catheter and bronchoscope is obtained, either by the bronchoscopist alone or with an assistant holding the proximal end of the catheter and being ready to advance it on command, and the bronchoscope is pushed forward firmly as the piggy-backed needle-catheter is jabbed forward. With practice, the TBNA needle can be made to traverse the mucosa at a nearly 90-degree angle, thus affording sampling of lesions in the distal left and right paratracheal angles, anterior precarinal space, and right bronchial lymph nodes (Fig. 75-7). Once the locked needle-catheter set is advanced until the entire length of the needle is buried up to the hub, the clear catheter is pushed from the proximal end until a bit of it is visibly protruding from the distal bronchoscope tip. At this point, inadvertent penetration of one of the major vascular structures, such as the aorta, pulmonary artery branches, superior vena cava, or azygous vein would be obvious from the complete backfill of the distal catheter with blood even without any suction applied. If there is no unexpected return of blood, a cytology or histology sample can be obtained with the forward-and-backward movement of the needle. Although suction has most often been applied by syringe attached to the proximal end of the TBNA catheters, this manipulation is not always necessary because it is really the capillary action plus the regular agitation motion that draws tissue into the lumen of the needle. This principle is especially applicable for looser, less organized malignant tissue, whereas suction may be required for acquisition of an adequate sample of a denser granulomatous or reactive lymph node.

Figure 75-7. Transbronchial needle aspiration of a left paratracheal lymph node, resulting in successful staging of stage IIIA disease.

The same TBNA needles can be used for the transbronchial sampling of peripheral lung masses, although as mentioned earlier, the acute bending of certain lobar segments may preclude successful passage of the TBNA needle into the desired airway segments.^11,13 Unlike in sampling of central mediastinal lesions or endobronchial pathology, the needle is not deployed until the catheter hub with the protected needle tip is advanced into position as indicated by fluoroscopy or CT.

There is some debate as to the ideal method to retrieve the needle-catheter and how to process the sample thereafter. Some experienced practitioners of TBNA withdraw the still extended and locked needle back into the bronchoscope and out the channel while simultaneously straightening the tip of the bronchoscope. The rationale for not first retracting the needle into the safety of the hubbed tip is to avoid sucking back bronchial epithelial cells that may dilute the presumed pathologic cells of interest within the needle. The obvious risk, however, is the much greater chance of damage wrought on the bronchoscope even if the needle is only pulled back, because a rigid needle measuring 13 to 15 mm can scratch and perforate the bronchoscope channel, which can be in a 130- to 180-degree angulation. Current teaching is therefore to always fully retract the needle before pulling the catheter backward, while still straightening the distal tip of the bronchoscope.

The retrieved samples can be prepared and preserved in a number of ways. Generally, more than a single pass is made to ensure adequate sampling, with the maximum yield leveling off after between four and seven passes at a particular site. The presence of rapid on-site evaluation by a pathologist or an experienced cytopathology technician is a helpful adjunct that improves the diagnostic yield of TBNA.¹⁴ The immediate feedback will direct the need for additional TBNA passes. Even when disease is noted, such as carcinoma or abnormal lymphocytes, extra passes for additional material to be spun down for immunostaining or preservation in media for flow analysis may aid in making the identification of a tumor source or cell type, with important implications for prognosis and as a guide for therapy. In the absence of cytopathology assistance, samples can also be injected into an aliquot of preservative solution such as Saccomanno’s fixative and spun down in the laboratory for further analysis. Flushing out the needle with 1 to 2 mL of saline after each pass, as reported earlier, is no longer practiced because this dilutes out small quantities of sample, and the needle loses some of its capillary effect when flushed with liquid. We therefore eject the sample from the needle with an air-filled syringe.

Published series quote a diagnostic yield rate of 75% to 90% for TBNA sampling of mediastinal lymph nodes, with lower rates for peripheral pulmonary lesions, once again depending on the location and size of the targets.^10,11,13 TBNA, however, remains an underused minimally invasive sampling technique because of uneven teaching of the technique and the average low yield for the occasional practitioner of this technique.⁹ A number of radiographic techniques have been used or are being developed as adjuncts to help in localization and to guide TBNA sampling of lung pathology. Fluoroscopy can help visualize the proper penetration of a lesion in the lung parenchyma but is generally less useful in accurately localizing mediastinal adenopathy and central masses that may be obscured by the cardiac silhouette and other normal mediastinal structures. Spiral CT, either with stopped frames or fluoroscopic, can be used to help localize and prove TBNA penetration of target lesions, but it is cumbersome to perform these bronchoscopic procedures in the CT scanner, and the patient and staff are exposed to a much higher levels of radiation.

The advent of rapid multislice detector CT scanners and the development of software to improve three-dimensional rendering may soon make available a number of high-fidelity “virtual bronchoscopy” programs, including the capability of rendering the airway wall “transparent” and highlighting the adjacent mediastinal structures of interest. The purpose of these programs is not to obviate the need for tissue diagnosis but to guide the approach for procedures such as TBNA and transbronchial biopsy. Another real-time guidance technique is the use of EBUS to localize lymph nodes and other mediastinal structures of interest for tissue sampling.^15,16 Most EBUS procedures use a radial balloon probe introduced via the working bronchoscope channel. After EBUS imaging is completed, the probe is withdrawn and TBNA is performed. Report of simultaneous imaging and sampling via a double-lumen bronchoscope is not generally applicable owing to the rarity of these bronchoscopes, which are largely being phased out, and by the imminent introduction of a dedicated EBUS bronchoscope with an angled side-port for TBNA. EBUS is currently available for clinical use, but in only at a limited number of centers because of the lack of experienced practitioners and the equipment cost.

The primary complication from TBNA of mediastinal structures is bleeding into the airways from puncture of vascular structures or vascular tumors. Less commonly, pneumothorax, pneumomediastinum, or hemomediastinum may occur. Bleeding is generally self-limited, and the bronchoscopist should be focused on clearing the airway of blood that would otherwise obscure the bronchoscopist’s view and induce coughing and desaturation. Suction should be directed downstream from the TBNA entry site, presenting no interference with the local formation of a small clot. TBNA of peripheral lung lesions entails the same risk as transbronchial biopsy, including bleeding and pneumothoraces.

General Principles

Virtual bronchoscopy is becoming more popular in simulating diagnostic bronchoscopy to diagnose airway pathology as a prequel to therapy, and minimally invasive therapies are now more and more favored over aggressive operations because of improved technology. Therefore the paradigm of bronchoscopy is shifting slightly from diagnostic implications to treatment with bronchoscopic interventional procedures.^18–20

Careful selection of a patient eligible for interventional bronchoscopy is critical to maximize benefit to patients who are generally quite ill. Depending on the particular intervention, the nature of the disease state, and the patient’s functional status, the risks associated with interventional procedures can be significant. The majority of our currently performed interventional procedures, such as repair of tracheobronchial-esophageal or bronchial-mediastinal fistulas, all strive to maintain airway patency and reestablish normal gas exchange, or to reestablish the airway structure to as near normal as possible.

It is important to recall that for ideal gas exchange to take place, there should be minimal ventilation-perfusion mismatching. Therefore, whereas the removal of a foreign body such as an aspirated object in a toddler or child can lead to immediate and full recovery, simply reestablishing airway patency may not be sufficient in other instances. For thoracic malignancies blocking the airways, whether primary or metastatic, débridement of airway tumor and debris when the accompanying vasculature is also infiltrated and obliterated may simply lead to increased “dead space.” Reestablishing ventilation of nonperfused lung segments can in fact worsen hypercapnia and not improve hypoxemia. A good-quality contrast-enhanced CT scan of the chest is therefore mandatory for review in all cases of airway obstruction, with the exception of patients with recent aspiration of a foreign body.

Knowledge of the position of the vasculature is furthermore critical for the interventional bronchoscopist to avoid potentially life-threatening complications of vascular injury by laser or mechanical débridement. The intravenous contrast agent in the CT scan serves another very important purpose. In the cases of known or highly suspected malignancies blocking the central airways, knowledge of whether there is functioning lung distal to the obstruction will help to predict the likelihood of success and to determine whether patients with tenuous medical status should be subjected to deep sedation or general anesthesia with mechanical ventilation from which they may not be successfully weaned. Experienced radiologists provide a reasonable estimate as to whether an interventional expedition from within the airway lumen will only reveal disease that is the “tip of the iceberg.” They can also comment on the presence of concomitant pleural disease that may portend the very poor prognosis of a “trapped” lung, even when the central airways are reopened and pleural fluid removal attempted.

Preparation of the Patient and Selection of Instruments

Careful history-taking should include any use of anticoagulants and antiplatelet agents. Physical examination, review of radiographs (preferably including a recent contrast CT scan), and measurement of platelet counts and other relevant bleeding parameters are routine. Because many of the patients undergoing interventional bronchoscopic procedures often have more advanced pulmonary diseases and possible comorbidities, a baseline electrocardiogram is often requested. Because the purpose of the procedures is often palliative in nature and the procedures are accompanied by higher risk than a standard diagnostic bronchoscopy, a detailed discussion of possible complications and the realistic likelihood of achieving subjective relief should be discussed with the patients and their families. In an airway interventional series of laser débridement in 1585 patients by Cavaliere and associates,²¹ the overall procedure-related mortality was 0.3% and the rate of major complications (including significant hemorrhage, pneumothorax, and pneumomediastinum) was 1.5%.

Most interventional procedures can be performed via an FOB, a rigid bronchoscope, or an FOB introduced via a rigid bronchoscope or via direct suspension laryngoscope. There are pros and cons to both approaches, but the operator should be capable of converting a procedure begun with an FOB into one using a rigid bronchoscope when the need arises.^9,18 The larger channel of the rigid bronchoscope facilitates the use of larger-caliber instruments, and certain rigid silicone stents require rigid instrumentation for their deployment. The bronchoscope itself can be used to core out tumor tissue or to tamponade hemorrhage from the side walls. It is also easier to remove noncancerous foreign bodies and to dilate benign stenotic segments via a larger rigid tube. Conversely, the larger and rigid instruments are more liable to cause trauma to the vocal cords and potentially cause a fistula when used to débride necrotic tissue in distorted airways. The constrained angulation provided by manipulation of the patient’s head and neck positions can limit the bronchial segments reachable for intervention. The rigid instruments also mandate the use of general anesthesia. When a flexible FOB is chosen for interventional procedures, larger-channel “therapeutic” bronchoscopes that can accommodate flexible interventional instruments are selected, but it is often helpful to also have available thinner pediatric bronchoscopes that can be used to bypass critical narrowings.

In the management of airway obstruction, the choice of the specific intervention depends on the location and severity of narrowing. Certain techniques, such as cryotherapy, photodynamic therapy, and endoluminal brachytherapy, simply do not work on malignant tissue rapidly enough to relieve critical stenosis. The short-term effect is, in fact, tissue edema as tumors undergo cell death and necrosis. In such instances, mechanical débridement with or without one of the heat thermal therapies would be more appropriate. In significant cases of central airway narrowing, in which both mainstem bronchi may be partially compromised, attention should first be directed to the less affected side, most often also the healthier lung, so that adequate single lung ventilation can be established. Even though the majority of airway interventions result in improved pulmonary function, the operating team of otolaryngologists, pulmonologists, anesthesiologists, and nursing personnel should always be prepared for and ready to perform interventions for acute and potentially catastrophic complications. These include turning the patient laterally and keeping the functioning lung upward in case of massive hemorrhage; keeping handy equipment for intubation, including double-lumen ET tubes for split lung ventilation, or at least bronchial blockers to tamponade a bleeding lung; and maintaining the capacity to perform rigid endoscopy if the situation is less dire but larger airway access is needed.

Foreign Body Removal

Although foreign body aspiration (FBA) is classically a pediatric problem, with the highest incidence occurring in children younger than 5 years, bronchial foreign body can occur in adults as well, albeit often with less acute symptoms.²² The classic signs—witnessed acute choking, wheezing, loss of unilateral breath sounds with corresponding volume loss, or hyperinflation due to air-trapping on the radiographs—have a high sensitivity (about 70%) but variable specificity for FBA. Other findings, such as chronic cough, recurrent pneumonias in the same chest region, atelectasis, and even pneumothoraces or pneumomediastinum, are more common in adults, who may or may not recall an episode of possible aspiration.¹⁸

Rigid bronchoscopy has been the standard procedure for removal of airway foreign bodies and remains so in the pediatric population. Conversely, in adults, a trial of foreign body removal with instruments compatible with a flexible FOB would be reasonable, although there should always be the backup plan for rigid bronchoscopy should the aspirated foreign body prove too stubborn for removal by the smaller flexible bronchoscopy instruments. Flexible bronchoscopy is indicated for patients with cervical spine instability and skull and jaw fractures, and such trauma patients may be particularly at risk for the aspiration of broken teeth or dentures, or a preceding aspiration leading to near asphyxiation and loss of consciousness may even be the cause of the subsequent head and neck trauma from a fall or a vehicular accident. Helpful adjuncts in directing the foreign body centrally include repositioning the patient in a Trendelenburg or decubitus position, movements that would not interfere with flexible FOB but may prove more challenging with a rigid bronchoscope. A number of “nonpulmonary” instruments can be adapted to assist in the retrieval of a foreign body; these include a Fogarty catheter pushed distal to the foreign body, then inflated and slowly pulled back, simulating the retrograde clot removal from a vascular lumen. Snares and baskets, such as the Roth basket developed for gastrointestinal procedures, can also be used to retrieve smooth or rounded items that are difficult to grasp, such as peanuts and marbles that are akin in texture and size to biliary stones. Cryotherapy probes used primarily for tumor and granulation tissue ablation can also be used to retrieve a foreign body that has a layer of aqueous condensation or secretions around it by virtue of the process of cryoadhesion.²³ (Recall the unfortunate child testing this hypothesis on a cold winter’s day and getting his tongue stuck to the metal pole.)

Hemorrhage can occur as a result of inflammation and granulation formation induced by the foreign body; this finding is especially true for certain pill fragments and other caustic compounds, oily food such as nuts, and on a more long-term basis, metal pins and other sharp objects. The manipulation of the various instruments can further aggravate this process. Therefore, having the capacity to provide hemostasis with vasoconstrictor compounds and mucosal surface coagulation is desirable. The routine use of corticosteroids to reduce airway edema has not been rigorously studied but is commonly recommended.

Tissue Débridement

The discussion of interventional bronchoscopic approaches in the débridement of malignant or scar tissue causing airway obstruction often becomes a catalog of technology and devices to deliver these tissue-destructive techniques. However, it is fair to say that the underlying common denominator is mechanical resection assisted by freezing, heating, or biochemical methods of causing cell death. Cold techniques include use of forceps, powered microdebrider, or cryotherapy. Laser, argon plasma coagulation (APC), and electrocautery are three methods of heat-assisted mechanical resection. Finally, photodynamic therapy (PDT) and endobronchial brachytherapy (EBBT) are biochemical destructive methods. Methods for tissue débridement are detailed in Table 75-2.

Balloon Bronchoplasty

In addition to reopening an obstructed airway, there is the task of maintaining airway patency. Furthermore, endobronchial débridement is not useful when the obstruction is extrinsic in nature. Dilation of a narrowed airway segment by mechanical means may be helpful in reestablishing airway patency, albeit temporarily, until more definitive solutions can be instituted. Through a rigid bronchoscope or a suspended laryngoscope, metal mechanical dilators can be gently corkscrewed through a length of tracheal stenosis from fibrotic tissue or tumor. However, areas beyond the proximal right or left mainstem bronchi are seldom accessible. For more distal portions of the right and left mainstem, and for narrowed lobar and segmental bronchioles, balloon bronchoplasty with fluid-expandable catheter balloons offer another option for mechanical dilation. These balloons were originally designed for endoscopic dilation of the biliary tract and the upper (esophageal and pyloric) or lower (colonic) gastrointestinal tracts. Their diameters at full deployment range from 6 mm (biliary) to 18 mm. The lengths of the balloons are fixed, ranging from 2 cm (biliary) to 8 cm (esophageal and colonic). Dedicated bronchoscopic balloons with a length of 3 cm mounted on shorter catheters have also been introduced. These controlled radial expansion (CRE Pulmonary Balloon Dilator, Boston Scientific) balloons have the additional benefit of being expandable to three sequential diameters, depending on the amount of fluid pressure applied, which can be monitored on a manometer supplied with the balloon kit. The fluid can be sterile water or saline or diluted contrast material, which will render the expanded balloon more visible under fluoroscopy.

Endobronchial Stent Placement

Placement of airway stents may be the definitive treatment or may maintain airway patency long enough for adjunctive treatment to control the underlying disease in a number of obstructive conditions. A large number of endobronchial stents have been developed or adapted for airway use over the past 20 years.^9,18,20,24 A detailed discussion of all of the individual types and their variants goes beyond the scope of this chapter. The stents can be grouped into metallic and silicone types. Most but not all of the metallic stents are self-expanding, whereas most of the silicone stents are fairly rigid and require rigid bronchoscopy or direct suspension laryngoscopy for placement.

The earliest airway stent was the Montgomery T-tube, a stiff acrylic polymer tube later replaced by silicone, but its placement required a tracheostomy. A number of silicone stents, some reinforced with metallic struts embedded circumferentially or three-quarters around to simulate the tracheal cartilage (e.g., Orlowski and Freitag Dynamic Stents, Rüschag, Germany), are available in various lengths and diameters, and there are optional limbs to fit the carina and proximal mainstem. With the exception of a single self-expanding polyester reinforced thinned-walled silicone stent (i.e., Polyflex, Rusch), these stents require rigid instrumentation for placement. Because of the intrinsic thickness of the stent material and the method of insertion, they are useful primarily for placement within the trachea and first- to second-generation airways only.

The earliest metallic stents used in the airways were Gianturco-Z stents adapted from their intended endovascular application. This type of noncovered stent has to be ballooned open, has no protection against ingrowth of tumor, and is associated with an unacceptably high rate of induction of severe granulation and airway or vascular perforation. Therefore, it has no role today in endobronchial stenting, given the number of dedicated endobronchial stents now available. The current generation of metallic stent is self-expandable, comes packaged in a much slimmer profile, can be delivered over a guidewire into the distal mainstem and lobar segments, and hence can be deployed without the need for rigid instrumentation. These self-expandable metal stents are made from stainless steel (e.g., Wallstent, Boston Scientific) or the nickel-titanium blend of nitinol (e.g., Ultraflex, Boston Scientific and Alveolus TB-STS, Alveolus, Inc. Charlotte, NC). They are available in a variety of lengths and diameters, with or without an outer polypropylene covering that helps prevent tumor ingrowth. There can still be the problem of tumor or granulation overgrowing the ends of the stents, and proper sizing is important to prevent excessive movement or excessive tension against the airway wall, either of which may promote the proliferation of granulation tissue. Once deployed, the stainless steel Wallstent with its sharp opened prongs is generally fixed in place, whereas the more pliable nitinol stents are maneuverable at least until granulation or tumor overgrows the open ends.

Complications of stent placement include trauma to a compromised airway during stent insertion, such as inadvertent tears to the tracheobronchial mucosa already compromised by tumor invasion. An improperly sized covered stent can occlude functioning airway segments because it is too large or too long; if it is too small, it can subsequently migrate. All stents, covered or otherwise, interfere with normal mucociliary clearance and, as foreign bodies, will promote biofilm formation. Stents can therefore become quickly overgrown with a variety of microorganisms. The problems of granulation and tumor ingrowth have been mentioned. The metallic stents can suffer metal fatigue and undergo fracture and, with the single strand weave of nitinol, can unravel.²⁵ This problem is especially prominent with tracheal stents in which the constant change in curvature of the posterior tracheal membrane with breathing in and out results in metal fatigue. We have therefore avoided placing self-expandable metal stents in the trachea if we anticipate long-term need for the stent in benign conditions such as tracheobronchomalacia or if the patient with a malignant condition has an anticipated survival beyond several months.

Esophageal-tracheal and esophageal-bronchial fistulas deserve special mention. The majority of such cases result from malignancies originating from the esophagus and, less commonly, from the bronchus. Fistula formation and poor healing may also be due to radiotherapy. Less commonly, such fistulas are congenital or are caused by acute trauma or chronic erosion from a tracheostomy tube. The most common presenting symptoms are coughing with feeding and other signs of aspiration. Swallow studies using a contrast agent (e.g., Gastrografin) and, occasionally, three-dimensional CT reconstructions may localize the fistula, but failure to demonstrate the defect should be followed by direct visual examination. Having a conscious patient swallow 15 to 30 mL of methylene blue or other dye immediately before the induction of anesthesia may be helpful in pinpointing the site of a small but clinically significant fistula. In the absence of an adequate tracheal replacement and the rarity of being able to resect the length of involved trachea for primary anastomoses, stenting to cover the fistula can provide palliation of symptoms, including aspiration of oral secretions and recurring lower respiratory tract infections, and can allow the patient to swallow for oral gratification in the terminal phase of a malignancy. Close collaboration with an interventional gastroenterologist is necessary for this application.

Autofluorescence Bronchoscopy

Autofluorescence bronchoscopy is used to detect early, preinvasive lung cancers and can also help thoracic surgeons in planning lung cancer resection. Since the early 1990s, trials have been ongoing to test and improve systems to detect alteration of tissue autofluorescence in dysplastic and cancerous bronchial tissues. Reduction of tissue autofluorescence in precancerous and cancerous tissue results in a change in the green autofluorescent hue of normal bronchial mucosa toward red-brown to blue-black tints. U.S. trials of several systems, including the LIFE (Laser Imaging Fluorescence Endoscope, Xillix Technologies, Richmond, BC, Canada) and D-Light (Karl Storz Endoscopy-America, Inc., Culver City, CA), validate a higher yield in the detection and localization of severely dysplastic and carcinoma in situ lesions in comparison with conventional white-light broncoscopy.^26–28

Endobronchial Ultrasonography

Endoscopic application of ultrasonography for characterization and localization of extraluminal structures such as lymph nodes, masses, and blood vessels has been mostly developed in the gastrointestinal field. The adaptation of a balloon-tipped ultrasound probe for use within the airway lumen allows for a more precise localization of regional lymph nodes for tumor staging and for diagnosis of lymphoma and other lymphoproliferative disorders. Ultrasound probes introduced through the working channel of the bronchoscope and directed peripherally have also been used to characterize pulmonary consolidation and may distinguish malignant from nonmalignant causes.^15,16,18 Higher-frequency high-resolution EBUS can also provide additional information about extrabronchial invasion of the serosal surface or submucosal infiltration by cancer, again with prognostic and therapeutic impact. Currently, sampling with EBUS-directed TBNA requires imaging followed by the removal of the probe and substitution of a sampling needle into the working channel. The next adaptation of ultrasound technology into the airways will be the introduction of a dedicated EBUS bronchoscope with a side-directed radial probe and aspiration port that will allow real-time aspiration.

Endoscopic/Bronchoscopic Lung Volume Reduction

The National Emphysema Treatment Trial established the benefit of surgical lung volume reduction surgery as an alternative to lung transplantation in selected patients with COPD.²⁹ Parallel studies have been undertaken to examine the possibility of affecting lung volume reduction through selective blockage of segmental bronchi leading to regional atelectasis. A number of such endoscopic/bronchoscopic lung volume reduction studies using biologic or synthetic adhesives, such as fibrin glue and removable valves, are currently ongoing. These procedures hold the promise of either being effective and less invasive methods of lung volume reduction surgery or of offering a less invasive and reversible trial of lung volume reduction before patients are subjected to the rigors of thoracic surgery.^30,31