General Thoracic Surgery (General Thoracic Surgery (Shields)) [2 VOLUME SET]

Editors: Shields, Thomas W.; LoCicero, Joseph; Ponn, Ronald B.; Rusch, Valerie W.

Title: General Thoracic Surgery, 6th Edition

Copyright 2005 Lippincott Williams & Wilkins

> Table of Contents > Volume I - The Lung, Pleura, Diaphragm, and Chest Wall > Section IV - Diagnostic Procedures > Chapter 16 - Bronchoscopic Evaluation of the Lungs and Tracheobronchial Tree

Chapter 16

Bronchoscopic Evaluation of the Lungs and Tracheobronchial Tree

William H. Warren

Penfield L. Faber

Visual inspection of the airways was once an art performed using rigid instrumentation in the hands of a handful of highly skilled surgeons. This procedure was almost always performed in the operating theater under general anesthesia. In the early 1970s, fiberoptic bronchoscopy was introduced, revolutionizing examination of the airways. Over the ensuing years, flexible bronchoscopy has almost completely replaced the rigid bronchoscope as the diagnostic instrument of choice. Flexible bronchoscopy is now performed by pulmonologists, anesthesiologists, otolaryngologists, critical care specialists, and thoracic surgeons in a variety of clinical settings, including the hospital ward, intensive care unit, and operating room. The well-trained thoracic surgeon must have a clear understanding of all aspects of both flexible and rigid bronchoscopy, including indications, anesthetic techniques, instrument options, and the management of complications.

RIGID BRONCHOSCOPY

The indications for rigid bronchoscopy include examination and management of obstructing airway lesions, retrieval of foreign bodies, suctioning of inspissated secretions, and obtaining tissue biopsy specimens of endobronchial lesions deeper and more generous than those provided by the flexible bronchoscope. A rigid bronchoscope should always be available when tracheal lesions are examined. Bleeding from biopsy sites or edema from tissue trauma can obstruct a compromised lumen, which can be forcibly dilated with a rigid instrument, and ventilation can be restored through the instrument.

The rigid bronchoscopes most commonly used in adults have an internal diameter of 6, 7, or 8 mm and are 40 cm in length (Fig. 16-1). Traditional models provide only a tunnel view, but modern rigid bronchoscopes also can be used with telescopic lenses. Illumination is supplied from a halogen light source. A fiberoptic cable is attached to a light carrier that passes down the side wall of the bronchoscope, through the telescope, or both. By using the telescope, generous biopsy specimens can be taken without compromising visualization. Both models have a ventilating side port permitting assisted ventilation (Fig. 16-2).

Rigid bronchoscopy almost always is performed under general anesthesia with all of its attendant risks. Despite the clearer view provided with telescopes, sampling the upper lobe or distal airway cannot be easily accomplished through the rigid bronchoscope. The advantages and disadvantages of rigid bronchoscopy are listed in Table 16-1.

Rigid bronchoscopy is generally performed under general anesthesia, using the ventilation port on the side of the bronchoscope and capping the end of the scope with an eyepiece to convert the procedure to a nearly closed system. If no telescope is being used, the glass eyepiece must be removed for biopsy and aspiration (Fig. 16-3). If a telescope is used, plastic caps seal the scope. Some loss of tidal volume around the bronchoscope is inevitable, but this can be minimized by packing the hypopharynx with saline-soaked gauze. The anesthesiologist must monitor the adequacy of the ventilation continuously; increased minute ventilation and tidal volumes may be required.

To pass the bronchoscope, the patient is placed in a supine position with an assistant positioning the head so that the neck is slightly flexed and the chin extended. The endoscopist elevates the epiglottis with the tip of the bronchoscope and passes the lubricated instrument through the glottis, into the upper trachea. Telescopes provide a magnified field of vision. Examination of the trachea is performed as the bronchoscope passes through the glottis and advances down to the carina. The carina is assessed for sharpness and mobility during ventilation. Splaying or fixation suggests the presence of a subcarinal mass. Biopsy of the bronchial mucosa on the carina is performed if mucosal or submucosal changes are observed. Thirty- and 90-degree angle-viewing telescopes allow the endoscopist to view the upper lobe bronchi. Alternatively, a flexible bronchoscope

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The risks of rigid bronchoscopy include injury to the gums and tooth dislodgment, hypoventilation, airway bleeding, and direct injury to the larynx or rupture of the tracheobronchial tree. With experience, these complications can be minimized.

The rigid bronchoscope must be sterilized after each use. The scope and ancillary equipment must be mechanically cleaned of all blood and mucous debris before they are sent for sterilization. All glass and metal components should be autoclaved, and the plastic caps should be wrapped separately and gas sterilized.

FLEXIBLE BRONCHOSCOPY

Ideally, flexible bronchoscopy should be performed in a dedicated area of the hospital or outpatient facility. Because

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A portable cart supplied with a light source, bronchoscope, and accessories is a convenient way to perform bedside bronchoscopy. It should be returned to the storage area for proper cleaning and restocking.

Flexible bronchoscopy has many advantages over rigid bronchoscopy, as listed in Table 16-2. Diagnostic material from peripheral as well as central lesions can be performed with minimal risk. The examination is usually performed under topical anesthesia and intravenous sedation, avoiding the risks of general anesthesia. Retained secretions can be aspirated at the bedside in the ward or in the intensive care unit. Patients receiving ventilator support can be examined without compromising the airway using a side-arm adaptor. The scope can be passed through narrowed and distorted airways or beyond an obstructing lesion. Flexible bronchoscopy is particularly valuable in assessing lobar and segmental airways to the upper lobes. Still or videophotography is easily performed to document findings (Fig. 16-5).

A new and persistent cough or a change in the cough pattern of a smoker warrants a bronchoscopic examination. Furthermore, a wheeze, particularly one that is unilateral and fails to clear with coughing, should be investigated. In so doing, lesions (especially those in the trachea and major airways) can be diagnosed, even in the absence of radiologic findings.

Sputum can be obtained in a sterile fashion to assess for opportunistic infections, especially in the immunocompromised patient. However, if the patient is suspected of having tuberculosis, induced sputum specimens (using inhaled saline) should be examined before contaminating the scope and the health care workers. Endoscopic lobar and segmental saline lavage have proven therapeutic benefit in postoperative patients unable to clear their secretions. Retained thick and tenacious mucous secretions are easily suctioned at the bedside with minimal patient discomfort.

Although the most common cause of hemoptysis is chronic bronchitis, carcinoma is common in patients with abnormal chest radiographs. Even if the chest radiograph is normal, according to Jackson (1985) and Poe (1988) and their associates, malignancy should be considered seriously if the patient is 40 years of age or older, has a significant smoking history, or has episodes of hemoptysis lasting for more than 1 week in duration. In addition to lung cancer, hemoptysis associated with a wheeze or atelectasis may be caused by a bronchial carcinoid or an inflammatory bronchial stricture.

An abnormal chest radiograph suggesting carcinoma warrants a careful evaluation of the entire tracheobronchial tree. Clinical judgment should always be used in deciding when

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Bronchoscopy is indicated in the diagnosis and management of lung abscess. The passage of brushes and biopsy forceps into the abscess cavity can promote bronchial drainage. Furthermore, occasionally an obstructing neoplasm or foreign body is discovered.

The therapeutic value of bronchoscopy to remove aspirated gastric contents remains in question. However, a rapid and efficient bronchoscopy examination can support the diagnosis and may have therapeutic benefit, particularly if particulate matter is retrieved.

After inhalation of smoke or caustic fumes, bronchoscopy is a safe and expeditious way of assessing damage to the tracheobronchial mucosa. In these compromised patients, the airways frequently need repeated bronchoscopy to d'bride necrotic mucosa and inspissated secretions. The inflammatory response to this injury may progress for days, leading to delayed airway obstruction.

Patients with cystic fibrosis may also, on occasion, require aspiration of persistently thick and tenacious secretions. However, routine bronchoscopy, once a mainstay of their care, has been largely supplanted by the routine use of vigorous physiotherapy and mucolytic agents.

The role of bronchoscopic examination of a patient with a fever of unknown origin or a pulmonary infiltrate after lung transplantation is widely accepted, as summarized by Higenbottam and colleagues (1987). However, the need for routine surveillance biopsies in lung transplant recipients is still controversial. According to Trulock (1995), routine surveillance bronchoscopies with random biopsies should be performed 2 to 3 weeks, 6 to 8 weeks, 9 to 12 weeks, 6 months, and 1 year after transplantation and annually thereafter. The most frequent unsuspected findings have been acute rejection and silent cytomegalovirus pneumonia. Early detection and treatment of these entities are thought to decrease the risk for chronic rejection according to Steinhoff and associates (1991). Others, such as Stillwell and colleagues (1995), maintain that, in asymptomatic patients, early stages of acute rejection or viral infection pose little risk for leading to more serious conditions.

Another indication for bronchoscopic assessment of the tracheobronchial tree is the suspicion of airway trauma. Wheezing, hemoptysis, and the presence of subcutaneous or mediastinal emphysema are the classic findings, but injury of the airway is often overshadowed by concomitant injuries such as aortic rupture or myocardial contusion. Even when suspected, the endoscopic findings of a torn bronchus can be remarkably subtle. Early diagnosis and repair of these injuries are of the utmost importance.

Transbronchoscopic bronchial biopsies, cytologic brushings, transbronchial needle aspiration (TBNA), and bronchoalveolar lavage (BAL) are readily performed, and the endoscopist should be familiar with indications, techniques, and complications of each. Airway bleeding can be the most devastating complication. Even severely ill and debilitated patients can undergo bronchoscopy safely if it is performed in an appropriate facility by an experienced endoscopist.

Currently available standard flexible bronchoscopes range from 6.2 mm in outer diameter (3.2-mm working channel to aspirate inspissated secretions and blood clots) to 2.7 mm in outer diameter (1.2-mm working channel) for pediatric patients (Table 16-3). One of the most often used adult bronchoscopes has an external diameter of 5.9 mm and a 2. 2-mm working channel, allowing clear visualization and specimen sampling of the entire tracheobronchial tree down to the fourth- or fifth-order bronchi (Fig. 16-6). A forward field of

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Videobronchoscopes provide a significantly larger image with higher resolution than is seen in standard flexible bronchoscopes. However, these images can only be viewed with a videoprocessor and monitor. For these superior images, however, these bronchoscopes have a larger outer diameter (Table 16-3). These scopes are fully immersible, and most can be autoclaved. The active endoscopist should have a variety of flexible bronchoscopes available for diagnostic and therapeutic versatility (Fig. 16-7).

The Examination

Anesthetic Considerations

Intravenous access is routinely available, and supplemental oxygen is provided usually through nasal cannulae as recommended by Prakash and Stubbs (1991). Pulse oximetry, cuff blood pressure, and electrocardiographic monitoring are routinely performed. Sedation should be administered to provide patient comfort and cooperation. In several studies, however, 50% of the life-threatening complications from bronchoscopy stemmed from hypoxemia, hypercapnia, and respiratory depression secondary to oversedation. Therefore, the agents and their dosages must be individualized and may not be necessary in every case.

Preoperative opiates are sometimes given for their analgesic and antitussive properties. Meperidine has an elimination half-life of 3.2 hours, but clearance is decreased in patients with renal, hepatic, or both renal and hepatic failure. It, like all opiates, can cause respiratory depression and hypotension. Naloxone, a specific opioid antagonist, must be available whenever opioids are administered.

Intravenous benzodiazepines are often administered, providing anxiolysis and antegrade amnesia. Midazolam has become the preferred agent according to a bronchoscopy survey reported by Colt and colleagues (2000). It is water soluble, with rapid onset, short duration of action, and an elimination half-life of only 2 hours in normal subjects. Renal failure does not alter the distribution, elimination, or clearance, but liver disease is associated with prolonged sedation. The recommended dose is 0.07 mg/kg. Diazepam is not water soluble and can cause significant, if only transient, phlebitis. Its elimination half-life is 24 to 57 hours in normal patients. Both agents should be used with caution, especially in elderly patients and those with limited pulmonary reserve. Respiratory depression is a major side effect of both benzodiazepines; the degree of respiratory depression is similar with both drugs. Flumazenil is a specific benzodiazepine antagonist and should be available any time these agents are used. Because its elimination half-life is only 1 hour, repeat doses or a continuous infusion may be needed. Matot and Kramer (1999) reported that alfentanil-propofol is a reasonable alternative to meperidine-midazolam, particularly in patients with known or at risk for coronary artery disease.

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Some physicians continue to premedicate patients with an antisialagogue, such as atropine or glycopyrrolate, to reduce secretions and inhibit vasovagal responses, as documented by Williams and colleagues (1998). These medications also make topical anesthesia more effective. However, according to Hasanoglu and co-workers (2001), tachycardias and episopes of hypotension were more commonly observed when atropine was administered. According to the survey reported by Colt and colleagues (2000), only 62% of respondents routinely use atropine as a premedication. Far fewer used glycopyrrolate.

Topical anesthesia is preferred for fiberoptic bronchoscopy, but general anesthesia may be considered, particularly for prolonged examinations required to identify carcinoma in situ in a patient with normal chest radiography findings. It is occasionally requested by extremely anxious patients.

The most common agents for topical anesthesia are lidocaine (1% and 2%) and tetracaine (0.5%, 1.0%, and 2.0%). Complications from topical anesthesia usually result from the administration of excessive amounts, as documented by Credle (1974), Suratt (1976), and Pereira (1978) and their associates. If carefully measured amounts are given and the endoscopist is always aware of the total milligram dosage instilled, reactions are minimized.

Lidocaine is a safe agent with a recommended dose of 0.2 to 0.3 mL of 1% lidocaine per kilogram, but larger amounts have been given without serious side effects. It is important to remember that the extent of absorption and bioavailability depends on tissue vascularity and the technique of application as well as the total dose administered, according to Mainland and associates (2001). Lidocaine should always be titrated slowly, and patients must be monitored for mental status changes. The first sign of toxicity is usually central nervous system excitation or seizure before cardiovascular collapse. The duration of action is short.

Tetracaine is another effective topical anesthetic, but side effects frequently occur when a dose of 80 mg is exceeded. The duration of action is prolonged, and the first sign of toxicity may be sudden cardiovascular collapse.

Combination of benzocaine-tetracaine is a popular topical anesthetic agent with rapid onset of action useful in rapid intubation. It is often administered in a propellant spray with a tolerance dose delivered in only 2 seconds. Dosing is therefore difficult to regulate, and this agent should be avoided when performing flexible bronchoscopy. Complications of all topical anesthetic agents include methemoglobinemia, whereby patients become cyanotic owing to the oxidation of iron from its normal reduced state, leaving it unavailable for oxygen binding and transport. Elderly, infant, and anemic patients are particularly susceptible, as documented by Karim and coinvestigators (2001). Intravenous methylene blue (1 mg/kg) is the recommended initial definitive treatment. Rarely, exchange transfusion or hemodialysis is necessary.

Several satisfactory methods are available to administer topical anesthesia. Using the nasotracheal route, the nasopharynx is anesthetized initially using an atomized topical agent, and the flexible bronchoscope is then passed through the nares to a level just proximal to the false cords. With the larynx in clear view, additional topical anesthetic is administered directly onto the vocal cords and into the trachea. The bronchoscope is then passed through the glottis, and additional topical anesthesia is instilled down the tracheobronchial tree.

A second method of delivering topical anesthesia consists of initial spraying of the hypopharynx with 1% or 2% lidocaine using an atomizer. Five milliliters of 4% lidocaine are then injected transtracheally through the cricothyroid membrane using a short 21-gauge needle to minimize the risk for lacerating the posterior wall of the trachea. Slight bleeding often occurs with this technique, so it should be avoided when a patient is being examined for hemoptysis of unknown origin. Care is taken to confirm the position of the needle in the tracheal lumen by aspirating air before injecting. It is possible to inject directly into the false cords and precipitating laryngospasm. Anesthesia of the larynx is achieved as the patient coughs out the medication. Supplemental 2% lidocaine is then instilled into the tracheobronchial tree while advancing the flexible bronchoscope. Because topical anesthetic agents inhibit bacterial growth, care should be taken to minimize the amount aspirated into collection traps for microbiological studies.

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Flexible bronchoscopy is accomplished easily using general anesthesia. In the adult, a swivel adaptor is attached to the endotracheal tube, and ventilation is maintained through the side arm of the adaptor. The bronchoscope is passed through a tight-fitting plastic diaphragm on the adaptor. As large an endotracheal tube as possible should be selected to minimize peak airway pressure and allow for adequate ventilation.

The flexible fiberoptic bronchoscope can be inserted either through the nose or the mouth into the hypopharynx. Although the nasal route may be more comportable for the patient and avoids possibility of the patient chewing the instrument, this option does not permit easy withdrawal and reinsertion for cleaning of the lens and clearing the channel of thick mucus. In addition, biopsy and brushing cytology specimens must be withdrawn through the entire length of the channel, leading potentially to a decreased yield of diagnostic material.

An alternative technique involves passing an uncuffed 8.0-mm endotracheal tube (overtube) through the orotracheal route (Fig. 16-8). The patient breathes around and through this overtube. Airway access is provided without repeated trauma to the larynx and subglottic region. The overtube allows rapid withdrawal and reinsertion of the bronchoscope. Brushing and biopsy specimens are retrieved, leaving the brush or biopsy forceps beyond the tip of the bronchoscope, avoiding loss of the specimen in the working channel. In addition, airway suctioning using a large-caliber catheter can be performed through the overtube in the event of significant airway bleeding. Airflow resistance, however, has been shown to increase significantly when a 5.8-mm bronchoscope is passed through an endotracheal tube smaller than an 8.5-mm outer diameter. The use of a smaller endotracheal tube could lead to hypercapnia and respiratory distress.

Supplemental oxygen, oximetry, and electrocardiogram monitoring are important because arterial desaturation and increases in the heart rate and cardiac index are very frequently observed during the procedure, according to Markou and collegues (1999).

The Endoscopic Examination

The first phase of a diagnostic bronchoscopy is visualization of the larynx and the vocal cords. Unsuspected leukoplakia, carcinoma in situ, and invasive carcinoma may be found. Vocal cord mobility must be assessed. Recurrent laryngeal palsy secondary to carcinoma of the lung generally is considered a sign of inoperability.

All lobar and segmental bronchi must be examined carefully and systematically because a second lesion not visible on the chest radiograph is occasionally identified. The tracheobronchial tree remote from the area in question is assessed first. This way, not only will a complete examination be performed, but also, if samples from a different site are taken, they are less likely to be subject to cross-contamination.

After this has been performed, the bronchus leading to the known area of disease is examined. The character of the secretions and the bronchial mucosa can be clues to the nature of the underlying pathologic condition. Subtle mucosal abnormalities associated with carcinoma include mucosal thickening, irregular bronchial folds or corrugation, and increased submucosal vascularity. These findings may be associated with a loss of definition of the cartilaginous rings or circular folds, bronchial stenosis, or extrinsic bronchial distortion. The extent and the exact location of these endoscopic findings must be carefully observed when anticipating surgical intervention.

Bronchial Biopsy and Brushing

When mucosal changes of malignancy are visualized, transbronchial brushing and biopsy should be performed, which results in a combined diagnostic accuracy higher than 90%. Biopsies should be attempted, even when the lesion is suspected to be a bronchial carcinoid, because lung-sparing resections can be performed with minimal resection margins with this pathologic entity. Small fragments of tissue are obtained with 1.5-mm biopsy forceps, and multiple biopsies are often necessary to provide diagnostic material. The differential diagnosis of this entity includes granulation tissue, polypoid squamous carcinoma, and an endobronchial papilloma. Bleeding, if it occurs, can be controlled with topical 1/100,000 epinephrine or neodymium:yttrium-aluminum-garnet (Nd:YAG) laser photoablation.

Biopsy specimens of segmental lesions beyond the field of vision are often obtained under fluoroscopic or, more recently, computed tomography (CT) control. Biopsy through the flexible bronchoscope requires persistence and practice, especially when the lesion is in the apical segments of the

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Bronchial brushings are generally performed after the biopsy tissue has been obtained. Several models are available. A 7-mm brush is our recommendation for routine use because more cellular material is obtained (Fig. 16-9); 1.7-mm brushes have the advantage that they can be ensheathed and withdrawn through the working channel of the bronchoscope, but the yield of material is smaller, as documented by Elkus (1994) and Lundgren (1983) and their associates. In a recent comparative study reported by Sato and colleagues (2002), the efficacy of cell collection is determined by the diameter, not the length, of the bristles.

The bronchial brush may be inserted into narrowed segmental bronchi to provide cytologically diagnostic material. The brush is passed vigorously over the surface of the lesion and is then promptly stroked onto the surface of the glass slide, which is immersed immediately in 95% ethanol (Fig. 16-10). Improved results are achieved if four separate brush specimens are obtained and sent to the laboratory.

Endobronchial mucosal changes may not be detected in peripheral masses. Under these circumstances, fluoroscopic guidance is invaluable. Ideally, the lesion is seen to move when it is sampled. When the lesion is beyond the field of vision, the diagnostic yield by biopsy alone is 46%; however, the yield increases to 60% when combined with bronchial brushings.

Transbronchial Biopsy and Brushing

Transbronchial brushings and biopsies also may be used to assess pulmonary infiltrates. The diagnoses of sarcoidosis, tuberculosis, bronchioloalveolar carcinoma, and pulmonary alveolar proteinosis can all be established on the basis of bronchoscopic material. The flexible bronchoscope is initially wedged in the segmental bronchus, and the biopsy forceps is advanced to the periphery of the diseased region. The forceps is then drawn back 3 to 4 mm, and the jaws are opened and advanced slightly to obtain the sample of the lung. Placement of the biopsy forceps near, but not at, the lung surface minimizes the risk for pneumothorax. The bronchoscope is left wedged in the segmental bronchus in the event of bleeding to allow irrigation with 1/100,000 epinephrine. Five to seven transbronchial biopsy specimens have been found to provide the optimal diagnostic yield. These samples should all be taken from the same lung to avoid the complication of bilateral pneumothorax and to help to localize the bleeding site in the event of significant hemoptysis. Coagulation studies and a platelet count should be obtained preoperatively to identify patients at high risk for bleeding. Uremic patients are also known to be at high risk for significant hemoptysis, and precautions must be taken.

Transbronchial Needle Aspiration

Since the mid-1980s, the technique of TBNA, championed by Wang (1995), has found increasing favor in sampling subcarinal and paratracheal lymph nodes and for examining widened spurs endoscopically.

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Cytologic and histologic specimens are obtained by passing an ensheathed 21-gauge needle down the working channel of the bronchoscope (Fig. 16-11). Failure to withdraw the needle into the protective outer sheath has led to serious and costly repairs of flexible bronchoscopes, as documented by Mehta and co-workers (1990). Once the sheath is advanced beyond the tip of the scope, the 1.5-cm needle is advanced beyond the sheath, through the wall of the trachea or bronchus, and into the mediastinal mass or suspicious lymph nodes (Fig. 16-12). Obviously, in chosing the location to be sampled, knowledge of the location of the major vessels adjacent to the airway is essential. The needle can be reinserted into the region in question several times, applying gentle suction each time the needle is advanced; suction must be avoided once the needle is completely withdrawn. Five milliliters of saline are then flushed through the needle to obtain an optimal cytologic sample, which is immediately centrifuged; the resulting pellet is resuspended in 1 mL of saline. The supernatant cell suspension is fixed in 95% ethanol and prepared with Papanicolaou's stain. Tissue fragments are fixed in Bouin's solution and submitted for a cell block.

Transbronchial needle aspiration should be performed before brushing or lavaging to avoid contaminating the airway, which could lead to an increased false-positive rate. There is increased diagnostic accuracy when TBNA is performed with visible evidence of submucosal or peribronchial tumor. Transbronchial needle aspiration has at least a 15% false-negative rate when assessing mediastinal nodes. This number has been much higher in the hands of most less experienced bronchoscopists.

Preoperative CT or magnetic resonance imaging is imperative to define precisely the lesion in question as well as to assess the proximity of major vessels. Recently, the technique of endobronchonial ultrasonography (EUS) has been used to assess and localize paratracheal and peribronchial pathology. Using this technique, a 2-mm diameter, 95-cm long catheter containing a single ultrasound transducer is located within an inflatable balloon. The catheter is passed down the working channel of the bronchoscope, and the balloon is inflated with sterile water. With the airway temporarily occluded, the motor of the ultrasound unit continuously rotates the transducer in the center of the balloon to obtain a real-time cross-sectional image of the airway. This technique produces a cross-sectional image of the peribronchial structures approximately 2 cm in depth (Fig. 16-13). The normal tracheobronchial wall is seen as a five-layered structure. This technique can reliably identify the depth of tumor invasion in the tracheobronchial wall and direct tumor invasion of contiguous mediastinal structures. However, using the criteria of size, echo density, homogeneity in structure, or demarcation of the nodal tissue from surrounding tissue, EUS cannot distinguish metastatic nodal disease from anthrasilicotic nodes. Therefore, although ultrasound can be used as an imaging technique, it has limited diagnostic value. After selection and evaluation of the biopsy site, the ultrasound catheter is withdrawn, and the needle apparatus is inserted. Unlike the gastrointestinal tract, at this time, it is not possible to perform TBNA simultaneously with real-time EUS imaging. Also, some of these balloons contain natural latex and must not be used in latex-sensitive patients. Experience with this technique in the United States is limited, but preliminary results are encouraging, as reported by Schuder (1991) and Goldberg (1994) and their associates and by Naidich and Harkin (1994). Silvestri and associates (1996) have used simultaneous

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Obviously, one of the main intraoperative complications of TBNA is airway bleeding. Mediastinal infection is a rare complication of TBNA of the peribronchial tissues.

Shure and Fedullo (1983) reported use of TBNA to establish the diagnosis of peripheral primary lung carcinoma presenting as a peripheral nodule or mass. Here, again, EUS has been used to localize the placement of the needle. In this case, a balloonless ultrasound probe is wedged into the segmental bronchus, placing the ultrasound transducer in direct contact with the bronchial wall.

BRONCHOALVEOLAR LAVAGE

BAL is a useful technique to recover material from the terminal bronchiole and alveolar sacs. BAL is performed by wedging the tip of the flexible bronchoscope into a subsegmental bronchus, irrigating and aspirating the segment with 20- to 50-mL aliquots of sterile saline. A total volume of 100 to 300 mL of saline is instilled, and 40% to 60% of this volume is recovered as a specimen, depending in part on the patience of the bronchoscopist. In patients who have loss of elastic recoil, recovery of fluid is less, according to Helmers and Hunninghake (1989), because the subsegmental bronchiolar walls collapse when suction is applied. In addition to microbiological studies, lavage specimens have been used to diagnose malignancies and to obtain inflammatory cells and pneumocytes for research studies as discussed by Kvale (1996).

BAL is a useful technique for obtaining microbiological specimens, especially in immunosuppressed patients. Fungal, bacterial, and viral culture specimens are easily acquired. In patients with acquired immunodeficiency syndrome, the diagnosis of Pneumocystis carinii pneumonia also can be made with a diagnostic yield exceeding 85%, according to Pisani and Wright (1992).

Cytologic specimens also can be obtained to establish the diagnosis in a variety of noninfectious, diffuse interstitial pulmonary diseases, including lipoid pneumonitis, histiocytosis, and berylliosis, all of which are uncommon entities, as documented by Daniele and associates (1985). BAL is of more limited value in the diagnosis of fibrosing alveolitis, sarcoidosis, and hypersensitivity pneumonitis, as noted by Stoller and colleagues (1987). Levy and associates (1988) reported that BAL has been used to establish the diagnosis of peripheral primary lung carcinoma. Rennard (1990) and Pirozynski (1992) also noted this fact, but BAL has not been widely advocated as a step in the diagnosis of cancer in North America, and it should not be considered a routine diagnostic procedure.

Potential complications of BAL include bronchospasm, hypoxia, fever, and transient decline in pulmonary function. Patients must therefore be observed carefully after the procedure. The safety of BAL in patients with symptomatic asthma or with a forced expiratory volume in 1 second of less than 60% of predicted value has not been established,

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Complications

Despite the relatively low risk, the benefits of performing bronchoscopy must be weighed against the potential for complication in each patient. Credle and colleagues (1974) reported a complication rate of 0.08% and a mortality rate of 0.01% in more than 24,000 flexible bronchoscopies. Premedication and topical anesthesia were responsible for 11 of the 22 major complications. More dilute solutions of the topical anesthetic agent provide a wider margin of safety. Intravenous diazepam counteracts the systemic effects of excessive amounts of lidocaine and should be readily available. Elderly and debilitated patients should receive minimal premedication, and topical anesthesia must be administered in carefully measured amounts. Respiratory depression is a frequent complication of intravenous sedation in this patient population.

Careful evaluation and preparation of the patient, as well as adequate facilities to monitor the patient, are required to minimize complications. Pulse oximetry, continuous electrocardiography monitoring, and intermittent cuff blood pressure readings are all important parameters. Supplemental oxygen is supplied to minimize the risk for hypoxemia. Respiratory depression has been documented in the recovery period. According to Peacock and associates (1990), topical anesthesia may be responsible for prolonged periods of respiratory depression. Belen (1981) and Matsushima (1984) and their associates recommend that patients should not undergo pulmonary function testing for at least 8 hours after bronchoscopy. General anesthesia may be indicated if the patient has a history of intolerance to topical anesthetic agents or of difficult endoscopic examinations under local anesthesia.

Massive bleeding is a recognized complication of bronchoscopy. Bleeding disorders must be corrected by anticoagulant reversal or by the infusion of platelets either during or immediately before the procedure. However, acccording to Herth and colleagues (2002), aspirin does not increase the risk for bleeding after transbronchial biopsies. No absolute contraindications exist for flexible bronchoscopy. A brushing or biopsy should not be done unless the prothrombin time is higher than 40% of normal and the platelet count is greater than 50,000/mL. Patients with uremia or pulmonary hypertension also bleed easily, and brushings and biopsies in these patients should be avoided. Topical epinephrine solution of 1/100,000 can be instilled into the segmental bronchus before brushing to minimize bleeding or to control established bleeding. In the event of endobronchial hemorrhage, the scope should be wedged in the segmental bronchus to tamponade the lumen, thereby allowing blood in the distal airway to clot.

A pneumothorax can occur in up to 3% of patients undergoing a transbronchial lung biopsy. When lung biopsies are performed for diffuse lung disease, it is important to perform this procedure under fluoroscopic control to avoid perforation of the lung. Patients may complain of sharp chest pain if the parietal pleura is irritated.

Bronchospasm is a potential complication in patients with known asthma, but it also may occur in patients with severe chronic obstructive lung disease. Severe asthmatics should be premedicated with corticosteroids and bronchodilators. Laryngospasm is the direct consequence of inadequate topical anesthesia; it can be avoided if the topical agent is placed precisely onto the vocal cords and into the tracheobronchial tree.

Patients with hepatitis, human immunodeficiency virus, or suspected active tuberculosis can undergo bronchoscopy if special care is taken by all personnel in the handling of the specimens and if all instruments used are appropriately sterilized. Infections transmitted after properly cleaning instruments are uncommon. However, tuberbulosis and gram-negative organisms have been transmitted by inadequately cleaned flexible bronchoscopes.

Sepsis immediately following bronchoscopy is uncommon, but fever is seen occasionally. Well-designed prospective studies have documented an exceedingly low risk for bacteremia during and following bronchoscopy. Nevertheless, BAL in patients with pneumonia can cause a sepsislike clinical picture, according to Pugin and Suter (1992). Therefore, considering the risks, Dajani and associates (1990) reported that the American Heart Association recommended that patients with underlying valvular heart disease should receive prophylactic antibiotics before bronchoscopy to minimize the risk for bacterial endocarditis. This recommendation holds true for patients with joint replacements.

Bronchoscopy should not be performed in a patient with bilateral vocal cord paralysis. The passage of the bronchoscope through the glottis can lead to edema, causing life-threatening airway obstruction and necessitating emergent intubation or tracheostomy. Patients with a tracheal obstruction should be examined cautiously, and biopsy or dilation of the tracheal lesion should be avoided if the airway is severely compromised, unless one is prepared to proceed directly to rigid bronchoscopy or definitive tracheal surgery.

Cleaning of Flexible Bronchoscopes

The care and cleaning of fiberoptic flexible bronchoscopes has become an issue of some concern. A variety of gram-negative and fungal organisms and Mycobacterium tuberculosis have been recovered from inadequately cleaned bronchoscopes, and some, including tuberculosis, have been allegedly transmitted to patients through a contaminated bronchoscope, causing clinical infection as reported by Sammartino (1982), Gubler (1992), Nicolle (1992), Frazer (1992), and Agerton (1997) and their co-workers, as well as by Prakash (1993). In some cases, the bronchoscope did not undergo adequate mechanical cleaning

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SPECIAL CONSIDERATIONS

Foreign Body Retrieval

The suspicion of foreign body aspiration is an indication for bronchoscopy both to establish the diagnosis and attempt removal. When using flexible bronchoscopy, however, the endoscopist must be absolutely certain that a more complicated problem does not result from either losing the foreign body, impacting it distally in the tracheobronchial tree, or causing airway bleeding from manipulation. In this regard, the rigid bronchoscope remains the instrument of choice, allowing good exposure and airway control, especially in removing foreign bodies from the airways of infants and children, according to Weissberg and Schwartz (1987) as well as Pasaoglu and colleagues (1991). Grasping forceps, snares, baskets, and balloon-tipped catheters have all been used to extract foreign bodies using flexible bronchoscopy, as summarized by Lan and co-workers (1989) and Mehta and Rafanan (2001). Although foreign bodies in adult patients can be retrieved with various types of snares passed down the working channel of the fiberoptic bronchoscope, most foreign bodies can be removed easily and quickly with a rigid bronchoscope, especially in the pediatric population.

Inglis and Wagner (1992) reported the advantages of combining flexible and rigid bronchoscopy to improve the detection and retrieval rate of foreign bodies, especially when fragments are lodged in the distal airway or in the upper lobe bronchi (Fig. 16-14). Clearly, endoscopists engaged in the art of foreign body retrieval must be facile with both rigid and flexible bronchoscopy, according to Kelly and Marsh (1996).

Autofluorescence Bronchoscopy

In some centers, sputum cytology is used to screen patients at high-risk for malignancy. Others believe that surveillance bronchoscopy should be performed in these patients because it is much more successful in establishing the diagnosis and can localize the pathology. Occasionally, patients with suspicious or positive cytologic findings are identified in the presence of a normal chest radiograph. In such cases, the mouth, pharynx, larynx, and entire tracheobronchial tree must be examined carefully to identify the site of the early carcinoma.

Autofluorescence bronchoscopy has been a particularly valuable aid in identifying the site and extent of disease. Using a helium-cadmium laser for illumination, in vivo spectroscopy with an optical multichannel analyzer is performed during the bronchoscopic examination. Areas of severe dysplasia and carcinoma can be easily recognized by their decrease in autofluorescence intensity, whereas normal tissues autofluoresce predominantly in the short (green) wavelengths of the visible spectrum, as documented by Lam and associates (1994). Preferential horizontal diffusion of longer wavelength fluorescent light from adjacent normal submucosa causes the premalignant and malignant epithelium to appear red (Fig. 16-15; see Color Fig. 16-15).

Several fluorescence bronchoscopy systems are currently commercially available. The ultimate value of fluorescence bronchoscopy depends on the cost of the equipment, ease of use, and future of screening bronchoscopy for detection of early lung cancer, including in patients who have undergone a previous curative surgical procedure, according to Weigel and coinvestigators (2001).

Massive Hemoptysis

Massive hemoptysis (600 mL in 24 hours) should be assessed with a rigid bronchoscope urgently, but under optimal conditions. Airway control with rapid and repeated

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When using YAG laser photoablation, rigid bronchoscopes permit photoablation and rapid d bridement of an obstructing or a bleeding lesion while simultaneously maintaining control of the airway and providing a suction channel for evacuation of clots and secretions. The rigid bronchoscope is necessary for the placement of silicone endobronchial stents. However, self-expanding metal bronchial stents can be deployed through a large endotracheal tube.

INTERVENTIONAL BRONCHOSCOPY

The past two decades have seen the advent of many endobronchial interventional procedures. These include the development endobronchial electrocaudery, Nd:YAG laser photoablation, cryoablation, photodynamic therapy (using chemical tissue sensitizers, such as porphyrin compounds), the placement of endobronchial stents, and the placement of radioactive brachytherapy sources in the form of seeds or catheters. These topics are discussed elsewhere (see Chapter 108).

PEDIATRIC BRONCHOSCOPY

Bronchoscopic examination of infants and small children requires expertise and familiarity with all available instrumentation, as emphasized by Wood (1996). Examination of the infant airway using smaller Storz rigid instruments with viewing telescopes is usually performed using general anesthesia (Fig. 16-16). A 3.0- or 3.5-mm sheath permits passage of the 2.7-mm optical telescope that provides a good view of the infant's bronchi. A small suction catheter can be passed down the barrel. Secretions are removed readily for microbiological studies. Small biopsy and foreign body forceps can be manipulated through this small channel with the viewing telescope in place. Muntz and associates (1992) reported their experience performing transbronchial lung biopsies in the pediatric population through a rigid bronchoscope.

Flexible fiberoptic bronchoscopy has become a practical tool in pediatrics with the development of a bronchoscope with an external diameter of 3.5 mm and a channel of 1.2 mm. It has found favor in clearing secretions as well as aiding in localizing and retrieving foreign bodies. Examination of infants may be performed using sedation and topical anesthesia, provided the procedure is brief. Airway stenosis and obstruction are contraindications to flexible instrumentation.

Complications related to pediatric bronchoscopy can be life threatening. A small bronchus may be perforated with resultant pneumothorax or pneumomediastinum. Laryngospasm, subglottic edema, and bronchospasm may all result from manipulation and may compromise the airway.

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