Bronchoscopy diagnostic and interventional

Bronchoscopy general (diagnostic) and interventional - technical

Summary

Bronchoscopy refers to examination of the tracheobronchial tree via a rigid or flexible bronchoscope. This chapter will review both diagnostic and therapeutic bronchoscopy, with a focus on the available technology and procedural techniques used to diagnose and treat a variety of lung diseases. As ‘Bronchoscopy: Regular and Interventional’ is a topic for which textbooks are available, the reader is encouraged to explore the relevant literature, with some pertinent references listed in the further reading section.

Introduction

Gustav Killian has been described as the ‘Father of Bronchoscopy’. With the vision of using a metallic tube, electric light, and topical cocaine to prevent glottic closure, Killian removed a pork bone from a farmer’s airway in 1897. Over the subsequent years, Killian went on to develop bronchoscopes, laryngoscopes, and endoscopes, as well as describe techniques such as using fluoroscopy and X-ray to define endobronchial anatomy.

Over the next 150 years, bronchoscopic techniques and instruments continued to be refined. In 1966, Shigeto Ikeda, presented the first prototype flexible fiberoptic bronchoscope at the 9th International Congress on Diseases of the Chest in Copenhagen. In 1968 Machita and Olympus introduced the first commercially available fiberoptic bronchoscopes.

In 1980, Dumon presented his use of the neodymium:yttrium aluminum garnet (Nd:YAG) laser via the fiberoptic bronchoscope, and since that time the flexible bronchoscope has been widely utilized as both a diagnostic and therapeutic tool for both diseases of the parenchyma and central airways.

With the miniaturization of electronic devices, Ikeda was able to incorporate the video chip into the bronchoscope, and Pentax introduced the first video bronchoscope in 1987. Suddenly, endoscopic pictures could be printed out and shared, and the physicians no longer needed to look through an eyepiece, but instead the endoscopic image could be projected onto monitors, allowing everyone in the room to visualize what was happening in the airway.

Modern Video Bronchoscopes

Little has changed in the appearance of bronchoscopes since 1968. The external diameter of the flexible bronchoscope varies from 2.7 to 6.3mm diameter. The diameter of the working channel ranges from 1.2 to 3.2mm. A working channel X2:8 mm is recommended for more therapeutic flexible bronchoscopy, as well as endobronchial ultrasound (EBUS), as it allows for better suction and the passage of larger instruments. Most flexible bronchoscopes can flex 1801 up and 1301 down. It is important to note the relative anatomy at the tip of the bronchoscope. By convention, as viewed from the operator’s perspective, the camera is at 9:00, suction at 6:00 and the working channel at 3:00. These landmarks play a role when navigating the airways as the bronchoscope may need to be rotated in order to visualize the intended target or guide a tool to its intended target.

Airway Anatomy

It is crucial that the bronchoscopist become an expert in airway anatomy. Anatomical knowledge should include the naso and oropharynx, as well as the larynx as these structures are visualized, yet often overlooked, by the pulmonologist, who is typically more concerned about lower airway/parenchymal disease. Additionally, the segmental anatomy of the lungs, from both an external and internal perspective, is required, and we recommend knowledge of both the name and number system. One must also be familiar with the anatomy external to the airway, primarily the intrathoracic vessels and lymph nodes, as these will serve as reference points for transbronchial needle aspiration and EBUS, and will help avoid injury should the bronchoscopist use therapy such as the Nd:YAG laser or brachytherapy. The use of endoscopic simulators has been associated with a more rapid acquisition of bronchoscopic expertise and we recommend the novice bronchoscopist use a simulator as much as possible.

Preparation

Prior to the procedure, it is crucial that the bronchoscopist review the patient’s relevant history, physical examination, and imaging studies. A distinct plan should be in place regarding the sequence of sampling techniques, and everyone participating in the procedure should be familiar with both this plan and also their particular roles during the procedure. Topical anesthesia is crucial, and we typically use 1% lidocaine, keeping the total dosage o400 mg. Stronger concentrations do not provide additional sensory anesthesia and will only limit the volume of lidocaine one can apply to the airways.

Most procedures are performed under conscious sedation with a narcotic and a benzodiazepine. All practitioners involved in the administration of conscious sedation are required to undergo formal training by their institution and should have a thorough understanding of the effects, side effects, and typical dosages, as well as antagonist drugs. The physician should also be comfortable in airway management including the use of bag-valve mask, oral airways, and endotracheal intubation.

If one plans to perform bronchoscopy through an endotracheal tube (or tracheostomy), the internal diameter should ideally be 47.5mm in order to accommodate the bronchoscope and maintain patient ventilation. Depending on the length of the procedure, it may be necessary to remove the bronchoscope intermittently to ensure adequate ventilation.

Diagnostic Bronchoscopy

There are many indications for diagnostic bronchoscopy. The most common indication is for the diagnosis and staging of suspected lung cancer. Other indications include evaluation of diffuse lung disease, infiltrates in the immunocompromised host, hemoptysis, and cough. Additionally, bronchoscopy with bronchoalveolar lavage (BAL) and/or brushing is useful for the diagnosis of community and healthcare associated pneumonia.

Cancer Diagnosis and Staging

Lung cancer is the leading cause of cancer deaths in the US, and the incidence and number of lung cancer deaths continues to increase amongst women in the US. Bronchoscopy provides a minimally invasive approach for the diagnosis of tumors in the central airways. Though the yield is somewhat lower for solitary parenchymal lesions, advances in navigation with techniques such as computed tomography (CT) fluoroscopy and electromagnetic guidance (to be discussed later) have significantly improved the yield for peripheral tumors.

The bronchoscopic evaluation of patients with suspected malignancy is guided by clinical symptoms as well as radiographic findings. Depending upon the history and chest CT findings, bronchoscopy may be the diagnostic modality of choice as it can both make the diagnosis and stage the patient at the same time. If appropriate staging is to be performed, biopsy of the lesion that will place the patient in the highest clinical stage should occur prior to other biopsies. For example, if a patient presents with a left lower lobe mass and a right paratracheal lymph node (4R), the appropriate procedure would be a bronchoscopy with transbronchial needle aspiration (TBNA) of the 4R node, with attention then turned to the left lower lobe lesion, as a positive TBNA would stage the patient as IIIb and therefore change the treatment plan. Initial biopsy of the mass could contaminate the working channel and make the TBNA a false positive, precluding the patient from curative surgery.

There are several available tools by which to obtain specimens during bronchoscopy including forceps biopsy, brushing, bronchial wash/lavage, and TBNA. Electrocautery snare forceps removal of a pedunculated airway lesion can also provide excellent tissue for the pathologist. The choice of the above modalities is primarily determined by the location of the pathology; however, data support the use of the combination of techniques to improve diagnostic yield, as opposed to using them in isolation. Endobronchial needle aspiration should be used with all visible lesions, as its use in combination with conventional techniques has been associated with an improvement in the diagnostic yield.

If the lesion is not visible endoscopically, BAL can be performed. Briefly, the bronchoscope is wedged in the target segmental or subsegmental bronchus leading to the lesion. Two or three aliquots of 40–60ml of normal saline solution are instilled, and then aspirated. Ideally, the return should be between 40% and 60% of the instilled volume, however this is dependent upon the segment lavaged, with better return coming from less dependant locations. BAL is thought to sample approximately 1 million alveoli and the cellular and noncellular contents of the lavage fluid have been shown to closely correlate with the inflammatory nature of the entire lower respiratory tract.

Transbronchial biopsy, brushing, and TBNA can also be performed for peripheral lesions. The diagnostic yield of bronchoalveolar lavage for peripheral cancer ranges from 4% to 68%. Without advanced guidance (discussed below), the yield for transbronchial biopsy ranges from 49% to 77%. The yield from brushing alone is 26–57%. The combination of all the three techniques results in a combined yield of upto 68%. TBNA of peripheral nodules has been shown to have a higher diagnostic yield than other sampling techniques, and should be used to biopsy peripheral lesions, as well as mediastinal and hilar lymph nodes.

Despite TBNA being introduced more than 25 years ago, it remains an underutilized technique, with only 12% of pulmonologists reporting its routine use for the diagnosis and staging of lung cancer. The technique, however, is incredibly useful, and may preclude further invasive surgery in 29% of patients. The yield with TBNA has been associated with tumor cell type (small cell 4 non-small cell 4 lymphoma), lymph node size, and lymph node location. The use of CT fluoroscopy to guide TBNA and transbronchial biopsy has several advantages over standard fluoroscopy. As opposed to standard fluoroscopy, which is typically used only in two dimensions, CT provides the ability to visualize the target in three dimensions. With standard fluoro, either the patient or the C-arm needs to be rotated to confirm the biopsy tool is not anterior or posterior to the target. CT fluoro provides real-time three dimensional confirmation of the appropriate (Figure 1) and inappropriate (Figure 2) biopsy sites. The use of CT fluoro to guide TBNA has been associated with an accuracy of 88%, including patients who have previously undergone a nondiagnostic bronchoscopy with standard TBNA.

Endobronchial ultrasound is another important modality used to help improve accuracy of TBNA. With the development of a miniaturized 20MHz transducer that can be inserted via a 2.8mm working channel, lymph nodes and masses adjacent to the airway can now be visualized (Figure 3). Like CT fluoro, EBUS has also been shown to improve the yield of TBNA. Recently, a bronchoscope with a dedicated ultrasound probe and distinct working channel has been developed (Puncturescope TM , Olympus Corporation, Tokyo, Japan), and has the benefit of providing real-time guidance for TBNA of mediastinal and hilar lymph nodes, with excellent results. EBUS has been shown to better differentiate airway invasion versus compression by adjacent tumor when compared to CT, and can suggest the histology of a solitary pulmonary nodule based on the ultrasound morphology.

Autofluorescence (AF) bronchoscopy is an increasingly popular tool used for the early detection of cancer in the central airways, primarily carcinoma in situ (CIS), and squamous cell carcinoma. When exposed to light in the violet–blue spectrum (400–450 nm), the normal airway fluoresces green. As submucosal disease progresses from normal, to metaplasia, to dysplasia, to CIS, there is a progressive loss of the green AF, causing a red–brown appearance of the airway wall.

Several studies have shown that the use of autofluorescence increases the detection of early stage lung cancer by up to sixfold when compared to white light bronchoscopy. The definitive role of AF bronchoscopy in the early detection of lung cancer remains to be defined.

Diffuse Parenchymal Lung Disease

Diffuse parenchymal lung disease describes a group of infectious, inflammatory, and fibrotic disorders which may involve the interstitial, alveolar, bronchial, and vascular structures of the tracheobronchial tree. The most commonly used sampling techniques for patients with diffuse disease include BAL, bronchial brushing, transbronchial biopsy (TBBx), and occasionally endobronchial biopsy (EBBx) and TBNA.

Though associated with a low morbidity, transbronchial biopsy should be used only when the potential results will impact on treatment decisions. Diseases in which transbronchial biopsy can prove diagnostic or has been shown to significantly increase the diagnostic yield as compared to less invasive means include lymphangitic carcinomatosus, sarcoidosis, rejection after lung transplantation, hypersensitivity pneumonitis, and sometimes, invasive fungal infection. The overall diagnostic yield for transbronchial biopsy in this category depends on the disease entity. For example, the yield for sarcoidosis can approach 90%, but is much lower for patients with vasculitis or cryptogenic organizing pneumonia.

Aside from providing a specific diagnosis in cases of cancer or infection, the results of BAL can serve to limit the differential diagnosis considerably. For example, a BAL with lymphocyte predominance suggests granulomatous disease such as sarcoidosis, berylliosis, or a lymphoproliferative disorder. Neutrophil predominance suggests bacterial infection, acute interstitial pneumonia, and can be seen in patients with asbestosis or usual interstitial pneumonitis. Eosinophils are seen in patients with eosinophilic pneumonias, hypereosinophilic syndromes, or Churg–Strauss syndrome. Patients with pulmonary alveolar proteinosis (PAP), have a unique appearance to the BAL fluid that is described as milky or opaque. The alveolar macrophages are filled with PAS-positive material, and lamellar bodies can be seen under electron microscopy.

Infectious Diseases

Community acquired pneumonia

The role of bronchoscopy in community acquired pneumonia (CAP) remains controversial. When used, BAL and protected brush are the main diagnostic procedures, and the specimens should ideally be sent for quantitative culture, with a threshold of 104 colonyforming units (CFU) for the BAL and 103 CFU for the protected brush (Figure 4). In addition to providing a microbiologic diagnosis, another important indication for bronchoscopy in patients with CAP is to rule out an obstructing endobronchial lesion in the right clinical setting. Obviously, it is crucial to avoid contamination with upper airway secretions when performing bronchoscopy in patients with pneumonia. Key procedural aspects include minimizing suctioning, as well as minimizing the instillation of lidocaine, as secretions in the working channel will be flushed back into the airways, and high concentrations can be bacteriostatic.

Healthcare and ventilator associated pneumonia

The American Thoracic Society and Infectious Disease Society have recently reviewed these topics in great detail, and used the techniques of evidence based medicine to guide their recommendations. Some major points included the collection of a lower respiratory tract culture prior to the initiation of antibiotics, the use of semiquantitative or quantitative culture data, and the use of negative culture data to discontinue antibiotics in patients who have not had changes in their antibiotic regimen within the last 72 h. Additionally, the use of a bronchoscopic strategy was supported as a way to reduce 14-day mortality.

Immunocompromised host

The early diagnosis and initiation of the appropriate antibiotic is the cornerstone of successful treatment of the immunocompromised patient with pneumonia. Additionally, it is important to note that multiple diagnoses can often be present simultaneously in these patients, and noninfectious conditions may have a similar presentation of cough, dyspnea, fever, and an infiltrate on imaging. Bronchoscopy is an excellent method of evaluating these patients as less invasive techniques can miss the diagnosis in approximately 30% of patients, and earlier diagnosis may improve mortality.

BAL is the most commonly used bronchoscopic technique used to obtain a diagnosis in immunocompromised patients, with an overall diagnostic yield of approximately 60–70%. In comparative studies, the sensitivity of TBBx has been shown to be roughly the same, though the combined use of both techniques may increase the yield. The results of BAL have been shown to change management in up to 84% of cases.

Even in the immunocompromised host, bronchoscopy with BAL remains a safe procedure. Brushing and TBBx, however, have been associated with a higher incidence of bleeding complications in patients who are thrombocytopenic. The ‘gold standard’ for tissue diagnosis remains open lung biopsy, which can yield a specific diagnosis in 62% of patients, and result in a significant increase in survival. There are no data suggesting that bronchoscopy reduces mortality in this patient population.

Hemoptysis

There are many causes of hemoptysis including infectious, inflammatory, vascular, and neoplastic processes. Though one would think that bronchoscopy can often make the diagnosis of a radiographic occult neoplasm in a patient with hemoptysis, a bronchoscopic diagnosis of malignancy is made in o5% of patients. Indications for bronchoscopy in patients with normal chest imaging include age 440 years, male gender, and a 440 pack-year smoking history. Though the appropriate timing for bronchoscopy is controversial, there is a greater likelihood of identifying the bleeding source when performed within the first 48 h of symptoms. The combined use of bronchoscopy and CT is also recommended. If patients are clinically stable, we prefer to obtain the CT first, as it can serve as a ‘road map’ to guide bronchoscopy.

Therapeutic Bronchoscopy

Bronchoscopy in Hemoptysis

The definition of massive hemoptysis has ranged from 100–1000 cm3 expectorated in a 24 h period. As the majority of patients with massive hemoptysis die from asphyxia, and not exanguination, and the anatomic dead-space is approximately 150cm3, we consider any amount over 100cm3 in 24 h as massive.

In addition to identifying the source and cause of bleeding, bronchoscopy clearly plays an important therapeutic role in patients with massive hemoptysis. If available, we strongly recommend rigid bronchoscopy as the procedure of choice in these patients. In addition to securing an airway, and providing oxygenation and ventilation, the rigid bronchoscope allows the passage of large-bore suction catheters as well as a variety of other tools that can help stop the bleeding including cryotherapy, electrocautery, argon plasma coagulation (APC), and Nd:YAG laser, as well as bronchial blockers. If rigid bronchoscopy is not available, we recommend tracheal intubation with the largest endotrachcal tube available, with selective right or left-mainstem intubation to protect the non-bleeding lung as needed. Double-lumen endotracheal tubes, or specialized tubes that come with an endobronchial blocker (e.g., Univent, Vitaid, Williamsville, NY), can be more difficult to place, especially in the setting of massive hemoptysis.

The main role of flexible bronchoscopy in the patient with massive hemoptysis lies in obtaining lung isolation, and ‘protecting the good lung’, as the suction channel of a flexible scope is relatively small. All bronchoscopists should become familiar with bronchial blockers (e.g., Arndt Bronchial Blocker, Cook Critical Care, Bloomington, IN), which can be passed in parallel to the flexible scope, and some, even inserted through the working channel. These catheters are guided to the culprit segmental, lobar, or mainstem bronchus and the balloon is inflated to the recommended volume/pressure. After a maximum of 24 h, the balloon should be deflated under bronchoscopic visualization.

Other bronchoscopic techniques used to control hemoptysis include the topical application of iced saline, epinephrine (1 : 20 000), thrombin/thrombinfibrinogen, or cyanoacrylate solutions.

Other Therapeutic Bronchoscopic Techniques

Argon plasma coagulation

Argon plasma coagulation (APC) is a noncontact method using ionized argon gas (plasma) to achieve tissue coagulation and hemostasis. As the plasma is directed to the closest grounded source, APC has the ability to treat lesions lateral to the probe, or around a bend, that would not be suitable for laser therapy. The depth of penetration for APC is approximately 2–3 mm, and hence the risk of airway perforation is also less when compared to lasers.

Laser therapy

The Nd:YAG laser is the most widely used laser in the lower respiratory system, and has been used for both benign and malignant disease. The primary advantage of laser photoresection includes rapid destruction/vaporization of tissue. Lesions most amenable to laser therapy are central, intrinsic, and short (o4 cm), with a visible distal endobronchial lumen. When lesions meet these criteria, patency can be re-established in more than 90% of cases. Care must be taken however, as the depth of penetration can approach 10mm and airway perforation with resultant pneumothorax, pneumomediastinum, and vascular injury have been reported. In view of this, we encourage its use only by experienced interventional bronchoscopists. Nevertheless, the safety record of laser bronchoscopy is excellent, with an overall complication rate of o1%.

Cryotherapy

Cryotherapy is a safe and effective tool for a variety of airway problems. By releasing nitrous oxide stored under pressure, the tip of the cryoprobe rapidly cools to 891C. We primarily use cryotherapy for the removal of organic foreign bodies with high water content such as grapes and vegetable matter, in addition to facilitating the removal of tenacious mucus or blood clots when performing flexible bronchoscopy. Compared to the other techniques described in this chapter, cryotherapy results in delayed tumor destruction, requiring a repeat bronchoscopy to remove the necrotic tumor. The distinct advantage of cryotherapy lies in the fact that the normal cartilage and fibrous tissue of the airway are relatively cryoresistant, in addition to the lack of risk of airway fires.

Electrocautery

Electrocautery uses alternating current at high frequency to generate heat, which cuts, vaporizes, or coagulates tissue depending on the power. Electrocautery is a contact mode of tissue destruction and a variety of cautery probes are available including blunt tip probes, knifes, and snares. We favor the use of the cautery snare for pedunculated lesions of the airway as the stalk can be cut and coagulated while preserving the majority of the tissue for pathologic interpretation. As with laser therapy the risks of electrocautery include airway perforation, airway fires, and damage to the bronchoscope.

Photodynamic therapy

Photodynamic therapy (PDT) involves the intravenous injection of a photosensitizing agent, then activating the drug with a nonthermal laser to produce a phototoxic reaction and cell death. As tumor cells retain the drug longer than other tissues, waiting approximately 48 h after drug injection will lead to preferential tumor cell death as compared to normal tissue injury. As with cryotherapy, maximal effects are delayed, and a repeat, ‘clean-out’ bronchoscopy should be performed 24–48 h after drug activation. The primary side effect from PDT is systemic phototoxicity, which can last up to 6 weeks after injection. Newer drugs are being developed with the hopes of increasing tumor selectivity and reducing the duration of skin phototoxicity. As laser activation uses a nonthermal laser source, airway fires are not an issue. PDT has been shown to be curative for early stage lung cancer of the airways and is an especially attractive option for patients with endobronchial CIS who are not surgical candidates due to other comorbidities.

Brachytherapy

Brachytherapy refers to endobronchial radiation, primarily used for the treatment of malignant airway obstruction. The most commonly used source of radiation is iridium-192 (192Ir), which is inserted bronchoscopically via a catheter. Brachytherapy may be delivered by either low-dose rate (LDR), intermediate-dose rate (IDR), or high-dose rate (HDR) methods, with most authors currently recommending the afterloading HDR technique. This allows the bronchoscopist to place the catheter in the desired location and the radiation oncologist to deliver the radiation in a protected environment.

The main advantage of HDR is patient convenience, as each session lasts less than 30 min; however, multiple bronchoscopies are required to achieve the total 1500 cGy dose that is currently recommended. The LDR technique may be appropriate for patients who live far from the hospital or who are otherwise hospitalized as it only requires one bronchoscopy, but the catheter has to stay in place for 20–60 h. The main advantage of brachytherapy as compared with external-beam radiation is the fact that less normal tissue is exposed to the toxic effects of radiation. The most common side effects include intolerance of the catheter, radiation bronchitis, airway perforation, and, occasionally, massive hemorrhage. Treatment of tumors in the right and left upper lobes has the highest incidence of hemorrhage, as these are located near the great vessels.

Airway stents

Montgomery is credited as initiating the widespread use of airway stents after his development of a silicone T-tube in 1965 for use in patients with tracheal stenosis. Dumon, however, introduced the first completely endoluminal airway stent in 1990. Airway stents are the only technology that can alleviate extrinsic airway compression. They are commonly used in conjunction with the other modalities for patients with intrinsic or mixed disease. Over the last 15 years, there has been an explosion in both stent design and the number of endoscopists who place airway stents. As with any procedure, it is crucial to understand the indications and contraindications of the procedure as well as be able to anticipate, prevent and manage the associated complications. Unfortunately, the ideal stent has not yet been developed. This stent would be easy to insert and remove, yet would not migrate; would be of sufficient strength to support the airway, yet be flexible enough to mimic normal airway physiology and promote secretion clearance; biologically inert to minimize the formation of granulation tissue; and available in a variety of sizes.

There are currently two main types of stents: metal, generally Nitinol, and silicone. Though metal stents are easily placed, they can be extremely difficult to extract, and may cause excessive granulation tissue formation. They are available in covered and uncovered varieties. For malignant airway obstruction, the only appropriate metal stents are covered models, which minimize tumor ingrowth. Some authors feel that there is no indication for an uncovered metal stent. The main advantage of metal stents is their larger internal : external diameter ratio as compared to that of silicone stents. Though silicone stents require rigid bronchoscopy for placement, they are more easily removed and are significantly less expensive. The future of airway stenting likely lies in the creation of bioabsorbable stents, made out of materials such as vicryl filaments or poly-L-lactic acid (SR-PLLA). In addition to malignant airway obstruction, airway stents can be helpful in patients with tracheobronchomalacia and tracheoesophageal fistula. In patients with tracheoesophageal fistula, doublestenting of the esophagus and airway is recommended to maximally prevent aspiration.

Powered instrumentation

The microdebrider is a tool consisting of a hollow metal tube with a rotating blade coupled with suction. We have had excellent results with this technology in the treatment of both benign and malignant central airway obstruction. A primary advantage of the microdebrider is the rapidity of obtaining a patent airway and the lack of risk of airway fires as compared to modalities using heat.

Future Directions in Bronchoscopy

In the appropriate patient, lung volume reduction surgery has been shown to improve both quality and quantity of life. The major drawback to this surgery is the associated morbidity and cost of the procedure. Recent studies have suggested that lung volume reduction can be obtained bronchoscopically, either by creating channels in the distal airways/parenchyma, or by the placement of one-way endobronchial valves to promote deflation of hyperinflated lung that does not significantly contribute to gas exchange. The results of large-scale, multicenter trials will become available within the next several years, but the preliminary data are promising.

The use of electromagnetic navigation is a novel technology that has been shown to allow accurate sampling of peripheral solitary pulmonary nodules o1 cm in diameter. Briefly, a virtual bronchoscopy is generated from the patients CT scan. Anatomic landmarks that are easily identified, such as the carinae, are marked, as is the target. At the time of bronchoscopy, the patient lies in an electromagnetic field and a steerable, ‘locatable guide’ is placed through an ‘extended working channel’ of the bronchoscope.

The location of the guide in the electromagnetic field is accurate to o5mm in the x, y, and z axes, as well as yaw, pitch, and roll. The points previously identified in the virtual bronchoscopy are then marked with the locatable guide, which in essence, marries the CT scan with the bronchoscopic image. Navigation is then performed by looking at the CT in the axial, sagittal, and coronal planes, and the guide is steered toward the target. Once found, the guide is removed, and standard bronchoscopic tools such as TBNA needles and forceps are placed through the extended working channel.

This technology not only has the potential to revolutionize diagnostic bronchoscopy, but therapeutic bronchoscopy as well. For example, if a patient with a 2.5cm, stage Ia, nonsmall cell cancer is not an operative candidate, this technology may allow for bronchoscopic treatment by either radiofrequency ablation or the implantation of fiducials to allow stereotactic radiosurgery.

Further Reading

Becker HD (1991) Atlas of Bronchoscopy: Technique, Diagnosis, Differential Diagnosis, Therapy. Philadelphia: BC Decker.

Bolliger CT and Mathur PN (2000) Interventional Bronchoscopy. Basel: Karger.

Detterbeck FC, DeCamp MM Jr, Kohman LJ, and Silvestri GA (2003) Invasive staging: the guidelines. Chest 123(90010): 167S–175S.

Ernst A, Feller-Kopman D, Becker HD, and Mehta AC (2004) Central airway obstruction. American Journal of Respiratory and Critical Care Medicine 169(12): 1278–1297.

Ernst A, Silvestri GA, and Johnstone D (2003) Interventional pulmonary procedures: guidelines from the American College of Chest Physicians. Chest 123(5): 1693.

Fagon JY, Chastre J, Wolff M, et al. (2000) Invasive and noninvasive strategies for management of suspected ventilator-associated pneumonia: a randomized trial. Annals of Internal Medicine 132(8): 621–630.

Guidelines for the management of adults with hospital-acquired, ventilator-associated, and healthcare-associated pneumonia. (2005) American Journal of Respiratory and Critical Care Medicine 171(4): 388–416.

Prakash USB (1994) Bronchoscopy. New York: Raven Press.

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