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Bronchoscopy, thoracoscopy, and tissue biopsy 

Bronchoscopy, thoracoscopy, and tissue biopsy
Chapter:
Bronchoscopy, thoracoscopy, and tissue biopsy
Author(s):

Pallav L. Shah

DOI:
10.1093/med/9780199204854.003.180303_update_001

August 28, 2014: This chapter has been re-evaluated and remains up-to-date. No changes have been necessary.

Update:

New bronchoscopic techniques—description of fluorescence bronchosopy and narrow band imaging for early detection of lung cancer.

Endobronchial ultrasound techniques—(1) expanded discussion of endobronchial ultrasound-guided transbronchial needle aspiration, now the first line investigation for staging the mediastinum in lung cancer; (2) description of radial ultrasound.

Therapeutic bronchoscopy—updated discussion of usage in emphysema and asthma.

Updated on 30 May 2013. The previous version of this content can be found here.
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Essentials

Bronchoscopy, thoracoscopy, and radiologically guided biopsy techniques provide different methods for visualizing and sampling thoracic lesions, the approach chosen in any particular case being based on a number of factors, including the anatomical location of abnormal areas, presence of coexisting pulmonary disease, presence of comorbidities, and local expertise. CT is useful in both selection and planning of the most appropriate sampling method.

Bronchoscopy

Bronchoscopy can be used for sampling central lesions, mediastinal lymph nodes, hilar lymph nodes, and—where magnetic navigation technology or radial ultrasound is available—peripheral nodules. Suspected lung cancer is the commonest indication.

Lung cancer—bronchoscopy is an essential tool in diagnosis and staging, when a combination of techniques such as bronchial washings, brushings, and biopsy improves diagnostic yield, as does review of CT imaging before the procedure. Any abnormal mediastinal lymph nodes should be sampled in the first instance by either transbronchial fine-needle aspiration (TBNA) or endobronchial ultrasound-guided TBNA. In the active palliation of lung cancer in patients with primary tumour or metastases involving the trachea or main bronchi, a variety of bronchoscopic techniques can be used to restore airway patency, including stenting in selected cases.

Diffuse lung disease and focal parenchymal infiltrates—bronchoalveolar lavage provides information on cellular processes involved, transbronchial lung biopsy on the pathological characteristics, and segmental lavage is a useful tool in patients with suspected respiratory infection.

Other indications—the role of therapeutic bronchoscopy is increasing with the development of new endoscopic treatments for respiratory diseases such as emphysema and asthma.

Thoracoscopy

Thoracoscopy allows visual inspection and direct sampling of pleural abnormalities, the commonest indications being (1) evaluation of an exudative pleural effusion when cytological analysis of aspirated fluid does not provide a conclusive diagnosis; and (2) in the treatment of a malignant pleural effusion, when a sclerosing agent such as talc can be evenly applied to the pleural surface, a technique which also has a role in the management of recurrent spontaneous pneumothorax.

Percutaneous biopsy

The role of ‘blind’ (unguided) pleural biopsy is diminishing as it has been superseded by either thoracoscopic or image-guided biopsy. Radiologically guided percutaneous biopsy is usually considered where cancer is suspected and there is no clear indication to proceed to surgical resection.

Introduction

Direct visualization of the airways by bronchoscopy has become an important tool in the diagnosis of respiratory disease since its introduction in Japan in 1966. The ability to visualize specific areas significantly improves diagnostic yield in comparison to blind procedures. Similarly, the diagnosis and treatment of pleural disease has improved significantly with the introduction of thoracoscopy, which allows the direct inspection of the pleural cavity. Tissue biopsy has also evolved, with more procedures now being performed with some form of image guidance.

Bronchoscopy

Bronchoscopy is an essential basic investigation for the respiratory physician. The first bronchoscopes were rigid instruments that were adapted from oesophagoscopes. The development of optical fibres enabled flexible bronchoscopes to be constructed, which significantly improved the utility of bronchoscopy, and today videobronchoscopes that provide high-quality images are used routinely.

Flexible bronchoscopy permits the visual inspection of the airways from the vocal cords, trachea, and endobronchial tree down to the subsegmental level. It also allows for a variety of samples to be easily obtained from the airways. The procedure is very safe and is performed as a day-case procedure, with local anaesthesia with or without short-acting intravenous sedation. Rigid bronchoscopy is still performed, primarily by thoracic surgeons and by some physicians for interventional procedures: the equipment has a greater intraluminal diameter than do flexible bronchoscopes and hence allows easier instrumentation, but at the expense of a more restricted field of view, limited manoeuvrability, and the requirement for general anaesthesia.

Indications

The main indications for flexible bronchoscopy are listed in Table 18.3.3.1: suspected lung cancer is the commonest, followed by the assessment of pulmonary infiltrates for microbiological sampling. The role of therapeutic bronchoscopy is increasing with the development of new endoscopic treatments for respiratory diseases.

Table 18.3.3.1 Indications for bronchoscopy

Investigation of symptoms

Haemoptysis

Persistent cough

Recurrent infection

Suspected neoplasia

Unexplained paralysis of vocal cords

Stridor

Localized monophonic wheeze

Segmental or lobar collapse

Unexplained paralysis of hemidiaphragm

Suspicious sputum cytology

Unexplained pleural effusion

Mediastinal tissue—diagnosis and staging

Assessing suitability for surgery

Staging of lung cancer

Infection

Assessment of pulmonary infiltrates

Identification of organisms

Evaluation of airways if recurrent or persistent infection

Interstitial lung disease

Differential cell counts and cytology

Transbronchial lung biopsy

Therapeutic

Clearance of airway secretions

Recurrent plugging of patient on ventilators following lobar collapse

Foreign body removal

Palliation of neoplasm

Endobronchial ablation of tumour

Insertion of stents

Bronchoscopic lung volume reduction

Bronchial thermoplasty for asthma

Contraindications

Informed consent from the patient or their representative is a prerequisite. The main contraindications for bronchoscopy are hypoxia that cannot be adequately corrected by oxygen supplementation, and a bleeding diathesis. However, even in these circumstances firm ‘cut-offs’ cannot be given—the risk-benefit must be evaluated on an individual patient basis. The procedure should only be performed by an individual with an appropriate level of experience, or under supervision by an experienced bronchoscopist. Adequate facilities for resuscitation, and the skills and equipment to deal with any potential complication, should be immediately available. Bronchoscopy staff should be trained and competent in dealing with problems such as respiratory failure, cardiac arrhythmias, haemorrhage, pneumothoraces, and the requirement for intercostal drain insertion.

Equipment

The flexible bronchoscope is a flexible tube containing bundles of optical fibres that carry light to the distal end to illuminate the airways, and a further bundle to transmit the image back to the eyepiece. The distal end of the bronchoscope can be angled through 160° by a lever at the head of the scope. This, in combination with rotation of the scope, allows it to be manipulated during the examination of the airways. There is an instrument channel that allows procedures such as biopsies to be performed and which also functions as a suction channel. A variety of instruments are available, with the specification of the bronchoscope influencing its use—those with larger instrument channels are more suitable for interventional procedures, whereas smaller instruments allow more distal airways to be examined. The latest generation of video bronchoscopes also have the ability to rotate the distal insertion portion of the bronchoscope through 150°, facilitating improved access for diagnostic and therapeutic purposes.

Modern videobronchoscopes have a charged couple device (CCD) chip at the distal end, which allows the image to be projected on to a monitor. The latest systems utilize high-definition TV technology and produce high-quality full-screen images, which significantly enhance diagnosis. There are also a number of hybrid devices that use fibre-optic bundles to carry light down and images back up towards the proximal portion of the bronchoscope. A CCD chip in the head of the scope allows the image to be transmitted onto a monitor, the image quality being determined by the number of optical fibres and the size of the CCD chip. These hybrid scopes have the advantage of having either a smaller external diameter or a much larger instrument channel than conventional videobronchoscopes.

An integrated bronchoscope with a linear array ultrasound probe at the distal end is now commercially available. Its primary use is to facilitate ultrasound-guided sampling of the mediastinum and it is discussed later in this chapter.

Disinfection

Bronchoscopes are cleaned and disinfected before and after the procedure. Particular care should be taken to clean the instrument channel and suction ports manually with a brush, as well as flushing the channel with sterile water. The instrument is then placed in a disinfection solution such as 2% alkaline glutaraldehyde (the commonest used), or phenyl or isopropyl alcohol, and automatic disinfection with 0.2% peracetic acid can also be used. In all cases the instruments should be soaked in the disinfectant solution for at least 20 min. Cross-infection has been observed with organisms such as environmental mycobacteria and pseudomonas species; processes must therefore be in place to document disinfection before use in each patient, and the serial number of the bronchoscope(s) used in individual patients should be recorded for tracing in the event of suspected cross-infection. In most cases of cross-infection, inadequate manual cleaning of bronchoscopes has been a factor. Biopsy forceps and needles are more invasive and hence need to be sterilized rather than simply disinfected.

The potential risk of infections with viruses and prions has driven the development of single-use disposable instruments, but the cost of single-use bronchoscopes would be prohibitive. The development of instruments that can be sterilized rather than disinfected is more realistic, but would still incur significant capital investment. Because there is a significant time delay for instruments that require sterilization (days, rather than the short time required for disinfection), more than 10 bronchoscopes would be required to maintain a clinical service.

Patient preparation

Patients need to provide informed consent before the procedure and should ideally be provided with written information in advance, with key aspects such as risks of the procedure and alternative approaches discussed prior to giving final consent. Bronchoscopy is usually performed as an outpatient procedure with conscious sedation, and patients should be advised not to eat or drink for at least 4 h beforehand. Box 18.3.3.1 provides a simple checklist for patient preparation.

All available imaging should be reviewed prior to bronchoscopy. Ideally, a recent CT scan should be available, as there is good evidence that review of such images before flexible bronchoscopy significantly improves the yield from the procedure. In one study, 171 patients being evaluated for suspected lung cancer were randomized: all had a CT scan performed before bronchoscopy, but in one group the scans were reviewed before the procedure, whereas in another (control) group they were not. The diagnostic yield of bronchoscopy was 73% in the former group compared to 54% in the latter and fewer investigations were required in the group where the CT scans were reviewed before bronchoscopy. This approach is therefore more cost-effective and this author advocates it for all patients undergoing assessment for possible lung cancer. It also allows additional staging procedures such as transbronchial needle aspiration to be performed at the same time as the initial diagnostic bronchoscopy.

A short-acting intravenous benzodiazepine such as intravenous midazolam or an opiate such as fentanyl or alfentanil may be used for sedation. Midazolam has the advantage of amnesic properties, whereas fentanyl and alfentanil have good antitussive properties. In some institutions a low-dose propofol infusion is used to induce and maintain sedation. Patients who have been given sedation should be advised not to drive or handle any machinery for at least 24 h after the procedure. The procedure can be performed without any sedation, which should be considered in some individuals who become aggressive and uncontrollable following intravenous benzodiazepines. It is also an option in patients who cannot be accompanied for 24 h after the procedure.

Patients are monitored by continuous oximetry throughout the procedure. Those with pre-existing cardiac disease, or where hypoxia is not fully controlled by oxygen therapy, should also have ECG monitoring and regular blood pressure measurements.

Basic procedure

Bronchoscopy can be performed with the patient semirecumbent and approached from the front, or alternatively the patient can be lying flat and approached from behind. The choice is determined by local practice and also the procedure that is being performed. Intubation can be performed through either the nose or the oropharynx. Again, local practice seems to influence the approach, but the external diameter of the bronchoscope and the procedure being undertaken should also be taken into account.

The oral pharynx is first anaesthetized with 4% lignocaine (lidocaine) for all procedures. The nasal passage is then anaesthetized with 2% lignocaine gel if a transnasal approach is used. With the nasal route, the bronchoscope is passed through the nares and nasopharynx under direct vision until the epiglottis is visualized. With the oral route, the patient is asked to gently bite onto a mouthguard and the bronchoscope is then placed through this mouthguard into the oropharynx to the level of the epiglottis.

The vocal cords should be visible from this level and their movement assessed, after which they are anaesthetized with 2 ml aliquots of 2% lignocaine. When the coughing subsides the scope is advanced through the widest part of the glottis, with care taken not to touch the vocal cords. The subglottic area of the trachea is very sensitive and patients initially feel as if they are choking. Further 2 ml aliquots of 2% lignocaine are administered in the trachea, carina, right main bronchus, and left main bronchus.

The trachea and endobronchial tree can be inspected down to the segmental areas (Fig. 18.3.3.1), the limiting factor being the size of the bronchoscope. The average bronchoscope with a 5 mm external diameter can reach the second or third generation subsegments. The following can be assessed at bronchoscopy:

  • Dynamic and fixed changes in airway calibre, including areas of extrinsic compression from enlarged lymph nodes or extrabronchial tumour masses

  • Distortion of the airways due to traction from fibrotic or collapsed areas of lung

  • The general appearance of the mucosa, with changes ranging from subtle abnormalities such as increased vascularity (Fig. 18.3.3.1d) and oedema through to gross tumour infiltration

Fig. 18.3.3.1 The videobronchoscopic appearance of (a) the trachea and main bronchi; (b) segmental bronchi in the right lower lobe; (c) polypoid tumour arising from a bronchial segment; and (d) submucosal disease.

Fig. 18.3.3.1
The videobronchoscopic appearance of (a) the trachea and main bronchi; (b) segmental bronchi in the right lower lobe; (c) polypoid tumour arising from a bronchial segment; and (d) submucosal disease.

Polypoid tumours involving the first or second generation subsegments should be easily identified at bronchoscopy (Fig. 18.3.3.1c). However, submucosal disease can be easily missed, and can range from subtle thickening of the airways through to small pearly nodules (may be present in tuberculosis or sarcoidosis). Small ulcers are also occasionally seen with tuberculosis or Wegener’s granulomatosis. In Kaposi’s sarcoma, cherry-red-like lesions are visible.

Basic techniques and sampling

Bronchial washings

Obtaining bronchial washings involves the instillation of 10 to 20 ml aliquots of 0.9% saline into a subsegment, as close as possible to the site of abnormality. The sensitivity is variable, being 48% (range 21–76%) in a recent review that evaluated 30 studies where the yield from the different bronchoscopic techniques was evaluated in at least 50 patients with suspected lung cancer.

Bronchial biopsies

Biopsy forceps can be inserted through the instrument channel of the bronchoscope and pinch biopsies obtained under direct vision, with several biopsies obtained to ensure that adequate tissue has been obtained for diagnosis. A higher yield can be obtained from endobronchial biopsies, with an overall sensitivity for lung cancer of 74% (range 48–97%), but where an exophytic tumour is visible the diagnostic yield should be at least 90%. The technique is generally very safe and the main complication is that of bleeding, particularly where vascular lesions are sampled, but this is rarely significant and can usually be controlled with conservative measures.

Bronchial brushings

A cytology brush can be used to scrape cells from the surface of any abnormal areas seen at bronchoscopy. These can then be either smeared onto a slide or rinsed in saline, according to local preference. In the meta-analysis described above the yield from bronchial brushings was 59% (range 23–93%). The main complication is minor bleeding, but there is a risk of a pneumothorax where a brush is advanced blindly beyond a subsegmental bronchus.

Transbronchial fine needle aspiration

In this technique a transbronchial fine needle is inserted through the mucosa and into a submucosal lesion beyond the endobronchial surface and a few cells are aspirated for cytological analysis. It has a sensitivity of around 56% (range 23–90%).

Transbronchial fine needle aspiration can also be used to sample lymph nodes and is particularly useful in the diagnosis and staging of lung cancer, with a recent CT scan of the thorax required for planning of the procedure. The needle is inserted through the instrument channel of the bronchoscope and then through the tracheal or bronchial surface at the position determined, as perpendicularly as possible (at least 45° angle) to the airway wall, with a jabbing motion, and with suction applied with a 20 ml syringe at the other end. The cells that are aspirated are sent off for cytological analysis. Occasionally a small piece of tissue is also obtained with this technique. The sensitivity of this technique in lung cancer is around 68% (range 45–85%). It provides both diagnostic and staging information, and is often the sole mode of diagnosis (25% of patients). The availability of rapid on-site cytological analysis significantly improves the diagnostic yield. However, a negative result does not exclude neoplastic disease and should be followed up by further investigations such as mediastinoscopy in appropriate cases.

Although it is possible to diagnose lymphoma with transbronchial fine needle aspiration, the samples obtained are predominantly cytological and do not provide the architectural information required to classify lymphomas. It is also a useful technique in the diagnosis of nonmalignant disease such as sarcoidosis and tuberculosis, but the sensitivity is lower.

Overall, transbronchial fine-needle aspiration is a very safe and effective technique: complications are rare, consisting of pneumothorax, pneumomediastinum, and bleeding (<0.01%).

Bronchoalveolar lavage

Bronchoalveolar lavage is a useful diagnostic test in the assessment of parenchymal lung disease. It enables sampling of the distal airways and alveolar spaces, and is particularly useful in the assessment of (1) diffuse drug induced interstitial lung disease, (2) parenchymal infiltrates, (3) pulmonary infiltrates in immunocompromised patients, and (4) assessment of occupational dust exposure.

The samples obtained provide information on the cellular composition of pulmonary infiltrates, types of infective organisms, and presence of particulate and acellular matter in the alveolar spaces (Table 18.3.3.2). Identification of specific bacteria, fungi, and acid-fast bacilli are diagnostic. Malignant cells may be identified in the lavage in patients with bronchoalveolar cell cancer, lymphangitis carcinomatosus, or diffuse metastatic disease. A milky lavage laden with amorphous periodic acid–Schiff positive staining cellular debris is diagnostic of pulmonary alveolar prognosis.

Table 18.3.3.2 Cellular composition of bronchoalveolar lavage according to disease aetiology

Lymphocytic cell composition

Sarcoidosis

Extrinsic allergic alveolitis

Hypersensitivity pneumonitis

Connective tissue disease

Tuberculosis

Viral pneumonia

Neutrophilic cell composition

Idiopathic pulmonary fibrosis/usual interstitial pneumonia

Desquamative interstitial pneumonitis

Acute interstitial pneumonitis

Acute respiratory distress syndrome

Pneumonia

Connective tissue disease

Wegener’s granulomatosis

Cryptogenic organizing pneumonia/obliterative bronchiolitis

Eosinophilic cell infiltrate

Eosinophilic pneumonia

Churg–Strauss syndrome

Allergic bronchopulmonary aspergillosis

Drug-induced pneumonitis

Mixed picture

Cryptogenic organizing/obliterative bronchiolitis

Connective tissue disease

Nonspecific interstitial pneumonitis

Bronchoalveolar lavage is performed by wedging the bronchoscope in the desired subsegment. In diffuse lung disease the right mid-lobe is the segment of choice as it drains well and hence provides the best yield; otherwise the optimal segment is selected on the basis of radiological findings. Once the bronchoscope is wedged, 30- to 60-ml aliquots of normal saline are instilled and aspirated back into a collecting bottle, either by gentle hand suction or with low-pressure suction. The total fluid instilled ranges from 100 to 250 ml, depending on the exact indication and local circumstances.

The main adverse effects of bronchoalveolar lavage are usually dyspnoea, wheezing, and transient fever. Many patients are hypoxic due to their underlying condition, and installation of significant volumes of saline can precipitate hypoxia and, in some cases, pulmonary oedema.

Transbronchial lung biopsy

Transbronchial lung biopsy is invaluable in the assessment of diffuse lung disease and in patients where there is localized parenchymal shadowing (at least of segmental distribution). It has a high diagnostic yield (>80%) in bronchocentric conditions such as sarcoidosis. It also has an important role in the diagnosis of lymphangitis carcinomatosis, disseminated malignancy, interstitial pneumonitis, and extrinsic allergic alveolitis.

The two main complications of transbronchial lung biopsy are haemorrhage and pneumothorax. The risk of the latter is 5 to10%, but a clinically significant pneumothorax requiring intervention occurs in about 1% of cases. The degree of bleeding is very variable, but blood loss of more than 250 ml is infrequent, and usually managed with aggressive suctioning of any blood combined with instillation of ice-cold saline and dilute adrenaline (1:100 000). Blocking balloons that occlude a lobar bronchus may be used to tamponade the bleeding, and blood transfusion may be required on rare occasions.

Bronchoscopy, thoracoscopy, and tissue biopsyFluorescence bronchoscopy

Fluorescence bronchoscopy, currently a research tool, is directed to the early detection of lung cancer. It utilizes the finding that normal tissue emits a green fluorescence when illuminated by a light of blue wavelength, whereas dysplastic or cancerous tissue absorbs this fluorescence and appears reddish brown in colour. These changes are not visible to the unaided eye, but can be visualized with the use of appropriate filters and image enhancement. Fluorescence bronchoscopy is significantly more sensitive at detecting severe dysplasia and carcinoma in situ than conventional white light bronchoscopy, but inflammatory lesions and metaplastic changes also appear abnormal, hence specificity is low and false-positive results are a limiting factor.

Bronchoscopy, thoracoscopy, and tissue biopsyNarrow band imaging

The new video bronchoscopes have a mode that accentuates the signal from blood vessels and highlights the superficial microvascular pattern. Patterns of neovascularization are associated with neoplasia , early changes of increased vessel growth, and networks of tortuous vessels progressing to small spiral or cork screw type vessels in micro-invasive carcinoma. Combination of conventional video bronchoscopy and narrow band imaging has a greater sensitivity for the detection of early neoplasia.

Advanced and research procedures

Endobronchial ultrasound-guided transbronchial needle aspiration

Endobronchial ultrasound was originally performed using a 20 MHz radial vascular mini-ultrasound probe enclosed in a water-filled balloon sheath. These ultrasound probes produce excellent images of the mediastinum and hilar structures, and can provide information on vascular invasion. They are able to identify the different bronchial layers from submucosa to adventitia and have the potential of determining if the mucosa has been breached by cancer and hence distinguish between carcinoma in situ and invasive carcinoma, but their value in a clinical setting is limited.

Bronchoscopy, thoracoscopy, and tissue biopsyThe development of a linear array ultrasound probe integrated into a videobronchoscope, which allows simultaneous ultrasound and conventional bronchoscopic imaging, has significantly improved the utility of ultrasound in bronchoscopy (Fig. 18.3.3.2). The probe can be applied against the tracheal wall and the mediastinum assessed for abnormal lymph nodes, which are visible as hypoechoeic lesions that can be distinguished from blood vessels using Doppler mode. A dedicated needle can be inserted through the instrument channel of the bronchoscope and transbronchial needle aspiration performed with real-time ultrasound imaging (Fig. 18.3.3.2). The probe can be applied against the tracheal wall and bronchial wall, and allows assessment of the mediastinal and hilar lymph nodes, which are visible as hypoechoeic lesions that can be distinguished from blood vessels using Doppler mode. Parabronchial masses can also be evaluated. A dedicated needle can be inserted through the instrument channel of the bronchoscope and transbronchial needle aspiration performed with real-time ultrasound imaging (Fig. 18.3.3.2). Abnormal lymph nodes as small as 5 mm in diameter can be sampled. This elegant technique, which allows sampling of lymph nodes and masses adjacent to the airway, has a diagnostic yield of 85% to 90% and has superseded mediastinoscopy as the first line investigation for staging the mediastinum in lung cancer.

Fig. 18.3.3.2 An ultrasound image demonstrating a needle in a hypolucent ovoid lymph node during endobronchial ultrasound-guided transbronchial fine-needle aspiration.

Fig. 18.3.3.2
An ultrasound image demonstrating a needle in a hypolucent ovoid lymph node during endobronchial ultrasound-guided transbronchial fine-needle aspiration.

Bronchoscopy, thoracoscopy, and tissue biopsyRadial ultrasound

Some peripheral nodules may be accessible via bronchoscopy using radial ultrasound. The yield is improved in-conjunction with fluoroscopy, when the radial ultrasound probe is inserted with a guide sheath through the instrument channel of a video bronchoscope and directed into the appropriate segment. When the radial probe approaches the peripheral mass the ultrasound signal changes to reveal an irregular mass. The guide sheath is secured in this position and the radial probe exchanged for sampling tools such as biopsy forceps, cytology brushes, and peripheral fine needle. Multiple samples should be obtained with fluoroscopic guidance to ensure that the guide sheath has not moved.

Magnetic navigation

Magnetic positional tip technology can be integrated with CT scanning data to create a virtual CT scanner in the bronchoscopy suite. A spiral CT with reconstructions of between 1.5 and 3 mm is required, the data from which is used to create a virtual bronchoscopy model. Specific landmarks such as the primary and lobar carina are marked. At bronchoscopy, a catheter with a magnetic tracking device is inserted through the instrument channel and the catheter tip is positioned and calibrated with the CT data by systematically examining the bronchial segments. The system then integrates the CT data with the bronchoscopy data and can be used to guide the catheter with the magnetic tracking device to the target lesion (Fig. 18.3.3.3). Once the target is reached, the tracking device is removed, the biopsy forceps or needle is inserted through the catheter, and appropriate samples are obtained for diagnosis.

Fig. 18.3.3.3 Magnetic navigation-guided bronchoscopy: (a) screen shot during planning stage with virtual bronchoscopy and CT images; (b) screen shot of procedure stage which demonstrates the location of the magnetic tracker in relation to the target lesion.

Fig. 18.3.3.3
Magnetic navigation-guided bronchoscopy: (a) screen shot during planning stage with virtual bronchoscopy and CT images; (b) screen shot of procedure stage which demonstrates the location of the magnetic tracker in relation to the target lesion.

The main benefit from this system is that it facilitates the biopsy of peripheral pulmonary lesions which measure more than 20 mm in size. The bronchoscopic route tends to be safer, with a lower incidence of complications such as pneumothoraces than percutaneous approaches. It may also improve the accuracy of transbronchial needle aspiration of mediastinal lymph nodes.

Fluorescence bronchoscopy

Fluorescence bronchoscopy, currently a research tool, is directed to the early detection of lung cancer. It utilizes the finding that normal tissue emits a green fluorescence when illuminated by a light of blue wavelength, whereas dysplastic or cancerous tissue absorbs this fluorescence and appears reddish brown in colour. These changes are not visible to the unaided eye but can be visualized with the use of appropriate filters and image enhancement. Fluorescence bronchoscopy is significantly more sensitive at detecting severe dysplasia and carcinoma in situ than conventional white light bronchoscopy, but inflammatory lesions and metaplastic changes also appear abnormal; hence specificity is low and false-positive results are a limiting factor.

Diagnostic role of bronchoscopy in lung diseases

Lung cancer

Suspected lung cancer is one of the main indications for bronchoscopy, the value of which in the diagnosis of central lesions is self evident. Although the diagnostic rate is much lower in peripheral lesions, a variety of techniques such as bronchoalveolar lavage, fluoroscopic biopsy, radial ultrasoung and magnetic navigation-guided biopsy can improve this. Where there is mediastinal adenopathy, consideration should be given to sampling of these lymph nodes by transbronchial needle aspiration with, where available, endoscopic ultrasound guidance.

Diagnosis and staging should be evaluated simultaneously, with every effort made to sample mediastinal lymph nodes where they are enlarged (>10 mm in short axis on CT) or where there is increased uptake on a 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) scan.

Diffuse lung disease

Bronchoalveolar lavage and transbronchial lung biopsies in conjunction with high-resolution CT form the basis of diagnosis for diffuse lung disease. The cell morphology of the lavage fluid is useful in the diagnosis of specific conditions (Table 18.3.3.2): in sarcoidosis there is a lymphocytic infiltrate which may demonstrate a high CD4/CD8 ratio; a mixed lymphocytosis with CD8 predominance in the presence of foamy macrophages and plasma cells is suggestive of extrinsic allergic alveolitis; haemosiderin-laden macrophages are found in alveolar haemorrhage.

Respiratory infection

Bronchial lavage is useful in the diagnosis of respiratory infection when sputum cannot be obtained. It is usually reserved for patients who are failing to respond to empirical treatment, but has a vital role in the diagnosis of pulmonary infiltrates in those who are immunocompromised. Bronchial lavage allows optimal specimens to be collected for microscopy and culture before starting antituberculous chemotherapy in patients with suspected tuberculosis who are not smear positive on sputum samples.

Therapeutic role of bronchoscopy in lung diseases

Lung cancer

About 30% of patients with lung cancer present with advanced disease that involves the trachea or main bronchi. They develop symptoms such as breathlessness, cough, and haemoptysis, and are prone to recurrent pneumonia. Progressive symptoms of respiratory failure and recurrent endobronchial sepsis lead to death. Endobronchial metastases from other tumour sites have a similar effect.

Bronchoscopy can have an important palliative role in the treatment of tumours that are accessible via the bronchoscope. A number of techniques allow tumour debulking and restoration of airway patency, but these are generally underutilized and most patients only receive external beam radiation or chemotherapy. Tumours can be debulked by flexible bronchoscopy using electrocautery, argon plasma coagulation, neodymium YAG laser, photodynamic therapy, and cryotherapy, most of which can be performed on a day-case basis in the endoscopy suite under conscious sedation. Improving access to these techniques in the palliation of endobronchial malignancy should improve survival.

In selected patients debulking may need to be combined with the insertion of self-expanding metal stents, the key indication being where there is significant airway narrowing due to extrinsic compression by tumour, or where the airway structure has been destroyed by the cancer. In both situations a stent attempts to improve airway patency by exerting an outward radial force. Covered stents can also be used to seal off airway fistulas and also prevent tumour ingress into the airway. However, the use of airway stents is associated with important complications including displacement and endoluminal wall damage, mucus impaction, granuloma formation, reobstruction, infection, halitosis due to biofouling, haemoptysis, pain, cough, and stent fracture.

Emphysema

Bronchoscopy, thoracoscopy, and tissue biopsyDynamic airway collapse in emphysema in conjunction with bullous lung disease leads to significant air trapping, flattened diaphragms, impaired respiratory muscle dynamics and breathlessness. Lung volume reduction surgery has been shown to be effective in patients with upper lobe emphysema and poor baseline exercise tolerance. In selected patients bronchoscopic lung volume reduction can be performed with much lower morbidity and mortality than are associated with open surgical procedures. Two main devices are available: one is a valve that is placed in a segmental bronchus and allows air and secretions to drain, but prevents air from entering into that lung segment (Fig. 18.3.3.4a); the other is an umbrella-like device (intrabronchial valve) that acts in a similar manner by blocking air from entering and allowing the drainage of secretions. Both methods are currently being used in clinical trials, with results thus far suggesting that segmental collapse is achieved in about 20% of patients, but improvements in exercise capacity and quality of life are observed in over one-third of patients treated. Improved results are observed by careful patient selection; upper lobe predominant disease in patients with an intact fissure. Other techniques that show promise in clinical trials are endobronchial coils, which restore the elastic recoil of the lung, thermal ablation, which causes fibrosis and contracture in the treated area of the lung, and a biofilm sealant, which induces localized inflammation and fibrosis.

Fig. 18.3.3.4 (a) A catheter delivering thermal energy during bronchoscopy in an asthmatic patient (b) image of a valve in-situ in a patient undergoing bronchoscopic lung volume reduction.

Fig. 18.3.3.4
(a) A catheter delivering thermal energy during bronchoscopy in an asthmatic patient (b) image of a valve in-situ in a patient undergoing bronchoscopic lung volume reduction.

A different approach, in which artificial airways are created between pockets of trapped gas and the segmental airways, has been developed for patients with homogenous emphysema. The technique identifies avascular areas in the airway with the use of Doppler ultrasound and employs a needle to create a hole measuring up to 5 mm in diameter, which is then maintained with a drug-eluting stent. These new airway passages allow trapped gas to escape and hence reduce lung volume. Preliminary reports suggest physiological improvements in lung volumes, exercise capacity and quality of life. Although proof of principle of efficacy has been established, the airways occlude over time and the benefit diminishes.

Asthma

Bronchoscopy, thoracoscopy, and tissue biopsyBronchial thermoplasty is a promising bronchoscopic treatment for asthma (Fig. 18.3.3.4b). The technique involves the application of thermal energy under direct vision to the wall of airways more than 3 mm in size, leading to a reduction in smooth muscle. Randomized control trials have demonstrated improvements in asthma-related quality of life measures, and reductions in exacerbations, hospitalization rates, and days lost due to ill health.

Thoracoscopy

Thoracoscopy is a simple invasive procedure which can safely be performed under local anaesthesia with or without conscious sedation. It provides excellent direct visualization of the pleural cavity.

Indications

The commonest indication for medical thoracoscopy is evaluation of an exudative pleural effusion when cytological analysis of aspirated fluid does not provide a conclusive diagnosis. It allows direct visualization of the pleura and targeted biopsies of any abnormal areas, and in experienced hands has a diagnostic sensitivity of 90 to 95%. It is also a key investigation in the assessment of patients with repeated pneumothoraces or a persistent air leak, and it is also used in some centres for the assessment of interstitial lung disease.

Contraindications

The main contraindication to thoracoscopy is absence of an adequate pleural space due to adhesions or previous surgery. Relative contraindications are a bleeding diathesis (INR >1.4), pulmonary hypertension, severe cardiac disease, or hypoxia. An uncontrolled cough or inability to lie still makes the procedure difficult and is another relative contraindication. However, as with bronchoscopy, the risk and benefits of the procedure should be evaluated for the individual patient.

Equipment

The basic equipment comprises of a rigid thoracoscope with a 9 or 11 mm diameter. These instruments have a variety of optics that allow straight and angled examination, and there are also integrated biopsy forceps with optics that allow accurate biopsy under direct vision. Other essential pieces of equipment include special needles (Verres or Deneke) for inducing an artificial pneumothorax in the absence of a pleural effusion. A gas insufflator is used to fill the pleural space with carbon dioxide or another gas to create a large enough space to facilitate inspection of the pleural cavity. The key precaution is to avoid inducing an artificial tension pneumothorax.

Sterilization

As thoracoscopy is an invasive procedure, it is not adequate to simply disinfect equipment as in bronchoscopy—all of the equipment used has to be sterilized by autoclaving.

Patient preparation and basic procedure

Patient preparation is as for flexible bronchoscopy. The procedure can be performed with local anaesthesia, with or without conscious sedation. Patients are fasted for at least 4 to 6 h beforehand, and oxygen saturation, ECG, and blood pressure are monitored during thoracoscopy. Aseptic conditions are required: operators should wash their hands thoroughly and use sterile gloves and gowns. The patient is usually placed in the lateral decubitus position and the entry site is cleaned with chlorohexidine, with appropriate sterile drapes placed around.

The access site is usually the 4th or 5th intercostal space in the midaxillary line, the exact entry port being influenced by the indication for the procedure and also guided by imaging such as CT or ultrasonography. The pleura is visualized and appears as a delicate, transparent, light-reflecting surface with a fine network of blood vessels within it. Any changes in its surface are recorded, varying from areas of increased vascularity or localized thickening to diffuse changes, and there may be obvious nodules or tumour deposits. An angle telescope is often used to inspect the far reaches of the thoracic cavity such as the apex, interlobar space, paravertebral gutter, and mediastinal surfaces.

Any fluid present can be sampled and sent for appropriate investigations, including cytology, and any areas of localized diffuse thickening may be biopsied. Whatever the visual findings, the parietal pleura should usually be biopsied, with care taken to obtain samples from the upper border of the ribs to avoid the neurovascular bundle that runs along the lower margin. It is possible to obtain visceral pleural biopsies and lung biopsies during thoracoscopy, but they carry a greater risk of bleeding and/or inducing a persistent air leak.

The main complications of thoracoscopy are bleeding and prolonged air leaks. Bleeding can usually be controlled by coagulation with either electrocautery or argon plasma photocoagulation. An intercostal drain should be placed whenever biopsy of the visceral pleura or lung has been performed. Serious but less common complications include secondary infection, mediastinal or subcutaneous emphysema, and air embolism. Re-expansion oedema is a theoretical risk, particularly in patients with long-standing effusions: this can be minimized with slow intercostal tube drainage and carefully managed re-expansion of the lung.

Therapeutic role of thoracoscopy

The most common therapeutic indication for thoracoscopy is in the treatment of a malignant pleural effusion. The procedure allows the even application of sclerosing agents such as talc on the pleural surface and is very successful in combination with tube drainage. Thoracoscopy also has a role in the management of spontaneous pneumothorax: small blebs may be identified and obliterated with argon plasma photocoagulation or electrocautery, usually combined with pleurodesis. It also has a therapeutic role in empyema and tuberculous pleuritis, where it can be used to break up adhesions and facilitate drainage of effusion.

Video-assisted thoracic surgery (VATS)

VATS is increasingly used in the management of patients with pleural disease (see Chapter 18.17) and also allows lung biopsy or resection in some patients in whom an open procedure would be high risk because of poor lung function. Under general anaesthesia the ipsilateral lung is collapsed with the use of a double lumen endotracheal tube, and a stab incision with adjacent instrument ports is made in the 6th or 7th intercostal space in the midaxillary line (Fig. 18.3.3.5). In other respects the technique is similar to standard thoracoscopy. Pulmonary tube drainage is required after the procedure, but hospital stay is shorter than after standard surgical thoracotomy.

Fig. 18.3.3.5 The arrangement of ports for video-assisted thoracic surgery (VATS). The principal access is in the midaxillary line.

Fig. 18.3.3.5
The arrangement of ports for video-assisted thoracic surgery (VATS). The principal access is in the midaxillary line.

Percutaneous biopsy

Pleural biopsy

The use of ‘blind’ (unguided) pleural biopsy is diminishing: wherever possible, pleural biopsies should be performed with image guidance.

Traditionally, pleural biopsy was performed using an Abrams needle, which has three components: an outer trochar with a notch on its side near the distal tip, an inner cutting cannula that interlocks with the trochar, and a central stylette. A 5 mm incision is made in the skin surface and the whole unit is inserted carefully through the intercostal space just above a rib. The central stylette is withdrawn and the inner cannula is rotated anticlockwise and withdrawn slightly. Aspiration of pleural fluid confirms position in the pleural space. The Abrams needle is then angulated and slowly withdrawn to catch a small piece of pleura within the notch of the trochar, at which point the inner cannula is rotated and moved forwards to cut off and retain the specimen. There are a number of variants of the Abrams needle, such as the Cope needle and the Radja needle, but they all obtain a biopsy by tearing or shearing a piece of pleura.

The blind nature of the procedure and the shearing technique for obtaining a biopsy specimen result in a variable diagnostic yield and a complication rate of 15%, with more serious consequences in about 0.1% of procedures. These range from haemorrhage and pneumothorax to laceration of adjacent organs such as the liver, spleen, and kidneys.

Blind pleural biopsy has largely been superseded by CT or ultrasound-guided procedures, and wherever possible by thoracoscopy. The Tru-cut needle is favoured by many radiologists and comprises an outer cutting column and an inner trochar that has a notch within which the biopsy material is collected.

Percutaneous lung biopsy

Percutaneous biopsies are primarily performed in the assessment of pulmonary nodules for suspected malignancy. They are a particularly important tool in the assessment of patients who are borderline candidates for surgery due to comorbidity or disease extent, but are less appropriate where a patient is operable and the nodule is considered highly likely to be cancer. Large masses may be more safely sampled with bronchoscopic techniques. Sampling of enlarged hilar or mediastinal lymph nodes should be considered as alternative sites for tissue biopsy and have the advantage of providing staging as well as diagnostic information.

The main contraindications to percutaneous lung biopsy are poor respiratory reserve (FEV1 <1 litre) and bleeding diathesis (INR >1.4). Relative contraindications are extensive bullous emphysema, intractable cough, patients who are unable to lie still, pulmonary hypertension, and contralateral pneumonectomy.

Fine-needle aspirates can be used to diagnose malignancy but are very poor at firmly diagnosing benign conditions. The use of cutting needles, which obtain a core of tissue, provides greater diagnostic confidence. Under CT guidance the needle is placed so that when the needle tip is fired its distal position remains within the mass being sampled (Fig. 18.3.3.6), care being taken to avoid blood vessels, pulmonary fissures, bullae, and adjacent organs. The outer sheath is held in position after initial biopsy so that the procedure can be repeated and further samples obtained without the need to perform repeated needle punctures.

Fig. 18.3.3.6 CT-guided Tru-cut needle biopsy of a left upper lobe mass.

Fig. 18.3.3.6
CT-guided Tru-cut needle biopsy of a left upper lobe mass.

Pneumothoraces and haemorrhage are the two main complications of percutaneous biopsy, the frequency of which is influenced by the size, depth and position of the mass. The presence of parenchymal lung disease, particularly emphysema, also influences the incidence of pneumothoraces. Air embolism is a rare but serious complication and can occur if the needle lies within the pulmonary vein.

Further reading

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