The debate over the relative merits of rigid versus fibreoptic bronchoscopy has largely been resolved with the recognition that they are complementary, both having advantages and disadvantages. Any experienced bronchoscopist should be familiar with both types of instrument. Rigid bronchoscopy was and still is mainly the province of the thoracic surgeon. Although it can be performed under local anaesthesia, general anaesthesia is felt to be kinder and more appropriate. It retains several advantages over fibreoptic bronchoscopy: the large calibre allows easier suction of retained secretions and better control of bleeding, foreign bodies can be removed more safely, and good control of ventilation and airway patency can be maintained. It can also be used to feel the mobility of the trachea and main bronchi, allowing assessment of operability of tumours.

The flexible fibreoptic bronchoscope, introduced in the late 1960s, can safely be used under local anaesthesia. It can be introduced through nasal or oral passages and can also be passed through an endotracheal tube or via a rigid bronchoscope. Its main advantage, other than the ability to dispense with the general anaesthetic, is the ability to visualize and sample from peripheral bronchi and lung parenchyma.

The most common indication for bronchoscopy is in the diagnostic assessment of patients with a suspected bronchial carcinoma or other localized obstruction within the bronchial tree. Clinical suspicion may be based on symptoms such as cough and haemoptysis, abnormal radiographic shadowing, or failed resolution of a pneumonia. It is easy to visualize and obtain diagnostic material from lesions in the central airways, including the segmental bronchi. Samples can also be obtained from peripheral lesions by undertaking transbronchial biopsies under fluoroscopic screening or by using bronchoalveolar lavage. Bronchoscopic findings help decision-making with regard to operability, but even if tumours are felt to be inoperable, a tissue diagnosis may enable more rational use of chemotherapy or radiotherapy.

Fibreoptic bronchoscopy allows access to subsegmental bronchi and is widely used in the investigation of pulmonary infections and interstitial lung disease. Bronchoalveolar lavage and transbronchial biopsy have both proved a useful adjunct in the investigation of patients with immune deficiencies. Both techniques can be used to obtain samples for isolating Pneumocystis carinii, cytomegalovirus, and both typical and atypical mycobacteria. In patients with diffuse interstitial lung disease transbronchial biopsies offer a higher diagnostic yield in conditions which have specific histological features, including sarcoidosis, malignant infiltrates, lymphoma, alveolar proteinosis, and histiocytosis X. Results are of limited value in patients with diffuse fibrotic lung disease. Differential cell counts on samples obtained from bronchoalveolar lavage in patients with conditions such as sarcoidosis and fibrosing alveolitis have not been sufficiently specific to be of use diagnostically or as a guide to treatment.

Therapeutic indications are limited, but fibreoptic bronchoscopy can be performed in patients on mechanical ventilation. Lavage and aspiration of retained secretions can be beneficial in critically ill patients, providing objective improvements in arterial blood gases. Removal of foreign bodies is best achieved using a rigid bronchoscope, although a variety of snares and forceps can be used with a fibreoptic instrument. Although laser photoresection using yttrium aluminium garnet can be performed using a fibreoptic bronchoscope, better control of this procedure is obtained if it is used in conjunction with rigid bronchoscopy.

Fibreoptic bronchoscopy is usually performed in a conscious patient under local anaesthetic. It is thus essential that the patient is given a careful explanation of the procedure to avoid unnecessary fear. Premedication is generally unnecessary, except in very anxious patients. Lignocaine is the most commonly used topical anaesthetic: there are a number of minor variations in technique used to achieve satisfactory anaesthesia for the nasal and oropharyngeal mucosa, larynx, and tracheobronchial tree. The nasal mucosa is anaesthetized using a 4 per cent spray or lignocaine gel, the spray also being used for the oral pharynx. Further lignocaine (2 per cent) can be injected through the bronchoscope operating channel directly on to the larynx and tracheal mucosa. An alternative approach is to inject the anaesthetic through the cricohyoid membrane: the initial paroxysm of coughing serves to distribute this on to the larynx and to the tracheobronchial tree.

Fibreoptic bronchoscopy is generally performed with a patient semirecumbent and the operator standing to one side and facing the patient. An alternative is to stand at the head of a supine patient, an approach which maintains the same spatial orientation of the bronchial tree as in rigid bronchoscopy. Insertion of the bronchoscope via the nose is preferred. In negotiating the nasal passages, the bronchoscope should be passed directly backwards and negotiated by gentle manipulation, not force. In 5 to 10 per cent of patients the size of the nasal airway is inadequate, and the oral route must be used. The bronchoscope should be protected by passing it through a mouthguard gently clasped between the patient's teeth.

As the bronchoscope is advanced the nares, naso- and oropharynx, and vocal cords should be inspected and the mobility of the cords assessed during phonation. When entering the trachea, coughing can be minimized by adequate local analgesia and avoiding contact with the mucosa as much as possible. Secretions can be aspirated but if vision is impaired by blood or mucus on the distal lens it can usually be cleared by gently wiping the tip of the instrument on the bronchial mucosa.

Full inspection of the bronchial tree requires a methodical approach and detailed knowledge of bronchial anatomy. Individual segmental bronchi cannot be recognized without appreciating the route taken to that particular airway. Practice in manipulating the instrument using a lung model is strongly recommended: descriptions of normal and abnormal appearances are inadequate substitutes for practical experience. Pathological findings can be recognized by the presence of excess secretions, mucosal abnormalities, or distortion of the normal anatomy, usually due to extrinsic pressure. Secretions may vary from excess amounts of normal clear mucus found in patients with chronic bronchitis to thick pus in patients with bronchiectasis or lung abscess (Fig.2(a)) 1976. Thick, viscid plugs of mucus can be found in patients with asthma. Inflammation may be accompanied by erythema of the bronchial mucosa, which is friable and bleeds easily.

The appearance of bronchial neoplasms is variable and they may be difficult to differentiate from an area of local inflammation ( Fig. 2(b) 1976, (c)). Polypoid tumours are clearly recognizable, and intraluminal obstruction with an ulcerated mass is usually diagnostic. However, small areas of mucosal irregularity and swelling can be due to sudden submucosal tumour. External pressure on the bronchial wall is commonly due to secondary lymph node enlargement and may result in widening of a carina. The majority of visible tumours prove to be bronchial carcinomas. The rare bronchial adenoma (carcinoid tumour) has a characteristic cherry red appearance due to its vascularity. Other rare tumours include cylindromas, lipomas, papillomas, and chondromas. The typical appearance of a Kaposi's sarcoma, which develops in patients with the acquired immune deficiency syndrome, is of a raised violaceous papule. Endobronchial abnormalities may also be seen in patients with sarcoidosis and amyloidosis.

The diagnostic yield from fibreoptic bronchoscopy depends on close co-operation between the bronchoscopist and laboratory based colleagues. Cytological samples both from central and peripheral lesions can be obtained using a sheathed cytology brush. For peripheral lesions which are not visible bronchoscopically, diagnostic yield can be increased by sampling under fluoroscopic control. Segmental lavage can also be used to obtain material for cytological examination.

Bronchial biopsies can be taken using a variety of biopsy forceps. The samples obtained are relatively small but when tumour is visible a histological diagnosis can be obtained in more than 90 per cent of patients. In patients with peripheral lung lesions and diffuse parenchymal disease, biopsies can be taken by passing forceps beyond the visible bronchi. Again the procedure is best undertaken with the aid of fluoroscopy. The bronchoscope is wedged into a segmental bronchus and not removed until the biopsy has been taken and haemostasis achieved. Closed biopsy forceps are passed into the lung peripherally to within 1 or 2 cm of the pleural surface. During inspiration the forceps are slightly withdrawn, opened, and then gently advanced during expiration. The forceps are then closed and withdrawn, with the object of obtaining a small amount of lung parenchyma between two distal airways. Several biopsy samples can be taken in this way if needed.

In order to perform bronchoalveolar lavage, the bronchoscope is again wedged in a segmental bronchus. Sterile warmed normal saline is injected in approximately 50 ml aliquots and the fluid is then withdrawn by gentle suction. Up to 50 per cent of the fluid can usually be retrieved. If excess suction is used trauma to the mucosa will adversely affect the viability of the cells. Despite the fact that culture of the aspirate may be misleading because of contamination with nasopharyngeal commensals, lavage remains the most effective way of isolating a number of organisms including Pneumocystis carinii, mycobacteria, cytomegalovirus, and various fungi.

There are no absolute contraindications to fibreoptic bronchoscopy. There are, however, increased risks in patients with ischaemic heart disease, respiratory failure, asthma, and bleeding diatheses. Bleeding, especially after biopsy, is the most frequent complication. Adenomas and other vascular tumours may bleed profusely and care should be taken in patients in whom cytological brushing induces brisk bleeding. Haemostasis may be achieved by wedging the bronchoscope in situ, and inflatable balloon catheters are also available.

Resting Pao&sub2; falls by an average of 2.5 kPa during fibreoptic bronchoscopy. Adverse consequences are more likely to occur in patients with pre-existing respiratory failure, and hypoxia may be accompanied by ventricular dysrhythmias. Monitoring of oxygen saturation and supplemental oxygen provide appropriate safeguards. Radiological screening can help to reduce the likelihood of a pneumothorax following transbronchial biopsy. This occurs in approximately 5 per cent of procedures but rarely requires specific treatment.

The risk of cross-infection is small provided that care is taken in cleaning and disinfecting the bronchoscope. Transmission of Pseudomonas and mycobacteria between patients has been reported. Cross infection with HIV is likely to prove less of a problem but adequate safeguards need to be taken by staff performing the bronchoscopy. Gloves, gown, goggles, and mask should be worn by the bronchoscopist to prevent accidental cross-infection.

Although fibreoptic bronchoscopy has an advantage over the rigid bronchoscope as a screening procedure for large numbers of patients, rigid bronchoscopy retains some advantages which have already been mentioned. It is preferred by most surgeons as a prelude to surgical resection of malignant tumours. The field of vision is more limited than with the fibreoptic scope. Views of upper lobe bronchi and apical divisions of lower lobe bronchi require the use of a lateral or oblique viewing telescope.

Almost all rigid bronchoscopies are performed under a general anaesthetic in a fully paralysed patient. Adequate ventilation can be achieved using the Saunder's oxygen venturi technique. The procedure is performed on a supine patient whose head should be supported on a well-filled pillow and extended so that the chin points vertically. The forefinger and thumb of the left hand protect the teeth and gums from trauma and serve to guide the bronchoscope. The instrument is introduced almost vertically, usually to the right of the mouth. As it follows the contour of the tongue the proximal end is brought downward towards the horizontal. Access to the glottis is obtained by passing posterior to the epiglottis. Once the glottis is seen the bronchoscope is advanced in the midline and the cord approached with the bronchoscope turned through 90°. At this stage the bronchoscope is now directed to the left vocal cord and can be gently passed through the vertical glottic chink. It is essential to avoid the use of force when negotiating the larynx or aligning the bronchoscope within the trachea. Positioning of the head and bronchoscope needs to be altered in order to intubate the main and lower lobe bronchi on either side. The left is more difficult and usually requires the head to be turned to the right with the bronchoscope remaining in the right hand corner of the mouth. The procedure is reversed for examining the right bronchial tree. Correct positioning of lateral or oblique viewing telescopes often proves difficult for the beginner. Having methodically inspected the bronchial tree and taken appropriate biopsies, removal of the bronchoscope requires as much care as its insertion.

Although rigid bronchoscopy remains essentially a diagnostic tool, it also has some therapeutic applications. The removal of foreign bodies has already been mentioned, and a variety of biopsy forceps and smears are available. Care should be taken not to dislodge material into more distal airways.

Palliative treatment of inoperable tumours obstructing the trachea can be achieved using a number of techniques. A diathermy loop can be used to core out large volumes of tumour from within the lumen. Laser resection is more elegant but no more effective. Local radiotherapy can be achieved by inserting radioactive gold grains; this technique may be supplanted by placing a cannula into the tumour site and inserting iridium-199.

Thoracoscopy permits direct visualization of the pleural space and enables biopsies of abnormal pleura to be taken. It is of value in the diagnostic investigation of pleural effusions when simpler techniques such as pleural aspiration and biopsy have proved unhelpful. Although initially introduced in 1910, only in recent years has it undergone a resurgence as a diagnostic tool. It is a safe technique which has high sensitivity and specificity, especially in patients with malignant disease or tuberculosis.

Thoracoscopy can be performed under local or general anaesthesia. The most commonly used instrument is a rigid 9 mm thoracoscope, which has excellent optics and is easy to control. Although a fibreoptic bronchoscope can be used through a rigid introducer, it can be difficult to control and has a lower diagnostic rate than the rigid thoracoscope.

Premedication with an opiate analgesic is combined with adequate local anaesthesia. Lignocaine is infiltrated into an intercostal space in the mid-axillary line and an 18-gauge cannula is used to aspirate pleural fluid and replace it with air. The patient is then positioned in the lateral decubitus position with the site to be examined uppermost. A chest radiograph is taken to ensure that free air is uppermost in the pleural cavity. A small 1 cm incision is made vertically through skin and subcutaneous tissue. The trocar and cannula are then inserted through the intercostal space applying gentle pressure combined with a rotating action. The guiding hand should hold the cannula near to the tip to prevent excess penetration. Once in the pleural cavity, the trocar is removed and any remaining fluid aspirated. The thoracoscope is then inserted and the pleural space inspected. After taking necessary biopsies, pleurodesis can be effected using iodinized talc or tetracycline. At the end of the procedure an intercostal drain connected to an underwater seal is inserted and left until the lung has reinflated.

Thoracoscopy is a safe procedure. It is, however, contraindicated if dense pleural adhesions obliterate the pleural space. Rare complications include persisting air leaks, secondary infection, and bleeding from intercostal vessels or torn adhesions. Its high diagnostic yield makes it a valuable procedure when other diagnostic methods have failed and it is important to establish a definitive diagnosis.

Mediastinoscopy is an endoscopic examination of structures adjacent to the anterior and lateral aspects of the trachea. It is often combined with anterior mediastinotomy, which permits access to the anterior and superior mediastinum.

Cervical mediastinoscopy was originally made popular by Carlens in 1959. It can be used to obtain diagnostic tissue in patients with radiographically documented mediastinal lymphadenopathy. More importantly, it is a valuable preoperative staging procedure in patients with bronchial carcinoma. The finding of tumour in lymph nodes obtained at mediastinoscopy is generally regarded as a contraindication to surgery. Cervical mediastinoscopy does not provide access to the anterior mediastinum or subaortic fossa, hence the need for left anterior mediastinoscopy or mediastinotomy. It is also unreliable in patients who have hilar adenopathy only.

Cervical mediastinoscopy is performed under general anaesthesia. A short transverse incision is made in the suprasternal notch, the strap muscles and veins being deflected laterally. Once the trachea is located, the pretracheal facia is incised. Blunt dissection beneath this is continued caudally until near to the carina. The mediastinoscope is inserted into this plane using the tracheal cartilages as a reference point. Biopsies can be obtained from nodes in the superior mediastinum, either paratracheal chain or at the carina. The superior pole of the right hilum is also accessible, but biopsies from this area are hazardous because of the proximity of the azygous vein and branches of the pulmonary artery.

Anterior mediastinoscopy is used to examine the left mediastinum. A vertical incision is made lateral to the sternum in the second intercostal space. The anterior and subaortic lymph nodes are exposed by blunt dissection medial to the pleura. The mediastinoscope is then introduced and biopsies taken.

Relative contraindications to mediastinoscopy are superior vena caval obstruction, and previous mediastinal surgery or radiotherapy. Tissue planes can be obliterated by fibrous scarring; this increases the complication rate. The proximity of many vital structures in the superior mediastinum means that biopsy is hazardous in inexperienced hands. Major complications are fortunately rare but include bleeding necessitating thoracotomy, recurrent laryngeal nerve palsy, pneumothorax, and mediastinitis.

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