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DIAGNOSTIC BRONCHOSCOPY
Darshit D Dalal*, JJ Vyas**
*Senior Resident; **Prof and Head of Thoracic Service, Surgical Oncology, Tata Memorial Hospital, Parel, Mumbai - 400 012.
INTRODUCTION
The bronchoscope is quite indispensable in the study of thoracic diseases, for it provides an information that is unattainable in any other way.
INDICATIONS OF BRONCHOSCOPY
In many centres, bronchoscopy is an underused procedure, usually because its diagnostic potential is underrated or supposed danger is greatly exaggerated. But, the modern techniques of anaesthesia and ventilation make the procedure so safe that a patient must be gravely ill, or have quite gross reduction in his respiratory, before bronchoscopy becomes dangerous.
Indications are as follows:
- Patient’s history
The patient’s symptoms together with the story of his illness are of paramount importance. The clinician should be prepared to undertake bronchoscopy on history alone.- Profuse or repeated haemoptysis (however slight) with or without radiological abnormalities or physical signs.
- Cough of recent onset, unexplained and persistent, with or without sputum. Less well recognised, however of significance, is a change in cough habit which is frequently missed in chronic bronchitis, with their already long history of cough and sputum. Bronchial carcinoma quite frequently presents in this way.
- Wheeze of recent onset and persistent-
Of particular significance is a unilateral wheeze which will not disappear on coughing or, if it does, always returns to the same place.- Dyspnoea
- Aspiration
The possibility of an aspirated foreign body, vomit or blood, particularly in children, must never be forgotten while taking the history.- Radiological changes
- Persistent or recurrent pneumonia
- Pulmonary collapse
- Typical enlarged hilar shadow
- More peripheral shadow, particularly if persistent, enlarging. Much information about the segment or involved bronchus can be obtained without a view of the presumed tumour itself.
- Miscellaneous
- Pleural effusion - to find out its cause
- Pleuritic pain without effusion
- Bonchiectasis
- Severe chest trauma
- Finding of malignant cells in sputum, even in absence of symptoms, physical signs or radiographic changes
- Extrathoracic indications-
If extrathoracic manifestations are otherwise unexplained, bronchoscopy should be done.
They are -
- Lymphadenopathy in neck or axilla
- Unexplained erythema nodosum
- Superior vena caval obstruction
- Hypertrophic pulmonary osteoarthropathy and/or digital clubbing
- Neuromyopathies
- Endocrine disturbances
- Gynaecomastia
- Voice changes due to left recurrent laryngeal nerve involvement in intrathoracic diseases
EXPLANATION TO THE PATIENTS
Patients should be explained for bronchoscopy by full but simple explanation. This includes explanation about premedication, induction of anaesthesia and after effects of the procedure like irritating cough lasting for a few minutes, occasional expectoration of blood following biopsy, soreness of mouth and throat.
RIGID BRONCHOSCOPY
The head is fully extended after keeping a pillow or a ring beneath it so that the chin points vertically upwards : in fact, the position usually assumed while shaving the chin. Dentures should be removed outside the operating room. The forefinger and thumb of the left hand form a supportive guide for the bronchoscope and protect the teeth or gums from trauma. Under no circumstances should be upper teeth or gum be used as a fulcrum to lever the bronchoscope into position.
The instrument is first introduced almost vertically, either via right side of the mouth or, in an edentulous patient, in the middle. As the scope is inserted further, its proximal end is brought downwards smoothly with slight movement of tip towards the pharynx. By this manoeuvre, the epiglottis can be seen. If this manoeuvre is done too rapidly, sometimes the clinician may enter epiglottic valleculae. Once the epiglottis is passed, laryngeal inlet is entered. Sometimes the clinician may enter the left pyriform fossa or the oesophagus. Once glottis is seen, the scope is advanced in the midline. The vocal cords should be examined. Tracheal walls, carina and bronchial tree must be examined.
Inspection must be carried out methodically. Secretions must be sucked out. Colour and condition of the mucosa must be examined. Any division, distortion of the tracheal/bronchial walls or the lumina and of the carina must be looked for. Right bronchial tree is easier to examine than the left because it is in the direct continuation with the trachea.
Withdrawal of bronchoscope also requires care. This should be done visually until the tip reaches the tongue. Vocal cord movements should be seen at this time.
FIBREOPTIC BRONCHOSCOPY
The introduction of the flexible bronchoscope, in the late 1960s, not only led to a remarkable increase of the diagnostic potential of the bronchoscopy, but to a revolution in the practice of thoracic medicine.
Advantages
- Can be done under topical anaesthesia
- Less chances of trauma
- Easy introduction
- Can be introduced through nasal or oral passages
- Ability to visualize and sample more peripheral bronchial pathologies than with rigid bronchoscope
Disadvantages
- View obtained is inferior to that seen through rigidoscope
- View can be easily obscured; which requires removal of the scope for cleansing and reinsertion.
- Very thick and tenacious secretions will defy removal via the narrow channel of the fibrescope
- Potential for foreign body removal is limited
- Control of rare profuse haemorrhage, caused by instrumentation, proves impossible. Vision is rapidly obscured and packing or insertion of balloon can’t be carried out. The often recommended practice of plugging the bleeding site with the bronchoscope is not possible. After removal; insertion of rigidoscope is of no use as the field is obscured by blood. Furthermore, without a tube in place; resuscitation, if necessary, will be far more difficult.
- In bronchitic patients or patients with tight tracheal stricture, blood gases can be deranged by passing the fibrescope; while use of rigidoscope with oxygen ventury ventilation is safer.
Method of introduction
The lens of the fibrescope must be treated with an antifogging agent.
- Flexible scope can be inserted via oral or nasal route under topical or general anaesthesia.
- The steps of insertion are similar to that of insertion of rigidoscope except for manoeuvring is not necessary to keep the long axis of the scope and that of the upper airway in one line.
ASSESSMENT OF THE TRACHEOBRONCHIAL TREE
- Normality
The clinician should have a sound knowledge of bronchial anatomy. Fig. 1 shows branching, as encountered during passage of the bronchoscope.
Fig. 1 : Shows main branching of the bronchial tree, as visualised by the bronchoscopist operating at the head of the supine patient.
- Inflammatory and associated changes
Inflammatory changes may be generalized (e.g. chronic bronchitis: Fig. 2) or localized (e.g. round a foreign body). They may be acute (e.g. associated with segmental pneumonia) or chronic (e.g. tuberculosis : Fig. 3).
The inflammatory changes include:
- Reddening and increased vascularity of the mucosa. Normal bronchial mucosa is palepink or peach-coloured. It becomes dark pink or even beefy red.
Fig. 2 : Shows inflammatory changes in chronic bronchitis. Fig. 3 : Shows inflammatory changes in tuberculosis with a string of secretion seen in right main stem bronchus. - Swelling.
In mild inflammation, there may be slight blunting of carinal edges and blurring or loss of the prominent contours of bronchial cartilages. In severe inflammation, there may be appreciable narrowing.
- Secretions
Normal mucosa produces only sufficient clear mucus for cleansing purposes. In inflammation, the secretions become profuse and the nature varies widely.
e.g. excessive mucoid - chronic bronchitis.
.......thick, viscid mucus
.......which may form plugs - asthma
.......purulent - severe infections, purulent bronchitis
- Localized changes
A localized reaction raises a number of diagnostic possibilities like simple pneumonia, lung abscess, tuberculosis, inhaled foreign body, bronchiectasis, carcinoma etc.
Fig. 4 : Shows gross forward protrusion of posterior tracheal wall by extrinsic pressure. - Associated Changes
Mainly seen in the patients of COPD. They are submucosal atrophy; hypertrophy of elastic bundles of membranous walls of small bronchioles, causing very prominent corrugations.
- Tuberculosis
This needs special mention. It produces 2 main bronchoscopically visible changes.
i. endobronchial inflammation
ii. luminal distortion of trachea/bronchus due to extrabronchial
.... lymphadenopathy.Tumours
Bronchoscopically, tumours, or metastatic lymph node enlargement therefrom, may produce visible changes of 3 main types.
- Distortion of the anatomy by external pressure on bronchial tree; which is usually due to secondary lymphadenopathy in form of widening of carinal angle, bulging of the wall of the trachea/major bronchi.
- Involvement of the bronchial wall with local distortion or ulceration of the mucosa. These mucosal growths, often fully or partly encircling the lumina, greatly reduce or block them.
- Intraluminal growth may be a primary growth itself (Fig. 5), an extension from the primary, or rupture of a secondary lymph node deposit through the bronchial wall. Intraluminal growth may partially or completely obliterate the lumen.
Tumour Bronchoscopic characteristics i. Carcinoma Fleshy, lobulated or necrotic and white/creamy coloured. Presence of blood streaking and engorged vessels on the surface. ii. Carcinoid Cherry red in colour, rounded, bleeds readily. iii. Chondromata Smooth, pale surface. Hard consistency.
- Miscellaneous conditions
- Bronchial bleeding
In some cases of haemoptysis, examination of bronchial tree proves to be normal. At the other extreme, sometimes so much blood is present that its origin is impossible to determine. Blood clots must be removed piecemeal with the grasping forceps. Cleansing the bronchial tree by normal saline may help in locating the bleeding point.
- Foreign bodies
They commonly cause intense local inflammatory reactions. Not infrequently, they may lead to widespread infection and destruction of bronchial and pulmonary tissues distal to their lodgement. They may produce purulent secretions and may be confused with tumours. But the ability to grasp something firm to hard with the forceps, which then moves on gentle pulling confirms one’s suspicion.
Fig. 5 : Shows fungating tumour at left main stem bronchus - Sarcoidosis
It produces 2 principal effects.i. Lymph node enlargement causing carinal and subcarinal widening; and ....tracheobronchial distortion.
ii. Mucosal changes in form of subacute tracheobronchitis with reddening of .....the mucosa and increased secretions.- Radiation changes
Changes follow a common pattern : an immediate, acute inflammatory reaction, subsequent shrinkage or disappearance of the tumour with subsidence of the inflammation, pallor of the mucosa and contractive scarring after some months and fibrosis of the affected area finally.
- Tracheal trauma
Bronchoscopic confirmation of tracheal or bronchial wall fracture occasionally be needed, particularly after road traffic accidents.
- Hodgkin’s disease
It affects parenchyma more occasionally than the bronchial tree. It forms raised, yellowish plaques on the bronchial walls.
- Bronchopleural fistula
It occurs secondary to empyema, lung abscess, rupture of an infected lung cyst, pneumothorax, trauma or postoperatively. This can be seen if the communication with the bronchialtree can be reached by the bronchoscope. The distinctive feature is occurrence of air bubbles, in the secretions at the site, during respiratory movements.
- Stitch granuloma
This may be mistaken for a foreign body. Extruding stitch can be seen, removal of which ensures the cure.
- Coal deposits
These present as glistening black plaques in the bronchi of coal miners and in less florid form, in city dwellers.
- Amyloidosis.
It occurs very rarely in the bronchial tree. Yellow/grey sessile nodules appear on the bronchial walls which can be mistaken for carcinomatous infiltration.TAKING SPECIMENS
Obtaining specimens from the bronchial tree during endoscopy is a vital part of diagnosis. Specimens can be taken as follows:
- Secretions
They are sucked gently with a sucker and sent for routine microscopy, culture/antibiotic sensitivity, cytology and other specific investigations.
- Bronchial lavage
If secretions are not of adequate quantity or very thick to be sucked directly, the area can be lavaged with little quantity of normal saline and suckings are obtained.
- Scrappings
Specimens are obtained by using swabs, sponges, brushes or curettes from the suspicious areas; especially when no visible growth is present.
- Endobronchial biopsy
The lesion should be close to the bronchoscope tip and well within the visual field. Biopsy can be taken with punch or cut forceps.
- Needle aspiration
A wide bore needle, sufficiently long to project beyond the bronchoscope tube is used to obtain material from the enlarged lymph nodes.
- Transbronchial lung biopsy
This is one of the safest ways to obtain biopsies of the lung parenchyma. The procedure can be particularly helpful in elucidating diffuse diseases which have defied diagnosis by other means. e.g. possible pneumocystis carinii infection in immunosuppressed patients.
Pneumothorax and haemorrhage are the possible complications. Pneumothorax may require drainage. Haemorrhage is not usually severe and stops by plugging the bronchus by the scope.
- Biopsy of peripheral lesions
It is done under general anaesthesia. With advent of fibrescope and delicate instruments, this procedure has become more acceptable and safer.CONTROL OF HAEMORRHAGE
Haemorrhage is usually due to biopsies, but sometimes follows sucking only. If mild to moderate, sucking only is required awaiting the natural clotting process. A small swab soaked in 1/1000 adrenaline is applied at the bleeding point for 2-3 minutes if needed.
Profuse haemorrhage such that the blood flows up the bronchoscope in a steady stream, or is clearly of arterial origin is rare. This may lead to asphyxia, cardiac arrest and death. Following are the cardinal rules to tackle this situation. *
The bronchoscope tube, the orifice of which should have been as near the point of biopsy as possible, must not be moved until the bleeding has stopped.
- Operating table must be tilted head down.
- Strong suction must be applied to keep the field as clean as possible.
- If this proves effective, pressure must be applied to the bleeding point with Fogarty catheter or by packing the bronchus with gauze swab.
- At the same time, resuscitation should be carried out in form of proper oxygenation, blood transfusion and plasma volume expansion.
- When patient’s condition is satisfactory, Fogarty catheter or pack can be removed gently. In many cases, bleeding does not recommence.
- If bleeding starts again, consideration must be given to thoracotomy or selective embolization of the bleeding arterial twig.
- It also is obvious that the technique described cannot be adequately applied while using the fibrescope alone.
CONCLUSION
Diagnostic bronchoscopy has its own merits. Though associated with some complications (even major), it is safe in the expert hands. Claim is sometimes made by many that the flexible scope completely replaces the conventional rigid scopes; but this is not agreeable. The two instruments are complementary : the disadvantages of one reflect the advantages of the other.
