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Ovid: Oxford Handbook of Respiratory Medicine

Authors: Chapman, Stephen; Robinson, Grace; Stradling, John; West, Sophie Title: Oxford Handbook of Respiratory Medicine, 1st Edition Copyright ©2005 Oxford University Press > Table of Contents > Part 4 – Practical procedures > Chapter 63 – Bronchoscopy Chapter 63 Bronchoscopy P.666
Indications and risks Bronchoscopy is the procedure of passing a telescope or camera into the trachea to inspect the large- and medium-sized airways. It may be performed with a flexible scope using local anaesthetic ± sedation, favoured by physicians, or under a general anaesthetic with a rigid scope, used mostly by surgeons. Airways can be visually inspected and samples taken and therapeutic procedures can be performed. This chapter focuses on flexible bronchoscopy. Indications for bronchoscopy

  • Suspected lung cancer Patients who have a central mass <4 cm from the origin of the nearest lobar bronchus, which is likely to be accessible for biopsy at bronchoscopy
  • Suspected pulmonary infection such as TB in a patient who is unable to produce sputum, or in immunocompromised patients, with fever, cough, hypoxia, or CXR changes (induced sputum with hypertonic saline may be an alternative; see page 701)
  • Suspected interstitial lung disease if a transbronchial biopsy will provide an adequate sample for diagnostic purposes, such as in sarcoid. Only indicated in a limited number of interstitial lung diseases, as more adequate biopsies are often obtained through open lung biopsy, which may be preferable
  • Foreign body removal if this is located proximally
  • Therapeutic indications include diathermy, laser, cryotherapy, argon plasma coagulation, endobronchial brachytherapy, and stenting.

Relative contraindications/take care

  • If a patient has saturations below 90% on air at rest, or PaO2 less than 8 kPa, the risk of significant hypoxia during bronchoscopy is increased
  • FEV1 < 40% predicted
  • Blood clotting abnormalities, particularly platelet level < 50,000/mm3
  • Uraemia, pulmonary hypertension, SVCO, liver disease, and immunosuppression predispose to haemorrhage
  • Recent myocardial infarction may be associated with cardiac ischaemia during bronchoscopy. Wait until 4–6 weeks after.

Risks associated with bronchoscopy Flexible bronchoscopy is a safe procedure, with reported mortality rates in large series being 0.01–0.04% and major complications of 0.08–0.12%. Complications include respiratory depression, pneumonia, pneumothorax, airway obstruction, laryngospasm, cardiorespiratory arrest, arrhythmias, pulmonary oedema, vasovagal episodes, fever (especially following BAL), septicaemia, haemorrhage, nausea, and vomiting. P.667
Bleeding and bronchoscopy

  • Bleeding occurs in approximately 0.7% of patients due to mechanical trauma from the scope, suctioning, brushing, or biopsy, but is more common with transbronchial biopsy (1.6–4.4%). Patients with malignancy, immunocompromise, or uraemia have an increased bleeding tendency
  • If bleeding does not stop spontaneously, the bronchoscope should be wedged to tamponade the bleeding in the segmental bronchus. Use minimal suction, to allow clot formation. 1 ml aliquots of 1: 10,000 adrenaline solution are administered via the bronchoscope as near to the bleeding point as possible, until it stops. Iced saline may be useful
  • If massive haemorrhage occurs, the patient should be turned on to the side of the bleeding to protect the other lung.

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Patient preparation and procedure Patient preparation

  • Information Patients should be given written information about the procedure ideally more than 24 hours prior to the procedure. Provide an information sheet for the patient to take home following the bronchoscopy, with advice about the effects of any sedation and possible complications, as well as telephone numbers in case help is needed
  • Consent The physician performing the bronchoscopy should obtain written consent, with a description of the procedure and its associated risks
  • Nil by mouth Patients should have no food for 4 hours beforehand and clear fluids only until 2 hours beforehand
  • Blood tests Patients do not need routine pre-procedure blood tests, unless there are specific concerns (uraemia, deranged LFTs, low platelets). Many physicians check platelet counts and clotting times prior to transbronchial biopsy (platelets > 75,000/mm3, PT and APTT within 1–2 seconds of control)
  • Bedside tests Consider performing an ECG in patients with a history of cardiac disease. Check blood sugar in patients with diabetes
  • Prophylactic antibiotics should be given to those at risk of endocarditis. In those with asthma, a nebulized bronchodilator should be given before the bronchoscopy.

Procedure

  • Practices vary between centres. Some perform bronchoscopy with the patient sitting up facing the operator; some from behind with the patient lying flat
  • IV access should be present in all patients
  • Nasal oxygen should be administered and oximetry measured throughout
  • Pre-medication may be given in addition for mild sedation, anxiolysis, and anterograde amnesia. A benzodiazepine such as midazolam 2 mg, with 1 mg increments as necessary, may be used with fentanyl. Some patients and operators prefer not to use sedation, due to concerns particularly in elderly patients, those with COPD, or those with cardiac disease. Midazolam can make some patients more agitated. Pre-medication with anticholinergics is not beneficial during bronchoscopy
  • Lidocaine Local anaesthetic spray or gel is applied to the nostrils and the vocal cords are anaesthetized by spraying local anaesthetic (lidocaine 10 mg/spray) to the back of the throat and allowing time to work. Peak plasma levels occur after 15 minutes
    • Transcricoid injection may be used to administer 4% lidocaine into the trachea, or this may be anaesthetized under direct vision through the bronchoscope, when the vocal cords are open
    • Aliquots of 1–2% lidocaine may be administered to right and left main bronchi via the bronchoscope when it is passed through the vocal cords into the trachea. Use the minimal dose required for P.669
      cough suppression. Peak plasma levels occur after 5 minutes via the scope. Airway inflammation increases lidocaine absorption
    • Maximum dose of lidocaine is 8 mg/kg (= 29 ml of 2% solution in 70 kg patient); 5 mg/kg if hepatic or cardiac insufficiency. Toxic effects include seizures and arrhythmias
    • The half-life of lidocaine is 1.5–2 hours
  • Most access the trachea via the nasal route, as this gives increased stability when taking biopsies. If this is not possible, a mouth guard is used and access obtained through the mouth
  • All sections of the bronchial tree should be visually inspected, including the cords and trachea. CXR or CT may help localize the area of concern so specimen site can then be targeted. This increases the diagnostic yield of bronchoscopy in cases of suspected lung cancer
  • Avoid unnecessary suction, as this can increase hypoxia.

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Sampling techniques Bronchial washings are taken by instilling about 10 ml of saline and then collecting it in a pot/trap to obtain superficial airway cells. Bronchial brushings are taken by inserting a covered brush into a bronchial segment, uncovering it, rubbing the bronchial wall, covering it, removing it, and wiping it on a slide. The slide is then sprayed with a cell fixing solution. Bronchial biopsies are taken with biopsy forceps. 5–7 should be taken to optimize yield. These may be taken blindly or from a visibly abnormal area, which gives a higher diagnostic yield than blind biopsies. They can be placed in formalin or saline solution depending on whether they are for histology or microbiology. Bronchoalveolar lavage (BAL) is performed by inserting 50–100 ml of saline through the bronchoscope when it is wedged well in a small airway. Ideally instil fluid during inspiration and, after allowing the fluid to dwell for 10–30 seconds, aspirate back into the syringe during expiration or collect in a trap. Best performed in the area of abnormality on CXR or CT, or non-dependent lobes such as the right middle lobe or lingula. Poor return if the patient is coughing excessively or if they have emphysema. Can cause hypoxia, proportional to amount of lavage fluid used. Transbronchial biopsy (TBB) Technique of passing transbronchial biopsy forceps down a terminal bronchus until resistance is first felt and taking a sample of parenchymal tissue. Safe to perform if patient is taking aspirin or on subcutaneous heparin, but omit clopidogrel for 5 days before and if on warfarin, wait until INR < 1.3. Some perform with radiological screening. Associated with a significant risk of bleeding in 9% and pneumothorax in 3.5%, but up to 14% if patient is mechanically ventilated. Half of all pneumothoraces require chest drains. Therefore perform on one side only and minimize risk by performing TBB in the lower lobes, in dependent segments. Perform CXR one hour after the bronchoscopy. Pneumothorax should be managed according to standard guidelines (page 294). Small pneumothoraces often resolve spontaneously, but the patient may need admission if there are concerns. When performing bronchoscopy:

  • Wear gloves, facemask and eye shields
  • Use particulate (duck) masks if there are concerns about TB or HIV.

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P.672
Interventional bronchoscopy Transbronchial needle aspirate (TBNA) Technique of inserting a biopsy needle through the bronchial wall into an enlarged lymph node or extrabronchial mass and aspirating cells. Used to give additional staging information in lung cancer. Appropriate lymph nodes should be identified on CT first. Should be performed initially, so the bronchoscope is not contaminated with malignant cells from the airway. Push sheath out through end of bronchoscope until the hub is just visible. Extend the needle and then position over nodal position and insert through bronchial wall. Subcarinal and right hilar nodes are the easiest to sample. Autofluorescent bronchoscopy (AFB) Emerging technique to differentiate central malignant areas from normal tissue, including pre-invasive tumours in situ. However the progression of these abnormalities is not known, so the role of AFB is unclear. Uses blue light to induce tissue autofluorescence, which means normal and abnormal tissues appear different colours when viewed through a specialized bronchoscope. Airway trauma, however, can also cause a different mucosal appearance and the test has low specificity. It is being used in some centres as a screening tool following surgical resection of lung cancer, or in patients with head and neck cancer suspected of having a lung primary, or following positive sputum cytology. Endobronchial ultrasound (EBUS) Technique of visualizing the bronchial wall and the immediate surrounding structures via an ultrasound probe either incorporated into the tip of the bronchoscope or passed down the scope. A balloon surrounding the probe is inflated with water, in order to achieve close circular contact and view surrounding structures. Useful to assess lymph node involvement in malignancy, to guide TBNA, to identify mediastinal structures or masses next to the airways, to assess the depth of bronchial wall tumour invasion, or to localize masses within the lung for biopsy. Not widely used currently. Bronchial diathermy, laser resection, argon–plasma coagulation, and cryotherapy These are all procedures that can be used to debulk obstructing endobronchial lesions, or coagulate a bleeding point. Diathermy is the use of an electrical current via a probe to coagulate tissue. Laser achieves the same effect. Argon–plasma coagulation is a non-contact method using argon gas. These are all effective immediately. Cryotherapy is the technique of freezing and then thawing an area with a probe in order to destroy tissue, such as an endobronchial obstructing lesion. It takes hours–days to have its effects. It can also be used to remove a foreign body, as freezing attaches foreign body to the end of the probe. Bronchial stent insertion via the bronchoscope to re-establish airway patency. Expanding metal stents used in cases of external compression, such as lung cancer, for palliation of breathlessness. Silicone stents are used in mainly benign disease and are inserted via rigid bronchoscopy. They are easily removed and manoeuvred, but can migrate and lead to problems with retained secretions. P.673
Brachytherapy Procedure of endobronchial irradiation using iridium192 via bronchoscope for endobronchial and intramural tumours. Delayed effect, requires several sessions. Complementary to other bronchoscopic therapies. Can cause fistulas and haemorrhage. Rigid bronchoscopy Visualize bronchial tree to level of segmental bronchi. Can remove or core out endobronchial tumours, insert a stent, dilate tracheal or bronchial stenosis, and manage massive haemoptysis. Useful to provide information regarding resectability in lung cancer by measuring airway length. Incidence of serious complications < 5%: hypoxia, laryngospasm, pneumothorax, bleeding. Further information Airway stenting for malignant and benign tracheobronchial stenosis. Wood DE et al. Ann Thorac Surg 2003; 76: 167–74 Therapeutic bronchoscopy in lung cancer. Lee P et al. Clinics in Chest Medicine 2002; 23: 241–56 BTS Bronchoscopy guidelines. Thorax 2001; 56 (suppl. 1) ERS/ATS Statement on Interventional Pulmonology. Europ Respir J 2002; 19: 356–73 An evaluation of CT as an aid to diagnosing patients undergoing bronchoscopy for suspected bronchial carcinoma. Bungay HK et al. Clin Radiol 2000; 55(7): 554–60 Role of CT scanning of the thorax prior to bronchoscopy in the investigation of suspected lung cancer. Laroche C et al. Thorax 2000; 55(5): 359–63

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