W13 Fiberoptic Bronchoscopy
Before Procedure
Indications
• Diagnostic uses:
• To evaluate problems associated with endotracheal tubes and airway stents (e.g., tracheal damage, device malposition, airway obstruction)
• To obtain lower respiratory tract specimens by bronchoalveolar lavage (BAL) or protected specimen brushing (PSB) for cytologic or microbiological analyses
Equipment
• Fiberoptic bronchoscope made up of a few components which are incorporated into a functional unit:
• Control handle; it contains:
• Eyepiece to which video or photographic devices may be attached. Just under the lens, a diopter adjustment ring is used to focus and adjust the eyepiece to fit each individual’s eyesight. In some bronchoscopes, the top of the endoscopic view is marked by an indent or black triangle to assist in orientation.
• Insertion cord: the flexible bronchoscopic element that hangs from the control handle and is introduced into the airways. Within it are the viewing bundle, one to three light bundles, the working channel, and two wires to control the distal end of the scope.
• Universal cord: arises from the side of the control handle and transmits light from the light source to the endoscope and then down to the insertion cord to illuminate the field of view. The light source is a metal box to which the universal cord attaches. In some types of bronchoscopes (portable), the universal cord is not needed, as the light source is built into the control handle of the instrument, and power is provided by a battery system. Modern digital flexible endoscopic systems use a charge-coupled device chip placed at the end of the scope to relay digitized information to the monitor via a processor. The venting connector is a component of the bronchoscope, usually located on the universal cord. The ethylene oxide sterilization venting cap and leakage tester are attached to this connector. The ethylene oxide cap must be installed when the endoscope is subjected to gas sterilization and during transportation by air; it must be removed prior to immersion or when the instrument is in use.
• Ancillary technical materials:
• Antifogging systems, including warm water (max 60°C), weak soap solutions, and commercially available antifogging solutions. When fogging occurs during procedure, bringing the tip of the endoscope into contact with the mucosal surface may eliminate lens fogging.
• Microbiology and cytology brushes, flexible forceps, retrieval valves, transbronchial aspiration needles, fixatives
• Specimen-collection traps, syringes for medication delivery, normal saline solution for bronchoalveolar lavage
• Oral intubating airway that provides an open air space in the oropharynx and protects the endoscope from being bitten by the patient; it is useful if the oral route is chosen in patients under general anesthesia.
• Endoscopy mask to assist fiberoptic intubation in patients being ventilated by face mask; provided with a rubber diaphragm that permits passage of either the endoscope or tracheal tube into the airways and prevents air leaking
• Laryngeal mask airway or other extraglottic devices in various sizes for ventilator support in emergency situations. Laryngeal mask airway may also be used to aid passage of the bronchoscope into the trachea.
• Adapter for insertion of the bronchoscope into the airways while preventing loss of respiratory gases and maintaining ventilation and positive end-expiratory pressure throughout procedure during either invasive or noninvasive ventilation (NIV) (Figures W13-1 and W13-2)
• Medications:
• Lidocaine for topical anesthesia. The minimum amount of lidocaine necessary should be used when instilled through the endoscope; the total dose should be limited to 8.2 mg/kg in adults. Great care must be given when administering lidocaine to patients with liver or cardiac failure
• Monitoring devices:
• Continuous intraarterial blood pressure or intermittent cuff blood pressure measurement at least every 5 minutes
• Cleaning and sterilization equipment:
• Dedicated room for cleaning and manual or automated sterilization; automated washer disinfectors are recommended to minimize staff contact with disinfectant and their fumes.
• Soft nonabrasive cleaning cloth to gently wipe the external surfaces and components of the endoscope immediately after use
• Water or neutral detergent solution to irrigate all accessible channels of the endoscope at the end of the procedure
• Cleaning brushes and neutral detergent solution for a thorough cleaning of internal and external surfaces of the endoscope. Cleaning brushes are passed through the working channel access port, the suction port opening, and the suction connector; they are also used to carefully clean the distal end of the instrument. The brush head should be cleaned each time it emerges from the endoscope.
• High-level disinfection or sterilization agent such as peracetic acid, glutaraldehyde, or ethylene oxide
Anatomy
Nomenclature of Peripheral Bronchi
• Right lung. The orifice of the bronchus to the right upper lobe is in the 3-o’clock position, and its distance from the carina is quite variable. The arrangement of the three segmental bronchi of the right upper lobe bronchus is nearly symmetric. Just beyond the lower part of the right main bronchus, or bronchus intermedius, the typical anatomic configuration consists of: the orifice of the middle lobe bronchus, anteriorly directed, in the 12- to 2-o’clock position; the orifice of the bronchus to the superior segment of the lower lobe, at the same level but in the 6- to 7-o’clock position; and directly in front, the basal segmental bronchi of the right lower lobe.
• Left lung. After entering the left main bronchus, the orifices of the upper and lower lobe bronchi generally lie in the top left and bottom right, respectively, of the bronchoscopic image. Within the orifice of the left upper lobe bronchus, the lingular division bronchus lies to the right of the superior division bronchus. Inside the entrance of the left lower lobe bronchus, the orifice of the superior segmental bronchus is in the 6- to 7-o’clock position, just as in the right lung.
Procedure
• Choose the size of the bronchoscope according to the indication for the procedure, patient’s size, and size of the endotracheal tube. A large bronchoscope with a wide working channel provides excellent suction performance and permits passage of large bronchoscopic tools. In adult patients who are tracheally intubated, an outer diameter of the bronchoscope at least 1.5 mm narrower than the lumen of the endotracheal tube can prevent excessive increases in airflow resistance and decreases in tidal volume.
• Connect the bronchoscope to the light source when it is present, turn on the light, adjust the focus (e.g., by looking at written material until a clear view is obtained), and ensure white balance.
• Place the patient in a supine, semirecumbent or even sitting position, depending on the type of procedure.
• Start topical anesthesia, general anesthesia, or intravenous sedation, based on the needs of the patient.
• Stand behind or to the left or right side of the patient. If you stand to the side, you can approach the patient either from behind or from the front. In the latter situation, once the bronchoscope has passed into the pharynx, the superior part of the endoscopic view will correspond to the inferior part in the patient.
• Handling the bronchoscope. Right-handed users will find it easier to hold the handle of the instrument with the right hand, with the index finger over the suction valve and the thumb over the bending lever, and to use the left hand to hold the insertion cord. The black cursor in the viewfinder, when present, describes the plane of movement of the tip of the endoscope.
• The bronchoscope may be inserted into the airway through the nose or the mouth in spontaneously breathing patients, or through the endotracheal tube in intubated patients; during NIV, the bronchoscope is passed through the NIV interface.
• The application of NIV during bronchoscopy may be useful either in at-risk hypoxemic patients who are initially breathing spontaneously and who start NIV to assist bronchoscopy, or in patients who are already receiving NIV and who are scheduled to undergo bronchoscopy during NIV. When NIV is given through a facial mask, a T-adapter with seal connector is attached to the mask for insertion of the bronchoscope through the nose or the mouth.
• Fiberoptic intubation. The endoscope may be passed transnasally or transorally through the vocal cords into the trachea. Then, the endotracheal tube is slipped over the instrument.
• Sampling techniques. Samples from the lower airways are commonly obtained by BAL, PSB, TBLB, and TBNA. When BAL or PSB is performed, the sampling area is selected based on the location of the new or progressive infiltrate on chest x-ray or the segment visualized during bronchoscopy as having purulent secretions. Data are lacking for the optimal sampling site in patients with diffuse lung infiltrates.
• BAL. The tip of the bronchoscope is wedged as far as possible into a distal airway—generally a fourth- or fifth-order bronchus—and sterile saline solution is instilled through the bronchoscope and then aspirated into a sterile trap. Aliquots of 20 to 60 mL are injected and aspirated back after each instillation. The total amount of fluid used to perform BAL ranges from 140 to 240 mL. In the supine patient, BAL fluid recovery is best from the right middle lobe or lingula. At least 5 mL of retrieved fluid is needed for adequate microbiological analysis. The first aliquot of aspirated fluid is likely to contain a large amount of material from the proximal airway and must be analyzed separately from the rest. The recovery of more than 5% squamous epithelial cells in the BAL specimen indicates tracheobronchial proximal contamination. Because lidocaine has bacteriostatic properties, use of this local anesthetic could alter microbiological results.
• PSB. This technique is performed using a retractable brush within a double-sheathed catheter device with a distal dissolvable plug occluding the outer catheter. First, the tip of the bronchoscope is positioned close to the sampling area. Next, the catheter is inserted through the working channel and advanced 1 to 3 cm beyond the distal end of the bronchoscope to avoid the collection of pooled secretions around the distal tip of the instrument. The inner catheter containing the brush is advanced to eject the distal plug into a large airway, and the brush is advanced under direct vision into the desired subsegment. Once the sample is obtained, the brush is retracted into the catheter, which is then withdrawn and removed from the bronchoscope. The brush is then advanced beyond the catheter, cut with sterile scissors, and placed into 1 mL of transport medium to avoid drying.
• TBLB. Histologic samples of bronchial mucosa, bronchial wall, lung parenchyma, and alveoli may be obtained using TBLB. In diffuse lung disease, the biopsy specimen should be taken from a peripheral airway, preferably the lower lobe. In this way, the danger of significant bleeding may be reduced, owing to the smaller caliber of the distal bronchial vessels. The number of biopsies needed for TBLB is not standardized. However, seven to eight biopsy specimens have been proposed for localized lung lesions, whereas five TBLB samples from one lung seem to ensure a high diagnostic yield for most diffuse lung diseases.
• TBNA. Tissue samples from paratracheal, hilar, and peribronchial areas may be obtained by TBNA. For visible tumors, the yield of TBNA and forceps biopsy is similar. A protected transbronchial needle is passed through the working channel of the bronchoscope and positioned with the needle perpendicular to the endobronchial wall. The tracheal wall, carina, mainstem bronchus, or major spur is pierced with a quick thrust. Suction is then applied to the proximal end of the needle sheath with a 20-mL syringe containing 2 mL of saline solution. The needle and sheath are removed from the bronchoscope, and the specimen is collected into a container for cytologic analysis. If a dry syringe is used, the specimen is smeared onto a glass slide before examination. At each biopsy site, two or three punctures are commonly made, employing a new needle for each location.
• Recommendations for bronchoscopy during mechanical ventilation through endotracheal tube. Insert a connection between the endotracheal tube and the ventilator tubing to slide the bronchoscope. Volume-controlled ventilation is usually preferred. Set fraction of inspired oxygen (FIO2) at 100%, and remove or reduce positive end-expiratory pressure, except in very severe respiratory failure. Increase respiratory frequency and decrease tidal volume; increase percent inspiratory time. Set the peak pressure alarm to a level to allow adequate ventilation. After procedure, return all ventilator parameters to their initial values. Over the first 30 minutes after termination of bronchoscopy, gradually reduce the applied FIO2 to the pre-bronchoscopy requirements as long as the patient is able to maintain arterial oxygen saturation of hemoglobin measured by pulse oximeter (SpO2) at greater than 92%.
• Other procedural considerations. Enteral feeding or oral food intake should be suspended at least 4 hours before procedure. Asthmatic subjects should be premedicated with a bronchodilator before the procedure. Platelet count and coagulation times should be checked before performing bronchoscopy in patients in whom a biopsy is anticipated. When biopsy specimens are needed, oral anticoagulants should be stopped at least 3 days before bronchoscopy, or they should be reversed with low doses of vitamin K. If anticoagulants cannot be withdrawn, the international normalized ratio (INR) should be maintained at less than 2.5, and heparin should be started.
After Procedure
Complications
• Common:
• Hypoxemia commonly occurs during bronchoscopy; insertion of a bronchoscope into the airways reduces the cross-sectional area available for airflow, thus increasing airway resistances and the work of breathing. Continuous suctioning through the instrument evacuates respiratory gases and decreases functional residual capacity, leading to the development of hypoxemia. Hypoxemia may be more severe after BAL, owing to ventilation/perfusion abnormalities induced by instillation of saline solution. The decrease in arterial oxygen partial pressure resulting from bronchoscopy may last a few minutes to several hours after removal of the bronchoscope.
• Infrequent:
• Major cardiac rhythm abnormalities; risk of arrhythmias is greatest during passage of the bronchoscope through the vocal cords in nonintubated patients, especially if hypoxemia is present.
• Pneumothorax; very uncommon after bronchoscopy but has an increased incidence in patients undergoing TBLB
• Significant bleeding, defined as more than 50 mL of blood loss; the likelihood of hemorrhage from bronchoscopy increases when biopsy or brushing procedures are performed. Patients at higher risk of bleeding include those with uremia, immunosuppression, pulmonary hypertension, liver disease, coagulation disorders, or thrombocytopenia.
Outcomes and Evidence
• Outcome after bronchoscopy depends on the patient’s coexisting condition. Flexible bronchoscopy is associated with a 0.3% incidence of major complications and a mortality rate of 0.02%; major complications requiring resuscitative measures are significantly more likely with rigid bronchoscopy as compared with flexible bronchoscopy.
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