Answer:

Four types of bronchoscopes are currently in use: flexible fiberoptic, EBUS bronchoscope, rigid ventilating, and rigid Venturi.

The flexible fiberoptic bronchoscope can be used either in sedated patients under local anesthesia (allowing examination of vocal cords movements) or under general anesthesia with a supraglottic airway device or an ETT. For the awake or sedated examination, viscous lidocaine can be gargled to anesthetize the upper airway and a 2% or 4% lidocaine solution inhaled via nebulizer mask to reach the lower airway. Bilateral superior laryngeal nerve blocks and transtracheal block can be added; however, they are not as popular as in the past due to potential complications. Intravenous sedation can be achieved with 0.5-mg increments of midazolam, 10 µg of remifentanil boluses or propofol infusion. Alternatively, dexmedetomidine (as a bolus of 0.5 to 1 µg per kg over 10 minutes followed by a continuous infusion of 0.2 to 1.5 µg/kg/hr) can also be used, with the main advantage of causing amnesia without impaired ventilation. When compared to propofol, the main disadvantage of dexmedetomidine seems to be the prolonged recovery time, limiting its use in the ambulatory setting. If the oropharynx is adequately anesthetized, a supraglottic airway device can be inserted without discomfort in sedated patients and used to assist ventilation at higher FIO₂ concentrations.

EBUS can be done with either sedation or general anesthesia, depending on the number and locations of the lymph nodes to biopsy. Good topical anesthesia is paramount to prevent coughing and bronchospasm. The EBUS bronchoscope is a 6.9-mm outer diameter flexible bronchoscope with a latex balloon tip, coupled with a 7.5-MHz convex ultrasound probe. When the balloon is inflated with normal saline, it allows a tight adhesion to the airway wall facilitating ultrasound identification of the lymph nodes. A 21-gauge needle is used through a dedicated channel in the bronchoscope for real-time biopsy. Color Doppler is available to differentiate the lymph nodes from vascular structures. In the sedated patient, or in the presence of a supraglottic airway device, attention should be used to avoid vocal cord trauma, due to the positioning of the optical view at a 30-degree angle. Intravenous steroids may be used to prevent inflammation and edema. In nonintubated patients, local anesthetic toxicity may result from larger doses necessary to tolerate the longer procedure and abolish the cough reflex. If an ETT is used, an 8.5 is recommended to accommodate the bronchoscope and ventilate. In the presence of precarinal lymphadenopathy, the ETT may require placement high in the trachea, potentially leaving the balloon between vocal cords. Trauma may occur with prolonged procedures or in the absence of paralysis. Other rare complications associated with the technique include pneumo- and hemomediastinum, pneumothorax, mediastinitis, and bacteremia.

Rigid bronchoscopy usually necessitates general anesthesia. Although spontaneous ventilation has been used, the risk of tracheal trauma is high with coughing. Therefore, muscle relaxation is commonly used unless contraindicated. The rigid ventilating bronchoscope has a side-port adapter that can be attached either to the anesthesia circuit or the jet ventilator, allowing the delivery of a high flow rate. A variable air leak usually exists around the bronchoscope, so high flow rates of inspired gases or packing of the oropharynx are needed. Significant loss of volatile anesthetic into the operating room environment needs to be considered; thus, the use of total intravenous technique is a good alternative.

The rigid Venturi-effect bronchoscope relies on an intermittent high flow (20 to 60 L per minute), high pressure (50 psi) oxygen jet to entrain air and insufflate the lungs. The jet is delivered through a reducing valve (25 psi) into a 16- or 18-gauge needle inside and roughly parallel to the lumen of the bronchoscope. Major disadvantages of this technique are the lack of control of the inspired oxygen concentration and the inability to administer inhaled anesthetics. Accordingly, anesthesia should be maintained by intravenous techniques. Inadequate ventilation (with resultant hypercapnia) can also occur.

Rigid bronchoscopic procedures can be relatively short. If sugammadex is available, patients can be fully paralyzed and reversed at the end of the case. Otherwise, continuous succinylcholine infusion is an alternative even though rarely used nowadays. When followed by another procedure (such as the mediastinoscopy scheduled for this patient), an intermediate-duration nondepolarizing muscle relaxant is often desirable.

• José RJ, Shaefi S, Navani N. Anesthesia for bronchoscopy. Curr Opin Anesthesiol. 2014;27:453-457.
• Metha AC, Jain P, eds. Interventional Bronchoscopy: A Clinical Guide. New York: Springer Science; 2013:85-106.