Endoscopic procedures include direct or indirect visualization of the pharynx, larynx, esophagus, trachea, and bronchi. Endoscopy may be undertaken to obtain biopsy samples, delineate airway anatomy, remove obstructing foreign bodies, assess hemoptysis, place stents and guidewires, position radiation catheters, apply photodynamic therapy, and perform cryotherapy and laser surgery.

1. Flexible bronchoscopy permits visualization from the larynx to the segmental bronchi.
   1. A “working lumen” is used for suctioning, administering drugs, and passing wire instruments.
   2. Ventilation must occur around the flexible bronchoscope. Bronchoscopes range in external diameter from approximately 5 mm (standard adult size) to 2 mm (neonatal bronchoscopes that lack a working lumen). Larger “therapeutic” bronchoscopes and ultrasound-equipped scopes have diameters ranging to 7 mm.
   3. Topical anesthesia is a common anesthetic approach.
      1. The patient should meet the American Society of Anesthesiologists preoperative fasting guidelines.
      2. Lidocaine (various formulations from 1% to 4%) is applied to the oropharynx or nasopharynx, larynx, and vocal cords. The trachea can be sprayed with anesthetic through the bronchoscope or by transtracheal injection. If good topicalization of the airway is achieved, no further anesthesia is required.
      3. Care should be taken with the total dose of local anesthetic due to high systemic absorption from the orotracheal mucosa.
      4. Premedication with atropine or glycopyrrolate will limit salivary dilution of the anesthetic and may improve the onset and efficacy of the anesthetic.
      5. Nerve blocks may be used to supplement airway anesthesia (see Chapter 13).
      6. The patient should have nothing by mouth until tracheal and laryngeal reflexes return, 2 to 3 hours following administration, to prevent postprocedure aspiration.
   4. General anesthesia may be indicated in anxious or uncooperative patients; in more extensive bronchoscopic procedures; or if bronchoscopy is part of a larger surgical procedure.
      1. Bronchoscopy is very stimulating but does not cause significant postoperative pain, so a potent short-acting anesthetic is preferable.
      2. Muscle relaxation or topical anesthesia to the trachea is generally needed to prevent coughing during the procedure.
      3. The endotracheal tube (ETT) used should be sufficiently large (7 mm inner diameter for a standard scope, 8.5 or 9 mm if ultrasound will be used) to permit ventilation in the annular space around the scope.
      4. If there are no contraindications to its use, a laryngeal mask airway (LMA) offers the advantages of a large lumen and the ability to visualize the vocal cords and proximal trachea.
2. Endobronchial ultrasound involves the use of ultrasound during bronchoscopy to visualize structures within the lungs, airway, and mediastinum. It is used to biopsy lesions (such as enlarged mediastinal lymph nodes) that are close to the airway.
   1. Although topical anesthesia with mild sedation can be used, the procedure is typically done under general anesthesia using a large ETT or LMA.
   2. Whichever anesthetic technique is used, it is imperative to prevent coughing and movement as this can increase risk to injury of major vessels within the thorax during the procedure.
3. Rigid bronchoscopy permits visualization of the airway from the larynx to the mainstem bronchi.
   1. A rigid bronchoscope has better optics and a larger working channel than a flexible bronchoscope. It can be used to establish an airway, visualize the trachea, and treat tracheal pathologies such as obstruction, stenosis, and hemorrhage.
   2. Ventilation is accomplished through the lumen of the scope, allowing better control of a marginal airway.
   3. Rigid scopes are not cuffed, so a variable leak will occur depending on the size of the scope, lumen of the airway, and depth of insertion.
   4. General anesthesia is required for rigid bronchoscopy. It is important to prevent coughing or movement to avoid tracheal disruption. Either deep inhalation anesthesia or muscle relaxation is required to prevent movement and coughing.
   5. Conventional ventilation can be used, with the anesthesia circuit attached to a side arm of the rigid bronchoscope. The proximal end of the rigid bronchoscope is closed by a clear lens or by a gasket through which telescopes may be passed.
      1. The potentially large leak requires an anesthesia machine capable of delivering high oxygen flows.
      2. An intravenous anesthetic technique is preferred. It can be difficult to maintain adequate anesthesia with an inhalational technique due to leak and interruption of ventilation. There will also be considerable operating room contamination with volatile anesthetics.
      3. Close coordination between the surgeon and anesthetist is needed because ventilation may need to be interrupted for surgery, and surgery in turn may be interrupted by the need to ventilate.
   6. In cases of severely compromised airways (eg, severe airway stenosis or airway disruption), maintenance of spontaneous ventilation is indicated. The patient may be given an inhalational induction with sevoflurane, and the rigid bronchoscope may be introduced under a deep plane of anesthesia. After securing the airway, intravenous agents could be substituted.
   7. Ventilating gas usually leaks out around the bronchoscope so that measurements of end-tidal carbon dioxide may be inaccurate. Adequacy of ventilation should be assessed by observation of chest excursion, pulse oximetry, and, if necessary, blood gas analysis.
   8. Rigid bronchoscopes are available that are designed for jet ventilation through a special small side lumen.
      1. The central lumen remains open. Severe barotrauma and pneumothorax may occur if gas is not allowed to escape. Observation of chest movement during the expiratory phase is critical. Conversely, ventilation may be ineffective with noncompliant lungs.
      2. An intravenous anesthetic technique (see Chapter 11) must be used. Muscle relaxation is required for the jet to inflate the lungs adequately.
      3. The inspired oxygen concentration is uncertain because the amount of room air entrained cannot be controlled.
      4. During laser surgery, the fractional inspired oxygen concentration should be reduced to below 0.3, either by jetting air or by using a gas blender for the jet intake.
      5. The advantage of the jet technique is that ventilation is not interrupted by suctioning or surgical manipulations because the proximal end of the bronchoscope is always open. This makes the bronchoscope suitable for use during laser surgery of the larynx, vocal cords, or proximal trachea.
      6. Automated jet ventilators carry the added safety feature of automatic hold when the expiratory airway pressure rises above a set threshold. This prevents breath stacking and subsequent barotrauma.
   9. Complications of bronchoscopy include dental and laryngeal damage from intubation, injuries to the eyes or lips, airway rupture, pneumothorax, and hemorrhage. Airway obstruction may be caused by hemorrhage, a foreign body, or a dislodged mass.
4. Flexible esophagoscopy may be performed under local anesthesia as described for flexible bronchoscopy (see Section IV.A) or after the induction of general anesthesia and endotracheal intubation. Use of a smaller caliber ETT will allow the surgeon more room to work in the pharynx and proximal esophagus.
5. Rigid esophagoscopy is commonly performed under general anesthesia with muscle relaxation. As with flexible esophagoscopy, a smaller ETT is used.
6. Laser surgery is performed on upper and lower airway lesions, including laryngeal tumors, subglottic webs, and laryngeal papillomatosis. A laser’s wavelength determines its penetration and biologic effect. The surgery may be performed via rigid bronchoscopy, laryngoscopy with jet ventilation, or traditional endotracheal intubation. The patient is often in laryngeal suspension, and this requires muscle relaxation. Postoperative pain is minimal.

   During laryngeal suspension, it is important to monitor vital signs as this maneuver can trigger vagal response and lead to severe bradycardia. Glycopyrrolate can be given and the surgeon can also be asked to remove the laryngoscope out of suspension until the bradycardia resolves.