Bronchoscopy: Flexible and Rigid; Esophagoscopy: Flexible and Rigid; Mediastinoscopy; and Anterior Mediastinotomy

Chapter 64 Bronchoscopy: Flexible and Rigid; Esophagoscopy: Flexible and Rigid; Mediastinoscopy; and Anterior Mediastinotomy



John C. Kucharczuk, MD



Bronchoscopy: Flexible and Rigid



INTRODUCTION


In the late 1890s, Gustav Killian used a rigid tube to remove an impacted piece of bone from the right main stem of an awake 63-year-old man. Twenty years later in Philadelphia, Chevalier Jackson popularized extensive examination of the airways using rigid bronchoscopy. Jackson’s techniques were effective, however, they required specialized training; only a few physicians possessed the skills required to perform the procedure safely. Today, awake rigid bronchoscopy is rarely practiced. Nevertheless, rigid bronchoscopy performed with the patient under general anesthesia remains a valuable diagnostic and therapeutic tool for the modern thoracic surgeon. It is irreplaceable in certain circumstances.


The advent of the flexible bronchoscope in the 1970s revolutionized the field of bronchoscopy. Flexible bronchoscopy can be easily performed in awake patients as well as in those who are anesthetized. Flexible bronchoscopes can be used for both diagnostic and therapeutic interventions and are available in a number of sizes and specialized configurations designed for particular applications. Working channels from 1.2 mm up to 3.2 mm allow for aspiration of secretions as well as deployment of a number of instruments into the airway under direct vision.


The modern thoracic surgeon must be an expert bronchoscopist comfortable with both flexible and rigid bronchoscopy. He or she must be able to choose the approach and instrument most appropriate to a given clinical situation.



BRONCHOSCOPY STEPS



Step 1 Select procedure (rigid vs. flexible)

Step 2 Select appropriate anesthesia (topical vs. general)

Step 3 Institute monitoring

Step 4 Supply supplemental oxygen

Step 5 Perform procedure

Step 6 Recover patient


BRONCHOSCOPY PROCEDURE



Select the Appropriate Bronchoscopy Technique


The greatest pitfall in bronchoscopy is the inappropriate choice of one technique (flexible or rigid) over another. Currently, rigid bronchoscopy is performed exclusively in anesthetized patients and allows for the examination of the trachea and proximal airway only. Flexible bronchoscopy, conversely, can be performed in awake or anesthetized patients and allows for examination of the airway down to the subsegmental level.



RIGID BRONCHOSCOPY


Rigid bronchoscopy should be performed in the operating room with the patient under general anesthesia. Specific applications for rigid bronchoscopy are listed later. Rigid bronchoscopes come in a variety of diameters and lengths, as shown in Figure 64-1. They are sized according to the outside diameter. Figure 64-2 shows the computed tomography (CT) scan of a patient with a tracheal mass and impending respiratory obstruction. This patient is an ideal candidate for rigid bronchoscopy for diagnosis and palliative relief of the airway obstruction using a “coring” technique. The final pathology is this case was a tracheal chondrosarcoma.


image

Figure 64-1 The most commonly used rigid bronchoscopes of varying sizes. Note the ventilatory attachment and the side ports.


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Figure 64-2 Computed tomography (CT) image of impending airway obstruction from a chondrosarcoma (arrow) of the trachea.



INDICATIONS



Removal of foreign bodies

Evacuation of tracheal stenosis

Placement of nonexpandable stents

Control of massive hemoptysis

Evaluation of tracheobronchial mobility

Evaluation of airway invasion or adherence by esophageal tumors

Palliation of airway obstruction by tumor (“coring out”)



Inappropriate Patient for Rigid Bronchoscopy


The preoperative assessment of patients undergoing rigid bronchoscopy includes examination of the neck and oral cavity. Severe cervical arthritis with a contracted neck makes rigid bronchoscopy difficult. Poor dentition and loose teeth are at risk during rigid bronchoscopy, and removable dental work such as bridges and dentures should be taken out prior to the procedure. The presence of a mature tracheostomy, conversely, is not a contraindication to rigid bronchoscopy. The tracheostomy device can be removed and the patient intubated with the rigid scope from above or, in some circumstances, directly through the stoma, with particular care being taken to avoid injury to the posterior membranous portion of the trachea. Likewise, rigid bronchoscopy can be performed through the mature stoma in patients who have undergone total laryngectomy.



• Consequence


Inability to position the patient appropriately, resulting in an inability to safely perform the procedure. Complications can range from minor damage to the dentition to life-threatening perforation of the pharynx or airway.

Grade 1–5 complication


• Repair


Select an alternative method for airway visualization and intervention.


• Prevention


Adequately evaluate the patient preoperatively. Do not attempt rigid bronchoscopy on patients with a fixed cervical spine or an inability to be positioned appropriately.


Inadequate Cooperation between Surgeon and Anesthesiologist


The performance of rigid bronchoscopy with the patient under general anesthesia requires close coordination between the anesthesiologist and the surgeon. While the anesthesiologist institutes the appropriate monitoring and intravenous access, the surgeon should prepare the rigid bronchoscope along with its light source and supporting hardware. During “routine” rigid bronchoscopy, general anesthesia is induced with a combination of intravenous and inhalation anesthetics. Secretions are aspirated from the posterior pharynx, and the patient is mask-ventilated. A muscle relaxant is then administered to allow easier placement of the rigid bronchoscope. Patients with large mediastinal masses or near-complete obstructing tracheal tumors represent a particular challenge and, as such, require special anesthetic consideration. Placement of these patients in a supine position or administration of general anesthesia with a muscle relaxant can lead to complete airway obstruction and life-threatening hypoxemia. In these patients, the airway should first be anesthetized with local agents. Patients should remain in a somewhat upright position while general anesthesia is slowly induced with intravenous agents. During this phase, the anesthesiologist assists the patient’s spontaneous ventilation. Use of muscle relaxants should be avoided until the airway is secure. Once anesthetized, the patient should be quickly positioned and intubated with the rigid scope. Ventilation through the anesthesia circuit connected to the side port of the ventilating scope can then begin. If a nonventilating scope is used, insufflation of oxygen via a Venturi apparatus can be used to maintain oxygenation.



• Consequence


Inadequate control of the airway resulting in hypercarbia, hypoxemia, and death.

Grade 3/4/5 complication


• Repair


Both the surgeon and the anesthesiologist must understand the conduct of the procedure and work together as a team. It is helpful to review the planned procedure with the entire operating room team as well as to have a contingency plan in case of a loss of the airway.


• Prevention


The procedure should be performed by a cohesive group of anesthesiologists, surgeons, and nurses. The entire team must understand the procedure before starting.


Inability to Place the Rigid Bronchoscope


When the surgeon is ready to introduce the rigid bronchoscope, the patient should be positioned supine with the neck slightly flexed (“sniffing position”). The surgeon stands behind the patient’s head, secretions are suctioned from the posterior pharynx, and tooth guards are placed. The surgeon controls the patient’s head by gripping the maxilla with the middle and ring fingers of the left hand. The index finger and thumb of this same hand hold the scope in the manner in which one holds a pool stick. The right hand grasps the scope at the level of the eyepiece. The instrument is introduced with the bevel down and advanced until the epiglottis is visualized. The scope is placed just under the leading edge of the epiglottis, which is then gently elevated to reveal the vocal cords. Elevation is achieved by the use of the left thumb. Use of the patient’s teeth or gums as a fulcrum to elevate the epiglottis results in damage to the teeth and must be avoided. One should avoid advancing the scope further than 1 cm beyond the tip of the epiglottis because this places the scope beyond the larynx.


When the vocal cords are visualized, the scope is rotated 90° to the right and advanced into the trachea. Once in the trachea, the scope is rotated back to its original position. The supporting pillow can then be removed from behind the head and the table headboard can be lowered to extend the neck. Ventilation is begun either through the side port with an eyepiece in place or via the Venturi apparatus if a nonventilating scope is being used.



• Consequence


Inability to insert the rigid bronchoscope can result from a number of causes: inadequate training, inability to position the patient appropriately, and inadequate visualization owing to secretions or blood. Complications can range from having to convert to an alternative technique, minor damage to dentition, life-threatening perforation of the pharynx or airway, and even loss of airway control and death.

Grade 1–5 complication


• Repair


If the patient is an inappropriate candidate for rigid bronchoscopy or the operator is not sufficiently trained, an alternative method for airway visualization and intervention should be selected.


• Prevention


Adequately evaluate the patient preoperatively.


Inadequate Visualization of the Airway


The patient’s head should be turned to the side opposite that which you wish to examine. When passing the scope into the right main stem, for example, the patient’s head should be turned slightly to the left. We typically hold ventilation and remove the eyepiece when advancing the scope. If closer inspection of the airway is required, a Hopkins rod telescope is passed through an adapter on the main channel of the rigid scope. These telescopes provide magnification as well as a variety of angled views. If telescopes are not available, a flexible bronchoscope can be passed through the rigid scope.



• Consequence


Advancing a rigid bronchoscope with inadequate visualization of the airway will likely result in airway perforation, necessitating thoracotomy and complex reconstruction.

Grade 3–5 complication


• Repair


The best strategy is not to advance a rigid bronchoscope in the airway unless a clear lumen can be seen ahead.


• Prevention


The patient’s head is manipulated to align the long axis of the airway with the scope, allowing the scope to be passed with clear visualization of the distal lumen.


Recover the Patient


After rigid bronchoscopy, the patient is recovered from general anesthesia in a postanesthesia care unit. Those patients undergoing laser ablation of an obstructing lesion or relief of airway obstruction by a “coring technique” utilizing the rigid bronchoscope should be hospitalized and observed overnight to ensure that an adequate airway has been achieved.



FLEXIBLE BRONCHOSCOPY


Unlike rigid bronchoscopy, awake flexible bronchoscopy can be performed in the outpatient setting for a variety of diagnostic and therapeutic indications, as listed later. Unfortunately, fiberoptic bronchoscopes are delicate instruments; they require specialized training for cleaning, maintenance, and storage, as shown in Figure 64-3.


image

Figure 64-3 Storage unit for flexible bronchoscopes to prevent damage.



INDICATIONS



Examination of airway to subsegmental level

Aspiration of secretions

Mucosal brushings

Biopsy of endobronchial lesions

Deployment of expandable airway stents

Removal of small foreign bodies

Transbronchial needle biopsy

Outpatient awake flexible bronchoscopy is performed in a specially designed endoscopy suite. The suite must include a supplemental oxygen supply, pulse oximetry, cardiac monitoring, and intubation equipment to be used in the event of an airway emergency. Supplemental oxygen—via either nasal cannula or face mask with a specially designed opening to allow for the passage of the bronchoscope—should be provided to all patients undergoing bronchoscopy. Adequate monitoring of the awake patient includes pulse oximetry and heart rate monitoring. Most patients have an intravenous line in place; however, with properly administered topical anesthesia, intravenous sedation is rarely required. Figure 64-4 shows the bronchoscopic view of a patient with an endobronchial lesion. This patient is an ideal candidate for outpatient diagnostic flexible bronchoscopy with endobronchial biopsy prior to embarking on definitive management.


image

Figure 64-4 Obstruction of the right upper lobe orifice by tumor.


Awake bronchoscopy during the postoperative period is frequently performed on the thoracic surgery ward. The most common indication for postoperative bronchoscopy is atelectasis due to mucus plugging. Well-timed therapeutic bronchoscopy in these patients can often prevent more serious complications such as pneumonia and reintubation. To facilitate the bedside procedure, bronchoscopy carts stocked with a flexible bronchoscope, a light source, suction tubing, bite blocks, oxygen masks, local anesthetics, pulse oximetry, and emergency airway equipment should be readily available. Carts should be inventoried and maintained daily by an adequately trained respiratory therapist. Having this simple cart available will minimize the frustration encountered when attempting a procedure on an awake patient without appropriate equipment. At our institution, we typically use a standard adult bronchoscope with an external diameter of 5.9 mm for awake procedures.


Flexible bronchoscopy with the patient under general anesthesia should be performed in the operating room under the supervision of an anesthesiologist. Monitoring should include pulse oximetry, noninvasive blood pressure monitoring, and three-lead electrocardiographic monitoring. Following the induction of general anesthesia, direct laryngoscopy is performed and an endotracheal tube is placed. Tube position is confirmed by auscultation, observation of the chest, and end-tidal CO2 monitoring. In the adult patient, an 8.0-mm endotracheal tube should be used. This tube size allows ventilation via a bronchoscopy adapter during the use of a standard 5.9-mm outside diameter (OD) flexible bronchoscope. The 5.9-mm OD flexible bronchoscope is preferred because its working channel of 2.8 mm is large enough to allow aspiration of thick secretions without becoming clogged. The use of smaller endotracheal tubes with smaller bronchoscopes is often frustrating because of difficulty in clearing secretions in order to obtain an adequate view. The “pediatric bronchoscope” has an OD of 3.5 mm and a working channel of only 1.2 mm. In the case of laser bronchoscopy and other specialized uses, a 6.2-mm OD scope with a 3.2-mm working channel can be used. If possible, a 9.0-mm endotracheal tube should be used in these patients.



Select Appropriate Anesthesia



Inadequate Topical Anesthesia for Awake Flexible Bronchoscopy


Adequate topical anesthesia is paramount to the performance of awake flexible bronchoscopy. Anesthesia should begin with the administration of nebulized lidocaine (5 ml of 1% lidocaine solution) by a respiratory therapist. The posterior pharynx, tonsillar pillars, and soft palate are then sprayed with 1% lidocaine. Next, 2 to 5 ml of a 2% lidocaine solution is injected transtracheally through the cricothyroid membrane with a 21-gauge needle. This maneuver causes the patient to cough but results in topical anesthesia of the airway. Finally, a bite block is placed in the mouth, and the bronchoscope is introduced through the mouth and advanced down to the level of the vocal cords. One milliliter of a 4% lidocaine solution is then sprayed through the working channel of the bronchoscope onto each vocal cord under direct vision. The scope is removed and the patient is encouraged to cough. At this point, local anesthesia is complete and awake bronchoscopy can be easily performed with satisfactory patient comfort. Intravenous sedation can lead to hypoxemia, hypercarbia, and hypotension and should thus be avoided. With properly administered local anesthesia, patients remain comfortable throughout the procedure and subsequent intravenous sedation is rarely required. After awake flexible bronchoscopy, patients should be monitored with pulse oximetry for a short period to ensure that oxygenation is satisfactory. A chest x-ray should be obtained to rule out pneumothorax, lobar collapse, and novel infiltrates. Because the posterior pharynx and vocal cords remain anesthetized, patients should remain on nothing by mouth for 3 to 4 hours after the procedure to minimize the risk of aspiration.



• Consequence


Inability to complete the procedure owing to patient discomfort.

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Jun 21, 2017 | Posted by in GENERAL SURGERY | Comments Off on Bronchoscopy: Flexible and Rigid; Esophagoscopy: Flexible and Rigid; Mediastinoscopy; and Anterior Mediastinotomy

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