Chapter 21. Fiberoptic Endoscopic Intubation

The flexible fiberoptic bronchoscope is a useful instrument for placing endotracheal (ET) tubes in awake and nonparalyzed patients who may have contraindications to paralysis, as well as in patients undergoing rapid sequence intubation when other means of orotracheal intubation have failed. The device is unique in that its flexible cord allows it to conform to the patient's anatomy, making intubation possible in a variety of clinical situations when intubation by direct laryngoscopy is likely to be difficult or impossible. It is most useful in performing awake intubations as it is accepted by more patients and is associated with fewer complications than awake laryngoscopy.1 Proficiency in the skills required for fiberoptic intubation requires both instruction and practice.2 Technical problems and failure to successfully intubate patients using this technique are usually due to a lack of familiarity and expertise with the fiberoptic bronchoscope, using it in the wrong clinical setting, and inadequate patient preparation.

A more detailed description of the airway anatomy is provided in Chapters 6 (Essential Anatomy of the Airway), 7 (Basic Airway Management), and 11 (Orotracheal Intubation). A brief description of the flexible fiberoptic bronchoscope is presented in this section. There are other sources for a more in depth description of the fiberoptic bronchoscope's anatomy.3

The basic anatomy of the flexible fiberoptic bronchoscope is shown in Figure 21-1. The major components are the handle, the insertion cord, and a light source. The handle contains the eyepiece for image viewing and a dial to bring the image into focus. A lever controls an angulation wire, which allows for movement of the bronchoscope's insertion cord tip in one plane.

The bronchoscope's insertion cord is composed of thousands of glass fibers, each approximately 10 μm in diameter. The fibers in the cord transmit an image to the proximal viewing lens. There is a side port that can be used for the insufflation of oxygen, instillation of local anesthetic or saline solution, limited suction (due to the small size of the port), passage of a guidewire, and end-tidal CO2 monitoring. Any fiberoptic bronchoscope used for intubation should have a length of at least 55 to 60 cm.4 Fiberoptic laryngoscopes or nasopharyngoscopes are usually unsuitable for intubation because of their short length.

Fiberoptic intubation of the airway is indicated in situations where an awake intubation technique is preferable to one that renders the patient unconscious. The awake technique is indicated when it is anticipated that direct laryngoscopy might be difficult to perform or if paralysis is contraindicated.2 This would include morbidly obese patients, those having limited mandibular opening, an unstable or immobile cervical spine, macroglossia, CHF, micrognathia, patients who appear to have pathologic airway anatomy (e.g., tracheal deviation, tracheal stenosis, tumors, and trauma), and those who appear to be at increased risk for dental damage.5 Fiberoptic bronchoscopy has been used successfully in the case of a rapidly enlarging neck mass.6 It should be considered in patients in whom neck extension should be avoided or who are at increased risk of aspiration of their gastric contents (e.g., those not fasted, pregnancy, alcohol intoxication, and bowel obstruction).4

Fiberoptic intubation is not recommended for patients who are actively vomiting or have significant oropharyngeal bleeding. Opaque fluids cover the fiberoptic port and prevent adequate visualization through the bronchoscope. Patients who are hypoxic or require assisted ventilation by mask are poor candidates for fiberoptic intubation as the technique may require several minutes to perform. An exception may be made if the patient can be ventilated by a laryngeal mask airway (LMA) through which fiberoptic ET intubation may be performed.7,8 Contraindications specific to nasal fiberoptic intubation would include coagulopathy, significant midface trauma, severe intranasal pathology, fracture of the cribriform plate, and leakage of cerebrospinal fluid.9

Relative contraindications to fiberoptic intubation of the airway are situations when instrumentation of the airway may further compromise airway patency, such as stridor resulting from airway edema, infection, or epiglottitis. Some authors advocate fiberoptic intubation as an option to consider in these circumstances, but only by individuals extremely proficient at fiberoptic endoscopic intubation and only with a qualified physician standing by to perform an emergent tracheostomy or cricothyroidotomy if the need arises.10 In these circumstances, it would probably be prudent to establish a surgical airway in the operating room, under a more controlled setting, rather than attempt a fiberoptic bronchoscopic intubation. Occasionally, an emergent tracheostomy or cricothyroidotomy cannot be successfully performed in these patients before complete airway obstruction occurs. Therefore, one should always be prepared to provide oxygen emergently by another route (e.g., transtracheal jet ventilation) to prevent hypoxic brain damage.

Nasal Anesthesia

• Cotton-tipped applicators
• 4% lidocaine
• 0.05% oxymetazoline (Afrin®)
• 4% cocaine

Oropharyngeal Anesthesia

• 1%, 2%, or 4% lidocaine or benzocaine spray
• Nebulizer device with tubing or a Mucosal Atomizer Device (MAD®, Wolfe Tory Medical, Salt Lake City, UT)
• Cotton 4 × 4 swabs soaked in 4% lidocaine
• Emesis basin
• Yankauer suction
• Tongue blade

Laryngeal Anesthesia

• Alcohol swabs
• 10 mL syringes
• 21 gauge needle, 1 ½ inches
• 2% lidocaine for atomization
• 1% and 4% lidocaine solution
• Nebulizer device with tubing

Fiberoptic Bronchoscopy and Intubation

• An assistant
• Fiberoptic bronchoscope with working channel
• Bite block
• Oral/nasopharyngeal airways
• Light source
• ET tubes, various sizes
• Suction source and catheters
• Cuffed tracheal tubes of various sizes, especially 5 and 7 mm
• Oxygen source
• Oxygen tubing
• Bag-valve device
• Face masks
• Water-soluble lubricant or anesthetic jelly
• Gauze 4 × 4 squares
• Antisialagogue (glycopyrrolate 0.3-0.4 mg IV or IM, atropine 0.5 mg IV)

Miscellaneous Supplies

• Povidone iodine solution or chlorhexidine
• Alternative intubation kit/devices (difficult airway cart)
• Cricothyroidotomy tray or kit
• Rapid sequence induction medications
• Crash cart
• Cardiac monitor
• Pulse oximetry

Fiberoptic intubation is best performed on awake and spontaneously breathing patients. Rendering the patient unconscious might relax and distort the airway anatomy, placing the patient at risk for more serious complications including apnea, airway obstruction, and aspiration of gastric contents.11 Proper patient preparation is essential to the successful completion of a fiberoptic intubation. Proper patient preparation includes counseling the patient, clearing the airway of secretions and blood, judicious sedation, and airway anesthesia (nasopharynx, larynx, and trachea).9 Counseling is an important and often underestimated part of patient preparation. Thoroughly explain the necessity for the procedure and the technique. The bronchoscopist can gain the patient's confidence and cooperation, which are invaluable aids for the performance of a successful fiberoptic intubation.

Before proceeding with fiberoptic bronchoscopy, monitors for electrocardiogram, blood pressure, and pulse oximetry should be placed along with an intravenous line for the administration of drugs. Supplemental oxygen should be administered and can be delivered either by nasal cannula, “blow-by,” or through the side port of the fiberoptic bronchoscope. Delivering oxygen through the side port offers the additional advantage of blowing airway secretions away from the fiberoptic bronchoscope's tip and can be used to help visualize the vocal cords when redundant tissue is obscuring the view. Unfortunately, it has the potential disadvantage of causing gastric distention and rupture.12,13

The patient may be in a sitting, semirecumbent, supine, or left semilateral position during fiberoptic bronchoscopy.14 In morbidly obese patients, the sitting position will, by virtue of gravity, displace redundant pharyngeal tissue anteriorly and open the pharyngeal space.15 However, use of the sitting position also requires the bronchoscopist to stand at the patient's side, thus inverting the image seen through the fiberoptic bronchoscope. Alternatively, the bronchoscopist can stand on a platform in order to be of sufficient height to correctly perform the procedure. When performing the procedure with the patient in the supine position, the patient's head should lie flat against the table surface with the neck extended (if it is safe to do so). This head position brings the tracheal axis more in line with the nasal and oral passageways and elevates the epiglottis from the posterior pharyngeal wall. The “sniffing position,” while optimal for direct laryngoscopy, increases obstruction of the glottis by the epiglottis during fiberoptic bronchoscopy and makes the passage of the fiberoptic bronchoscope more difficult.15 Maneuvers performed by an assistant, such as the jaw thrust or pulling the tongue forward with a cotton swab, can help to move the pharyngeal soft issues anteriorly and allow increased maneuverability of the fiberoptic bronchoscope's tip.9

Instrumentation of the airway may cause the patient to produce copious secretions, making an otherwise straightforward fiberoptic bronchoscopy extremely difficult. Bronchoscopy via a “dry” airway devoid of secretions can be accomplished in most instances by administering 0.3 to 0.4 mg of glycopyrrolate. This is a potent antisialagogue and should be administered intravenously at least 10 minutes before or intramuscularly 30 minutes before fiberoptic bronchoscopy. Atropine is often more readily available in the Emergency Department than glycopyrrolate. It can be administered in a dose of 0.5 mg intravenously at least 10 minutes before fiberoptic bronchoscopy. The only disadvantage of atropine is that it crosses the blood–brain barrier and can cause central nervous system effects whereas glycopyrrolate does not. Please refer to Chapter 8 for a more complete discussion of these two antisialagogues.

Sedation can be extremely beneficial in gaining the patients cooperation during the performance of a fiberoptic bronchoscopy. Sedative drugs, if used at all, should be judiciously titrated to the desired effect with continual assessment of the patient's level of consciousness, while at the same time avoiding respiratory depression. Ketamine given in small doses (0.5 to 1.0 mg/kg) has the advantage of producing minimal respiratory depression and may be preferable to opioids in some cases. Other agents that have been successfully used for sedation during fiberoptic intubations include midazolam, propofol, fentanyl, dexmedetomidine, and remifentanil.4,16 Please refer to Chapter 8 for a more complete discussion of the pharmacologic adjuncts to intubation. Avoid sedation if the patient has a tenuous airway, labored respirations, a distended abdomen, or is vomiting.

Airway Anesthesia

Adequate anesthesia of the airway is extremely important when intubating an awake patient. In order to establish a quiet larynx devoid of reflexes, it is extremely helpful, prior to attempting fiberoptic bronchoscopy, to provide anesthesia of the airway. It is especially effective in improving the success rate of individuals who are less experienced at performing fiberoptic intubation. The regional anesthesia technique employed to anesthetize the larynx is the bilateral superior laryngeal nerve block.

Bilateral blockade of the superior laryngeal nerves will provide effective anesthesia of the supraglottic structures. Prepare a 5 mL syringe attaching a 21 gauge needle and filling it with 1% or 2% lidocaine solution. Identify the hyoid bone by palpation. Slide your finger laterally to identify the superior cornua. Clean and prepare the skin over the superior cornua bilaterally. Insert the needle and advance it until it contacts the superior cornua of the hyoid bone. Contact with the bone can be made easier by extending the patient's head and gently palpating the hyoid bone with the thumb and forefinger of one hand. By applying gentle pressure to one side, the opposite cornua comes into closer contact with the skin and is subsequently easier to contact with the needle. Walk the needle tip inferiorly and off the bone. Advance the needle 3 to 4 mm and through the thyrohyoid membrane (Figures 21-2 & 21-3). Aspirate before injecting the local anesthetic solution to confirm that the needle has not entered the external carotid artery. Inject 2 to 3 mL of lidocaine. Repeat the procedure on the contralateral side. The hyoid bone may not be palpated due to obesity, infections, or masses. In those instances, a superior laryngeal nerve block should not be attempted.17

It remains an unresolved controversy whether to abolish the laryngeal reflexes of a patient considered to have a “full stomach.” In considering this option, one must weigh the risk of abolishing the laryngeal reflexes and rendering the patient potentially vulnerable to gastric aspiration versus leaving the laryngeal reflexes intact and thus causing significant discomfort for the patient. When deliberating whether or not to proceed with a regional block of the larynx in a patient considered to be at risk for gastric aspiration, bear in mind that aspiration of gastric contents occasionally does occur in patients with intact laryngeal reflexes. Instrumentation of the airway in patients with an intact gag reflex can induce vomiting.

The larynx and trachea can be effectively anesthetized by performing a transtracheal injection of 4 mL of lidocaine. Clean and prepare the surface of the skin over the cricothyroid membrane. Prepare a 20 gauge intravenous catheter-over-the-needle on a 5 mL syringe containing 2 to 3 mL of sterile saline. Prepare a second syringe containing lidocaine solution. Insert the catheter-over-the-needle on the syringe containing sterile saline perpendicular through the skin in the midline over the cricothyroid membrane (Figures 21-2 & 21-4). Advance the syringe until the tip of the catheter-over-the-needle is in the trachea. The lumen of the trachea is identified by the loss of resistance. Aspirate air into the syringe, as evidenced by the presence of bubbles in the saline, to confirm that the catheter-over-the-needle is within the trachea. Care should be taken to not advance the catheter-over-the-needle too far and perforate the posterior trachea, as this could result in a pneumomediastinum.18 Securely hold the syringe in place and advance the catheter into the trachea. Securely hold the catheter hub at the skin. Withdraw the needle and syringe. Attach the syringe containing lidocaine to the catheter. Briskly inject 3 to 4 mL of lidocaine through the catheter and into the tracheal lumen. This will cause the patient to cough and disperse the local anesthetic solution throughout the trachea and larynx. Remove the syringe and catheter. The physician performing this block should be wearing a gown, a face mask, and eye protection to prevent exposure to the respiratory secretions when the patient coughs.

The nasal passages, pharynx, and larynx can be anesthetized by several other techniques. If the nasal passageways are the anticipated route for intubation, they should be prepared by shrinking and anesthetizing the nasal mucosa. Cocaine (4%) applied topically (maximum dose 200 mg) has the advantage of providing profound vasoconstriction and anesthesia to the nasal passageways. Similar effects can be provided by applying 0.25% to 1.0% phenylephrine topically to the nasal mucosa, followed by lidocaine 4% via cotton-tipped applicators. These applicators should be gently placed, one at a time, through the middle meatus and back to the inferior turbinate. A nasal passage that accommodates four to five single cotton-tipped applicators will usually allow passage of a 7.0 mm ET tube.9 Also effective in providing profound vasoconstriction of the nasal mucosa is the use of three to four sprays of atomized oxymetazoline (Afrin®) into one or both nares.

Once the antisialagogues have taken effect, the tongue and pharynx can be anesthetized. Place a tongue blade on the patient's tongue and apply topical anesthetic spray (Figure 21-5). Benzocaine or lidocaine spray will usually provide effective anesthesia for the posterior pharynx within 30 seconds. They can be administered from a commercially available spray container or using an atomizer device. There are reports of methemoglobinemia from the overzealous use of benzocaine.19 Its use should be limited to several short sprays.

Alternatively, the patient can swish 2% viscous lidocaine in their mouth for several minutes to provide effective anesthesia. One of the most effective methods of blocking the glossopharyngeal nerve is the “lollypop method.” Create a lollypop by soaking sterile gauze in lidocaine ointment and taping it to a tongue depressor. Place the lidocaine lollypop into the patient's posterior mouth while setting up for the bronchoscopy. Advance the lollypop 1 cm every 2 minutes until the patient's posterior pharynx is completely anesthetized.

As an alternative, nebulized 4% lidocaine administered at least 20 minutes prior to fiberoptic bronchoscopy will usually provide adequate anesthesia of the supraglottic structures. A second alternative is the “spray as you go” technique.20 Once the epiglottis is visualized through the fiberoptic bronchoscope, instill 3 to 4 mL of 2% lidocaine through the working channel of the scope and onto the epiglottis and the surface of the vocal cords. This will induce coughing and temporarily obliterate the view of the laryngeal structures. Allow 2 to 3 minutes for the anesthetic solution to exert its effect before proceeding with fiberoptic bronchoscopy.

After anesthesia is accomplished, place a suction catheter into the oropharynx. This will clear the airway of secretions and blood that can impair the visual image. It will also determine the adequacy of the topical anesthesia for preventing coughing and gagging.

Prepare the fiberoptic bronchoscope. Attach the light source. Check the focus of the image by holding the tip of the insertion cord 1 to 2 cm over a printed page. Adjust the eyepiece until the letters on the image are clear. Note how the image appears as you move toward and away from the page. Briefly use the angulation lever to move the tip of the insertion cord and learn its movements. The most difficult aspect of mastering fiberoptic bronchoscopy is learning to simultaneously angle the tip, rotate the scope, and advance the insertion cord.21 It requires repetition and practice to develop these skills before attempting to intubate a patient.

Before placing of the fiberoptic bronchoscope insertion cord into the ET tube, let the insertion cord hang toward the floor to straighten the inner fiberoptic strands. Identify the plane in which the angulation lever moves the tip. When fiberoptic bronchoscopes are stored coiled in a case, over time the insertion cord may develop a curve. Slightly rotate the fiberscope to the right or left until the angulation of the tip is in the midline plane. Look through the eyepiece and note the position of the directional arrow (▼) on the anterior edge of the image that correlates with the midline.

To prevent fogging, apply an antifog solution to the insertion cord tip or place the tip in warm water before inserting the fiberoptic bronchoscope into the patient's nose. Warming the ET tube with warm water just prior to placing it on the insertion cord will soften the tube and may make the later advancement of the ET tube through the mouth or nares easier.

Apply a thin film of silicone spray or a water-soluble lubricant over the insertion cord to facilitate passage of the ET tube over the flexible cord. Insert the flexible insertion cord completely through the ET tube, taking care not to get any of the lubricant on the lens tip. The insertion tip should exit the distal tip of the ET tube. Do not place the tip of the insertion cord through the Murphy eye of the ET tube. Lubricate the ET tube liberally.

Estimate the distance from the patient's mouth to their glottis. Place the tip of the insertion cord by the patient's ear. Mark the point the insertion cord touches the patient's mouth. The distance from the mouth to the ear is approximately the distance from the mouth to the glottic opening. Add 3 cm to this length if performing the procedure through the nose instead of the mouth.

Hold the fiberoptic bronchoscope in your dominant hand with the angulation lever operated by the thumb and the suction port (if used) covered by the index finger. The other end of the scope should be held between the index finger and the thumb of the nondominant hand. Place the nondominant hand at the patient's nose or mouth. There should be no slack in the fiberoptic bronchoscope between the two hands. The removal of slack from the insertion cord makes more precise rotary movements of the tip possible.

Nasal Intubation

Nasal fiberoptic intubation has several advantages over the oral route. For those less experienced at fiberoptic bronchoscopy, nasal fiberoptic bronchoscopy is usually easier to perform because less angulation of the tip is required. Once inserted, nasal ET tubes are better tolerated by patients and are associated with a lower incidence of accidental extubation. Disadvantages include a higher incidence of bacteremia, middle ear infection, epistaxis, and alar necrosis.9 Nasal intubation, unlike oral intubation, may produce bacteremia; therefore appropriate endocarditis prophylaxis should be provided for those at risk.

Examine the patient to determine which is the most patent nostril. Insert and navigate the insertion cord's tip along the posterior floor of the nares (Figure 21-6). Continue to advance the insertion cord and ET tube as a unit until the ET tube enters the oropharynx (Figure 21-7). This will serve to minimize patient discomfort and the risk of epistaxis early in the procedure. Occasionally, loss of view and maneuverability of the insertion cord tip occur in the oropharyngeal area as the tip encounters the pharyngeal mucosa. Pulling the patient's tongue forward with gauze, using the jaw-thrust maneuver, or simply advancing the insertion cord a few centimeters further will usually bring pharyngeal structures back into view. Continue to advance the tip of the insertion cord until the epiglottis is visualized (Figure 21-7). Maneuver the insertion cord tip with the lever until the glottis comes into view (Figure 21-8). Continue to advance the insertion cord tip through the vocal cords and to a point approximately 3 cm above the carina. Advance the ET tube over the insertion cord and into the trachea to the appropriate depth.

The distance from the nares to the epiglottis is usually about 15 to 17 cm. At this position, the epiglottis should be visible. If the 15 cm mark has been passed, it is very likely that the insertion cord has entered the esophagus. If that is the case, withdraw it to 12 cm and redirect the tip upward with a slight downward movement of the angulation lever.21 This will usually bring the glottic opening into view (Figure 21-8). Occasionally, the epiglottis will obscure the glottic opening. Position the tip of the insertion cord just above the tip of the epiglottis, then advance it a few millimeters posterior to the epiglottis while angulating the tip of the insertion cord slightly anterior by pressing down on the angulation lever. This will bring the glottic opening into view. Simultaneously rotate, angulate, and advance the insertion cord tip toward and past the vocal cords.

An alternative technique would be to advance the ET tube through the nares until the tip is just past the soft palate. This is usually at a depth of 10 to 12 cm. The insertion cord is then passed through the ET tube and through the vocal cords (Figure 21-9). The ET tube is then advanced over the insertion cord into the trachea. This approach has the advantage of bringing the tip of the insertion cord directly midline and toward the epiglottis. However, this can cause some patient discomfort early on in the procedure and may decrease patient cooperation before the insertion cord has entered the trachea. There is the potential for epistaxis, making visualization of laryngeal structures difficult if not impossible. Despite the application of topical anesthesia to the nasal passages, they are difficult to anesthetize completely. For the awake patient, passage of the ET tube is often the most uncomfortable part of the fiberoptic intubation procedure.

Occasionally, some operators have difficulty passing the insertion cord through the vocal cords. There are several causes for this. The tip of the insertion cord may remain angulated and abut against the wall of the trachea. The vocal cords may not be properly anesthetized and may have closed reflexively. Finally, the insertion cord tip may be abutting the arytenoid cartilages or the pyriform sinus. If inadequate anesthesia is the cause, inject 2 mL of either 2% or 4% lidocaine through the working channel of the insertion cord and wait several minutes for it to take effect. Additionally, having the patient inspire deeply will bring the vocal cords into greater opposition. Once the insertion cord tip has passed the vocal cords, bring the tip into neutral position with a light downward motion of the angulation lever.

Once past the vocal cords, advance the insertion cord tip further to bring the bifurcation of the trachea at the carina into view. The trachea can easily be identified anteriorly by the cartilaginous rings and posteriorly by the smooth mucosa of the posterior wall. Advance the ET tube over the insertion cord and into the trachea. The arytenoids or the interarytenoid soft tissues can impede advancement of the ET tube past the vocal cords and into the trachea. If the ET tube advancement is inhibited, withdraw it slightly, rotate it 90° counterclockwise, and reattempt intubation.22 If this maneuver fails, rotate the ET tube so that its bevel faces either posteriorly or to the left and laterally. The inability to advance the ET tube occurs with greater frequency when the diameter of the insertion cord is significantly smaller than that of the ET tube or with oral fiberoptic intubation, due to the greater curve that the ET tube must assume for it to enter the trachea.21 If these maneuvers are unsuccessful, consider substituting a smaller ET tube, a spiral-bound ET tube, or an ET tube with a flexible tip.23

Occasionally, when the trachea is not anesthetized, the patient's subsequent coughing and the associated muscular contractions of the trachealis muscle will collapse the trachea almost completely. This makes it difficult to discern if the insertion cord tip is actually in the trachea or whether to advance the insertion cord or ET tube into the trachea. Wait until the trachealis muscle relaxes and then continue with the procedure.

To prevent endobronchial intubation in adults, which can occur with flexion of the head, confirm that the tip of the ET tube is 3 cm above the carina. This is accomplished by advancing the tip of the insertion cord to the carina with the thumb and forefinger of the nondominant hand. Mark the point on the insertion cord where it exits the ET tube. Withdraw the insertion cord until the distance on the insertion cord between the marked point and the tracheal tube connector is 4 cm. While looking through the eyepiece, advance the ET tube until its tip is visible. This places the tip of the ET tube at approximately 3 cm above the carina.

Occasionally, difficulty is encountered while attempting to pass the ET tube through the nares and nasal cavity. This might be caused by a deviated nasal septum, enlarged turbinates, a nasal spur (which can also tear the ET tube cuff), or nasal polyps. Selection of an ET tube that is too large, inadequate lubrication, or failure to presoften the ET tube can be the cause. Reattempt insertion with a well-lubricated, presoftened ET tube that is 0.5 to 1.0 mm smaller. Alternatively, try placing a 5.0 mm inner diameter (ID) ET tube in a 7.0 mm ID ET tube as discussed below.

Oral Intubation

Begin by noting any loose or broken teeth. After ensuring an adequate sensory block by the absence of a gag reflex, insert an oral intubating airway into the patient's mouth. These devices are placed in the patient's mouth like any other oral airway. They allow for the midline passage of the insertion cord and protect the delicate glass fibers within it from the patient's teeth.

Technical problems exist in attempting oral fiberoptic intubation. As stated earlier, oral fiberoptic intubation requires that the insertion cord tip traverse a more acute angle to reach the vocal cords than it would by the nasal route. If one can safely do so, maximally extending the patient's head at the atlantooccipital joint will bring the oropharyngeal and laryngeal axes more closely in line. This maneuver will reduce the angle that the insertion cord tip must traverse.

In performing an oral fiberoptic intubation, the ET tube becomes hung up on the vocal cords more frequently than with the nasal route. A technique believed to significantly improve the first-time pass rate with oral fiberoptic bronchoscopic intubation is to pass a lubricated 5.0 mm ID ET tube through a 7.0 mm ID ET tube that has been cut to 24 cm. This should leave 2 cm of the 5.0 mm ID ET tube protruding from the distal end. It is believed that the close approximation of the diameters of the 5.0 mm ID ET tube and the fiberoptic bronchoscope allows easier passage of the scope. After the 5.0 mm ID/7.0 mm ID ET tube complex is in place, withdraw the 5.0 mm ID ET tube, leaving the 7.0 mm ID ET tube in the trachea.24

Alternative techniques that have been shown to be as effective as fiberoptic intubation for intubating patients with unstable cervical spines include the Bullard laryngoscope25 and the lighted stylet.26 Blind nasotracheal intubation is as successful as nasal fiberoptic intubation in anesthetized patients with unstable cervical spines.27 The Glidescope, a video laryngoscope, causes less cervical spine movement than direct laryngoscopy.28

A combined technique using oral fiberoptic intubation through a LMA or alternative supraglottic airway can be extremely helpful in instances where there is severe oropharyngeal bleeding or when direct laryngoscopy is not possible.7,29 After confirming successful placement of the LMA, place a self-sealing bronchoscopy elbow over the proximal end of a 6.0 mm ID ET tube. Advance the ET tube tip through the LMA until the LMA grille is encountered (resistance will be felt). Inflate just enough air into the ET tube cuff to provide a seal for positive-pressure ventilation via the ET tube. Advance the insertion cord through the ET tube and into the trachea under direct visualization. Deflate the ET tube cuff. Advance the ET tube over the insertion cord and into the trachea until the ET tube adapter meets the adapter of the LMA. Inflate the ET tube cuff and confirm ventilation through the ET tube.

Because standard ET tubes are not long enough to allow removal of the LMA, longer ET tubes have been developed. If you do not have access to a specially made ET tube, use a nasal Rae tube, which is 6 cm longer than a standard ET tube. If a longer ET tube is not available, another ET tube can be temporarily lengthened by removing the adapter of the 6.0 mm ID ET tube and placing the tip of a 5.0 mm ID ET tube into the lumen of the 6.0 mm ID ET tube. This maneuver lengthens the ET tube enough that the LMA cuff can be deflated and withdrawn, leaving the 6.0 mm ID ET tube correctly placed in the trachea. Additionally, ventilation can be maintained the entire time simply by using a bag-valve device connected to the 5.0 mm ID ET tube adapter. After removing the LMA, remove the 5.0 mm ID ET tube from the 6.0 mm ID ET tube, replace the adapter, and resume ventilation.30 After removing the LMA and establishing ventilation, always confirm by fiberoptic bronchoscopy that the ET tube is correctly positioned.

An alternative to the traditional LMA is the intubating LMA or ILMA. The ILMA is a valuable resource in patients with an anticipated difficult airway.31

The placement of an ET tube should be followed by an assessment to ensure its proper positioning. Please refer to Chapter 12 for a more complete discussion. This includes visual inspection of chest rise and lack of abdominal movement with ventilation, fogging in the ET tube for at least six breaths, auscultation, and end-tidal CO2 monitoring. This should be followed by a chest X-ray to confirm proper positing of the ET tube within the trachea.

The steps of ensuring proper placement of the ET tube and securing the tube are the same as for any patient who has undergone orotracheal intubation (Chapter 11).

Many of the complications associated with fiberoptic intubation are the same as those seen with direct laryngoscopy (Chapter 11). The most severe complication is hypoxemia from a prolonged procedure or delays due to an inexperienced bronchoscopist. Use the suction channel on the bronchoscope to provide oxygenation to the patient during the procedure. Epistaxis can be minimal or significant enough to complicate the procedure. Bleeding can be minimized by using the correct ET tube size and pretreatment with a nasal vasoconstrictor and anesthetic. Failure to intubate can be due to narrow nasal or airway passages, blood or vomitus limiting the fiberoptic field of view, or an inexperienced bronchoscopist.

While the insertion cord is passed through the glottis and into the trachea under direct vision, the ET tube is passed blindly over the insertion cord tip. It is thus possible to cause injury to the arytenoids, resulting in permanent hoarseness, particularly if the ET tube bevel faces anteriorly. However, in a recent randomized control trial, there was no difference in the incidence of vocal cord injury for nasotracheal fiberoptic intubation versus orotracheal intubation.32 The ET tube may also become blocked in the nasal cavity or larynx, resulting in epistaxis, nasal turbinate fracture, and tearing of the ET tube cuff1,9 Sinusitis and otitis media are known complications from nasal intubation.9

Awake intubation under direct visualization in spontaneously breathing patients by either the oral or nasal route is possible with the fiberoptic bronchoscope. Intubation by means of the fiberoptic bronchoscope is an option to consider when direct laryngoscopy is difficult, or impossible. In some instances, awake fiberoptic intubation may be preferable to other emergency intubation techniques that render the patient unconscious and apneic. Fiberoptic intubation is associated with a high success rate when performed by appropriately trained individuals. Training and practice are required to develop and master the necessary skills.33 Appropriate patient selection, preparation, and physician patience are essential for a safe and successful fiberoptic intubation.

The benefits of performing regional anesthesia of the oropharynx, larynx, and trachea prior to fiberoptic intubation are a quiet visual field and improved patient acceptance. Oral fiberoptic intubation may be performed in conjunction with an LMA. It should be emphasized that while in most instances fiberoptic intubation is an extremely safe and effective means of securing the airway, one must be prepared to implement an alternate plan for securing the airway and for providing oxygen to the lungs in the case of failure or sudden deterioration of the patient's condition.