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 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 technique of placing the fiberoptic bronchoscope insertion cord into the nares. Note the position of the ET tube over the proximal portion of the insertion cord.
Visualization of the epiglottis (at the top of the photo) through the flexible fiberoptic bronchoscope.
Visualization of the glottis through the flexible fiberoptic bronchoscope just prior to its insertion cord passing through the vocal cords.
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.
The ET tube has been inserted into the nares and advanced into the oropharynx. The insertion cord is advanced through the ET tube.
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.
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