with direct laryngoscopy. If a Cormack Grade 3 (epiglottis only) view persists despite “best look” laryngoscopy, while retaining that view with ongoing laryngoscopy, the tip of the scope/tube assembly is placed, under direct vision, close to, but slightly below and away from the tip of the epiglottis (“tip-to-tip,” Fig. 6–25 A). 39 This position can be retained by resting the tube gen- tly against the upper teeth while the clinician then transfers from direct vision to indirect fiberoptic visualization through the scope eye- piece. Once the glottic opening has been iden- tified, the ETT/scope assembly is advanced through the cords. During this advancement, to conform to the axis of the trachea, the proximal (eyepiece) end of the scope will have to be gradually rotated downward. After the trachea has been accessed, the laryngoscope can be removed. While visualization through the eye- piece is maintained, the left hand can now be used to slide the ETT away from the tube holder housing, and further on down the trachea. Alter- natively, the laryngoscope can be maintained in position while a briefed assistant advances the ETT off the stylet. Once the ETT is placed, the fiberoptic stylet is withdrawn from the tube by forward rotation. After cuff inflation, the posi- tion of the ETT is confirmed with a second objec- tive method. In the very rare situation in which a Cormack Grade 4 (no identifiable structures) view is obtained at direct laryngoscopy, the fiberoptic stylet/tube assembly can be advanced along the laryngoscope blade, using the blade as a guide until the epiglottis is visualized through the eyepiece. Appropriate maneuvers are then per- formed to advance the tube beneath the epiglot- tis and through the cords. To attain and maintain skills with the device, some clinicians have espoused the use of optical stylets with every intubation attempt 39 : if the cords are easily visualized with direct laryn- goscopy, the tube can be advanced in regular fashion with the fiberoptic stylet acting as a ALTERNATIVE INTUBATION TECHNIQUES 113 A B Figure 6–25. The Levitan FPS is placed under direct vision with aid of a laryngoscope. Once the scope’s distal tip is positioned under the tip of the epiglottis (A), visualization of the glottic inlet is sought through the eyepiece and the instrument then advanced through the cords (B). standard malleable stylet, but if a Grade 3 or worse view is obtained, the fiberoptic stylet/tube assembly can be used to aid indirect visualization of, and passage through the glottic opening, as described above. Stand-Alone Fiberoptic Stylet Use Fiberoptic stylets can also be used on their own. With such stand-alone use, the distal curvature of semimalleable versions should be increased for the midline approach, as mentioned above. The scope should be antifogged and the patient’s oropharynx suctioned. While performing a jaw lift (Fig. 6–26) with the nondominant hand, the scope is inserted either in the midline over the tongue or via a more lateral approach, over the molars. A midline insertion will involve the clin- ician’s significantly bending over the patient to access the scope’s eyepiece (Figure 6–27). Anatomic landmarks are then sought as the scope is advanced: uvula, base of tongue, then epiglottis and cords with a midline approach, or epiglottis then cords with an over-the-molar approach. The tube/stylet assembly can be gen- tly advanced through the cords, at which point the tube is further advanced off the stylet down the trachea. Awake Intubation Using a Fiberoptic Stylet Fiberoptic stylets may be used in the sitting, cooperative patient for an awake tracheal intu- bation, using a face-to-face approach. 40 Follow- ing appropriate application of topical airway anesthesia (Chap. 8), gentle tongue traction is applied by an assistant. The stylet with pre- loaded ETT is guided through the mouth in the midline, and advanced behind the tongue, until its tip disappears. At this point, the long axis of the scope will be parallel to the floor. The clin- ician then looks through the proximal eye- piece and seeks the anatomic landmark of the epiglottis, leading to the glottic opening. In the stand-alone manner described earlier, the distal tip of the tube/ stylet assembly is navigated to and through the glottic opening into the proximal trachea. The tube is then further advanced off the stylet, and the scope is removed by forward rotation of the proximal end back toward the patient’s chest. 114 CHAPTER 6 Figure 6–26. The Shikani SOS is inserted from the side of the mouth, advanced over the molars, and then rotated upright. Fiberoptic Stylet Troubleshooting • Getting “lost.” It should be appreciated that navigation of any fiberoptic instrument through the airway is contingent on advancing the device through a patent airway lumen. While an awake patient will maintain air- way patency, an obtunded or relaxed patient (as during an RSI) must have a patent lumen created by a laryngoscope blade, with a jaw thrust, or gentle tongue traction during the procedure. The stylet should not be blindly advanced if no lumen is appreciable. In the event that orientation is lost (often manifested by “pink-out”), the scope should be partially withdrawn until an anatomic landmark (e.g., uvula or epiglottis) can be reidentified and at that point, advancement can resume. • Fogging. If fogging is encountered once the stylet is already in use, briefly holding the stylet tip against the patient’s buccal mucosa will help clear the view. • Blood and secretions. It should be under- stood that there is no integrated suction mechanism with most of these instruments. Blood, secretions, and vomitus will make use of an indirect fiberoptic system difficult. For this reason, fiberoptic scope use should always be preceded by suctioning of the oropharynx. Also, as blood and secretions will pool posteriorly, the scope should be kept anterior in the airway during navigation toward the laryngeal inlet. The difficulty which blood and secretions can cause with the use of a fiberoptic scope points to the need for its early use, before the airway has been trauma- tized by multiple intubation attempts! Fiberoptic Stylet Effectiveness R OUTINE AND D IFFICULT A IRWAY M ANAGEMENT Shikani studied 120 patients, 74 of them chil- dren, including 7 patients with Cormack Grade 3 or 4 views. All patients in the series, including 5 awake patients, were successfully intubated with the scope, 88% on the first attempt. Five of ALTERNATIVE INTUBATION TECHNIQUES 115 Figure 6–27. While maintaining a jaw lift, the user looks through the proximal eyepiece of the SOS in an attempt to view the glottic structures. the seven Grade 3 and 4 patients required con- comitant direct laryngoscopy. 41 Bein et al. 42 studied use of the Bonfils fiberoptic stylet in 80 patients with predictors of difficult DL, com- paring it to LMA Fastrach use. Thirty-nine of 40 patients randomized to the Bonfils were intu- bated on the first attempt, in contrast to a 70% first attempt success rate for the Fastrach. A second study looked at Bonfils use after failed DL. In 25 patients recruited following two failed DL attempts, 88% were successfully intubated with the Bonfils at the first attempt, and all but one (96%) by the second attempt. 43 Evans and coworkers compared the SOS to the bougie in a manikin study with a fixed Grade 3 view. In this model, the SOS resulted in faster intubation times than the bougie, with significantly fewer esophageal intubations. 44 A second manikin study, this one comparing the bougie with the Levitan FPS scope, showed the fiberoptic scope to be significantly more successful than the bougie in managing a simulated Grade 3B view, 45 but did not demonstrate a significant difference in intubation success in a simulated Grade 3A view. The latter finding has been con- firmed in a subsequent human study using sim- ulated Grade 3 views in elective surgical patients, in which the bougie was found to be equally effective to the Levitan FPS scope. 46 Finally, a recently published case series has documented successful use of the Bonfils in six patients in whom difficulty had been encoun- tered in the prehsopital setting. 47 S KILLS A CQUISITION These devices are relatively easy to learn on manikins, as dealing with “pink out” is rarely an issue, and the upper airway lumen is widely patent. Skill transfer to the live setting is likely to be more challenging. One study looking at the learning curve of the Bonfils stylet suggested that proficiency was attained after 20–25 intu- bations. 48 Other studies with fiberoptic stylets have reported that most of the failed intubations occurred within the first 10 uses of the device. 41,49 The fact that the fiberoptic stylet can be used as an adjunct to the core skill of direct laryngoscopy may contribute to an easier learn- ing curve. C- SPINE P RECAUTIONS In a study comparing intubation using Macin- tosh blade direct laryngoscopy with the Bon- fils stylet, Bullard laryngoscope, or LMA Fas- trach, each of the Bonfils, Bullard, and Fastrach resulted in significantly less C-spine movement than Macintosh blade-facilitated intubation, although Bonfils and Fastrach intubations took significantly longer than those using the Mac- intosh and Bullard blades. 50 A second study, also using fluoroscopy to assess C-spine movement, found that Bonfils intubations caused significantly less extension of the upper C-spine than Macintosh laryngoscope- aided intubations. 51 ᭤ VIDEOLARYNGOSCOPY Displaying the view obtained at laryngoscopy on a video monitor has a number of advantages: • Display of an enlarged, panoramic viewing field. 52 • In those devices using integrated video tech- nology on rigid blades, as the camera is located toward the distal end of the blade, an improved view may be obtained com- pared to direct laryngoscopy. • Aids in teaching. • Assisting personnel can see the results of their manipulations, for example, external laryn- geal manipulation (ELM). • The procedure can be digitally stored for documentation, teaching, or research pur- poses. • The user is at a greater distance away from the patient’s face, decreasing the chance of exposure to potentially infectious respiratory secretions and spray. Video technology can be applied in two ways: (a) using an adapter, a video camera 116 CHAPTER 6 can be attached to the eyepiece of conven- tional fiberoptic devices such as the Shikani, Levitan FPS, Bullard, or flexible fiberoptic bronchoscopes, or (b) integrated video is used as the primary viewing mechanism (e.g., the Glidescope). The Glidescope Commercially introduced in 2002, the Glidescope ® (GVL ® ) is a video laryngoscope which has become increasingly available in and out of the OR, as an alternative intubation device. The one-piece blade and handle is made of a durable medical-grade plastic. The blade has a vertical profile of 14.5 mm, a 60° bend midblade, and distally, houses a minia- ture video camera and light-emitting diode (LED) light source. The image obtained by the camera is projected by cable to a liquid-crystal display (LCD) color monitor. A heating element covering the camera provides effective antifog- g device has been turned on for 10–30 seconds. The reusable blades are avail- able in large (patients 30 kg and up), midsize (10 kg and up), and small (1.5 kg and up) sizes, and can be sterilized. More recently introduced versions of the GVL include the GVL Ranger, which is a compact, battery- based unit, and the GVL Cobalt, which fea- tures a reusable internal video baton for placement within large or small-sized dispos- able blades. The GVL is inserted orally in the midline. As the scope is advanced, the uvula, base of tongue and then epiglottis will be visualized on the screen, helping to retain orientation to the mid- line. Although the blade is designed to be placed above the epiglottis in the vallecula, in contrast to direct laryngoscopy, the blade tip need not be advanced completely into the glossoepiglot- tic fold: a more proximal tip location allows a wider field of view and more room for ETT manipulation (Fig. 6–28). A styletted ETT is inserted immediately on the right side of the blade and is navigated to the laryngeal inlet under indirect visualization on the LCD screen. An accompanying nonmalleable, reusable stylet has been made available by the manufacturer to facilitate tube passage (Fig. 6–29), or a regular malleable stylet can be used, angled at about 60° ALTERNATIVE INTUBATION TECHNIQUES 117 Figure 6–28. Glidescope video system use. just proximal to the cuff. 53,54 Once the tip of the ETT has been passed through the cords, the stylet should be withdrawn 2 inches (4 cm), whereupon the tube can be further advanced off the stylet down the trachea. 55 There is a growing literature on the use of this device, primarily in the OR setting. It is clear that the GVL does provide good and often superior views of the glottic opening when compared with conventional laryngoscopy, including a high rate of conversion of Cormack Grade 3 (epiglottis only) views to Grade 2 or better. 53,54,56,57 However, somewhat longer intu- bation times have been reported with the GVL compared to DL, even in the setting of Grade 1 views by DL, possibly related to user inexperi- ence with tube delivery. 54,57–59 The GVL has been successfully used for awake intubations in adults. 60 C-spine motion during GVL use has been compared, using flu- oroscopy, to that incurred with Macintosh blade DL. Motion with GVL use was less than that incurred by Macintosh laryngoscopy at only one (C2-5) of 4 neck levels studied. 37 There are some recent reports of upper airway trauma during GVL use. 55,61,62 This sug- gests that especially in the patient with a smaller oral cavity, awareness of the ETT tip location must be maintained as it is advanced, ideally by direct vision of the ETT until it has passed the palatoglossal arch. Thereafter, the clinician’s vision can be transferred to the screen and indi- rect, videoscopic ETT navigation can occur to and through the cords. Alternatively, some clin- icians prefer to place the ETT into the patient’s pharynx prior to insertion of the GVL blade. 55 The Berci-Kaplan DCI Video Laryngoscope The Berci-Kaplan DCI video laryngoscope (Karl Storz Endoscopy, Culver City, CA) is a hybrid of fiberoptic and video technology: an image-light bundle in a laryngoscope blade delivers an image to a video camera located in the handle of what otherwise looks like a regular direct laryngoscope. A cable attaches the device to a cart-based camera-control unit, and also delivers light from the remote light source. The image obtained is displayed on a video monitor. Macintosh # 3, Mac 4, adult- and pediatric-sized Miller, and Dörges blades are available for use with the system. This system offers the advan- tage of being a familiar intubation technique and may deliver a superior view of the laryn- geal inlet compared to that obtained with direct laryngoscopy. 52 The LMA CTrach The LMA CTrach (LMA North America Inc, San Diego CA) is a version of the previously discussed LMA Fastrach TM which adds video-guidance capability (Fig. 6–30). Looking otherwise like the LMA Fastrach TM , the CTrach mask contains fiberoptic bundles for light and image transmis- sion, emerging at the distal end of the airway barrel. In addition, a removable viewing moni- tor (the CTrach Viewer) attaches to the CTrach handle by way of a magnetic latch connector. The battery-powered viewer is rechargeable, and provides controls for focusing and image adjustment. For use, the CTrach Viewer is detached, and the mask is deflated, lubricated posteriorly, and antifogged with application of an appropriate solution to the fiberoptic lenses. Mask insertion is identical to the technique used 118 CHAPTER 6 Figure 6–29. Dedicated rigid stylet (below) for use with the Glidescope. for the LMA Fastrach TM , with the head and neck in a neutral position. Once seated, the mask is inflated and the patient ventilated. The CTrach viewer is then turned on and attached to the magnetic latch connector on the mask, while firmly holding the CTrach handle. The mask is then manipulated as needed to attain a clear image of the glottic opening. For intubation, while lifting vertically on the CTrach handle (i.e., the Chandy maneuver, as described for LMA Fastrach TM intubation), the dedicated sili- cone-based ETT is advanced through the cords under indirect vision. The ETT cuff is inflated, and tube position confirmed. The viewer is then detached, whereupon the CTrach mask can be removed in identical fashion to the Fastrach, leaving the ETT in situ. At the time of writing, early published clini- cal experience with the CTrach suggests a high rate of successful mask insertion and patient ventilation, as with the LMA-Fastrach TM . 63,64 Although a view of the cords is not always easily attained, even after manipulation. 63,64 a num- ber of corrective maneuvers will help to attain or improve the view of the laryngeal inlet. 65–68 As with the LMA Fastrach TM , the “up-down” (withdrawing the inflated mask 6 cm, then readvancing it) will often help release a down- folded epiglottis. 65,66,68 If only the posterior cartilages are visualized, withdrawing the mask 1-cm and lifting will improve the view. 65 The need for medial-lateral corrections of the mask can also be visualized on the screen. 66 Once a good view is attained, intubation usu- ally succeeds, and even with poor visualiza- tion, successful intubation follows in some cases. 63–65 In published series, CTrach use has permitted visualization of the larynx and suc- cessful intubation in most patients presenting Grade 3 or worse views at direct laryn- goscopy. 63, 64, 68 Other case reports and series have detailed successful CTrach intubation in very difficult situations, 68 even when the LMA Fastrach TM had failed. 69 ALTERNATIVE INTUBATION TECHNIQUES 119 Figure 6–30. The LMA CTrach. (With permission from LMA North America). The McGrath Video Laryngoscope The McGrath video laryngoscope Series 5 (LMA North America, San Diego, CA) is an additional example of a video-based device (Fig. 6–31). The scope features a rubberized handle with an attached 1.7-inch video screen. The screen tilts and rotates on the handle to optimize the view- ing angle for the clinician. The blade is some- what adjustable in length for different patients, and is designed for use with a single-use disposable plastic sleeve. The entire unit is portable, and operates using a single AA bat- tery. As with the Glidescope, once the laryn- geal inlet has been indirectly visualized, the clinician guides a styletted tube toward and through the cords. Early experience suggests easy McGrath blade insertion and a good view of the larynx, even in patients with predictors of difficult direct laryngoscopy. 70 As with the Glidescope, tube passage to and through the larynx can be challenging until the learning curve is ascended. 70 A similar intubation tech- nique to that described above for the Glidescope should be successful. ᭤ OTHER RIGID AND FLEXIBLE FIBEROPTIC AND OPTICAL INSTRUMENTS Rigid Fiberoptic Devices Other rigid fiberoptic scopes exist. Some have attained a small but loyal following, mainly in the OR setting, however due to expense or unfa- vorable learning curves, as a group, they are rarely used in out-of-OR settings. One such is the Bullard laryngoscope (Fig. 6–32), an L-shaped rigid fiberoptic laryngoscope. The Bullard has a blade enabling good tongue con- trol, and a choice of two dedicated attached stylets to facilitate tube passage. With or without the attached stylet, tube passage can be difficult, however, and this fact has limited its popular- ity over the years. The Bullard has been shown to result in less cervical spine movement than that caused by Macintosh or Miller laryn- goscopy, 71 although the clinical significance of this finding is unclear. Similar J- or L-shaped rigid fiberoptic scopes include the UpsherScope Ultra and the WuScope System. 120 CHAPTER 6 Figure 6–31. The McGrath Video laryngo- scope Series 5. ALTERNATIVE INTUBATION TECHNIQUES 121 Figure 6–32. Bullard laryngoscope. Rigid Optical Device: The Airtraq The Airtraq optical laryngoscope (King Sys- tems Corp., Noblesville, IN) is a single-use, L- shaped device which uses a series of mirrors to deliver an image of the laryngeal inlet to a prox- imal eyepiece (Fig. 6–33). Insertion of the device begins with the handle parallel to the patient’s chest. As the blade is advanced into the oropharynx, it is rotated down and around the tongue, with the clinician looking through the eyepiece to visualize airway structures. The blade tip is placed into the vallecula and the cords centered in the viewfinder, whereupon the pre- loaded ETT is advanced into the trachea via a built-in tube delivery channel. The ETT is then separated from the delivery channel to the side, and while holding the tube in place, the scope is rotated back out of the patient. At the time of writing, the Airtraq was available in two sizes: “Regular,” accommodating tube sizes 7.0–8.5 mm ID, and “Small Adult”, appropriate for use with ETTs of size 6.0–7.5 mm ID. Early manikin studies comparing the Airtraq to Macintosh direct laryngoscopy have shown a favorable learning curve for novice 72 and inex- perienced 73 clinicians. With “difficult airway” simulator features activated, tracheal intubation has required less time and fewer attempts by experienced clinicians using the Airtraq, com- pared to Macintosh laryngoscopy. 74 In elective surgical patients with no predictors of difficult laryngoscopy, performance of the Airtraq was comparable to Macintosh DL. 75 With known dif- ficult laryngoscopy, however, the Airtraq was successful in providing a view and enabling intubation in a series of 8 elective surgical patients in whom a Cormack Lehane Grade 4 laryngoscopy had been encountered. 76 Flexible Fiberoptic and Video Devices Flexible fiberoptic or video-based broncho- scopes have been the mainstay of difficult airway management in the OR. Most awake intubations are performed with flexible fiberop- tic bronchoscopes in this setting, although many of the other techniques and devices described in this and other chapters (including direct laryngoscopy) can also be used on the awake patient. Unfortunately, flexible fiberoptic- or videobronchoscopes are expensive to attain and maintain, and skills acquisition is also an issue, resulting in these instruments rarely being used for intubation by non-anesthesia clini- cians. Having said this, flexible fiberoptic scopes can be used in various capacities, including nasopharyngoscopic upper airway assess- ment, or flexible fiberoptic guided intubation through the LMA Fastrach TM or AirQ extra- glottic devices. With time, flexible fiberoptic intubation may become a more commonly used technique for awake intubation of the difficult airway patient in out-of-OR locations, by non-anesthesia personnel. For more details on the technique, the reader is referred to reviews 77 in other publications. ᭤ PEDIATRIC ALTERNATIVE INTUBATION OPTIONS For those departments or environments having care of pediatric patients in their mandate, when choosing equipment, consideration should be directed toward whether it is avail- able in pediatric sizes. It must be emphasized that most children without congenital dys- morphisms can be successfully intubated with direct laryngoscopy and can almost always be easily bag-mask ventilated. How- ever, in the event that difficulty is encoun- tered with direct laryngoscopy, the follow- ing is a summary of the availability of pediatric versions of the devices discussed above: • LMA Fastrach TM . At the time of writing, the smallest reusable or disposable Fastrach avail- able is the adult #3, appropriate for use in patients weighing 30–50 kg. 122 CHAPTER 6 Figure 6–33. Airtraq optical laryngoscope (single-use). [...]... Ovassapian A Use of the intubating LMA-Fastrach in 254 patients with difficult-to-manage airways Anesthesiology 2001; 95( 5):11 75 1181 14 Shung J, Avidan MS, Ing R, Klein DC, Pott L Awake intubation of the difficult airway with the intubating laryngeal mask airway Anaesthesia 1998 ;53 (7):6 45 649 15 Frappier J, Guenoun T, Journois D, et al Airway management using the intubating laryngeal mask airway for the morbidly... 21/2 3 1 1 .5 2 2 .5 3 Neonates/infants up to 5 kg Infants 5 10 kg Infants/children 10–20 kg Children 20–30 kg Children 30 50 kg Infants 5 10 kg Children 10–20 kg Children 20–30 kg Children 30 50 kg Children 30 50 kg Children 10–20 kg Children 20 50 kg . A. Use of the intubating LMA-Fastrach in 254 patients with difficult-to-manage airways. Anesthesiology. 2001; 95( 5):11 75 1181. 14. Shung J, Avidan MS, Ing R, Klein DC, Pott L. Awake intubation of. difficult airway with the intubating laryngeal mask airway. Anaesthesia. 1998 ;53 (7):6 45 649. 15. Frappier J, Guenoun T, Journois D, et al. Airway management using the intubating laryngeal mask airway. latex-free and consist of a large-bore airway tube with proximal stan- dard 1 5- mm connector, and a bowl-shaped dis- tal cuff which is inflated via a valve on an infla- tion line. With the opening