++
Rigid video laryngoscopes (VLs) are devices that have a small video camera and light source incorporated into a rigid metal or plastic blade. The real-time image from the camera is displayed on a video screen and can be recorded for later viewing, teaching, or research. VLs are designed to improve the view of the larynx to ease tracheal intubation. Because they do not rely on a straight line of sight, the user can "see around the corner" of the natural airway, obviating the need for alignment of the oral, pharyngeal, and laryngeal axes.87 This facilitates visualization of the glottic opening with minimal force against the airway structures.
++
A viewing angle of up to 80 degrees is possible compared with the 15-degree viewing angle of direct laryngoscopy.88 This extended viewing angle may be helpful in difficult intubations secondary to limited neck mobility, cervical spine immobilization, retrognathia, or reduced thyromental or interincisor distance.89 In addition to facilitating laryngoscopy and orotracheal intubation, VLs can be used for awake, nasotracheal or fiberoptic intubation, confirmation of proper tracheal tube placement, and placement of a transesophageal echocardiography probe.
++
Views of the glottis are generally better with VLs than with direct laryngoscopy. A better view, however, does not always translate into an easy tracheal intubation. Tracheal intubation is difficult when the glottic view is obstructed by secretions, blood, gastric contents, fogging of the lens, or most commonly, the inability to advance the ETT through the larynx or into the trachea. Difficult ETT manipulation under indirect visualization has been shown to account for increased time to intubation, oxygen desaturation, hemodynamic instability, and the potential for airway trauma.90
++
Since 2001, several VLs have been introduced, which can be divided into 2 groups: non–channel-guided VLs and channel-guided VLs.
+++
Non–Channel-Guided Videolaryngoscopes
++
Non–channel-guided VLs include the GlideScope (Verathon Inc, Bothell, WA), the McGrath Series 5 (Aircraft Medical, Edinburgh, UK), and the Storz C-MAC (Karl Storz, Tuttlingen, Germany). These devices are similar to a Macintosh blade in shape and in use; a view of the glottis is obtained before the introduction of the ETT (Figs. 36-21, 36-22, and 36-23).
++
++
++
++
To perform videolaryngoscopy with a non–channel-guided VL, the blade is inserted into the midline of the oropharynx under direct visualization until the tip of the blade is past the posterior tongue. Performing this under direct vision helps prevent damage to the soft palate or palatoglossal arch.91 When the device is past the tongue, attention is directed to the video screen and the blade is advanced midline until a Cormack-Lehane grade II view is achieved. A grade II glottic view is acceptable because if additional anterior force is applied to the blade, the larynx may be directed further anterior, impeding passage of the ETT into the trachea.91 After the glottis is visualized, the operator's attention is directed away from the video screen to the oropharynx, and the ETT is inserted under direct visualization until its tip is past the posterior tongue, paying careful attention not to injure the soft palate or palatoglossal arch with the ETT. The operator then looks at the video monitor while directing the tip of the ETT into the vestibule of the larynx and then advancing the tube over the stylet, through the vocal cords, and into the trachea.
++
As the ETT passes over the stylet, its trajectory becomes less parallel to the axis of the trachea, occasionally causing the tip of the ETT to impact the anterior tracheal wall. This problem can be addressed in 3 ways. The ETT may be loaded on the stylet with "reverse camber" orienting the natural curve of the tube posteriorly. This allows the tube to pass off the stylet in direction parallel to the axis of the trachea. The operator may also spin or "corkscrew" the ETT as it passes off the stylet to minimize the impact of the ETT with the anterior tracheal wall. Finally, an ETT with no curve such as the Parker Tube (Parker Medical, Highlands Ranch, CO) or the Verathon Glideright tube may be used.
++
The GlideScope was introduced in 2001. The blade, available in 3 sizes, has a steep 60-degree curvature, which improves the view of the glottis because the tongue is not displaced anteriorly. (Fig. 36-21) The maximum thickness of the largest blade is less than 15 mm, allowing use in a patient with an interincisor distance of 2 cm.91 The camera lens, heated to prevent fogging, requires no other preparation before use.
++
Tracheal intubation with the GlideScope generally requires use of a preloaded, specially curved stylet.92 The GlideRite Rigid Stylet, curved to follow the 60-degree angulation of the blade, or a standard stylet can be used. If a standard stylet is used, the ETT and stylet should be bent to approximate the angle of the convex side of the GlideScope blade to facilitate advancement of the ETT into the trachea.91
++
The primary advantage of the GlideScope over direct laryngoscopy is an equal or improved glottic view in both normal and difficult airways. In patients with anticipated difficult airways, the GlideScope increased the percentage of Cormack-Lehane grade I to II views compared with views with direct laryngoscopy.89,93
++
Because the improved views are attained without aligning the oral, pharyngeal, and laryngeal axes, less cervical manipulation is required. Cervical spine motion was reduced 50% during GlideScope intubation compared with cervical spine motion during direct laryngoscopy.94 The GlideScope can accommodate any size and type of ETT, and ratings for time to intubation and "ease of use" were better with both experienced and inexperienced users in simulated difficult airways.95
++
Although the GlideScope may offer improved glottic views, advancement of the ETT into the trachea still can be difficult. Difficult advancement may prolong intubation times; increase the number of intubation attempts; and lead to failed intubation, oxygen desaturation, hemodynamic instability, and trauma to the soft palate and palatoglossal arch.87,89,92,93,96,97 If difficult intubation is encountered, the blade can be withdrawn 2 to 3 cm and the stylet 3 to 5 cm to lessen the anterior displacement of the larynx. Withdrawal improves the alignment of the axes of the larynx, trachea, and ETT.91,92
++
The McGrath Series 5 (Aircraft Medical, Edinburgh, UK) was introduced in January 2006 (Fig. 36-22). This VL has a reusable CameraStick handle, which incorporates a small camera and light source. A sterile, transparent, single-use blade with a 60-degree angle covers the CameraStick. The camera image is displayed on a screen that tilts for viewing and is located on the handle. Within the handle is a single AA battery, which provides 60 minutes of operating time.
++
Similar to other VLs, the McGrath Series 5 has been shown to improve glottic views in both routine and difficult airways. Compared with direct laryngoscopy with a Macintosh blade, the McGrath improved Cormack-Lehane views by 2 to 3 grades in more than 90% of patients.90 Similar to the GlideScope, the McGrath Series 5 requires a stylet to facilitate intubation. This requirement may pose difficulties with ETT manipulation, leading to multiple intubation attempts, airway trauma, or failed tracheal intubation. As with the GlideScope, the blade and stylet can be withdrawn slightly, and the handle can be rotated caudally to advance the tube through the vocal cords without abutting the anterior tracheal wall.
++
The C-MAC was introduced in 2003. It has a Macintosh-shaped steel blade with a slim 14-mm profile, can be equipped with a suction catheter, and is available in 3 sizes98 (Fig. 36-23). The C-MAC incorporates a digital video camera and a high-power light-emitting diode located laterally in the distal third of the blade. The image from the camera is displayed on a lightweight, portable, color LCD monitor and can be recorded as a single image or a video stream. The monitor houses a rechargeable lithium ion battery for approximately 2 working hours.98
++
The C-MAC differs from other VLs because it can be used as a direct or indirect laryngoscope. As with a Macintosh blade, advancement of the ETT into the trachea does not routinely require a stylet. The C-MAC improved glottic views and facilitated successful tracheal intubation when attempts with direct laryngoscopy failed.98 Compared with the GlideScope, Airtraq, and Macintosh blade in airway simulations, the C-MAC had the highest ratings for ease of use, provided the best glottic view (along with the Airtraq), and needed the shortest time for intubation.87 The Storz D-blade has a unique shape and works with the C-MAC platform. More curved than other C-MAC blades, the D-blade lets the user "see around the corner" of the tongue. Although this blade improves visualization of the larynx in some settings, it may require intubation techniques similar to those for the Glidescope system.
+++
Channel-Guided Videolaryngoscopes
++
The channel-guided VLs include the Pentax AWS-100 (Pentax Medical Company, Montvale NJ) and the Airtraq (Prodol Meditec, SA, Guecho Vizcaya, Spain) (Figs. 36-24 and 36-25). These VLs have highly curved blades with a channel to hold the ETT during laryngoscopy and guide it during intubation.
++
++
++
With channel-guided VLs, view of the glottis is indirect, obviating the need for alignment of the oral, pharyngeal, and laryngeal axes.87 A well-lubricated ETT is positioned in the tube channel of the blade, with only the tip visible on the LCD screen. The blade is inserted midline into the oropharynx under direct visualization until its tip is past the posterior tongue, preventing damage to the soft palate and palatoglossal arch. When it is past the tongue, the blade is kept midline and attention is turned to the video display. The Pentax AWS PBlade is inserted under the epiglottis and used like a Miller blade. The Airtraq blade may be placed in either the vallecula (Macintosh style) or under the epiglottis (Miller style). After the glottic opening is observed on the monitor, the device is lifted up, and the ETT is advanced into the trachea. If the ETT abuts the epiglottis or arytenoids, the manufacturers recommend rotating the devices back (ie, out of the mouth) and lifting them anteriorly before readvancing the ETT.
++
The Pentax AWS, a battery-operated, channel-guided VL, was introduced in Japan in 2006. It has a handle with a 2.4-in LDC screen; a 12-cm image tube with a camera and light source; and a disposable rigid blade, the PBlade99 (Fig. 36-24).
++
The tube channel can accommodate an ETT with a 6.0 to 8.5 mm ID. The PBlade comes in only 1 size (18 mm thick) and is larger than the blades of other VLs. It is used only if a patient's mouth opening is larger than 2.5 cm. A distinct feature of the Pentax AWS is a target symbol on the monitor that highlights the intended path of the ETT as it advances from the tube channel. This target mark is aligned with the glottic opening, and the ETT is advanced into the trachea. Because the monitor is attached to the handle and the ETT is preloaded and directed toward the target symbol, the operator does not have to look away while advancing the ETT, which may lower risk for airway trauma.
++
Studies comparing the AWS with direct laryngoscopy show improved glottic visualization and tracheal intubation and less cervical spine motion in routine and difficult airways with the AWS.94,99 Novice operators using the AWS have a high success rate visualizing the larynx. Tracheal intubation was faster and more likely to be successful on the first attempt for novices using the AWS compared with Macintosh direct laryngoscopy.95
++
The Pentax AWS has been used for awake intubation of the trachea. When the glottic view is obtained on the monitor, lidocaine can be injected through the suction channel to anesthetize the airway, and the ETT can be advanced through the tube channel.100
++
As with other VLs, advancement of the ETT into the trachea may be problematic after the glottic view is obtained on the monitor. The ETT may impinge on the epiglottis or arytenoids, in which case a gum elastic bougie is used. The bougie is inserted through the ETT and directed into the glottic opening. When the bougie is in the trachea, the ETT can be advanced over the bougie through the glottis. The bougie also has proved useful when the PBlade is too short to reach the epiglottis or larynx.101
++
The Airtraq is a single-use, channel-guided VL with a viewfinder and disposable blade (Fig. 36-25). The blade has 2 separate tracks, the optical channel and the tube channel. The optical channel contains a series of lenses, a prism, and a viewfinder at the proximal portion of the device. There is an optional video camera, which can be attached to the viewfinder to transmit the image to a monitor, and a rechargeable battery-operated LED at the tip of the blade for illumination up to 90 minutes. The antifog system for the lenses is activated by the LED for 30 to 60 seconds before use to warm the lens. The Airtraq comes in 4 sizes for orotracheal intubation with ETTs from 2.5 to 8.5 mm ID. The Airtraq has special blades for nasotracheal and endobronchial intubation and can accommodate double-lumen tubes from 35 to 41 Fr.
++
The Airtraq blade containing the ETT is inserted midline into the oropharynx while the airway structures are visualized through the viewfinder. The blade tip is directed either into the vallecula (Macintosh style) or to the epiglottis (Miller style). The blade is manipulated in all planes until the vocal cords are in the center of the viewfinder at which time the ETT is advanced through the channel into the trachea. If advancement is difficult, the Airtraq is rotated slightly out of the airway and lifted anteriorly. If these maneuvers fail, the operator can try reducing cervical extension.102 When ETT placement in the trachea is confirmed, the Airtraq blade is tilted laterally away from the ETT and removed.
++
The Airtraq has advantages in routine and difficult laryngoscopy. Compared with direct laryngoscopy, it improves glottic views; facilitates first-attempt tracheal intubations; and lowers the incidence of oxygen desaturation, airway trauma, and hemodynamic instability. The Airtraq is easy to master for both novice and experienced anesthetists. It reduces cervical spine motion but causes less dental compression than other VLs and the Macintosh blade.103,104
++
Hemodynamic stability with use of the Airtraq versus the Macintosh blade may be attributed to less force needed to elevate the mandible during laryngoscopy. Constant visualization of the glottis and alignment of the preloaded ETT with the trachea cause less trauma to the vocal cords.104
++
The introduction of VL has significantly changed difficult and routine airway management. All of the commercially available devices improve glottic visualization even in the hands of novice operators. The user should understand the fundamental differences between direct and VL. Direct laryngoscopy requires a straight line of sight from the operator's eye to the vocal cords. The line of sight may be difficult to establish, but once the vocal cords are seen, tracheal intubation is usually easily achieved. On the other hand, VLs make viewing the larynx easy even when the airway maintains its normal, highly curved architecture. Thus, viewing the cords is often easier with a VL than with direct laryngoscopy, but passage of the tube through the cords may be harder. As with any tool, its proper use and unique strengths and weaknesses must be understood.
+++
Fiberoptic Intubation
++
A flexible fiberoptic bronchoscope (ie, a fiberscope) (Fig. 36-26) can be used for routine or challenging intubations in patients with airway tumors, infections, or cervical spine fractures or fixation (Fig. 36-27).3,105-110 Indications for fiberoptic tracheal intubation are summarized in Box 36-15.
++
++
++
++
Because normal airway architecture is maintained, fiberoptic intubation is easier in conscious patients: The tongue and epiglottis are less likely to obscure the vocal cords, and patients can assist by phonating or protruding the tongue. Haste is unnecessary in a breathing patient. The patient with a history of failed intubation, upper airway abnormality, or expected difficult intubation may benefit from an awake fiberoptic intubation. Proper topical anesthesia and sedation ease the task. With experience, topical anesthesia of the larynx and trachea may be achieved by spraying local anesthetic through the working channel of the fiberscope. Inhalation of nebulized lidocaine may minimize coughing.
+++
Oral Fiberoptic Approach
++
After applying topical anesthetic to the tongue and oropharynx, a special oropharyngeal airway is inserted to prevent biting on the fiberscope, to keep the instrument in the midline, and to restrain the tongue (Fig. 36-28).3 The oropharynx is suctioned, and the lubricated ETT is placed 4 or 5 cm inside the airway. The fourth and fifth fingers of the right hand stabilize the ETT while the index finger and thumb feed the fiberscope through it (Fig. 36-29). If the fiberscope is accidentally passed through the Murphy eye of the ETT, intubation will not be successful even after the fiberscope is guided into the trachea.
++
++
++
As the fiberscope is advanced toward the oropharynx, the soft palate and uvula come into view (Fig. 36-30). With entry into the oropharynx, the tip is deflected anteriorly to expose the epiglottis and vocal cords. To separate a floppy epiglottis from the posterior pharyngeal wall, the head is extended at the atlanto-occipital joint and tongue traction or jaw thrust are applied. In an obese patient or one with a difficult airway, the sitting position will improve airway patency and pulmonary physiology.
++
++
After the glottis is exposed, it is maintained in the center of the field of view by fine manipulations of the control lever. The fiberscope is advanced into the midtrachea, as confirmed by a view of the carina and flat posterior wall. The ETT is slipped over the fiberscope and advanced with a twisting motion into the trachea, positioning the tip 3 to 4 cm above the carina.
++
In many patients, even though the fiberscope has entered the trachea, the ETT catches on laryngeal structures and cannot pass. In such a case, the ETT is pulled back and rotated 90 degrees counterclockwise until the leading edge of the bevel is oriented anteriorly. The patient is instructed to inspire deeply, abducting the vocal cords, and the tube is readvanced over the fiberscope. In some patients, this maneuver may have to be repeated 2 or 3 times, particularly when a large discrepancy exists between the size of the fiberscope and the ETT. Passage of the tube over the fiberscope into the larynx can be facilitated by using a larger fiberscope,111 a special tube with tapered tip112 such as the tube used to intubate through the Fastrach LMA (Fig. 36-31), or a Parker tube (Parker Medical, Highlands Ranch, CO). Laryngospasm also may prevent ETT advancement. Additional topical anesthesia applied through the fiberscope usually remedies this problem.
++
++
In the conscious patient, fiberoptic nasotracheal intubation often is easier than an oral approach.3 Minimal pressure on the base of the tongue causes less gagging, and the patient cannot bite the tube. By creating a "straight shot," passing the fiberscope through the nose facilitates locating the glottis and advancing the fiberscope and tube into the larynx. A warmed, softened, lubricated tube advanced into the pharynx through a nasal passage prepared with anesthetic with or without a vasoconstrictor serves as a channel to suction the pharynx and to find the glottis with a fiberscope. Laryngeal anesthesia and intubation proceed as described for the oral approach. The gag reflex is minimized or eliminated during nasal intubation, so minimal or no oropharyngeal topical anesthesia is needed. If the tube does not easily pass from the nasopharynx to the posterior oropharynx, it is pulled back, rotated 90 degrees, and reintroduced. If this maneuver fails, the ETT is withdrawn and a lubricated fiberscope is advanced from the nasopharynx to the posterior oropharynx. The ETT is then gently advanced over the fiberscope into the oropharynx.
++
Passing the tube too far into the oropharynx may direct the fiberscope into the esophagus or away from the midline, preventing laryngeal exposure. The oropharynx is suctioned thoroughly through the ETT before the lubricated fiberscope is inserted through it. In most patients, the epiglottis and vocal cords are seen immediately with minimal manipulation of the fiberscope tip. In heavily sedated or edentulous patients, the tongue and pharyngeal tissues may block exposure of the glottis, necessitating head extension, jaw thrust, or tongue traction. The fiberscope is advanced into the mid trachea followed by the ETT.
+++
Asleep Fiberoptic Intubation
++
Fiberoptic oral and nasal intubation in an anesthetized patient requires an assistant to monitor the patient and apply jaw thrust.3 Intubation attempts are interrupted to ventilate the patient's lungs as needed. With oral and nasal approaches, the ETT is loaded on the fiberscope before intubation is attempted. The fiberscope is then passed through the nostril or intubating airway into the mouth and advanced through the glottis into the trachea. The ETT then is advanced over the fiberscope into the trachea (Fig. 36-32).
++
++
Failed direct rigid laryngoscopic intubation during a rapid-sequence induction leaves the patient vulnerable to aspiration. If the patient's lungs can be ventilated via face mask, oral fiberoptic intubation with cricoid pressure is an effective technique that should be seriously considered. The ability to perform rapid fiberoptic intubation may prevent airway catastrophes. Repeated unsuccessful attempts at blind nasal intubation or rigid laryngoscopy traumatize the airway, converting a manageable airway into one that is impossible to ventilate.
++
In a rapid-sequence induction incorporating fiberoptic intubation, 1 assistant maintains cricoid pressure while another applies jaw thrust (Fig. 36-33). Excessive cricoid compression may block the endoscopist's view of the glottis by folding the epiglottis posteriorly. In this setting, it may be appropriate to gradually release cricoid pressure until the larynx is visualized.
++
+++
Retrograde Intubation
++
In retrograde intubation, a guidewire is passed through a needle that has been percutaneously inserted into the larynx. The wire is delivered through the mouth or nose to serve as a guide for the ETT.113-119 Dedicated kits (Cook Retrograde Intubation Set, Bloomington, IN) are available for pediatric and adult use.
++
The supine patient is placed in the sniffing position. Then the oropharynx, larynx, and trachea are topically anesthetized. A Touhy or other 18-gauge needle attached to a syringe containing 2 mL of lidocaine 4% is inserted into the larynx through the cricothyroid membrane in a slightly cephalad direction. Aspiration of air confirms correct placement of the needle, and the local anesthetic is injected into the larynx. The guidewire is threaded through the needle into the pharynx, and the tip is delivered through the mouth. A guide is passed over the wire, through the mouth, through the vocal cords, and into the trachea. Before the wire is removed, the ETT is advanced over the guide into the trachea (Fig. 36-34).
++
++
A fiberscope loaded with an ETT may be advanced over the guidewire or next to the guidewire to assist retrograde intubation.113,115,117 A technique that involves passing the guidewire through the suction channel of the fiberscope has greatly improved the success rate of retrograde intubation.
++
If the larynx is entered through the cricotracheal membrane rather than the cricothyroid membrane, the ETT can be advanced farther into the larynx.119 In this method, the cricothyroid arteries that cross the cricothyroid membrane at its proximal section are avoided.
++
The most common complication in the retrograde technique is bleeding in and around the airway. Bleeding usually is minor and does not require special treatment. Other complications are trauma to the airway, pneumomediastinum, and failed intubation.120
+++
Blind Nasal Intubation
++
Blind nasal intubation is a valuable technique in patients who are uncooperative, unable to open the mouth, or have a fair amount of secretions or blood in the airway.75,121-123 The nasal mucosa is prepared with cocaine or a mixture of vasoconstrictor and local anesthetic. If sedation is needed, ketamine has been used for sedation with spontaneous ventilation or to induce general anesthesia for blind nasal intubation.121
++
The head is placed in the sniffing position, and a lubricated ETT is advanced gently into the oropharynx. If resistance is encountered at the oropharynx, the tube is pulled back about 2 cm, rotated 90 degrees, and readvanced. If the maneuver is unsuccessful, a suction catheter or a nasogastric tube passed through the ETT into the oropharynx serves as a guide. The intensity of breath sounds and bulging in the neck guide maneuvers.122 As the tube is advanced toward the larynx, the breath sounds become louder. To help pass through the cords, the patient is encouraged to breathe deeply and rapidly, and the tube is advanced swiftly during inspiration. Successful intubation is confirmed by continued breath sounds through the tube and the patient's inability to phonate. Coughing is common when topical anesthesia is omitted.
++
If breath sounds stop being transmitted through the tube, the tube has not entered the trachea. It may be in the esophagus, vallecula, or one of the piriform recesses. A loss of breath sounds without resistance to passage indicates esophageal placement. In this case, the tube should be withdrawn and readvanced after further elevating and extending the patient's head. Inflating the tracheal tube cuff with 15 mL of air may accomplish the identical end.123 The tube is advanced 1 to 3 cm before the cuff is deflated and advanced farther into the trachea. Entry into a piriform recess is corrected by withdrawal and rotation. Obstruction by the epiglottis necessitates neck flexion and jaw thrust or application of traction on the tongue.
++
Success rates between 86% and 97% have been reported for blind nasal intubation. Success rates in emergency room patients are approximately 90%.124 Blind nasal intubation is less successful when the larynx is distorted by a mass, edema, or scarring from previous surgery. Contraindications to blind nasal intubation include nasal pathology, coagulopathy, thrombocytopenia, severe midface trauma, or prior transsphenoidal surgery after which an ETT may pass into the cranium.
++
Complications of blind nasal intubation include trauma to the nasopharyngeal mucosa, entry into the submucosal plane of the pharynx, dislodging nasal polyps, pushing foreign bodies into the larynx, and nasal bleeding.122,124 Difficulty advancing the tracheal tube into the oropharynx may be the result of a deviated septum, a turbinate spur, hypertrophied inferior turbinates, or nasopharyngeal lymph nodes. A smaller tube or use of the other nostril may remedy these problems.
+++
Intubation through a Laryngeal Mask Airway
++
The LMA can be used to manage a "cannot intubate, cannot ventilate" situation or to facilitate tracheal intubation.125-132 There are 3 distinct techniques for tracheal intubation through a classic or unique LMA: blind passage of a 6.0-mm inner diameter or smaller ETT,131 blind insertion of a guide to facilitate the threading of a large ETT after LMA removal,130 or fiberoptic-assisted tracheal intubation through the LMA.63,129,132 With perfect LMA position, the aperture lies opposite the glottic inlet for blind insertion of an ETT or guide. When the epiglottis partially blocks the laryngeal inlet, fiberoptic assistance is needed. The Aintree intubation catheter (Cook Critical Care, Bloomington, IN), which is 56 cm long with a 4.7 mm internal diameter, is specifically designed to facilitate intubation when an LMA is in place. A fiberoptic bronchoscope is placed through the catheter. The fiberscope and catheter are then directed through the LMA into the trachea. Leaving the Aintree catheter in place, the fiberoptic scope is removed, and then the LMA is removed over the catheter. The trachea is intubated over the catheter.
++
If rescue intubation is attempted by passing an ETT blindly through a classic LMA, it is important to remember that the distance from LMA aperture bars to the vocal cords is 3.5 cm.133 If the length of a 6-mm ETT is limited to 26 cm, the cuff of the ETT will be positioned inside the larynx just millimeters beyond the vocal cords, which increases the possibility of a laryngeal nerve palsy.
++
The LMA Fastrach is an SGA device designed to aid endotracheal intubation. It can serve as a primary airway, but its primary purpose is to serve as a conduit for endotracheal intubation. Blind endotracheal intubation with the LMA Fastrach is successful 96.5% of the time. One study of high-risk airway patients showed that using a flexible fiberoptic bronchoscope in conjunction with an intubating LMA produced a 100% success rate for tracheal intubation.63
++
Properly positioning the LMA Fastrach facilitates introduction of an ETT into the trachea, but suboptimal positioning can result in failure. The Chandy maneuver is a 2-step technique used to improve position of the Fastrach before using it for blind intubation.63 The first step of the Chandy maneuver uses the device's metal handle for rotation in the sagittal plane until ventilation is optimized. In the second part of the Chandy maneuver, the Fastrach is lifted to displace it anteriorly away from the posterior pharyngeal wall. The second part of the Chandy maneuver is applied as the ETT is advanced through the device.63
++
Correct position is important for success during LMA Fastrach–assisted endotracheal intubation, but the type of ETT is also a consideration. The manufacturer produces a reusable, reinforced ETT for use with the LMA Fastrach. The Fastrach ETT is made of silicone with a blunted tip, features that help with its smooth introduction into the trachea. Standard PVC ETTs can be used with the LMA Fastrach, but their rigid design and sharper bevel increase the risk of resistance or injury during blind intubation. A comparison of the manufacturer's ETTs and standard PVC ETTs during blind intubation via the Fastrach showed better success with the silicone Fastrach ETT even when the standard ETTs were rotated on advancement to avoid bevel impact on glottic structures.64 Another study evaluating Fastrach-assisted blind endotracheal intubation found similar success rates with the manufacturer's silicone ETT and a warmed PVC ETT.65 Reverse loading of a standard ETT, so that the curve of the tube points posteriorly, has been reported to increase first attempt success at blind intubation with the LMA Fastrach, although overall success was the same with a traditionally loaded standard ETT.66 The unique ability to establish ventilation in an unanticipated difficult mask ventilation, coupled with a mechanism to definitively secure the airway, makes the LMA Fastrach a strong addition to the airway management arsenal.
+++
Cricothyrotomy and Tracheostomy
++
Surgical airway access through the anterior neck is indicated in patients with severe upper airway obstruction or failed tracheal intubation combined with impossible ventilation. Cricothyrotomy involves entering the larynx through the cricothyroid membrane to pass a small ETT or a special cricothyrotomy tube into the trachea. Cricothyrotomy is preferred to tracheostomy when an airway must be established promptly. Cricothyrotomy is faster, easier to perform, and is farther away from the mediastinum than a tracheostomy. Several kits are available for percutaneous cricothyrotomy, including the Melker cricothyrotomy system, (Cook Critical Care, Bloomington, IN). Applying the Seldinger technique for cricothyrotomy is familiar for nonsurgeons treating a patient with a difficult airway.134 Cricothyrotomy usually is performed during emergency situations and under less-than-optimal conditions, which increases the chances for laryngeal injury. After the patient's condition is stabilized, the wound and the larynx should be examined.
+++
Percutaneous Transtracheal Ventilation
++
Placement of a large-bore catheter through the cricothyroid membrane (needle cricothyrotomy) into the trachea gives rapid access to the airway and can be lifesaving when mask ventilation and tracheal intubation have failed.135-137 Percutaneous transtracheal jet ventilation is also an interim means of oxygenation during difficult intubation.136
++
The incidence of malfunctioning of thin-walled 16- or 14-gauge IV catheters caused by kinking or dislodgement is high and can cause major complications. This problem is more likely to happen with an awake, struggling patient. The Arndt emergency cricothyrotomy catheter set (Cook Critical Care, Bloomingdale, IN) may minimize these problems. The set features a 3-mm kink-resistant catheter with a 15-mm connector coaxially positioned over a Luer lock connector. A hollow, tapered-tip dilator assists the placement of the catheter into the trachea. After it is in place, the airway catheter and its 15-mm connector may be attached to the common gas outlet of the anesthesia machine, self-inflating resuscitating breathing bag (Ambu bag) or directly to a jet ventilator through the Luer lock connector. The relatively large tracheal catheter is effective for high-pressure jet ventilation. Bag-valve manual ventilation delivers oxygen but is ineffective for ventilation with a progressive increase in CO2 concentration.
++
Rupture of the lungs may produce a pneumomediastinum, pneumothorax, or other serious complications. In the event of total upper airway obstruction, percutaneous transtracheal jet ventilation requires that an exit airway be established. The technique can cause barotrauma, including pneumothorax; pneumomediastinum; or injury to the larynx, trachea, and esophagus. Inadequate time for exhalation or inability of gas to escape can lead to "breath stacking" or pulmonary tamponade. The resultant impairment of venous return can lead to hypotension and even pulseless electrical activity similar to that seen with a tension pneumothorax. It is prudent to practice the technique first on a mannequin and then during controlled patient care conditions before applying it to emergency situations.