INTRODUCTION — A wide range of devices have been developed to aid in the management of the difficult airway or to facilitate endotracheal intubation in adults. Many of these devices are available in sizes suitable for use in children and incorporate a variety of fiberoptic, video, optical, and mechanical technologies.
This topic will review the techniques for use of advanced airway management devices for difficult endotracheal intubation in children. The following pediatric topics on the difficult airway are provided separately:
●Identification of the difficult airway (see "The difficult pediatric airway")
●Specific techniques for use of rescue devices (eg, laryngeal mask airway) when endotracheal intubation has failed (see "Supraglottic airway devices in children with difficult airways")
●Needle cricothyroidotomy (see "Needle cricothyroidotomy with percutaneous transtracheal ventilation")
●Wire-guided cricothyroidotomy (see "Emergency cricothyrotomy (cricothyroidotomy)", section on 'Seldinger technique')
●Difficult airway management during anesthesia (see "Management of the difficult airway for pediatric anesthesia")
The general principles of pediatric airway management and rapid sequence intubation are discussed elsewhere. (See "Basic airway management in children" and "Emergency endotracheal intubation in children" and "Rapid sequence intubation (RSI) outside the operating room in children: Approach".)
DEFINITIONS — The choice of airway device for difficult endotracheal intubation in children is dependent upon whether the patient has a difficult or failed airway:
●Difficult airway – A difficult airway is present when a clinician experiences problems with face mask ventilation, laryngoscopy, or intubation. In an emergency setting, this also includes difficulty performing an emergency surgical airway, such as needle cricothyroidotomy. Pediatric causes include congenital anomalies (table 1), epiglottitis, anaphylaxis, airway trauma, and airway foreign bodies. (See "The difficult pediatric airway", section on 'Causes of the difficult pediatric airway'.)
Whenever possible, a difficult pediatric airway should be identified prior to endotracheal intubation attempts (see "The difficult pediatric airway", section on 'Identification of the difficult pediatric airway'). In any child in whom laryngoscopy and endotracheal intubation is anticipated to be difficult, an alternative plan that involves the use of devices that enhance the clinician's ability to visualize and intubate the trachea should be employed, and the clinician with the greatest experience and skills should perform the intubation (algorithm 1A-D).
●Failed airway – A failed airway exists when the clinician cannot oxygenate or ventilate a patient. Clinically, this occurs when a patient cannot be intubated, and ventilation with a bag and mask or extraglottic device fails to maintain oxyhemoglobin saturations above 90 percent.
A contingency plan in the event of a failed endotracheal intubation should be developed for all patients, ideally before rapid sequence intubation is necessary (algorithm 1A, 1D). Clinicians should have rescue devices available whenever performing emergency pediatric intubation. (See "Supraglottic airway devices in children with difficult airways".)
CHOICE OF DEVICE — The choice of device depends upon the specific obstacles to conventional endotracheal intubation that are encountered or anticipated during video or direct laryngoscopy:
●Able to see epiglottis but not vocal cords (Cormack-Lehane grade III (figure 1)):
•Video laryngoscope (if not yet attempted)
•Intubating introducer (gum elastic bougie)
●Unable to visualize epiglottis or vocal cords (Cormack-Lehane grade IV (figure 1)):
•Video laryngoscope (if not yet attempted)
•Optical stylet
•Flexible intubating scope (FIS)
●Limited mouth opening or neck mobility:
•Optical stylet
•FIS
In some cases, a combination of devices is employed to secure the airway. (See 'Techniques' below.)
Choice of device is also influenced by the clinical experience of the provider. Use of devices that require extensive training and practice (eg, the flexible intubating bronchoscope) should typically be limited to those providers with regular exposure to difficult pediatric airways (eg, pediatric anesthesiologists).
Training — The choice of device depends upon the training and experience of the practitioner. Many of the devices for difficult endotracheal intubation require some assembly prior to use, and all require orientation and training. Inexperienced operators should not use these devices without prior practice. Just as providers must learn to use a standard laryngoscope, they must be trained to use advanced airway devices. Ideally, this training should be conducted first in a manikin or cadaver model and then, when possible, in an operating room setting.
The degree of training depends upon the expected frequency with which the clinician will encounter a difficult pediatric airway:
●All providers should have training and experience in the use of rescue airway devices such as supraglottic devices (eg, laryngeal mask airway or i-gel laryngeal airway). (See "Supraglottic airway devices in children with difficult airways".)
●Providers who are only occasionally exposed to difficult pediatric airways should gain capability with a limited number of relatively easy to use devices (eg, video laryngoscope, intubating introducers, or optical stylet). It is unlikely that an individual provider will have access to all possible devices, so it is most important that providers learn to use the devices available to them.
●Providers whose exposure to difficult pediatric airways is extensive (eg, pediatric anesthesiologists, emergency physicians in busy departments with high acuity, and pediatric intensivists) should develop facility with a wide variety of devices, including those that require repeated use to be most effective (eg, FIS).
TECHNIQUES — The major devices for difficult endotracheal intubation in children include video laryngoscopes, specialized stylets, and indirect rigid laryngoscopes.
Video laryngoscope — Video laryngoscopes provide indirect laryngoscopy and display the glottic view on a video monitor during endotracheal intubation [1]. The video laryngoscope can be categorized according to the shape of the blade (acute angle versus Macintosh or Miller type) and whether or not they have channels that hold and guide tracheal tube advancement. (See "Video laryngoscopes and optical stylets for airway management for anesthesia in adults", section on 'Classification of video laryngoscopes'.)
Common devices — Examples of devices that can be used as video laryngoscopes and are available in sizes appropriate for infants and children include [2]:
●GlideScope video laryngoscope (picture 1) – The non-channeled GlideScope is essentially a camera mounted on a specially shaped laryngoscope handle with an acutely angled blade (GlideScope blades are also available in shapes/sizes similar to Miller and MacIntosh). The operator guides the intubation attempt using a video monitor rather than under direct vision. There are a variety of other GlideScope products available, including fully portable and reusable designs, but all are variations on the device described above.
●C-MAC video laryngoscope – The C-MAC is a non-channeled standard geometry blade video laryngoscope that can be fitted with various MacIntosh and Miller-style laryngoscope blades, including Miller 0 or 1 style blades. Observational studies have documented successful use in infants and children and a child with Treacher Collins syndrome [3-5]. The wide handle was reported to contact the chest and cause difficulty with intubation in a child with Klippel-Feil syndrome and a fixed flexion deformity of the neck [6].
●Truview PCD infant (picture 2) – The non-channeled Truview PCD can be used as a direct optical laryngoscope or can be converted into a video laryngoscope by attaching a camera with a magnetic adapter. The blade height of 8 mm permits successful use in neonates, including those with difficult airways [2]. It also permits insufflation of oxygen during intubation attempts.
●AIRTRAQ disposable optical laryngoscope (picture 3) – The AIRTRAQ channeled video laryngoscope can be used as a direct optical laryngoscope or can be converted to a video laryngoscope with a wireless monitor. It comes in two pediatric sizes and is capable of passing an endotracheal tube (ETT) as small as 2.5 mm internal diameter (picture 4). Unlike the other laryngoscopes, the AIRTRAQ provides a channel for directing the ETT through the vocal cords (movie 1). Use is discouraged for infants with limited mouth opening (eg, Pierre Robin or Treacher Collins syndrome) because the relatively large blade height (12 to 13 mm) may be associated with intubation failures [7]. However, in a manikin study of pediatric patients with a simulated Cormack-Lehane grade 4 view of the glottis, the AIRTRAQ proved superior to the McGrath MAC video laryngoscope and a standard Macintosh laryngoscope [8]. Additionally, in a study of nonexpert operators using a manikin designed to simulate the Pierre Robin sequence, use of the AIRTRAQ led to a shorter duration of the intubation attempt as compared with the GlideScope. However, setup time was significantly longer for the AIRTRAQ [9].
●UEScope – The UEScope is a video laryngoscope with a blade configuration similar to a MacIntosh blade, except that the tip of the blade is angled to 45 degrees. It is available in sizes that permit use in neonates and children of all sizes, including adolescents with marked obesity.
In a manikin study of inexperienced paramedics that compared intubation using the UEScope with direct laryngoscopy using a standard Miller laryngoscope, a definitive airway was established more quickly and more successfully with the UEScope for a simulated difficult airway and in scenarios involving ongoing chest compressions [10].
In the hands of practitioners with training in airway management, all of the devices function as intended. However, as described above, some of the devices have limitations under certain circumstances that might be encountered in the management of children with difficult airways (eg, the size limitation of the AIRTRAQ in patients with limited mouth opening).
Based upon manikin studies, even novice learners can achieve high success rates for intubation (eg, 95 to 100 percent) when using video laryngoscopes [11,12]. Furthermore, intubation skills gained with a video laryngoscope may transfer to the use of a standard laryngoscope when the video laryngoscope configuration is similar to a standard laryngoscope [12]. Finally, the use of video laryngoscopy permits effective oversight of trainees performing endotracheal intubation.
Efficacy — Compared with direct laryngoscopy, video laryngoscopy may improve the chance of successful intubation of children with difficult airways (eg, limited mouth opening, cervical spine immobility, or severe micrognathia due to genetic syndromes such as Pierre Robin or Treacher Collins). Multiple studies have compared video laryngoscopes with direct laryngoscopy in simulated difficult pediatric airway models and in children with predicted difficult airways [2,13-18] during patient care in the operating room, emergency department, and the intensive care unit [4,19-22]. In a review of a multicenter difficult airway database that included operating room intubation with video laryngoscopy of almost 800 children with suspected difficult airways (379 who had failed direct laryngoscopy), video laryngoscopy was associated with first-pass success of 51 percent and overall success of 79 percent [19]. On adjusted analysis, this first-pass success rate was not significantly different than flexible scope intubation with intubation through a supraglottic airway (FSI-SGA). However, FSI-SGA was associated with a higher overall success rate (89 percent) and a better first-pass success among infants younger than 12 months of age than video laryngoscopy (54 versus 36 percent, respectively). Of note, all children in this study were undergoing elective procedures and could be oxygenated during preparation and performance of FSI-SGA.
However, in otherwise normal children undergoing intubation, the use of video laryngoscopy compared with direct laryngoscopy is not necessarily associated with improved outcomes such as fewer adverse events or higher first-pass success rate [23]. Furthermore, video laryngoscopy may result in longer intubation times, although results may vary by setting, patient age, provider experience, and technique:
●Pediatric emergency department – In a multicenter prospective observational study of nearly 500 children undergoing endotracheal intubation in pediatric emergency departments, overall first-pass success rate was 67 percent, and hypoxemia occurred in 15 percent of patients [23]. Videolaryngoscopy with a standard geometry video laryngoscope (Storz C-MAC) was used for at least part of the procedure in 48 percent of patients and was not associated with successful intubation or a lower risk of hypoxemia. When used for the entire procedure, video laryngoscopy was associated with a longer duration of laryngoscopy (median difference six seconds) compared with direct laryngoscopy.
In a separate prospective observational study of 153 children undergoing standard geometry blade video laryngoscopy in a pediatric emergency department that evaluated video screen use during intubation attempts, overall first-pass success rate was 79 percent; the video screen was viewed a median 42 percent of the time during the intubation attempt, and percent time spent viewing the screen during intubation was not associated with first-pass success [24]. However, a greater number of gaze switches between the patient and the video screen was associated with a lower likelihood of first-pass success (adjusted odds ratio 0.8, 95% CI 0.7 to 0.9).
●Intensive care unit – In a review of a national registry of airway management in pediatric intensive care units that compared 8875 endotracheal intubations by direct laryngoscopy with 928 performed by video laryngoscopy, video laryngoscopy was associated with fewer tracheal intubation adverse events (eg, mainstem bronchial intubation, esophageal intubation with immediate recognition, or vomiting without aspiration) but not fewer severe events (eg, cardiac arrest, laryngospasm, esophageal intubation with delayed recognition, or emesis with witnessed aspiration) or need for multiple (≥3) attempts [22].
●Neonates – In a meta-analysis of three trials (467 neonates) that evaluated intubation by inexperienced providers in the delivery room, operating room, or neonatal intensive care unit, the use of a video laryngoscopy was associated with a significantly higher number of successful intubations on first-pass when compared with direct laryngoscopy (61.1 per 100 intubations versus 42.4 per 100 intubations, respectively) but did not decrease the time to intubation or the number of attempts [25].
Technique — The technique for video laryngoscopy varies based upon whether the intubator uses a standard geometry or acute angle blade.
Standard geometry blade — A video laryngoscope with a standard geometry blade permits both direct and indirect laryngoscopy. The technique for direct laryngoscopy is provided separately. (See "Emergency endotracheal intubation in children", section on 'Laryngoscopy'.)
●Indications – A standard geometry blade video laryngoscope (eg, Storz C-MAC or GlideScope standard configuration blades) can be used in patients with difficult or normal airways. This video laryngoscope may permit easier delivery of the ETT into the trachea than acute angle blade laryngoscopes. This device can be used in conjunction with the intubating introducer. (See 'Intubating introducers (gum elastic bougie)' below.)
●Contraindications – Blood or excessive secretions in the oral cavity or pharynx will make visualization difficult. These should be cleared with suction prior to intubation.
●Technique
•Turn on the monitor and device at least one minute prior to laryngoscopy to minimize condensation on the lens.
•Select an appropriately sized ETT, and if a cuffed tube is being placed, test its balloon and insert a lubricated stylet while ensuring that the tip of the stylet does not protrude beyond the ETT. (See "Emergency endotracheal intubation in children", section on 'Endotracheal tube'.)
•Suction the patient's oral cavity and, if desired, provide optional pretreatment with anticholinergic agents (eg, atropine or glycopyrrolate). (See "Rapid sequence intubation (RSI) outside the operating room in children: Approach", section on 'Pretreatment'.)
•Lubricate the video laryngoscopy blade lightly to facilitate passage around the tongue (ensuring that lubricant is not applied near the camera).
•Position the patient into the "sniffing position" to align the pharyngeal, tracheal, and oral axes (picture 5).
•Under direct vision, insert the blade into the midline of the patient's mouth, maintaining control of the tongue, and guide it past the soft palate.
•Once the blade is past the soft palate, either proceed with direct visualization or continue the procedure with indirect visualization using the monitor.
•Once the epiglottis comes into view, either use the blade to directly elevate it (as with a standard straight blade) or place it into the vallecula and use it like a standard curved blade. In either case, gently lift the video laryngoscope upward and forward, maintaining the axis of the laryngoscope handle, until the vocal cords are seen.
•Hold the blade in position and insert the ETT into the oral cavity under direct vision until it is past the soft palate.
•Once the ETT tip passes the palate, either advance the ETT under direct vision, or watch the monitor and advance the ETT until it passes through the cords.
•Secure the tube in the usual fashion and confirm its location using an end-tidal carbon dioxide (CO2) detector. (See "Emergency endotracheal intubation in children", section on 'Confirming tube position'.)
Acute angle blade — The technique below describes the use of the GlideScope acute angle video laryngoscope. Although use of other indirect acute angle video laryngoscopes is similar, the specific descriptions for other types of video laryngoscopes may be obtained from their manufacturers. A comparison of the advantages and disadvantages of pediatric use of the four video laryngoscopes is provided elsewhere [2].
●Indications – The GlideScope acute angled blade can be used in patients with difficult or normal airways. Additionally, the shape of its blade permits intubation without neck movement, making it a good choice for intubation of trauma patients and those with limited cervical spine mobility [26].
This device can be used in conjunction with the intubating introducer. (See 'Intubating introducers (gum elastic bougie)' below.)
●Contraindications – Blood or excessive secretions in the oral cavity or pharynx will make visualization difficult. These should be cleared with suction prior to intubation.
●Technique [2,27]:
•Turn on the monitor and device at least one minute prior to laryngoscopy to minimize condensation on the lens.
•Select an appropriately sized ETT, if a cuffed tube is being placed, test its balloon, and insert a lubricated stylet while ensuring that the tip of the stylet does not protrude beyond the ETT. Alternatively, GlideRite stylets are specifically designed to be used with the GlideScope acute angled blade and are available for ETTs sized 3.0 and larger. (See "Emergency endotracheal intubation in children", section on 'Endotracheal tube'.)
•Bend the tip of the tube so that it forms a 60 to 80 degree angle with the body of the tube.
•Suction the patient's oral cavity and, if desired, provide optional pretreatment with anticholinergic agents (eg, atropine or glycopyrrolate). (See "Rapid sequence intubation (RSI) outside the operating room in children: Approach", section on 'Pretreatment'.)
•Lubricate the video laryngoscopy blade lightly to facilitate passage around the tongue (ensuring that lubricant is not applied near the camera).
•Keeping the patient's head and neck in the neutral position (the curve of the GlideScope blade makes neck extension unnecessary), insert the blade into the midline of the patient's mouth and past the soft palate under direct vision.
•Once the blade is beyond the soft palate, watch the monitor and advance the blade. Rotate the blade in the sagittal plane around the base of the tongue, watching the monitor, and avoid excessively deep insertion.
-Deep insertion of an acute-angle blade rotates the laryngeal axis anteriorly, which may make insertion of the ETT more difficult despite good laryngeal exposure.
-Shallow insertion provides two additional benefits:
1. A wider visual field.
2. A shorter distance from the lips to the camera, and therefore a shorter blind zone in which the clinician cannot see the tip of the ETT. Ideally, the laryngeal opening should appear in the upper half of the video screen, leaving the lower half open to visualize the path of the tube as it is advanced.
•Once the epiglottis comes into view, either use the blade to directly elevate it (as with a standard straight blade) or place it into the vallecula and use it like a standard curved blade. In either case, gently lift the video laryngoscope upward and forward, maintaining the axis of the laryngoscope handle, until the vocal cords are seen.
•Hold the blade in position and insert the ETT into the oral cavity under direct vision until it is past the soft palate.
•Once the ETT tip passes the palate, watch the monitor and advance the ETT until it passes through the cords. If the GlideRite stylet is being used, it may be necessary and helpful to use the thumb of the dominant hand to gently lift the stylet an inch or two so that the endotracheal tube can be advanced.
•Secure the tube in the usual fashion and confirm its location using an end-tidal CO2 detector. (See "Emergency endotracheal intubation in children", section on 'Confirming tube position'.)
A video demonstrating the use of the GlideScope Cobalt for intubation in an infant can be found elsewhere [28].
●Pitfalls – The clinician must be careful to look at the patient when initially placing the video laryngoscope blade and when passing the ETT through the oropharynx to avoid damage to the dentition, palate, and throat. The pitfalls associated with standard intubation also apply to the GlideScope. (See "Emergency endotracheal intubation in children", section on 'During laryngoscopy/intubation'.)
Specialized stylets
Intubating introducers (gum elastic bougie) — In adults, multiple randomized trials and observational studies have shown that intubating introducers facilitate intubation, especially in patients with Cormack-Lehane system grade 3 glottic views (figure 1). (See "Endotracheal tube introducers (gum elastic bougie) for emergency intubation".)
The same benefit is probably achieved in children although reports of pediatric use are limited [27]. In one operating room series, the use of a bougie with paraglossal laryngoscopy permitted intubation in five of six infants with Pierre Robin syndrome who could not be intubated with conventional laryngoscopy [29]. Additional case reports have demonstrated that the gum elastic bougie can be an effective adjunct to pediatric nasotracheal intubation, the insertion of the Pro Seal laryngeal mask airway, and prehospital tracheal intubation [30-32]. One case report describes the use of the Boussignac bougie (bougie that permits oxygen delivery during placement) passed through a size one Laryngeal Mask Airway to successfully intubate an infant with Goldenhar syndrome after several attempts at direct laryngoscopy failed [33].
●Indications – Intubating introducers are helpful when the epiglottis is visible but the vocal cords cannot be seen [34]. These devices are semi-rigid solid or hollow rods with the distal tip bent at a 30 degree angle (picture 6 and picture 7). The bend allows the intubator to direct the tip anteriorly under the epiglottis and through the vocal cords. Once the introducer is placed in the trachea, an ETT is threaded over it using a Seldinger-like technique. This approach generally requires an assistant to place the ETT on the proximal end of the introducer. The intubator then advances the ETT over the introducer into the trachea and the introducer is withdrawn. Depending upon the manufacturer, intubating introducers are available in sizes as small as 8 Fr. These can be used with ETTs that have an internal diameter of at least 3.0 mm.
Intubating introducers can be used in conjunction with direct laryngoscopy, video laryngoscopy (see 'Video laryngoscope' above), or fiberoptic intubation techniques (see 'Optical stylets' below and 'Flexible intubating scope' below). They can also be used to secure a definitive airway using some supraglottic devices (eg, laryngeal mask airway) as conduits. (See "Supraglottic airway devices in children with difficult airways", section on 'Laryngeal mask airway (LMA)'.)
●Contraindications – Intubating introducers are unlikely to be beneficial when the airway anatomy is not visible. In addition, airway guides should be used with caution when there is possible laryngeal or tracheal injury.
●Technique:
•Lubricate the guide so that the ETT will pass over it easily.
•Using direct or video laryngoscopy, identify the epiglottis.
•Pass the airway guide (with its curved tip up) beneath the epiglottis. Entry into the trachea is associated with the tactile sensation of running the tip of the airway guide along the rigid rings of the trachea. This is sometimes described as a feeling similar to running your finger along an irregular surface. Because the tracheal rings of infants and young children are less rigid, this sensation may be very subtle or absent. Upon completion of intubation, correct tube position should be confirmed with the use of an end-tidal CO2 detector. If the airway guide is in the trachea, it will also wedge into the small airways and not pass any further. In contrast, if the guide has entered the esophagus, no such sensation will be felt, and no clear stopping point will be reached. Thus, the guide should be advanced into the trachea and moved back and forth (gently) a few times to ensure that it is in the correct location.
•Once certain that the airway guide rests within the trachea, insert the proximal end of the guide into the distal end of an appropriately-sized ETT and advance the tube along the guide (picture 7).
•Using direct laryngoscopy or video laryngoscopy, advance the ETT until it rests within the trachea. Alternatively, if direct laryngoscopy is not used, advance the ETT over the bougie into the trachea, carefully noting the depth of insertion indicated by the ETT marking at the gum line or incisor.
•Remove the guide and confirm the position of the ETT using an end-tidal CO2 detector. (See "Emergency endotracheal intubation in children", section on 'Confirming tube position'.)
●Pitfalls – Excessive force while advancing the airway guide or the ETT can damage the trachea or larynx. In addition, the ETT, especially a cuffed tube, might become impeded by the epiglottis during placement. This problem can be overcome by using direct laryngoscopy or video laryngoscopy during the procedure and/or by rotating the ETT 90 degrees as it approaches the larynx. If the procedure takes a considerable period of time to perform, the patient can become hypoxemic.
Based upon a single animal study, hollow exchange catheters that are used to administer oxygen have the potential to cause barotrauma if the catheter is advanced below the carina, regardless of the oxygen flow rate [35]. Thus, when hollow exchange catheters are used to administer oxygen during intubation attempts or tracheal tube changes, the tip of the catheter should remain above the carina.
Optical stylets — Optical stylets can be used for blind intubation or to perform visually guided intubation [27]. The Shikani optical stylet (SOS) comes in two sizes: an adult size, which can accommodate ETTs as small as 5.5 mm ID, and a pediatric size intended for use with ETTs from 2.5 mm ID to 5.0 mm ID (picture 8). This device can be used in several ways, but it is primarily intended as an easy-to-use alternative to the flexible intubating scope (FIS) when the vocal cords cannot be visualized [36].
The Bonfils Retromolar Intubation Fiberscope (Bonfils) is another optical stylet designed to allow insertion of the device laterally, along the gum line. It has an adjustable eyepiece and is available in adult and pediatric sizes. The Levitan fiberscope is a similar device, available only in adult sizes. Finally, a small-diameter fiberoptic scope of sufficient length (eg, the Foley Airway Fiberoptic Stylet) can be used as an adjunct to the intubating laryngeal mask airway.
Evidence for use of fiberoptic stylets in children is limited. However, in one case series, four infants and children with congenital anomalies and known prior difficult intubations were intubated on the first or second try using the SOS [37]. In a manikin study, paramedics used either a standard Macintosh laryngoscope or a Clarus Levitan fiberoptic stylet (FOS) in three scenarios: a normal child, a normal child undergoing chest compressions, and a child with a difficult airway. In the latter two scenarios, the FOS performed better than the standard laryngoscope, even in the hands of paramedics with limited experience in the use of the FOS [38].
Several devices permit the simultaneous administration of oxygen through the fiberoptic stylet, which prevents secretions from obscuring the optic view and can help maintain oxygen saturation during intubation attempts. The fiberoptic stylet can be used with or without direct laryngoscopy.
●Indications – The SOS is especially useful when standard laryngoscopy is difficult or impossible because the patient has limited mouth opening or neck mobility. It is also useful when the patient has certain anatomic abnormalities that make endotracheal intubation difficult (eg, small mandible, large tongue, very anterior airway).
This device may be used in conjunction with the laryngeal mask airway (see "Supraglottic airway devices in children with difficult airways", section on 'Laryngeal mask airway (LMA)') or with direct laryngoscopy. (See "Emergency endotracheal intubation in children", section on 'Laryngoscopy'.)
●Contraindications – Like all fiberoptic devices, the SOS may be difficult to use when the patient has blood, debris, or excessive secretions in the oral cavity, though in these circumstances the SOS can be used blindly by those who have sufficient training. Additionally, the fiberoptic lens can fog when introduced into the oral cavity. This problem can be avoided by applying anti-fog solution to the lens prior to use and administering medications (eg, atropine) that will reduce secretions.
●Technique (preparation) [27]
•Prepare and inspect a properly sized ETT, if a cuffed tube is used check that the balloon inflates properly.
•Apply anti-fog solution to the lens of the SOS and lubricate its shaft so that the ETT slides off easily.
•Make certain that the light is working properly. The SOS can be used with either a battery pack or a fiberoptic light source powered by a wall socket.
•Suction the patient's oral cavity well and, if time permits, administer atropine (IV dose 0.02 mg/kg, minimum dose: 0.1 mg, maximum dose: 1 mg) or glycopyrrolate (IV dose 10 micrograms/kg, maximum dose: 0.2 mg) to decrease secretions.
•Slide the ETT over the stylet so that the lens of the SOS lies just barely within the ETT.
•Clamp the tube in place using the tube clamp. This device also allows air or oxygen to be blown down the ETT, which can serve as a source of oxygen in the sedated, spontaneously breathing patient and can be used to blow secretions aside to improve the view.
•Gently bend the distal portion of the ETT/stylet assembly into the desired angle.
●Technique (intubation) (figure 2)
•Insert the stylet in the midline and direct it below the tongue.
•Using the eyepiece, identify the vocal cords and direct the ETT and stylet through them, stopping just above the carina.
•Release the tube from its clamp and slide the stylet out while holding the ETT in position.
•Confirm the tube's position using an end-tidal CO2 detector.
●Pitfalls
•Visualization may be obscured by secretions or bleeding
Flexible intubating scope — The FIS is essentially a 60 cm long flexible and directable stylet that can be used for airway management in patients for whom difficult intubation is predicted and neuromuscular paralysis is best avoided [27]. FISs are available in sizes down to 2.2 mm, thus permitting placement of ETTs as small as 2.5 mm internal diameter in infants and neonates. However, FISs 2.5 mm and smaller do not have a suction channel.
Use of a FIS for intubation requires extensive training and experience and should not be attempted in emergent settings by inexperienced personnel. Because of the time required and the patient preparation necessary, intubation using a FIS is generally not performed in children who require immediate establishment of an airway. If time allows for adequate patient preparation, the FIS is an invaluable intubating device. FIS has been shown to improve first-pass success rate in children with difficult airways undergoing endotracheal intubation in the operating room. The use of FIS in the operating room is discussed in greater detail separately. (See "Management of the difficult airway for pediatric anesthesia", section on 'Alternative intubation techniques'.)
●Indications – FIS-assisted endotracheal intubation is appropriate in patients with abnormal airway anatomy or lesions (eg, angioedema), impaired neck movement, or limited mouth opening who can be ventilated. Topical analgesia (eg, lidocaine 4 percent, 4 mg/kg nebulized over 10 to 15 minutes, maximum dose: 160 mg [4 mL]) and sedation (eg, ketamine dexmedetomidine) are typically necessary for children to be able to tolerate the procedure. (See "Pharmacologic agents for pediatric procedural sedation outside of the operating room", section on 'Ketamine' and "Selection of medications for pediatric procedural sedation outside of the operating room", section on 'Moderately or severely painful procedures'.)
This device can be used in conjunction with a laryngeal mask airway [39]. (See "Supraglottic airway devices in children with difficult airways", section on 'Laryngeal mask airway (LMA)'.)
When compared with video laryngoscopy, FIS through a supraglottic device is associated with improved first-pass success rate in children younger than one year of age. (See "Management of the difficult airway for pediatric anesthesia", section on 'Alternative intubation techniques'.)
●Contraindications – Because of increased procedural time, FIS-assisted endotracheal intubation should not be attempted in patients with a failed airway (unable to intubate and unable to ventilate). Bleeding and oral secretions must be controlled or of a limited extent to allow for airway visualization.
●Technique [27]
•Apply antifog solution to the lens of the FIS.
•If present, connect the suction port to wall suction, or if preferred, attach the port to an air or oxygen outlet to blow away secretions rather than suction them.
•Apply water-soluble lubricant to the fiberoptic bundle and thread the ETT onto the FIS, assuring easy movement of the tube along its length.
•Administer medication to control secretions (eg, atropine [IV dose 0.02 mg/kg, minimum dose: 0.1 mg, maximum dose: 1 mg] or glycopyrrolate [IV dose 10 micrograms/kg, maximum dose: 0.2 mg]) and, if using the nasal approach, a topic vasoconstrictor spray (eg, phenylephrine 1 percent, one spray into each nostril).
•Administer topical anesthetic (eg, lidocaine 4 percent, 4 mg/kg, nebulized over 10 to 15 minutes, maximum dose 160 mg [4 mL]) to the airway and sedate the patient while maintaining adequate ventilation.
•For nasopharyngeal passage, after application of a topical vasoconstrictor spray (eg, phenylephrine 1 percent, one spray into each nostril) to the nasal mucosa, gently pass the lubricated ETT into the nasopharynx and then insert the FIS through the ETT until the glottic opening is identified (figure 3).
•For oropharyngeal passage, place a bite block. Thread the ETT over the lubricated FIS. While maintaining midline position, advance the FIS with threaded ETT over the tongue into the posterior pharynx.
•For both nasopharyngeal and oropharyngeal passage, once the glottis is identified, advance the FIS towards and through the vocal cords and down to the level of the carina (figure 4).
•Position the ETT by advancing it along the FIS (sometimes referred to as "railroading") (figure 4).
•Once the ETT is properly placed, remove the FIS (figure 4).
•Confirm the position of the tracheal tube using an end-tidal CO2 detector. (See "Emergency endotracheal intubation in children", section on 'Confirming tube position'.)
●Pitfalls
•The FIS requires extensive training and experience for proper use.
•Bleeding or secretions may make visualization difficult or impossible.
SUMMARY AND RECOMMENDATIONS
●Difficult airway – A difficult airway is present when a clinician experiences problems with face mask ventilation, laryngoscopy, or intubation. Pediatric causes of a difficult airway include congenital anomalies (table 1), epiglottitis, anaphylaxis, airway trauma, and airway foreign bodies. (See 'Definitions' above and "The difficult pediatric airway", section on 'Causes of the difficult pediatric airway'.)
●Failed airway – A failed airway exists when the clinician cannot oxygenate or ventilate a patient. Clinically, this occurs when a patient cannot be intubated and ventilation with a bag and mask or extraglottic device fails to maintain oxyhemoglobin saturations above 90 percent.
●Approach – The approach to a difficult or failed airway is provided in the algorithms and discussed in detail separately (algorithm 1A and algorithm 1B and algorithm 1C). (See "The difficult pediatric airway", section on 'Identification of the difficult pediatric airway'.)
●Choices of device – The choice of device depends upon the specific obstacles to conventional endotracheal intubation that are encountered or anticipated during direct laryngoscopy and upon the training and experience of the practitioner (see 'Choice of device' above and 'Training' above):
•Able to see epiglottis but not vocal cords (Cormack-Lehane grade III (figure 1)) (see 'Video laryngoscope' above and 'Intubating introducers (gum elastic bougie)' above):
-Video laryngoscope (if not yet attempted)
-Intubating introducer (gum elastic bougie)
•Unable to visualize epiglottis or vocal cords (Cormack-Lehane grade IV (figure 1)) (see 'Video laryngoscope' above and 'Specialized stylets' above):
-Video laryngoscope (if not yet attempted)
-Optical stylet
-Flexible intubating scope (FIS)
•Limited mouth opening or neck mobility (see 'Specialized stylets' above):
-Optical stylet
-FIS
●Training – The degree of training depends upon the expected frequency with which the clinician will encounter a difficult pediatric airway (see 'Training' above):
•All providers should have training and experience in the use of rescue airway devices (eg, laryngeal mask airway and other supraglottic airways). (See "Supraglottic airway devices in children with difficult airways".)
•Providers who are only occasionally exposed to difficult pediatric airways should gain capability with a limited number of relatively easy to use devices (eg, intubating introducers, fiberoptic stylet, or video laryngoscope).
•Providers whose exposure to difficult pediatric airways is extensive (eg, pediatric anesthesiologists, emergency physicians in busy departments with high acuity, and critical care subspecialists) should develop facility with a wide variety of devices, including those that require repeated use to be most effective (eg, lighted stylet, FIS).
●Techniques – Indications, contraindications, procedure, and pitfalls are described for a variety of devices designed to facilitate difficult endotracheal intubation in children. (See 'Techniques' above.)
