Supraglottic airway devices in children with difficult airways

INTRODUCTION — In patients with difficult airways, supraglottic airways (eg, laryngeal mask airway or i-gel) permit oxygenation and ventilation until a definitive airway can be secured. Supraglottic airway devices may be lifesaving in children with difficult airways in whom conventional endotracheal intubation has failed. They should be available for any child undergoing emergency endotracheal intubation. This topic discusses the indications, contraindications, and techniques for use of such devices in children.

The following pediatric topics on the difficult airway are presented elsewhere:

●Identification of the difficult airway (see "The difficult pediatric airway for emergency medicine")

●Devices to facilitate endotracheal intubation (see "Video laryngoscopy and other devices for difficult endotracheal intubation in children")

●Needle cricothyroidotomy (see "Needle cricothyroidotomy with percutaneous transtracheal ventilation")

●Wire-guided cricothyroidotomy (see "Emergency cricothyrotomy (cricothyroidotomy) in adults", section on 'Seldinger technique')

The general principles of pediatric airway management and rapid sequence intubation are discussed separately. (See "Basic airway management in children" and "Technique of emergency endotracheal intubation in children" and "Rapid sequence intubation (RSI) in children for emergency medicine: Approach".)

TERMINOLOGY — Extraglottic airway devices are designed to provide oxygen and ventilation without direct entry into the airway (larynx) [1]. Those devices that are placed above the glottis without extension of any components into the esophagus are also called supraglottic airway devices. Thus, a laryngeal mask airway is a type of supraglottic airway while a Combitube is an extraglottic airway that is not supraglottic.

CONTINGENCY PLAN FOR THE FAILED AIRWAY — 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 1). Clinicians should have rescue devices available whenever performing an emergency pediatric intubation. Rescue devices permit oxygenation and ventilation in situations where endotracheal intubation cannot be performed in a timely manner and can also facilitate endotracheal intubation in patients with difficult airways.

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 supraglottic airway device fails to maintain oxyhemoglobin saturations above 90 percent. (See "The difficult pediatric airway for emergency medicine", section on 'Identification of the difficult pediatric airway'.)

CHOICE OF DEVICE — The laryngeal mask airway and similar laryngeal tracheal devices (eg, King LAD, air-Q, i-gel, Ambu Aura, or CobraPLA) are the most versatile airway rescue devices for children and are available in sizes that permit placement in all pediatric patients (table 1).

There is some evidence to suggest that one supraglottic device, the LMA Supreme (size 1) might be superior to BVM ventilation in neonatal resuscitation, making it a potential rescue airway for neonates [2].

Acquiring the skill to use these devices appears to be rapid with most providers able to successfully insert them in simulated difficult pediatric airway scenarios within 30 seconds, although the primary determinant of success with a particular device appears to be operator experience [3].

Since the laryngeal mask airway (LMA) was first used in 1988, numerous similar devices have been developed. Some investigators describe the original devices, like the LMA Classic as "First Generation" supraglottic devices and later devices, with additional features as "Second" and "Third Generation" devices.

Regardless of the "generation" to which the device belongs, these supraglottic devices all share a similar functional principle; if the peripharyngeal area can be occluded with a mask or balloon and the laryngeal opening can be isolated from the esophagus, the relatively lower resistance of the distal airway will permit ventilation without direct tracheal intubation. Because blind insertion of a supraglottic airway is likely to be much easier than tracheal intubation, these devices represent a true advance in airway management. Based upon operating room experience in children predicted to have a difficult airway, these devices permit successful airway management in over 90 percent of such patients [4,5]. When comparing airway leak pressures, ease of insertion, first pass success rate, and the airway view via a fiberoptic bronchoscope when using the LMA Supreme, the AirQ, or the Ambu Aura-I, the LMA Supreme was easiest to insert and had the highest first pass success rate [5].

Training — Supraglottic airway devices are likely to be used by the emergency care provider when standard airway management techniques have failed, and tensions are high. The patient’s life may well depend upon the clinician’s ability to secure an alternative airway, and the clinician will be under considerable stress. These are not the circumstances under which to use an unfamiliar device for the first time. Thus, emergency physicians and others who might need to use a rescue airway device should learn to use it well in advance of need. Training can be accomplished in a simulation center, a cadaver lab, or an operating room, depending upon the type of device and the availability of mentors [6]. Additionally, several organizations offer training in difficult airway management for emergency practitioners.

Studies suggest that successful placement of laryngeal mask airways in the first attempt after formal training is as high as 90 to 94 percent [7-9]. Additionally, there are data from the pre-hospital literature to suggest that providers using supraglottic airways are able to rapidly establish effective oxygenation and ventilation and that skill retention remains high with these devices, which is an advantage when providers are faced with a rarely-used technique in an emergency situation [3,10,11].

LARYNGEAL MASK AIRWAY (LMA) — The LMA is widely used in children. It comes in sizes that permit placement in all pediatric patients (table 1). The recommended approach to selection of an appropriately-sized LMA is based upon the child’s weight. When the weight is not known, use of an LMA with an outer diameter approximately the same as the child’s auricle is an alternative method that is practical and moderately correlates with the weight-based approach [12].

The LMA Supreme is a single use device that is similar to the ProSeal. It is available in sizes appropriate for use in infants and children. In anesthesia studies in children, LMAs can be successfully inserted on the first attempt 80 to 100 percent of the time, depending on the technique (rotational, lateral, or standard placement) and specific device (Classic LMA or ProSeal LMA) used [13].

Most sources have recommended inserting the LMA until resistance to further insertion is felt. However the optimal depth of insertion can also be calculated using the child’s height and weight in the following formula:

Depth of insertion (in centimeters) = 7.0 + 0.04 X Patient’s Height (in centimeters) + 0.05 X Patient’s Weight (in kilograms) [14].

The Classic LMA is a scaled down version of the adult LMA while the pediatric ProSeal LMA has specific design features that may permit a better seal and greater protection against aspiration and gastric inflation, especially in infants and young children, including a gastric channel which permits passage of a nasogastric tube and gastric decompression while the LMA is in place [13].

Indications — The LMA may be effective in situations in which tracheal intubation is difficult or impossible, and when placed correctly can avoid the need for continuous mask seal during bag-mask ventilation. It can also be attempted in the "cannot intubate-cannot ventilate" situation, but care must be taken to ensure that the patient does not experience an excessively long period of hypoxemia. The LMA can serve as a bridge between bag mask ventilation and intubation and can facilitate the use of devices for difficult endotracheal intubation (eg, fiberoptic stylet, flexible fiberoptic bronchoscope) [15-18]. (See "Video laryngoscopy and other devices for difficult endotracheal intubation in children", section on 'Optical stylets' and "Video laryngoscopy and other devices for difficult endotracheal intubation in children", section on 'Flexible scope intubation'.)

Contraindications — Like almost all supraglottic devices, the LMA is unlikely to be effective in cases of airway obstruction (eg, croup, asthma) when the pressure in the airway is higher than the sealing pressure of its mask, allowing air to leak around the mask cuff. It should not be used when the airway anatomy is significantly distorted (eg, laryngeal trauma, congenital anomalies of the larynx) or in patients with upper airway infection that distorts anatomy (eg, epiglottitis). However, in one operating room study, the LMA had a failure rate of less than one percent. In most cases, failure was related to airway obstruction or to coughing or "bucking" in an inadequately sedated patient [19]. The degree to which this information is applicable to the emergency department setting is unclear.

The LMA provides less protection against aspiration than endotracheal intubation, but in situations requiring the insertion of a rescue airway, the risk of aspiration is generally outweighed by the benefits [20].

Failure of the LMA is rare in children (<1 percent) [21].

Choice of technique — There are three techniques available for LMA placement: standard, rotational, and lateral. The standard technique is appropriate for children over seven years of age (see 'Standard technique' below). We recommend that clinicians use the rotational technique instead of the lateral or standard technique when placing LMAs in children under seven years of age (see 'Rotational technique' below). This recommendation is based upon the following evidence:

●In a cross-over trial of 78 children between three months and 10 years of age undergoing elective eye surgery, the rotational technique was associated with a significantly higher success rate (96 versus 81 percent first pass success rate), lower time to successful insertion (12 versus 16 seconds) than the standard technique [22]. Laryngospasm (6 versus 0 percent), blood on the LMA (13 versus 3 percent), and need for airway maneuvers (9 versus 1 percent) were all significantly greater with the standard technique when compared to the rotational technique.

●A trial compared LMA placement using rotational, lateral, and standard techniques in 168 children, six months to six years of age, who were undergoing elective surgical procedures [23]. The rotational technique had a first time insertion rate of 96 percent versus 84 percent with the lateral technique and 80 percent with the standard technique. No patient undergoing rotational placement of an LMA had laryngospasm compared with 5 percent of patients following the lateral technique and 9 percent of patients after the standard technique.

●A trial evaluating LMA placement using the rotational or standard technique in 145 children, 10 months to seven years of age, who were undergoing elective surgery found that the rotational technique had a significantly greater first time insertion success rate than the standard technique (99 versus 79 percent, respectively) [24]. The rotational technique was also found to have a significantly lower incidence of airway trauma than the standard technique (5 versus 17 percent).

●An observational study of 158 children undergoing LMA placement by the standard technique for elective surgery found that significant malposition as seen by fiberoptic bronchoscopy was present in 72 to 80 percent of infants weighing less than 10 kg (LMA size 1.0 to 1.5) [25].

Taken together, these studies indicate that placement of the LMA using the rotational technique in young children under seven years of age has a significantly higher success rate on first attempt and is associated with a significantly lower risk of airway trauma or laryngospasm.

Rotational technique — This technique is recommended for infants and young children under seven years of age [23,26].

●If the LMA is placed due to a failed airway, summon additional airway experts (eg, anesthesiologist, otolaryngologist, emergency medicine, or critical care subspecialist), if needed and if available, while establishing a rescue airway.

●Select an appropriately sized LMA (table 1) and remove it from its packaging.

●Partially inflate the cuff until all indentations are gone.

●Lubricate the cuff with water-soluble lubricant.

●Stand at the patient's head as for a standard intubation.

●Open the child’s mouth using your non-dominant hand.

●Using your dominant hand, insert the LMA with the opening facing the palate until resistance from the posterior pharyngeal wall is felt.

●Rotate the LMA 180 degrees and pass it downward into position behind the larynx.

●Attempt bag ventilation. If the patient can be properly ventilated, fully inflate the cuff. No further action is necessary. If not or if there is a significant air leak, the LMA must be removed or repositioned.

Standard technique — This technique is appropriate for children over seven years of age (figure 1) [27].

●If the LMA is placed due to a failed airway, summon additional airway experts (eg, anesthesiologist, otolaryngologist, emergency medicine, or critical care subspecialist), if needed and if available, while establishing a rescue airway.

●Select an appropriately sized LMA (table 1) and remove it from its packaging.

●Completely deflate its cuff using the special deflation tool or by placing the LMA cuff down on a flat surface and then placing the first and middle finger on either side of the cuff and deflating the cuff using the syringe (figure 2). When the cuff is correctly deflated, the LMA should look like a small boat with a curved mast or smokestack (it should be noted that successful insertion of the LMA may be facilitated by partial cuff inflation. You may wish to insert the device with cuff partially inflated, as described in the rotational technique above).

●Lubricate the cuff using water-soluble lubricant.

●Stand at the patient's head as for a standard intubation.

●Open their mouth using your non-dominant hand while holding the LMA in your dominant hand so that your index finger or middle finger is resting inside the mask and the remaining fingers are holding the LMA like a pencil.

●Insert the LMA with its ventilating surface facing the patient's tongue and advance it along the palate until it can be advanced no further.

●Inflate the cuff. This step often causes the LMA to "seat itself" into the proper location while rising up out of the airway a few millimeters.

●Attempt bag ventilation. If the patient can be properly ventilated, no further action is necessary. If not or if there is a significant air leak, the LMA must be removed or repositioned using a jaw thrust or a combination of a jaw thrust and partial removal and reinsertion. If the latter method is chosen, the cuff should be partially deflated prior to repositioning the LMA.

Pitfalls

●The LMA can fail when there is significant airway obstruction or anatomical distortion.

●The LMA cuff can be damaged during insertion. The cuff may also become folded on itself during insertion.

●The cuff may catch on the epiglottis or in the vallecula.

●The LMA may fold the epiglottis down onto the glottic aperture and prevent ventilation

●The LMA does not completely protect the patient from aspiration.

●Insertion in patients who are inadequately anesthetized or who awaken during ventilation can result in laryngospasm or airway trauma.

i-gel LARYNGEAL AIRWAY — The i-gel is a unique supraglottic airway because it does not employ balloons to isolate the laryngeal opening. Instead, its cuff is made of a thermoplastic elastomer gel. Once inserted, the patient’s own body temperature helps the mask to conform to an appropriate configuration. The i-gel appears to function in a fashion similar to the laryngeal mask airway (LMA). However, it may cause higher positive inspiratory pressure and decreased tidal volume when the neck is flexed when compared with the LMA [28].

In studies comparing various types of supraglottic airways, the i-gel appears to offer the advantage of rapid insertion. For example, in a study of paramedics' use of several supraglottic airways in a manikin model, the i-gel was one of the three devices that was inserted most rapidly [10]. In another study, insertion of the i-gel by inexperienced physicians was compared with two other supraglottic devices (the AirQ and the Ambu AuraGain) in a manikin model of blind tracheal intubation for both normal and difficult airways and with and without continuous chest compressions [29]. In this study, the i-gel was superior or noninferior to the other devices in all scenarios. Other potential advantages of the i-gel include an internal bite block to prevent the tube from collapsing should the patient awaken and clench the teeth and a gastric channel that, like the LMA ProSeal, allows for passage of nasogastric or orogastric tube to decompress the stomach. However, in one study of the i-gel, anesthesiologists found that the device had a tendency to be displaced upward, toward the mouth, and that attempts to reposition the tube could result in an inadequate airway. Nonetheless, the device was abandoned in favor of an alternative in less than 5 percent of cases [30].

The i-gel is available in the following sizes:

●Size 1: 2 to 5 kg

●Size 1.5: 5 to 12 kg

●Size 2: 10 to 25 kg

●Size 2.5: 25 to 35 kg

●Size 3: 30 to 60 kg

●Size 4: 50 to 90 kg

●Size 5: >90 kg

All of the i-gels except the size 1 have an integrated port that allows the passage of a gastric tube to decompress the patient’s stomach.

Standard technique

●Summon additional airway experts (eg, anesthesiologist, otolaryngologist, emergency medicine, or critical care subspecialist), if needed and if available, while establishing a rescue airway.

●Select an appropriately sized i-gel and have immediately available one size smaller and one size larger than you anticipate needing.

●Remove the i-gel from its packaging and then remove the device from the protective cradle.

●Apply water soluble lubricant to the cradle.

●Grasp the i-gel by the ventilating tube and, using the cradle as a base, apply lubricant to the i-gel without touching the mask with your hands.

●Ensure that the patient is adequately anesthetized or is unconscious.

●Grasp the i-gel by the integrated bite block portion of the ventilating tube.

●Open the patient’s mouth and insert the tube with the mask opening facing the patient’s chin. Unless neck movement is contraindicated, the patient’s head and neck should be positioned in the so called "sniffing" position.

●Guide the tube along the palate and advance it until resistance to further advancement is felt. Unlike other supraglottic devices, the manufacturer of the i-gel does not recommend that you use your fingers to facilitate insertion but instead they suggest that you guide the tube into place using only the ventilation tube. The size 3 to 5 i-gels have a line on the ventilating tube that indicates the appropriate depth of insertion. When this line is located between the patient’s central incisors, the i-gel is located at approximately the appropriate depth. The smaller sized i-gels do not have an indicator line.

●The manufacturer recommends that the i-gel be secured using the strap, which is located in the package, or with adhesive tape. In the latter case, they recommend that the device be taped in place from maxilla to maxilla.

●Adequate chest rise, auscultation of breath sounds bilaterally, lack of gastric distention, and detection of expired carbon dioxide are all indications of proper placement.

Rotational technique — Although evidence is limited in children, the rotational technique has been used in adults with good success and may be an alternative in children if the standard technique fails.

●Summon additional airway experts (eg, anesthesiologist, otolaryngologist, emergency medicine, or critical care subspecialist), if needed and if available, while establishing a rescue airway.

●Select an appropriately sized i-gel and have immediately available one size smaller and one size larger than you anticipate needing.

●Remove the i-gel from its packaging and then remove the device from the protective cradle.

●Apply water soluble lubricant to the cradle.

●Grasp the i-gel by the ventilating tube and, using the cradle as a base, apply lubricant to the i-gel without touching the mask with your hands.

●Ensure that the patient is adequately anesthetized or is unconscious

●Grasp the i-gel by the integrated bite-block portion of the ventilating tube.

●Open the patient’s mouth and insert the tube with the mask opening facing the patient’s chin. Unless neck movement is contraindicated, the patient’s head and neck should be positioned in the so-called "sniffing" position.

●Insert the i-gel into the oral cavity and then rotate the device 90 degrees counterclockwise.

●Advance the i-gel past the body of the tongue and until resistance is felt in the hypopharynx, then rotate the device 90 degrees clockwise into the standard position, ensuring that it is positioned in the mid-line. The manufacturer of the i-gel recommends that you guide the tube into place using only the ventilation tube rather than using your fingers. The size 3 to 5 i-gels have a line on the ventilating tube that indicates the appropriate depth of insertion. When this line is located between the patient’s central incisors, the i-gel is located at approximately the appropriate depth. The smaller-sized i-gels do not have an indicator line.

●The manufacturer recommends that the i-gel be secured using the strap, which is located in the package, or with adhesive tape. In the latter case they recommend that the device be taped in place from maxilla to maxilla.

●Adequate chest rise, auscultation of breath sounds bilaterally, lack of gastric distention, and detection of expired carbon dioxide are all indications of proper placement.

Pitfalls — Because the i-gel lacks an inflatable mask that can compensate for size problems, appropriate size selection is especially important. As previously mentioned, one study found that it had a tendency to be displaced upward and that attempts to reposition the i-gel could lead to an inadequate airway. It was especially noted that flexion of the proximal portion of the tube toward the patient’s feet increased airway obstruction and that this was relieved by moving the tube toward the patient’s head [30]. This might have significant implications for securing the tube in place. One series suggested that adequate sealing pressures were harder to obtain with smaller-sized i-gel tubes, and this may be a problem when positive pressure ventilation is used in such children [31].

OTHER DEVICES — The laryngeal mask airway and the i-gel supraglottic airway are among the most commonly used rescue airways, but there are several other effective devices available. Some of these are described below.

Intubating laryngeal mask airway (ILMA) — The ILMA is a modified laryngeal mask airway (LMA) designed as a conduit for tracheal intubation. It may be used in children weighing 30 kg or greater. Rather than a flexible ventilating tube, the ILMA has a U-shaped metal tube designed to accommodate a specially adapted, flexible, endotracheal tube. Within the mask is a lever which is intended to lift the epiglottis as the tip of the endotracheal tube passes through the mask. A special handle is attached to the side of the tube. This is intended to facilitate placement. Finally, the kit contains a rubber stabilizing bar which is used during tracheal intubation through the ILMA [32,33]. A similar device (the air-Q masked laryngeal airway) permits intubation using standard endotracheal tubes through a supraglottic device in smaller children although there is limited evidence for its use in children.

The ILMA permits successful fiberoptic endotracheal intubation in children under 30 kg by experienced airway specialists [34]. However, poor glottic views are common in children under 17 kg. Thus, blind intubation through the ILMA should be avoided.

Indications — The ILMA may be used to facilitate endotracheal intubation in children weighing 30 kg or greater. The ILMA may be used with several devices as follows:

●A small flexible fiberoptic laryngoscope or bronchoscope may be inserted by an experienced clinician to ensure that the ILMA is properly positioned for intubation. (See "Video laryngoscopy and other devices for difficult endotracheal intubation in children", section on 'Optical stylets' and "Video laryngoscopy and other devices for difficult endotracheal intubation in children", section on 'Flexible scope intubation'.)

●A small bougie may be directed through the ILMA and inserted into the trachea. This can then be used to guide the endotracheal tube into position. However, because the distal holes of the special endotracheal tube are smaller than the distal hole of a standard tube before using a bougie, first be certain that the bougie will pass easily through the tube. (See "Video laryngoscopy and other devices for difficult endotracheal intubation in children", section on 'Intubating introducers (gum elastic bougie)'.)

●Some operators have used the ILMA to insert standard endotracheal tubes. This is somewhat more difficult than insertion of the specially designed tube. If a standard endotracheal tube is used with the ILMA, the tube should be thoroughly lubricated and inserted into the LMA with the curved portion of the tube facing the operator.

The ILMA should only be used in children under 30 kg with the assistance of a fiberoptic bronchoscope.

Contraindications — The ILMA is likely to be ineffective in cases of airway obstruction (eg, croup, asthma) because the pressure in the airway will be higher than the sealing pressure of its mask, allowing air to leak around the mask cuff. It should not be used when the airway anatomy is significantly distorted (eg, laryngeal trauma, congenital anomalies of the larynx) or in patients with upper airway infection that distorts anatomy (eg, epiglottitis).

Technique — The following steps describe endotracheal intubation using the LMA Fastrach (figure 3).

●If the ILMA is placed due to a failed airway, summon additional airway experts (eg, anesthesiologist, otolaryngologist, emergency medicine or critical care subspecialist), if needed and if available, while establishing a rescue airway.

●Prepare the ILMA just as you would a standard LMA by deflating and lubricating the cuff (figure 2). Also, prepare the endotracheal tube by checking its cuff and lubricating its external surface.

●Taking care to follow the midline of the patient's mouth, insert the LMA and direct it along the palate until it cannot be advanced further.

●Inflate the cuff, attach a ventilating bag and attempt ventilation.

●If ventilation is successful then you may proceed with tracheal intubation. However, since the intubation attempt might leave the patient briefly apneic, the patient should be oxygenated before intubation is attempted. Furthermore, sedation and paralysis as for rapid sequence intubation may be necessary (table 2). (See "Rapid sequence intubation (RSI) in children for emergency medicine: Approach".)

●Remove the ventilating bag and insert and advance the endotracheal tube while gently lifting the LMA. Passage of the endotracheal tube into the trachea may be facilitated by having an assistant apply slight pressure over the patient's thyroid cartilage. The endotracheal tube should advance easily. Significant resistance to passage suggests that the endotracheal tube is not entering the trachea and it should be removed and another attempt made after the patient has been ventilated and oxygenated.

●If the tube advances easily then its position can be confirmed with an end-tidal CO2 detector.

●If the endotracheal tube is located within the trachea, then you may proceed with the next step; removal of the ILMA.

●Once again, before starting, ventilate and oxygenate the patient. You may need to inflate the cuff on the endotracheal tube to ventilate them effectively.

●Deflate the cuff on the ILMA, but leave the endotracheal tube cuff inflated.

●Next, carefully remove the adapter from the endotracheal tube and insert the rubber stabilizing bar in its place.

●Gently remove the ILMA over the endotracheal tube and stabilizer bar while maintaining slight downward pressure on the stabilizer bar. Once the mask has been removed from the mouth, remove the stabilizer bar so that the pilot balloon on the endotracheal tube can pass through the bore of the ILMA.

●Once the ILMA is completely removed, attach the adapter to the endotracheal tube, confirm its position with capnography, and ventilate the patient.

●Secure the endotracheal tube in the usual fashion; however, consider using a bite block to protect the flexible, wire-reinforced endotracheal tube from damage. (See "Technique of emergency endotracheal intubation in children", section on 'Securing the tube'.)

●Confirm proper positioning of the endotracheal tube with an end-tidal CO2 detection device. (See "Technique of emergency endotracheal intubation in children", section on 'Confirming tube position'.)

Pitfalls

●Use of the ILMA has all of the potential complications associated with use of the standard LMA. (See 'Pitfalls' above.)

•Additionally, one might not be able to perform tracheal intubation using the ILMA.

●Inadvertent deflation of a cuffed endotracheal tube balloon during LMA removal can cause dislodgement.

●Failure to deflate the ILMA cuff during attempted removal may cause laryngeal injury.

Air-Q masked laryngeal airway — The air-Q intubating masked laryngeal airway (ILA) is a modified laryngeal airway that comes in sizes that permit tracheal intubation in neonates and children under 30 kg as follows:

●ILA 1.0: 4 to 7 kg

●ILA 1.5: 7 to 17 kg

●ILA 2.0: >17 to 30 kg

The main advantage of the air-Q is that it allows for ventilation in a fashion much like the standard LMA but is also designed to facilitate intubation using standard endotracheal tubes (ETT) in young children. Specifically, the ventilation tube of these devices is wide enough to allow the passage of the cuffs and pilot balloons of cuffed endotracheal tubes, thus overcoming a problem that limits intubation using some other devices. Intubation can be either be accomplished blindly or using a fiberoptic bronchoscope, optical stylet, or lighted stylet.

Additionally, this device has a bite-block built into the tube to prevent tube occlusion if the patient awakens and clenches their teeth. In one study of 34 children who had a difficult airway, intubation through the air-Q was successful on the first attempt in 33 patients and on the second attempt in the remaining child [35].

Technique: Insertion of the air-Q

●Ensure that the mask inflation valve is open either by leaving the red tag in place or by inserting an empty syringe barrel into the inflation valve.

●Thoroughly lubricate the mask

●Open the patient’s mouth and, if possible perform a mandibular lift. This elevates the tongue and facilitates placement of the air-Q. If this is not possible, consider using a tongue blade to depress the base of the tongue.

●Place the front portion of the air-Q mask into the oral cavity and advance it until it sits between the soft palate and the base of the tongue. Angling the tube portion of the device slightly forward might facilitate proper placement.

●Gently advance the air-Q into the pharynx using a downward and inward pressure. If necessary, the back of the left (or nondominant) index finger can be placed behind the mask and then finger flexion can be used to guide the tube into position. Once the mask has been directed into the pharynx, the non-dominant hand should be used to again perform a mandibular lift.

●When resistance to further advancement is felt, inflate the cuff per the manufacturer’s recommendations and secure the air-Q with tape or a tube clamp.

Technique: Intubation using the air-Q

●For best results, the patient should be sedated and paralyzed prior to the intubation attempt. If the patient cannot be safely paralyzed then local anesthetic should be administered to the vocal cords using a nebulizer, atomizer, or a similar device. Preoxygenation is also recommended.

●Select an appropriately sized endotracheal tube. Use of a cuffed tube is preferred, as this allows for less precise tube size selection.

●Inspect the endotracheal tube cuff to ensure that it is intact then deflate the cuff as much as possible to facilitate passage through the air-Q. Liberal lubrication of the endotracheal tube is also recommended.

●Remove the adapter from the air-Q tube and insert the endotracheal tube into the air-Q and advance the endotracheal tube until the tip of the endotracheal tube should be just proximal to the distal opening of the air-Q tube (the opening inside of the mask).

From this position several intubation techniques are possible:

●Bougie

•Lubricate a gum elastic bougie or other malleable, blunt-ended stylet and pass it into the endotracheal tube. Once the bougie or stylet enters the trachea, you should be able to feel it scrape along the tracheal rings. This sensation can be enhanced by placing the fingers of your non-dominant hand over the larynx.

•Advance the endotracheal tube over the stylet or bougie. If you cannot advance the ETT, try rotating it counter-clockwise and then repeat the attempt. If this fails, consider the use of a smaller tube.

●Lighted stylet

•Lubricate a lighted stylet and advance it through the ETT. An intense glow (sometimes called a "jack-o-lantern" glow) coming from the thyroid cartilage and cricoid area indicates that the stylet is within the trachea.

•Withdraw the malleable style inside of the lighted style and advance the lighted stylet so that you see the glow in the suprasternal notch or, if the stylet is not long enough, advance the lighted stylet as far as possible.

•Pass the endotracheal tube over the lighted stylet and into the trachea. As described above, manipulation of the tube or selection of a smaller tube might be necessary.

●Optical technique – This technique offers the greatest assurance of tracheal intubation.

•Lubricate an optical stylet or a fiberoptic bronchoscope and advance the stylet or bronchoscope into the ETT tube under direct vision then advance the stylet or bronchoscope directly into the trachea. Note that some optical stylets are designed to be advanced only until the glottic opening is visualized. When using such a stylet, advance the stylet until you have a good view of the glottic opening and then advance the ETT under direct vision.

•Advance the ETT into the trachea over the stylet or fiberoptic scope.

●Blind intubation – Blind intubation through the air-Q is possible but one of the above techniques is preferred.

•Once the lubricated ETT is in position, attempt to advance it directly into the trachea. As mentioned, it may be necessary to manipulate the tube or select a smaller size in order to successfully intubate the patient.

•Once you are reasonably certain that the endotracheal tube is within the trachea, partially inflate the cuff and confirm tracheal position using end-tidal CO2 detection.

•When you have determined that the ETT is within the trachea, advance it into the proper position and inflate the cuff.

Removal of the air-Q — Once tracheal intubation is achieved, the clinician must decide what to do with the air-Q device. Options are to either safely leave it in place and remove it in a more controlled environment (eg, the ICU or operating room) at a later time or remove it as soon as tracheal intubation is accomplished. In most cases, the safest course of action is to leave the laryngeal airway in place with its cuff deflated until it can be removed electively. The removal technique is as follows:

●Preoxygenate the patient.

●Deflate the cuffs of both the ETT and the air-Q.

●Remove the adapter from the ETT and insert the tapered end of the air-Q removal stylet into the proximal end of the endotracheal tube and ensure that it fits snugly within the ETT.

●Maintain distal pressure on the ETT and stylet and remove the air-Q over the stylet.

●Reposition the ETT, if necessary, replace the adapter, inflate the balloon, and ventilate normally.

Pitfalls — Some have suggested that blind intubation using the air-Q and similar devices is inadvisable in children because the epiglottis might actually lie within the mask and blind passage of an endotracheal tube could actually damage the epiglottis or other structures. These authors advocate the use of an intubation technique that employs direct visualization such as fiberoptic bronchoscopy, whenever possible [36,37]. The air-Q and other intubating laryngeal devices might be difficult or impossible to insert when the patient has limited mouth opening [35].

CobraPLA — The CobraPLA (CPLA) differs slightly from other laryngeal or extraglottic airways. This device consists of a ventilation tube with a flexible "cobra-shaped" head at its distal end and a ventilation port at its proximal end (picture 1). The head is soft and flexible with a ventilation grill on one side. Immediately proximal to the head is a single ring-like balloon which is intended to occlude the hypopharynx. The CPLA is available in sizes appropriate for patients as small as 2.5 kg [38].

Randomized trials comparing the CobraPLA with the laryngeal mask airway for airway management in children during brief surgical procedures indicate that the CobraPLA is as effective for establishing an airway and is also easy to insert and maintain [39-41].

Indications and contraindications — The CobraPLA may be effective in situations in which tracheal intubation is difficult or impossible. It is likely to be more effective than bag-mask ventilation during resuscitation situations. It can also be attempted in the cannot intubate-cannot ventilate situation, but care must be taken to ensure that the patient does not experience an excessively long period of hypoxemia.

The CobraPLA is unlikely to be effective in cases of airway obstruction (eg, croup, asthma) because the pressure in the airway will be higher than the sealing pressure of its mask, allowing air to leak around the mask cuff. It should not be used when the airway anatomy is significantly distorted (eg, laryngeal trauma, congenital anomalies of the larynx) or in patients with upper airway infection that distorts anatomy (eg, epiglottitis).

Technique — An instruction manual and training video are available from the manufacturer [42,43].

●Summon additional airway experts (eg, anesthesiologist, otolaryngologist, emergency medicine, or critical care subspecialist), if needed and if available, while establishing a rescue airway.

●Remove the CobraPLA (CPLA) from its package and check the balloon.

●Deflate the balloon and fold it back against the ventilation tube

●Lubricate the distal portion the device, paying special attention to the back of the "cobra" head.

●Pull the cuff down around the proximal portion of the tube.

●Perform a jaw thrust maneuver and insert the device with ventilation grill facing the patient's tongue.

●Advance the CPLA distally until you feel resistance. The device should be positioned such that the ventilation grill is facing the glottis.

●Inflate the balloon with air as recommended by the manufacturer (maximum pressure in adults is 60 cm of water). Air can be added to the cuff if there is an air leak around the balloon during attempted ventilation.

●Adequate chest rise, auscultation of breath sounds bilaterally, and lack of gastric distention, and detection of expired carbon dioxide are all indications of proper placement

Pitfalls — The CobraPLA (CPLA) is usually easily inserted, although difficulties have been encountered in some patients with obesity. However, the primary difficulties associated with the CPLA are either not inserting the device far enough such that the ventilating surface does not cover the glottis or advancing it too far. In the former case, the tongue might be pushed out of the mouth, indicating the need to advance the CPLA further. In the latter case, ventilation will not be possible, and as in all such cases, the device should be removed and replaced. Additionally, the CPLA does not prevent aspiration [44] and like all such devices, is likely to be ineffective in patients who have significant distal airway resistance.

Laryngotracheal airways — Several manufacturers make laryngotracheal airways (eg, King LAD Airway, King LTD Supraglottic Airway, Portex Soft Seal Laryngeal Mask). Many function (and look) similar to the laryngeal mask airway (LMA), while others are designed to be placed directly into the esophagus, thus occluding it with a sealed distal balloon and facilitating air flow into the trachea. While these devices function in a fashion similar to an older device, the Combitube, they have two advantages over the Combitube. They are softer and therefore less likely to damage the esophagus, and they are available in multiple sizes so that they can be used in smaller children. For example the King LTD Supraglottic Airway, size 2 can be used in patients as small as 12 kg or 35 inches in height.

The Combitube is rarely used in children, is primarily a pre-hospital device, and contains latex, which makes it less suitable for airway management in the emergency department.

Indications and contraindications — These devices have the same indications and contraindications/cautions as the other supraglottic rescue airways described. Also, most do not contain latex. (See 'Contraindications' above.)

Technique — Devices that function like the LMA are inserted in a fashion similar to the LMA (see 'Choice of technique' above). Two insertion techniques have been described for the devices that are intended to be placed into the esophagus.

Blind technique

●Summon additional airway experts (eg, anesthesiologist, otolaryngologist, emergency medicine, or critical care subspecialist), if needed and if available, while establishing a rescue airway.

●Remove the device from its packaging, inspect and test the balloons, and lubricate its external surface with water soluble lubricant.

●If the patient’s neck can be safely moved, slightly extend the chin so that it is in the so called "sniffing position". Note that the device can still be used effectively in patients whose necks cannot be manipulated (eg, cervical spine precautions), neck extension merely facilitates placement.

●With your dominant hand, hold the device near its connector and place it in the right corner of the mouth with the ventilation port turned approximately 90 degrees to the right of the patient’s midline.

●With the nondominant hand open the mouth, and if it is safe to do so, gently lift the mandible using your nondominant thumb and forefinger.

●Advance the device along the right side of the mouth until it is past the tongue; then, rotate it 90 degrees to the patient’s left so that the ventilation port is roughly aligned with the patient’s midline.

●Continue advancing the device as far as recommended by the manufacturer. In many cases, this will be the point at which the base of the connector is aligned with the patient’s incisors.

●Inflate the balloons, distal first and then proximal. In general, the balloons should be inflated with the minimal volume of air necessary to seal the airway.

●Attempt ventilation. You should be able to see chest rise and hear breath sounds on auscultation. Expired carbon dioxide should be detected by an end-tidal CO2 detector. If necessary, the tube may be withdrawn slightly or advanced slightly to achieve maximal ventilation.

●Secure the laryngotracheal airway to prevent dislodgement.

Alternative technique

●Summon additional airway experts (eg, anesthesiologist, otolaryngologist, emergency medicine, or critical care subspecialist), if needed and if available, while establishing a rescue airway.

●Remove the device from its packaging, inspect and test the balloons, and lubricate its external surface with water-soluble lubricant.

●Using a laryngoscope, direct the device into the esophagus.

●Inflate the balloons.

●Check for ventilation. If the patient cannot be ventilated the device must be removed immediately because it may have been inadvertently placed into the trachea.

●These devices are generally not used in combination with other tools but sometimes can be used with airway guides or flexible fiberoptic laryngoscopes.

Pitfalls — The major pitfall associated with these tools is inadvertent placement into the trachea. Other pitfalls include over-inflation of the balloons, which can distend the esophagus causing potential injury to the esophagus itself or compression of the trachea, and placement of the ventilating port too distally or too proximally to allow for effective ventilation.

SUMMARY AND RECOMMENDATIONS

●Definition – Supraglottic airway devices are placed above the glottis without extension of any components into the esophagus and permit oxygenation and ventilation until a definitive airway is secured and can facilitate endotracheal intubation. Clinicians should have supraglottic airway devices available whenever performing an emergency pediatric intubation. (See 'Terminology' above and 'Contingency plan for the failed airway' above.)

●Choice of device – The laryngeal mask airway (LMA) and similar laryngeal tracheal devices (eg, King LAD, air-Q, i-gel, Ambu Aura, or CobraPLA) are the most versatile airway rescue devices for children and are available in sizes that permit placement in all pediatric patients (table 1). (See 'Choice of device' above and 'Laryngeal mask airway (LMA)' above.)

The advantages of the LMA are (see 'Indications' above):

•It may be effective in situations in which tracheal intubation is difficult or impossible.

•It can be attempted in the cannot intubate-cannot ventilate situation.

•It can serve as a bridge between manual ventilation and intubation and can facilitate the use of devices for difficult endotracheal intubation (eg, fiberoptic stylet, flexible fiberoptic bronchoscope).

The LMA is less likely to be effective in patients with distorted airway anatomy (eg, laryngeal trauma) and patients with conditions associated with airway obstruction (eg, croup, asthma). (See 'Contraindications' above.)

●LMA placement – The standard technique for LMA placement is appropriate for children over seven years of age (see 'Standard technique' above). We recommend that clinicians use the rotational technique instead of the lateral or standard technique when placing LMAs in children under seven years of age (Grade 1B). (See 'Rotational technique' above.)

●i-gel – The i-gel is a unique airway device that employs a thermoelastic polymer rather than an inflatable cuff to achieve an effective airway seal. This device is available in sizes appropriate for very small children and appears to offer the advantage of easy insertion. The i-gel may be superior to other supraglottic airways when it is used as a conduit for blind tracheal intubation. (See 'i-gel laryngeal airway' above.)

Other devices that may be used in older children and adolescents but not in young children include the intubating LMA, the Air-Q, the CobraPLA, and laryngotracheal airways that are placed in the esophagus. Indications, contraindications, and placement techniques are described. (See 'Intubating laryngeal mask airway (ILMA)' above and 'Air-Q masked laryngeal airway' above and 'CobraPLA' above and 'Laryngotracheal airways' above.)