INTRODUCTION

For the most part, the airway devices and techniques used in older children and adolescents are no different from those used in adults. The same cannot be said of small children (younger than 3 years) and infants (younger than 1 year), mostly related to two factors: the airway anatomy in these age groups is substantially different from the adult form, and some of the commonly used rescue devices are not available in pediatric sizes (e.g., Combitube, LMA Fastrach). We limit our discussion to those rescue devices that are available for the pediatric population and that have evidence of successful use in children.

Mastering these techniques is straightforward and necessary if one is to manage the emergent pediatric airway. The following discussion describes the appropriate use of the various airway modalities in pediatrics, with emphasis on age appropriateness.

TECHNIQUES USED IN ALL CHILDREN

Bag-Mask Ventilation and Endotracheal Intubation

Refer to Chapters 9 and 13 for a detailed description of bag-mask ventilation (BMV) and endotracheal intubation. As in adults, nasopharyngeal and oral airways are important adjuncts to BMV, especially in small children in whom the tongue is relatively large in relation to the volume of the oral cavity. Recommendations and the rationale for the use of specific equipment (curved or straight blades, cuffed vs. uncuffed tubes) are described in Chapter 24. Use of size-appropriate equipment for pediatric airway management is critical to success, even in the most experienced hands. Proper BMV technique is particularly important in pediatric patients because the indication for intervention is most often primarily related to a respiratory disorder, and the child is likely to be hypoxic. In addition, pediatric patients are subject to more rapid oxyhemoglobin desaturation, so that BMV with cricoid pressure (Sellick maneuver) applied to prevent gastric insufflation is frequently required during the preoxygenation and paralysis phases of rapid sequence intubation. Pediatric BMV requires smaller tidal volumes, higher rates, and size-specific equipment. The pediatric airway is particularly amenable to positive-pressure ventilation, even in the presence of upper airway obstruction (see Chapters 24 and 26).

Tips for Successful BMV Ventilation in Children

Although BMV in the pediatric population fails infrequently, attention to detail remains critical to success: the mask seal must be adequate, the airway open, and the rate and volume of ventilation appropriate to the patient’s age. Two errors of technique tend to occur. First, there is a tendency in the excitement of the situation to press the mask portion of the unit downward in an attempt to obtain a tight seal, resulting in neck flexion and upper airway obstruction. The head should be extended slightly rather than flexed, thereby relieving, rather than producing, obstruction caused by the tongue and the relaxed pharyngeal anatomy (Fig. 25-1).

Second, there is a tendency to bag at an excessive rate. The cadence for bagging should permit adequate time for exhalation (actually repeating the words “squeeze, release, release” is helpful to assure adequate cadence). Textbooks recommend faster rates for smaller children. From a practical point of view, however, this cadence can be used for all ages. Always place an oral airway in the unconscious child before ventilating with a bag and mask because the pediatric tongue is large relative to the size of the oropharynx and is more prone to obstruct the upper airway.

The positioning described in the previous paragraph is usually obtained while applying the one-handed, C-grip technique to the mask. The thumb and index finger support the mask from the bridge of the nose to the cleft of the chin, avoiding the eyes. The bony prominences of the chin are lifted up by the rest of the fingers, placing the head in mild extension to form the sniffing position. Care is taken to avoid pressure on the airway anteriorly to prevent collapsing and obstructing the pliable trachea.

The two-handed technique can also be used. While this technique is critical for successful rescue mask ventilation of adults, it may be selectively applied in small children. By opening the jaw slightly and pulling it forward, an obstruction may be relieved. The jaw can be moved further forward after opening the mouth slightly (“translating the mandible” forward; see Chapter 9), while using the thenar eminences of the palm to seal the mask on the face. The thenar grip is more effective at creating a uniform seal and minimizing leak around the margin of the mask. Once the mask is applied, a second provider squeezes the bag. If ventilation is not immediately facilitated with these maneuvers, positioning should be reassessed and a nasopharyngeal airway be placed to supplement the oropharyngeal airway.

• FIGURE 25-1. A: Bad bagging. Fast cadence. B: Good bagging. Squeeze, release, release. Part A demonstrates the flexed position causing obstruction, whereas Part B demonstrates extended position which relieves obstruction.

1. Position correctly: Proper patient positioning is key to prevent obstruction and provide optimal alignment of the axes of the airway. Optimal alignment of the laryngeal, pharyngeal, and oral axes in adults usually requires elevation of the occiput to flex the neck on the torso and extend the head at the atlanto-occipital joint. Because of the larger relative size of the occiput in small children, elevation of the occiput is usually unnecessary, and extension of the head may actually cause obstruction. Slight anterior displacement of the atlanto-occipital junction is all that is needed (i.e., pulling up on the chin to create the sniffing position). In small infants, elevation of the shoulders with a towel may be needed to counteract the effect of the large occiput that causes the head to flex forward on the chest. As a general rule, once correctly positioned, the external auditory canal should lie just anterior to the shoulders. Whether this position requires support beneath the occiput (older child/adult), the shoulders (small infant), or no support (small child) (Fig. 25-2A) can be determined using this rule of thumb. These are guidelines only, and each individual patient is different. A quick trial may be required to find the optimal position. Figure 25-2B demonstrates the most common position for intubating the small child, the so-called sniffing position, and how this is achieved in a child of this size.

• FIGURE 25-2. A: Clinical determination of optimal airway alignment, using a line passing through the external auditory canal and anterior to the shoulder B: Application of the line to determine optimal position. In this small child, the occiput obviates the need for head support, yet the occiput is not so large as to require support of the shoulders. Note that a line traversing the external auditory canal will pass anterior to the shoulders. With only slight extension of the head on the atlanto-occipital joint, the sniffing position is achieved.

Although virtually every textbook chapter, article, or lecture on pediatric airway management refers to the technique of needle cricothyrotomy as the recommended last-resort rescue procedure, there is little literature to support its use and safety. Few of the “experts” who write about needle cricothyrotomy have experience performing the procedure on live humans, but nevertheless, any clinician who manages pediatric emergencies as part of his or her practice must be familiar with the procedure and its indications, and must have the appropriate equipment readily accessible in the emergency department.

Various commercially available needles are also available for percutaneous needle cricothyrotomy (Table 25-1). The simplest equipment, appropriate for use in infants, consists of the following:

• 14G over-the-needle catheter

• 3.0-mm ETT adapter coupled with an IV extension set (These can be obtained commercially or constructed by cutting off 6 in of distal IV tubing and inserting a 2.5 m adapter into the opening; see Fig. 25-3.)

• 3- or 5-mL syringe

It is good practice to preassemble the kit, place it in a clear bag, seal the bag, and tape it in an accessible place in the resuscitation area.

Procedure

Place the child in the supine position with the head extended over a towel under the shoulder. This forces the trachea anteriorly such that it is easily palpable and can be stabilized with two fingers of one hand. The key to success is strict immobilization of the trachea throughout the procedure. The following statement appears in many textbooks describing this procedure: “Carefully palpate the cricothyroid membrane.” In reality, it is difficult to do this in an infant and is not essential. Indeed, in smaller children, it may be impossible to precisely locate the cricothyroid membrane, so the proximal trachea is utilized for access (hence the name percutaneous needle tracheostomy [PNT] vs. “needle cric”). The priority is an airway and provision of oxygen. Complications from inserting the catheter elsewhere into the trachea besides the cricothyroid membrane are addressed later. Consider the trachea as one would a large vein, and cannulate it with the catheter-over-needle device directed caudally at a 30° angle. Aspirate air to ensure tracheal entry and then slide the catheter gently forward while retracting the needle. Attach the 3.0-mm ETT adapter to the hub of the catheter and commence bag ventilation. The provider will note exaggerated resistance to bagging. This is normal and is related to the small diameter of the catheter and the turbulence created by ventilating through it. It is not generally the result of a misplaced catheter or poor lung compliance secondary to pneumothorax. It is helpful to practice BMV through a catheter to experience the feel of this increased resistance. The operator must allow for full expiration through the patient’s glottis and not through the catheter in order to prevent breath-stacking and barotrauma. This can be accomplished by watching for the chest to fall after inspiration.

• FIGURE 25-3. Components of a needle cric extension set. This extension set is constructed by cutting off the terminal 6 in of standard IV tubing and inserting a 2.5 mm ETT adapter. The BVM is attached to the adapter at the proximal opening, and the distal end is inserted into the catheter that has been introduced into the trachea. This setup allows more freedom of movement during bag mask ventilation (BMV), with less concern for “kinking” or obstructing the catheter—a complication observed in animal studies when the bag was connected directly to the 3.0 ETT adapter.

The required pressures are well above the limits of the pop-off valve; therefore, it must be disabled in order to permit gas flow through the catheter. Jet ventilation has also been advocated in children; indeed, the terms “needle cric” and jet ventilation are frequently referred to in the literature as the procedure of choice. The reality is that the pressures generated by the classic jet ventilator are extremely high, both unnecessary and too dangerous as an adjunct for use with this procedure in children.

Ventilation with the percutaneous needle technique is said to be contraindicated in patients with complete upper airway obstruction. The reality is that the scenario of complete obstruction, implying no potential for egress of gas during ventilation, is extremely rare. Referring to the explanation of usual mechanism of obstruction (Chapter 26), one can see that the terminal events are respiratory arrest from closure of the airway secondary to negative patient breaths, which result in airway collapse. Once arrest occurs, negative patient breaths cease, and the airway relaxes and expands slightly. Also the negative patient breaths are replaced with positive-pressure ventilation, which may further expand the narrowed airway. Thus, egress of gas during ventilation is not an issue.

TECHNIQUES USED IN ADOLESCENTS AND ADULTS

Blind Nasotracheal Intubation

Nasotracheal intubation in children is uniformly discouraged and is frequently considered contraindicated. This recommendation is based on the fact that the sharp angle of the nasopharynx and pharyngotracheal axis in children precludes a reasonable likelihood of success with this technique when performed blindly. A second reason is that children are at increased risk for hemorrhage because of the preponderance of highly vascular and delicate adenoidal tissue. The direct visualization technique is, however, commonly used in small infants and children for chronic ventilator management in the intensive care unit setting. Using direct visualization with a laryngoscope once the ETT has passed into the oro- and hypopharynx, tracheal placement is aided with Magill forceps. However, this technique is not helpful in emergency airway management. In general, the technique of blind nasotracheal intubation, which is essentially the same as that described for adults, has few, if any, primary indications in pediatric emergency airway management, and, in any case, is not recommended for patients younger than 10 years.

The cricothyroid membrane in small infants and children is minimally developed (Fig. 25-4). Surgical or cricothyrotome-based cricothyrotomy should not be attempted in children younger than 10 years of age because the size of the trachea and cricothyroid membrane precludes it. In children younger than 10 years, PNT with BMV is recommended. Note that our recommended limit of 10 years of age is not meant to be a rigid guideline. Various ages have been recommended as a cutoff for performing one procedure versus the other. For cricothyrotomy, it is really an issue of size. If the size of the patient’s airway and cricothyroid membrane would permit performing a surgical cricothyrotomy, i.e., easily identifiable landmarks are present, then, regardless of age, it can be done. If not, then the needle technique should be performed. Cricothyrotomy using a commercially available kit (Pedia-Trake) has not been shown to be successful or even safe. Box 25-1 summarizes recommendations for invasive airway procedures in children.

• FIGURE 25-4. Cricothyroid Membrane. Comparative size of the adult (left) versus pediatric (right) cricothyroid membrane. Note that not only is the larynx smaller, but the actual membrane is also proportionately smaller in comparison, involving one-fourth to one-third the anterior tracheal circumference versus two-thirds to three-fourths in the adult. This pediatric drawing is that of a toddler, which accommodates a 4.5-mm ETT.

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