Appreciation of pediatric airway conditions is based on the anatomy of the airway. Figure 18-1 (A and B) shows lateral neck radiographs of a child with croup. The patient’s nose (anterior) is on the right and the occiput (posterior) is on the left. Note the lordotic (extended) cervical spine vertebral bodies.

Physical factors that differ between adults and children account for the airway differences that are clinically important. The most important of these is a smaller airway diameter. Smaller airways with the same degree of airway edema result in proportionately greater obstruction (Fig. 18-2). Some textbooks have quoted Poiseuille’s equation describing airflow resistance as proportional to the fourth power of the radius. This is not quite correct under conditions of respiratory distress, since Poiseuille’s law describes laminar flow, and during respiratory distress, nonlaminar flow dominates; however, airway resistance is proportionately greater, and coupled with a weaker patient, the degree of ventilation compromise is greater.

The tongue of children is relatively larger.¹ The posterior portion of the tongue can easily fall backward in the supine position, compromising the upper airway. Some patients have a particularly large tongue, amplifying this factor. The narrowest point of the child’s upper airway is the cricoid ring (which is below the vocal cords), whereas the narrowest portion of the adult airway is the vocal cords.¹ This is important because occasionally an endotracheal tube (ETT) will pass through the cords but cannot be advanced further because the cricoid region is too narrow for this tube, in which case a smaller tube should be used. The larynx in children is more cephalad, the epiglottis is softer and more curved, and the airways are less rigid.¹ This is especially noticeable in patients with tracheomalacia and laryngomalacia.

An airway emergency will present with an acute process that adversely affects a normal airway, or an exacerbation of a chronic airway condition. Some children have airway conditions that place them at higher risk of airway obstruction, some children have airway conditions that make intubation and visualization of the airway more difficult, and some children have both. Children with chronic airway conditions include those with Down syndrome, Pierre Robin syndrome, and other congenital conditions and malformations that affect the tongue, mandible, and neck. Tumors, masses, swelling, and edema (e.g., burns, chemical inhalations, and allergic reactions) in this area can also lead to airway compromise and difficult intubation.¹ Laryngomalacia and tracheomalacia place patients at higher risk for airway obstruction. Head trauma, neck trauma, and multiple trauma require cervical spine immobilization, making visualization of the larynx potentially more difficult. Trauma of the face, mouth, neck, and airway structures can directly injure the airway resulting in airway compromise. Infections such as croup, epiglottitis, bacterial tracheitis, and retropharyngeal abscess can narrow the airway, with epiglottitis and bacterial tracheitis presenting with the most serious degree of airway obstruction. Patients with an altered sensorium and patients who are pharmacologically sedated are at higher risk for airway compromise as the oral structures relax and fall posteriorly over the airway when the patient is in a supine position.

Air exchange and the degree of airway obstruction can be assessed by observation, auscultation, and technology, but preferably by all three.

A patient with an airway obstruction might have visibly abnormal chest movements with retractions and exaggerated respiratory efforts. A gentle rise and fall of the chest suggests good air exchange. If the patient is wearing an oxygen mask, you might be able to see condensation on the mask with each breath, which suggests significant exhaling (a good sign).

A patient with an airway obstruction might have noisy breathing. More severe obstruction might have no noise if all air movement has ceased. Auscultation of the chest can usually assess the degree of air exchange. Noisy environments and obese or muscular individuals can make auscultation difficult.

End-tidal CO₂ (ETCO₂) monitoring is useful to confirm the degree of air exchange. While monitors are often used inline on a ventilator for intubated patients, they can also be used near the patient’s mouth or nose, or within a nasal cannula, to assess air exchange. Colorimetric ETCO₂ detectors are less sensitive for this purpose. Pulse oximetry does not measure air exchange directly, but the presence of hypoxia suggests that air exchange might be poor.

The ability to rescue a patient from an airway emergency in order to maintain oxygenation is a vital skill that emergency physicians must possess.

Most airway repositioning maneuvers work by moving the posterior portion of the tongue to a more anterior location so that it does not block the airway. Figure 18-3(A and B) demonstrates how the jaw thrust maneuver opens the airway. Note that this maneuver should not move the cervical spine if immobilization is required. While placing your thumbs on the patient’s zygoma or maxilla, grasp the mandibular angle with your fingers and pull it anteriorly (Fig. 18-4). The chin-lift maneuver is similar but if the head is tilted, this could move the cervical spine. If cervical spine movement is not a concern, then other maneuvers that can be attempted with varying degrees of success include the following:

1. 
   

   Raising the patient’s occiput (putting a thick towel underneath it) into the sniffing position. This brings the tongue more anterior, opening the airway and improving the angle of view for laryngoscopy and intubation.

   
   
2. 
   

   Placing a towel roll under the patient’s scapulae and upper thoracic spine while permitting the head to tilt backward. This essentially does the opposite of raising the occiput, but the backward tilt of the head can often raise the posterior portion of the tongue. An excessive head tilt can stretch and compress the airway.

   
   
3. 
   

   Placing the patient on his/her side with the face slightly downward. This permits gravity to move the tongue forward.

   
   
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   Placing the patient prone. While this position permits gravity to move the tongue forward and secretions to drain out of the mouth, it does not permit easy access to the airway for other manipulations such as laryngoscopy. However, bag-mask ventilation (BMV) can be done in this unconventional position. This position might be especially optimal for a patient with epiglottitis in respiratory failure. The large inflamed epiglottis in the prone position falls backward obstructing the airway. The patient prefers to be in the “tripoding” position (erect, leaning forward) to keep the epiglottis off the airway. As the patient tires and succumbs to respiratory failure, placing the patient in the prone position utilizes gravity to swing the epiglottis anteriorly off the airway opening and facilitating BMV, which should optimally be performed using the two-rescuer method.

Aerosolized epinephrine can improve air exchange in croup and other conditions resulting from upper airway edema. Note that the standard dose of 0.5 mL of 2.25% racemic epinephrine is equal to 5.5 mg (5.5 mL of 1:1000) epinephrine. Aerosolized and systemic corticosteroids can also reduce airway swelling caused by inflammation. Anticholinergics (atropine, ipratropium) and albuterol can reduce airway resistance in some instances.

For spontaneously breathing patients, supplemental oxygen can be delivered via nasal cannula, blow-by oxygen mask, nonrebreather oxygen mask, or Rusch bag and mask (Fig. 18-5). Nasal cannula and blow-by oxygen enrich the oxygen concentration in the oral–nasal area to improve the inspired fraction of oxygen depending on the flow rate. Even at higher flow rates, this enrichment is modest. Conventional oxygen masks leak and entrain substantial amounts of room air. Nonrebreather oxygen masks have a reservoir bag that should be inflated with pure oxygen such that when the patient inhales, pure oxygen from the reservoir bag is inhaled. Ultra-high-flow nasal cannula oxygen results in better oxygenation via a combination of a higher fraction of inspired oxygen (FiO₂), positive pressure in the airways, and a beneficial modification of air flow dynamics. A Rusch bag and mask is a closed circuit so that with a tight mask seal, close to 100% FiO₂ can be delivered. In addition, continuous positive airway pressure (CPAP) and positive-pressure ventilation can be administered with a Rusch bag and mask.