Pediatric Airway Management

Key Concepts

Pediatric advanced airway management is a relatively rare skill to perform in most emergency departments (EDs), and skill maintenance is difficult based solely on clinical practice.
There are several anatomic differences that impact pediatric airway management, and these occur mostly in the very young child (<2 years of age). Infants have a large occiput and a high, anterior airway, which impacts positioning during intubation. The narrowest portion of the pediatric airway is at the level of the cricothyroid membrane which means a foreign body could be lodged below the cords. They are also more dependent on diaphragmatic excursion for ventilation, thus gastric insufflation can result in difficulty with rescue ventilation.
Children are prone to desaturation due to their high metabolic rate and their lungs’ small functional residual capacity, making preoxygenation and maintenance of oxygenation during intubation attempts crucial.
The cognitive burden inherent in dealing with the large age/size spectrum in pediatrics can be overcome with reference aids that organize equipment selection and drug dosing based on length/age/size. Formulas have been developed to aid in selection of the correct endotracheal tube (ETT) size and determine appropriate depth of ETT insertion. For estimation of uncuffed tube sizes in children older than 1 year old: ETT size = 4 + (age in years/4). Subtract 0.5 in size for cuffed tubes. To estimate the depth of ETT insertion (the so-called “lip to tip” distance), multiply the ETT size × 3 (e.g., a 5.0 ETT would be inserted to 15 cm at the lip).
Rapid sequence intubation (RSI) is the preferred method of airway management in the vast majority of pediatric cases in the ED.
Compared to adults, children are more prone to desaturation over the time it takes for a neuromuscular blocking agent (NMBA) to take effect. Use of high-flow nasal cannula during the apneic period of RSI has not been well studied in children in the emergency setting, but we recommend its use at 1 to 2 L/min/year of age to a maximum of 15 Lpm. Because children desaturate more rapidly than adults, we recommend that assisted ventilation (coordinated with the child’s respiratory efforts if not yet fully paralyzed) be initiated if oxygen saturation drops below 95%.
Video laryngoscopy is an evolving technology for use in pediatrics and assists in visualization of the airway but may prolong time to intubation.
Surgical airway techniques differ in infants and young children, necessitating a needle technique that is different from the older child or adult. This technique provides a mechanism to oxygenate the “can’t intubate, can’t ventilate” child, but should not be relied on as a definitive airway.

Foundations

Background and Importance

Pediatric airway management is an uncommon, but critical resuscitation skill. Acquisition and retention of necessary skills is difficult when relying solely on clinical practice. Although the skills required to perform advanced airway management between adults and children are similar, there are anatomic and physiologic nuances of pediatric patients. These differences are most prevalent in the first 2 years of life and necessitate modifications to the “typical” intubation approach in older adolescents and adults. Additionally, because of the size and weight spectrum inherent in the pediatric patient population, there is a large spectrum of equipment and medication dosages.

Even in large children’s hospitals, there are few opportunities to perform endotracheal intubation as part of clinical practice. Of 1000 pediatric emergency department (ED) patients, 1 to 3 will require intubation, compared to 1 out of 100 adults. Many providers will leave residency training with fewer than 10 pediatric intubations and will not routinely intubate children as part of their clinical practice after training. At the same time, pediatric intubation success and skill mastery improves with increasing experience. Operating room studies demonstrate first-pass intubation success rates are less than 50% after 10 airways but rise to more than 90% after 50 intubation attempts. Fortunately, through experience with older patients, most emergency clinicians can recognize critical illness and have the skills necessary to manage the pediatric airway. These translational skills can be augmented using a simulated environment or with dedicated training in the operating room. Developing a systematic approach to pediatric airway management, while recognizing the anatomic and physiologic differences in the young child, is critical to success and will help to eliminate much of the anxiety associated with performing a time-dependent, infrequent critical procedure.

Anatomy

There are several anatomic differences in pediatric patients that directly impact airway management ( Table 156.1 ). These differences are most notable in the first 2 years of life; children 2 to 8 years old represent a transitional stage where the anatomy becomes more adult-like, yet there remains variability with medication dosing and equipment size selection.

TABLE 156.1

Anatomic Differences in Pediatric Airway Management

Anatomic Difference	Implications for Airway Management	Solution
Large occiput and head	Neck position flexed when lying supine and flat on stretcher	Shoulder roll required for optimal positioning of young infant
Large tongue	May occlude airway in the unconscious or obtunded patient	Jaw thrust and oral or nasopharyngeal airway useful adjuncts during airway management
High, anterior airway	Visualization of the vocal cords may be difficult	Correct positioning prior to laryngoscopy critical
Upper airway anatomy and narrow subglottic region	Upper airway prone to dynamic collapse and inflammation (e.g., croup)	Cuffed tubes safe, and sometimes preferred, as long as cuff pressure monitored
Large tonsils and adenoids	Prone to bleeding with manipulation	Blind nasotracheal intubation relatively contraindicated younger than 10 years old
Small cricothyroid membrane	Surgical cricothyrotomy difficult	Needle cricothyrotomy recommended in infants and young children
Large stomach, dependence on diaphragmatic excursion for ventilation	Insufflation of the stomach during BMV can compromise ventilation	Use orogastric or nasogastric tube for decompression

BMV, Bag-mask ventilation.

By correctly positioning the patient, the oral, pharyngeal, and laryngeal axes can be aligned to visualize the glottis during direct laryngoscopy. The small infant has a relatively large head and occiput in relation to their body size. This can cause slight flexion at the neck when the patient is lying supine, impeding the ability to visualize the glottis. The patient should be positioned so that a line drawn through the external auditory canal and the anterior shoulder is horizontal and parallel to the bed ( Fig. 156.1 ). In the infant (younger than 6 months old), this is accomplished by placing a towel roll under the patient’s shoulders, elevating the body, and overcoming the neck flexion associated with their large occiput. In the small child (6 months to 5 years old), correct positioning can likely be achieved without the need for support. In the older child/adolescent, the head is smaller in relation to the size of the body, and the head may need to be elevated. As long as cervical spine injury is not suspected, correct positioning combined with slight head extension will optimize conditions for direct laryngoscopy.

Fig. 156.1, Correct positioning of a pediatric patient to ensure optimal airway alignment utilizing a line passing through the external auditory canal and the anterior shoulder. (A) The small infant requires a shoulder roll to achieve optimal positioning, the small child typically requires neither a shoulder roll nor head support, and the older child/adolescent may require head support. (B) In this small child, a line drawn through the external auditory canal and the anterior shoulder reveals the child to be in good position without support. Slight extension of the head results in the achievement of the sniffing position.

Infants and children have large tongues relative to the size of their mouths and tend to have a large, floppy epiglottis. Because of these differences in anatomy, they are prone to obstruction when sedated or obtunded, and manipulation of the epiglottis during direct laryngoscopy is frequently required to achieve intubation. Practically, these differences may necessitate the use of an oral or nasopharyngeal airway during bag-mask ventilation (BMV) to bypass the large tongue. Furthermore, a straight (Miller) laryngoscope blade may better manipulate the floppy epiglottis.

The vocal cords and glottic opening are situated at the level of the first cervical vertebrae in infants, gradually dropping to the C3 to C4 level by age 7, and further descending to the C6 level by late adolescence. Therefore, the airway is higher and more anterior in small infants than what is encountered in adults, making correct positioning prior to direct laryngoscopy critical to ensure success of intubation ( Fig. 156.2 ).

Fig. 156.2, High, anterior airway of the small child. Anatomic difference in the relation of the glottis in the small child compared with the adult.

Historically the narrowest portion of the pediatric trachea was felt to be subglottic at the cricoid ring. However, recent studies using airway CT in anesthetized pediatric patients have confirmed prior MRI and bronchoscopy findings demonstrating anatomic narrowing at the level of the vocal cords and an elliptical-shaped subglottic region. ^, Because of the non-distensible nature of the cricoid cartilage, the subglottic region functionally remains the narrowest in the spontaneously breathing child.

The unique anatomy of the pediatric upper airway has traditionally led to the use of uncuffed endotracheal tubes (ETTs) in the small child. Support for uncuffed tubes came at a time when the cuffs were relatively stiff and there was not a reliable, easy way to identify high cuff pressures that can lead to subglottic tracheal injury. Current cuff technology can accurately measure cuff inflation pressures, and we recommend using cuffed tubes for intubation of children, particularly in instances of high airway pressures or poor compliance (e.g., asthma, pneumonia, and acute respiratory distress syndrome [ARDS]). Utilizing a cuffed ETT may obviate the need to replace and upsize a tube when there is significant air leak that impacts ventilation, avoiding the risk of losing an already secured airway.

The pediatric trachea is more flexible and prone to dynamic collapse. In addition to implications with positioning during assisted BMV and intubation, the trachea can narrow due to upper airway pathology (e.g., croup, bacterial tracheitis). In cases of upper airway pathology, keeping the patient in a calm and quiet environment is important. Children with “complete” upper airway obstruction often respond well to positive pressure via BMV, which can act to stent open the upper airway. Heliox, typically a 70% to 30% mixture of helium to oxygen, can help decrease a child’s work of breathing by increasing laminar flow in partially obstructed airways. Where available, a trial of heliox may be considered in cases of partial upper airway obstruction (e.g., croup), although it has been found no more effective than racemic epinephrine or humidified oxygen in reducing the level of distress in these patients.

The anatomic variations in children impact recommendations in pediatric airway management. Children have relatively prominent tonsillar and adenoidal tissue that is prone to bleeding with even minor trauma. Thus, blind nasotracheal intubation is relatively contraindicated and not routinely recommended in pediatric patients younger than 10 years old. Anatomic landmarks in the neck may be difficult to identify in young infants and children with short necks, and the cricothyroid membrane is small. Thus, needle cricothyrotomy is the recommended invasive airway of choice rather than surgical cricothyrotomy in emergency department settings when the airway cannot otherwise be managed with BMV, intubation or supraglottic device.

Finally, small children are dependent on diaphragmatic excursion for ventilation and have relatively large stomachs and low gastroesophageal sphincter tone. They are predisposed to gastric insufflation during BMV, which can impede diaphragmatic motion and compromise ventilation. Use of cricoid pressure in infants and young children is controversial and not well supported in the literature. If gentle cricoid pressure is used during BMV to reduce gastric insufflation and chest rise is poor, we recommend release of cricoid pressure to see if effective ventilation can then be maintained. We recommend placement of a nasogastric or orogastric tube and aspiration of air immediately following endotracheal intubation, or before intubation attempts if the abdomen is becoming distended and impeding ventilation during BMV.

Physiology

Owing to a high metabolic rate and low functional residual lung capacity, young children are prone to quick desaturation once apneic, even with adequate preoxygenation. Whereas a fully preoxygenated adult with healthy lungs may not desaturate below 90% for a full 6 minutes, a normal healthy 10-kg child may fall below 90% in half that time and a sick infant may desaturate in less than 1 minute. Thus, careful attention to preoxygenation is crucial. Additionally, use of nasal cannula (1–2 L/min/year of age to a maximum of 15 L/min) during the apneic period may help support oxygenation until intubation can be achieved. BMV should be provided between intubation attempts when oxygen saturation levels start to decline below 95%.

Children have a large extracellular fluid volume compared with adults. Many of the drugs used to facilitate endotracheal intubation (sedatives and paralytics) need higher per kilogram doses and their duration of action may also be shorter when compared with adults.

Equipment

The cognitive burden that occurs when caring for a critically ill child is significant. Equipment selection and medication dosing should be calculated based on weight and size, which can vary tremendously across the spectrum of pediatric patients, from the 3 kg newborn to the 100 kg adolescent. Every ED that cares for pediatric patients should have airway equipment stocked, accessible, and organized by age and size to facilitate easy use. There are numerous mobile device and computer applications, as well as color-coded length-based systems, which can be utilized to simplify medication and equipment selection ( Fig. 156.3 ). Regardless of method, elimination of the reliance on rote memorization lessens the cognitive burden of caring for pediatric patients across the age/size spectrum, particularly during periods of high stress.

$Fig. 156.3, The Broselow-Luten zones for pediatric drugs and equipment. BVM, bag-valve mask; ET co 2 , end-tidal carbon dioxide; ETT, endotracheal tube; Fi o 2 , fraction of inspired oxygen; LMA, laryngeal mask airway; NP, nasopharyngeal; PED, pediatric; PEEP, positive end-expiratory pressure; PIP, peak inspiratory pressure; RR, respiratory rate; RSI, rapid sequence intubation; SCh, succinylcholine.$

There are several “formulas” that are useful in selecting the appropriate equipment for pediatric patients. To determine ETT size, a number of methods are used. Measure the length of the child with a length-based resuscitation tape that has tube sizes based on length and weight recorded on the tape, or use of age-based formulas for a child older than 1 year old:

4 + (age in years / 4)

$4 + (age in years / 4)$

Example: 4-year-old patient

4 + (4 years / 4) = 5.0 uncuffed ETT

$4 + (4 years / 4) = 5.0 uncuffed ETT$

4.5 cuffed ETT (subtract 0.5 from above formula for cuffed tube sizing)

$4.5 cuffed ETT (subtract 0.5 from above formula for cuffed tube sizing)$

ETT depth of insertion (lip to tip distance) can be visualized during intubation by watching the vocal cord marker go past the vocal cords, or estimated by use of the Broselow-Luten tape or by the following formula:

3 \times uncuffed tube size = lip to tip distance (midtrachea)

$3 \times uncuffed tube size = lip to tip distance (midtrachea)$

Example: 5.0 ETT

3 \times 5.0 = 15 cm depth of insertion

$3 \times 5.0 = 15 cm depth of insertion$

Management

Decision Making

For a child who is effectively stabilized using noninvasive means (such as BMV), the additional benefit of a secure airway needs to be weighed against the risk of potential difficulty or complications. Failure to successfully oxygenate or ventilate a child by other means forces immediate action, whereas other conditions allow medical interventions and recurrent assessments over time to determine if advanced airway management is required.

Overall, an equal number of pediatric intubations in the ED are performed on trauma and nontrauma patients. Indications for pediatric intubation can be placed into four categories: (1) inability to oxygenate and ventilate; (2) inability to maintain or protect the airway; (3) potential for clinical deterioration; and (4) facilitation of necessary diagnostic studies, procedures, or for safe patient transport (e.g., high risk of decompensation on route).

Respiratory compromise is a leading contributor to morbidity and mortality in the pediatric population, and more likely than a primary cardiac disease to be the cause of arrest. Respiratory failure can result from intrinsic pulmonary disease or from conditions with infectious, neuromuscular, traumatic, toxicologic, or environmental etiologies. Respiratory failure is a clinical diagnosis, identified by characteristic examination findings and supported by noninvasive measurement of oxygenation (pulse oximetry) and ventilation (capnography). Blood gas analysis can also be informative but should not be relied upon to determine need to perform necessary advanced airway management.

Signs of partial obstruction (sonorous or stridulous airway noises) or complete obstruction (inability to phonate or produce audible breath sounds in a patient with adequate respiratory effort) suggest an inability to maintain the airway and should prompt immediate basic airway maneuvers, including airway repositioning or insertion of oral and nasal airways to help stent open the upper airways. Suctioning and removal of any foreign material might also be required. When these efforts are ineffective, patients may require an advanced airway. For patients with severely depressed mental status, the loss of protective airway reflexes may necessitate airway control, regardless of the ability to maintain the airway. For example, the use of a Glasgow Coma Score (GCS) of 8 or less is often cited as an indication for intubation in head-injured patients. Systemic illness, toxicologic exposure, and other etiologies of central nervous system (CNS) depression may also increase risk of aspiration; the presence of a gag reflex correlates poorly with GCS and the risk of aspiration. Thus, testing for a gag is not recommended, because it may increase the risk of vomiting and subsequent aspiration.

When airway compromise is progressive (e.g., from acute thermal injury), airway management should be initiated early to avoid increased difficulty later in securing the airway. Similarly, patients with systemic illnesses (e.g., sepsis) may require intubation to maximize oxygen delivery and decrease the metabolic demands of increased work of breathing.

Children often require sedation to perform diagnostic testing, such as computed tomography (CT), magnetic resonance imaging (MRI), or invasive procedures. The risk of airway compromise during procedural sedation is greater in patients with significant illness or medical instability. Therefore, securing the child’s airway may be necessary to ensure safety during the procedure, particularly in circumstances where accessibility for assessment and intervention may be compromised (e.g., a patient under surgical drapes or tunneled into a CT or MRI scanner). Because many acutely ill and injured children will require transfer to a pediatric tertiary care center, the stability of the patient’s overall condition and risk of airway compromise should be carefully considered. Securing the airway prior to transfer can obviate the need for emergent advanced airway management in a less controlled setting.

Rapid Sequence Intubation

Rapid sequence intubation (RSI) is the preferred method to perform endotracheal intubation in children, provided no contraindications exist. We do not recommend attempting emergency pediatric endotracheal intubation with sedation only as studies have demonstrated higher success and lower complications rates with RSI. A small number of medications are used for pretreatment, sedation/induction, and neuromuscular blockade during ED pediatric RSI ( Table 156.2 ).

TABLE 156.2

Common Rapid-Sequence Intubation Medications in Children ^a

Medication	Dosage	Comments
Premedications
Atropine	0.02 mg/kg	Not routinely used in RSI. Consider use in young infants (<1 year of age) Should be given for preexisting or periprocedure bradycardia not responsive to oxygenation and ventilation
Lidocaine	1.5 mg/kg	Not routinely used in RSI. Very limited pediatric-specific data to support use in increased ICP Needs to be given 3 minutes prior to laryngoscopy No data for bronchodilatory effect in children
Induction Agents
Etomidate	0.3 mg/kg	Rapid and reliable sedation Preserves hemodynamics Known to cause adrenal suppression even with single dose, although limited data on impact on clinical outcome Consider stress dose hydrocortisone with use No analgesic properties
Ketamine	1 to 2 mg/kg	Causes release of endogenous catecholamines May support hemodynamics in hypotensive patients Beta-agonist effect may help with bronchodilatation, favoring its use in asthma Preserves airway reflexes and respiratory drive Can be used without NMBA for “awake sedated look” in suspected difficult airways
Propofol	3 mg/kg	Rapid onset, short acting May cause hypotension Apnea possible Higher dose recommended in infants No analgesic properties
Midazolam	0.3 mg/kg	Higher dosing required than used for antiepileptic dosing or anxiolysis At induction dosing, may cause hypotension Often used concomitantly with opioids No analgesic properties
Fentanyl	1 to 5 mcg/kg	Often used with midazolam Lower dosing (1–2 mcg/kg) recommended for shock or hemodynamic concerns
Paralytics
Rocuronium	1 to 1.2 mg/kg	Nondepolarizing agent Equivalent onset as succinylcholine but longer duration of action No specific contraindications in patients suitable for RSI
Vecuronium	0.1 mg/kg	Nondepolarizing agent Slower onset of action than rocuronium Suitable alternative for rocuronium if more readily available
Succinylcholine	0–11 years: 2 mg/kg>11 years: 1.5 mg/kg Double the dose when given IM	Fasciculations without clinical relevance in children Shorter duration than rocuronium Very low risk of bradycardia with IV induction agents used in ED (see earlier) Risk of hyperkalemia and arrest in patients with known and undiagnosed myopathies and neuromuscular disease
Sugammadex	16 mg/kg (full reversal dose)	Rapid reversal agent for rocuronium or vecuronium Neuromuscular blockade generally reversed within 3 minutes

ED, Emergency department; ICP, intracranial pressure; IM, intramuscular; IV, intravenous; NMBA, neuromuscular blocking agent; RSI, rapid sequence intubation.

a RSI medications can be given intraosseous (IO) when IV access cannot be obtained.

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