Management in Children

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© Springer Nature Switzerland AG 2020
Craig Sims, Dana Weber and Chris Johnson (eds.) A Guide to Pediatric Anesthesia

4. Airway Management in Children

Britta von Ungern-Sternberg1, 2   and Craig Sims1  

Department of Anaesthesia and Pain Management, Perth Children’s Hospital, Nedlands, WA, Australia

Medical School, The University of Western Australia, Perth, WA, Australia



Britta von Ungern-Sternberg (Corresponding author)


Craig Sims


Upper airway, childUpper airway obstruction in pediatric anesthesiaPediatric endotracheal tubeSupraglottic airways in childrenPediatric difficult airwayLaryngospasm, managementCuffed tracheal tubes for children

The core airway skills for anesthetists caring for children are face mask ventilation, LMA insertion, laryngoscopy and intubation, and selecting the appropriate sized ETT. Airway management is such an important part of pediatric anesthesia because respiratory complications are the commonest cause of morbidity and mortality in children without cardiac malformations. Respiratory events cause over three quarters of critical incidents and nearly a third of perioperative cardiac arrests. Not surprisingly, airway obstruction leading to hypoxia and bradycardia or asystole is a huge fear for anesthetists who do not routinely look after children. Airway management, especially face mask ventilation, is the most important skill to learn during pediatric training. It is the technique that will be required when there is airway obstruction and hypoxia.


Anesthetized children have airway problems more than cardiovascular problems. As a trainee, to gain more experience with airway management, avoid just inserting an LMA early on in the anesthetic then returning the child to recovery with the LMA in situ as you might with an adult.

4.1 Airway Anatomy

A child’s airway is different to an adult’s airway and is managed with different techniques and equipment (Table 4.1). The differences are more pronounced in infants—airway problems are four times more common in infants than in older children.

Table 4.1

Anatomical differences in infants and children compared to adults and their consequences for clinical practice

Difference in neonate and infant


High metabolic rate

Desaturate quickly during apnea or airway obstruction

Large head

Use head ring rather than pillow (Fig. 4.3)

No nasal turbinates

Less resistance to passage of nasal ETT

Soft, compressible floor of mouth in infants

Pressure from anesthetist’s fingers can push tongue against roof of mouth obstructing the airway—be careful to place fingers only on bony structures during airway maneuvers

Obtuse mandibular angle of 140° (adult 120)

Large tongue relative to mouth size

Higher, slightly anterior larynx (vocal cords opposite C3; adult C5)

Tongue closer to roof of mouth and obstruction more likely. Harder to compress tongue with laryngoscope and align visual axes of mouth, pharynx and larynx. Larynx appears to be more anterior at intubation, and forward flexion of neck does not improve laryngeal view

Long, thin U-shaped epiglottis with small amount of cartilage. Broad and fleshy ary-epiglottic folds. Large, mobile arytenoids

Vocal cords angled slightly anterior (adult perpendicular)

Large floppy epiglottis more likely to require physical displacement to view glottis (lift directly with straight blade). More likely to have ETT catch on glottic opening

Supraglottic structures more likely to feature in pathology

Cricoid ring is narrowest part of airway until puberty (adult: glottic opening)

Determines ETT size

Trachea soft and compliant

Collapse of extrathoracic trachea in upper airway obstruction

Ribcage soft and compliant

Indrawing of chest in upper airway obstruction

4.1.1 Nasal Breathing

Most infants are primarily nasal breathers for the first months of life. Their oral airway can easily be obstructed by a relatively large tongue and high epiglottis that may rest against the soft palate, and coordination between the respiratory and pharyngeal muscles is immature. Some neonates and infants can switch to mouth breathing if their nose is occluded (8% of preterm babies, 40% of term babies). Infants easily mouth breath after 3–5 months of age. The nose contributes only 25% of airway resistance in infants, compared to 60% in adults—most of an infant’s airway resistance is in the distal airways. Nevertheless, a young infant whose nose is blocked by secretions or a nasogastric tube may struggle and persist with nasal breathing rather than mouth breath.


Infants can feed and breathe at the same time. This is possible because the larynx is high in the neck, bringing the epiglottis and soft palate together. This and other changes allow milk to enter the esophagus at the same time as air is entering the trachea. Two of the consequences of this anatomy are that young infants breath primarily through the nose and they cannot have articulated speech.

4.1.2 The Pharyngeal Airway

Infants have a collapsible pharyngeal airway due to lax tissues and a small muscular contribution to airway patency. Airway patency improves over the first 8 weeks as muscle coordination matures. Skeletal growth during the first year increases the size of the mandible and maxilla relative to the tongue and further improves airway patency.

4.1.3 The Larynx and Cricoid Cartilage

The larynx is higher in the neck to allow breathing during feeding (Fig. 4.1). The larynx descends during the first 2 years, then remains in the same position until puberty when the thyroid cartilages grow and it descends to the adult position. Although the infant larynx is slightly more anterior than in the adult, it is its high position that makes it appear to be anterior at laryngoscopy because alignment of the visual axes of the mouth and glottis is more difficult.


Fig. 4.1

Cross section of infant and child airway, showing anatomical changes that cause obligate nasal breathing (Modified from Isono, Pediatr Anesth 2006;16: 109–22 and Westhorpe, Anaesth Int Care 1987;15: 384–8)

The infant larynx is said to be funnel-shaped because when the vocal cords are widely abducted, its inlet tapers from the glottic opening to the smaller and almost circular cricoid ring. Although recent MRI studies suggest the narrowest part may be the glottis, this part of the airway is pliable and moves out of the way during intubation. The cricoid ring is the narrowest part of the airway until puberty and determines the size of an ETT in children. The cricoid is classically described as circular like a signet ring (because the posterior part is broader than the thin anterior part). It is however, slightly elliptical. Nevertheless, its almost circular shape means that a round ETT can usually make a sufficient seal without a cuff. Mucosal edema at the level of the cricoid is a concern in infants and young children. In a baby with a cricoid diameter of only 4 mm, even a small amount of edema over the cricoid greatly increases airway resistance and may cause post-extubation stridor (Fig. 4.2).


Fig. 4.2

A small amount of mucosal edema over the cricoid cartilage in the infant significantly narrows the airway diameter and increases airway resistance. The same edema in an adult does not significantly affect the airway


The larynx is higher in the neck of neonates and infants, making it appear more anterior at laryngoscopy.


Airway trauma from intubation in a young child may cause edema and post extubation stridor in the short term, and subglottic stenosis in the long term.

4.2 Assessment of the Airway

Older children can be assessed as an adult would be, although the Mallampati score and thyromental distance tend not to be used because they are not validated in children. History is usually non-specific in routine cases, although symptoms of obstructive sleep apnea (OSA) may indicate adenotonsillar hypertrophy and more difficult mask ventilation. Younger children may not cooperate with a formal examination. Instead, they are observed for abnormalities of mouth opening and neck movement. Children differ from adults in that a child who is difficult to intubate will usually look difficult to intubate, whereas adults who are difficult to intubate may look normal. However, the unexpected difficult airway does exist and preparations for it need to be taken for any anesthetic.

The most important observation of the airway in children is the jaw size. A small jaw (retrognathia or micrognathia ) gives less space between the tongue and soft palate for a clear airway and less space to compress the tongue during laryngoscopy. It is the reason babies with Robin sequence can be difficult to intubate.


Micrognathia is a common and important indicator of intubation difficulty. It makes direct laryngoscopy difficult because there is little room for the blade to compress the tongue and give a direct line-of-sight view of the vocal cords.

4.3 Upper Airway Obstruction

Anatomical differences predispose children to upper airway obstruction, and hypoxia may develop quickly because they have a high oxygen consumption and smaller oxygen reserve (lower functional residual capacity (FRC), higher closing volume).

4.3.1 Signs of Upper Airway Obstruction

The symptoms and signs of airway obstruction vary with the level and cause of obstruction and with the age of the child (Table 4.2). Extrathoracic airway obstruction worsens during inspiration, and so inspiratory stridor and prolonged inspiration are the cardinal signs of upper airway obstruction. The pitch of the stridor may give clues to the location of the obstruction, as does the voice—a muffled voice indicates a supraglottic obstruction (for example, epiglottitis), whereas a hoarse voice or aphonia indicates glottic obstruction (eg laryngotracheobronchitis; croup).

Table 4.2

Signs of upper airway obstruction in children

Signs of upper airway obstruction

Inspiratory stridor and prolonged inspiration

Voice changes

Rocking chest and abdomen during breathing

Use of accessory muscles:

– Tracheal tug

– Flaring nostrils

– Intercostal chest retractions

Tachypnea and tachycardia

Anxious and restless initially, lethargic later

Indrawing of the chest wall occurs during obstruction, especially in young children who have pliable, cartilaginous rib cages. Obstruction also causes a rocking paradoxical movement of the chest and abdomen—the abdomen moves outwards from descent of the diaphragm while the chest collapses inwards from negative intrapleural pressure. As obstruction worsens, the work of breathing increases and accessory muscles become active with flaring of the nostrils and tracheal tug. Initially, an awake child with airway obstruction is tachypneic and tachycardic. Eventually the child may tire and respiratory effort fades. Infants and neonates rapidly fatigue and may develop apneic episodes as a result of airway obstruction.

4.3.2 Site of Upper Airway Obstruction During Anesthesia in Children

In sedated or anesthetized children, loss of muscle tone in the airway reduces patency and narrows the entire upper airway. Most obstruction, however, is at the level of the soft palate and the epiglottis. In contrast, upper airway obstruction in adults occurs at the level of the base of the tongue from loss of tone in the genioglossus muscle. At either age, resistance during inspiration generates a negative airway pressure and worsens airway collapse.

4.4 The Mask Airway and Mask Ventilation

Many adult techniques are applicable for the management of a child’s airway. Always actively manage the child’s airway to learn the best way to obtain a clear airway in that child and to detect airway obstruction within a breath or two. Active airway management means holding the rebreathing bag and moving your hand gently with each breath, assisting the breathing and providing continuous positive airway pressure (CPAP) if needed.

4.4.1 Face Masks

Children have large cheeks and a relatively small nose bridge, resulting in their face being in one plane. This allows masks with a soft, flat cuff to form a seal—even a circular shape such as the Laerdal silicone resuscitation mask can be used. The cuff should be neither too soft nor too hard—soft enough to conform to facial contours, but not so soft that forming a seal is difficult and not so hard that the mask does not conform to the face. Adults have a more prominent nose bridge, and a contoured mask is needed to form a seal. Teenagers have a prominent nose bridge and may need an adult mask.

The size of the facemask should allow the mouth to be slightly open, but not cover the eyes—sit the top part of the cuff on the bridge of the nose and ensure the lower part sits in the mental groove on the chin. If the mask comes up onto the eyes or down onto the chin, it is too big. If an infant is settled with a soother or dummy in its mouth, sometimes a larger mask can be placed over the top of the soother during the early stages of induction, changing to a smaller mask later when the soother is removed.

4.4.2 Opening the Upper Airway

Table 4.3 outlines the most important maneuvers to open the upper airway. Mask ventilation during upper airway obstruction inflates the stomach. Gastric insufflation is common in young children when ventilation has been difficult, when no pressure relief valve is used on the circuit, or when the operator is not experienced in mask ventilating children.

Table 4.3

Summary of main airway maneuvers to obtain patent airway in a child

Important airway maneuvers to overcome upper airway obstruction

Head and neck position

Jaw thrust (not just chin lift)


Oral (or nasal) airway

Positioning child on side may help


Gastric distension pushes the diaphragm upwards and inhibits ventilation. Remove the air by inserting a suction catheter through the mouth—suction may or may not be required. Head Position

Because the larynx is relatively high in a young child’s neck, flexion of the neck does not improve airway patency or the view at intubation—there aren’t enough cervical vertebral bodies above the larynx for flexion to have any effect. Children also have a relatively large head and don’t need a pillow to fill the gap between the back of the head and the bed. Instead, a head ring is used to stabilize the child’s head (Fig. 4.3). Babies have an even larger head, and although a head ring alone is usually fine, occasionally a small roll under the shoulders may stop the neck from flexing. Flexion of the head of a neonate or baby may also cause airway obstruction. This is why it is often recommended that an infant’s head be in a neutral position. However, neonates and infants benefit from extension of the atlanto-occipital joint just as the older child does, provided extreme extension is avoided.


Fig. 4.3

Babies and children have a relatively large head, do not have a gap between the back of the head and their back, and do not need neck flexion for intubation. A head ring stabilizes the head and provides a suitable head position for intubation. Adults need a pillow to fill the gap and flex the neck to achieve the ‘sniffing’ position needed for intubation


Positioning for direct laryngoscopy is different in adults and children. Adults are placed in the ‘sniffing’ position (neck flexed, head extended). Children don’t benefit from neck flexion during intubation because their larynx is relatively high. Only extension of the atlanto-axial joint to tilt the head back is needed. Hand Position

In preschool children, the nasal passage is often blocked, making ventilation via the nose difficult. It is therefore important to hold the mouth open during mask ventilation. An oral airway can be used, but appropriate sizing is vital since it can irritate the airway and lead to respiratory adverse events or block the airway if the wrong size has been chosen. The most effective maneuvers to get an open airway are forward jaw thrust and CPAP. Jaw thrust can be achieved with the third or fourth (little) finger behind the angle of the jaw (Fig. 4.4). Tilting the chin and head backwards is not as effective. It is important not to apply pressure to the floor of the mouth as this may compress the tongue against the palate.


Fig. 4.4

Pulling the jaw forward is more effective than tilting the chin and head backwards. The fourth (little) finger is behind the angle of the jaw pulling it forwards while the mask is held by the thumb and index finger


Try to hold the mask using a technique that incorporates jaw-thrust. This technique doesn’t force the mouth shut, doesn’t apply pressure to the floor of the mouth, and keeps one hand free for ventilation or CPAP. It avoids the need for a two-handed, two-person technique when difficulties arise. Oral and Nasal Airways

Oral airways may be useful, but are not routinely needed in children. The correct sized airway is chosen by measuring against the side of the face—with the flange at the level of the incisors, the tip should be adjacent to the angle of the mandible. If the airway is too small it is ineffective and if too large it may touch or fold down the epiglottis and cause obstruction or laryngospasm (Fig. 4.5). Insertion of the airway at an inadequate depth of anesthesia can trigger laryngeal responses.


Fig. 4.5

Oral airway size selection. Correct size (left) sits over tongue and away from epiglottis. Too small (middle) is occluded by tongue, and may push the tongue backwards. Too large (right) may touch epiglottis and fold it down or trigger laryngospasm

Nasopharyngeal airways are occasionally used as they are better tolerated in the conscious patient. Small, soft nasopharyngeal airways are available, but some are too long if inserted fully with the collar against the nostril. The size of the airway is selected by matching its length to the distance between the nose and tragus of the ear. An alternative to a purpose-made made nasopharyngeal airway is a shortened, age-appropriate ETT taped or pinned in place so that it cannot migrate inwards or outwards, and labelled so that it is not mistaken for a tracheal tube. Position the nasal airway carefully so that it is just below the soft palate, but not touching the epiglottis. They can sometimes cause trauma and bleeding from the nose or adenoids. CPAP

Continuous positive airway pressure (CPAP) refers to a positive airway pressure maintained throughout spontaneous breathing. The aim is to keep the airway pressure positive during inspiration and stop collapse of the extra-thoracic part of the airway (Fig. 4.6a). CPAP increases functional residual capacity, may reduce the work of breathing and improves oxygenation. It is a very important airway skill to learn, and is the technique needed during airway obstruction at induction or emergence.


Fig. 4.6

Airway pressure during spontaneous ventilation. (a) Without CPAP (left curve), airway pressure becomes negative during inspiration and the extrathoracic airway may collapse and obstruct. In theater, CPAP is provided by gently squeezing the bag just before and during inspiration so that airway pressure is always above atmospheric pressure (right curve). (b) Some suggest CPAP by partially closing the adjustable pressure limiting (APL) valve, or partially occluding the T-Piece. When this is done, note that expiration is now the positive waveform, and airway pressure still falls during inspiration. Also, resistance to expiratory flow increases the work of breathing when the APL valve is partly closed. Insp Inspiration, Exp Expiration


CPAP and jaw thrust are the most important maneuvers to learn to maintain an open airway in children.

Tip: To Apply CPAP

Ensure you have an effective mask seal (use finesse, not force!) with one-handed jaw thrust.

Partially close the APL valve and keep the bag tight during the expiratory pause.

Feel the bag & watch the chest for the start of inspiration.

Gently squeeze the bag as soon as inspiration starts.

Squeeze gently, feeling for feedback that air has entered chest. If the bag is squeezed too hard before confirming this, the stomach might inflate.

Once you have the ‘feel’ for airway patency and respiratory rhythm, increase the bag squeeze and pressure support, and start to squeeze slightly before inspiration starts (anticipating when the next breath is about to start).

CPAP requires a circuit that can keep the airway pressure positive during inspiration. Simply closing the APL valve on a circle circuit or kinking the tail of a T-piece circuit does not produce CPAP (Fig. 4.6b). The simplest method in practice is to gently squeeze the rebreathing bag at the very start of inspiration, keeping the bag slightly distended during expiration so that there is minimal lag between the start of the child’s inspiration and the bag producing a positive pressure. This technique is called CPAP, but is probably more correctly a manual form of pressure support ventilation. Some centers use the pressure-support mode of the anesthetic ventilator during induction. Difficult Facemask Ventilation

Unexpected difficult facemask ventilation is the commonest problem in clinical practice. Although imperfect technique, inadequate anesthetic depth and large adenoids and tonsils are the commonest causes, there are several others to consider (Table 4.4). Difficult mask ventilation is resolved using the same steps as in adults: optimize the head position, open the mouth, and consider anesthetic depth, muscle relaxation and equipment issues. Then insert an oral airway, try an LMA or other SAD, and finally attempt intubation.

Table 4.4

Common causes of difficult facemask ventilation in children

Common causes of difficult facemask ventilation


Large tonsils and adenoids; obesity

Inadequate depth of anesthesia or paralysis


Congenital or pathological conditions

Alveolar collapse and reduced compliance

Air in stomach


The first three are the commonest soon after induction

4.5 The LMA and Other Supraglottic Airway Devices

The LMA has become as popular in children as in adults for allowing a hands-free technique. Avoiding intubation of the easily irritated pediatric tracheobronchial tree confers additional benefits. There are fewer respiratory events during anesthesia in infants and children having minor elective surgery when an LMA is used rather than ETT (Fig. 4.7).


Fig. 4.7

The LMA is associated with a lower frequency of serious airway complications in infants older than 3 months and children. Data from Drake-Brockman TFE et al., Lancet 2017

4.5.1 Classic and Classic-Style LMA

The Classic LMA is a scaled-down model of the adult version, and disposable versions are available in pediatric sizes (Table 4.5). The size 1 LMA tends to give a less reliable airway than the larger sizes, and the pre-formed second generation LMAs are superior to the classic model. Inflating the cuff to a pressure of 40 cmH2O gives the best airway seal in children with the least air leak and sore throat. Inflation of the cuff with a set volume or to a clinical end point causes hyperinflation and increases air leak and sore throat. If there is a leak around the cuff, deflation of the cuff or repositioning of the LMA have a higher rate of success than the often-performed additional inflation (which in turn leads to a stiffer cuff that does not mould to the pharyngeal shape). Insertion of sizes 2.5 and smaller can be straight-in as recommended by the manufacturer, or with a twisting, upside-down technique with a partially inflated LMA—similar to inserting a guedel airway. This rotational technique has a high success rate with the advantage of guiding the LMA tip past the tonsils and down behind the tongue without placing fingers in the patient’s mouth.

Table 4.5

Child weight and recommended LMA size

Device size


Weight range (kg)











A clinically acceptable airway is obtained with the LMA in 92–99% of children (similar to adults), but the incidence of partial airway obstruction seen on fiberoptic assessment in children is up to 19% (higher than adults). In infants, the pharyngeal seal is not as good and there is a lower cuff leak pressure compared with older children. Malpositioning is more common with the smaller sizes of LMA, and is usually due to the epiglottis being caught within the LMA. Bilateral jaw thrust by a second person during insertion of the LMA improves positioning. The chest and abdomen sometimes have a rocking movement during spontaneous ventilation due to partial airway obstruction. Despite all of this, a clear airway is usually obtained with an LMA, although it is important to check that the tidal volume is adequate and that the child is not working too hard at breathing. Pressure support ventilation is usual nowadays with modern anesthesia ventilators.

4.5.2 Second Generation LMAs and Other Supraglottic Airway Devices

The first generation LMA is still commonly used in children because of cost, familiarity and good performance in clinical practice. However, there is good evidence second generation devices are superior, with the gastric channel being useful to release trapped air. The pediatric Proseal LMA® (PLMA) does not have the dorsal cuff of the adult sizes, and is not available in single-use versions. The iGel® is effective in infants and children, but there may be a large leak until the cuff warms, softens and conforms to the pharynx. It also has a tendency to migrate outwards, requiring extra taping or repositioning.

4.5.3 Removal of LMAs

LMAs are commonly removed while the child is still deeply anaesthetized. A deeply anaesthetized child in the lateral position usually has a clear airway (unlike adults) and so there is less to gain from leaving the LMA in situ in PACU. Although it is clear awake removal is better in adults, in children it is not so certain and studies point either way, partly because of differences in definitions of ‘awake’, or of complications. There is little difference in the incidence of laryngospasm if the LMA is removed deep or awake in healthy children. However, in children with increased bronchial hyper-reactivity or those with risk factors for respiratory adverse events, deep removal is superior to avoid complications. The experience of PACU staff must be considered before planning to leave the LMA in for later awake removal. If removing deep, the child should be in the lateral position. If awake, the child should be very awake, defined by Archie Brain as being after the onset of swallowing and when the child is either able to open the mouth to command or expel the LMA spontaneously.

4.6 Laryngoscopes

There are several blades for direct laryngoscopy available for children. However only two are needed for routine anesthesia in children—the size 1 Miller blade for neonates and infants, and the size 3 (adult) Mac blade for children.

4.6.1 The Miller Blade

The Miller blade is a straight blade for neonates and infants up to about 18 months. It is the classic blade for neonates because of their small mouth, high larynx and floppy epiglottis. Size 1 is the most commonly used size, and size 0 is best for neonates weighing less than about 1 kg. The technique requires some practice, and is outlined in Table 4.6. Common mistakes are failing to control the tongue and sweep it across to the left (same as when using a Mac blade), and failing to get the blade out of the corner of the mouth, so the ETT has to almost be passed down the bore of the Miller blade, blocking the view. Although the classic technique with the Miller blade is to lift the epiglottis directly, it is usually adequate to lift it indirectly, like a Mac blade, and use laryngeal pressure if needed to improve the view. This technique was described by Miller himself, and perhaps has the advantage of causing less stimulation during laryngoscopy.

Table 4.6

Tips for using the Miller blade in infants and neonates

Technique for using the size 1 Miller blade in neonates

Insert blade in right corner of mouth and sweep tongue swept across to the left

Look in the mouth as you gently advance the blade

Get the blade out of the corner of the mouth and have your assistant retract the right corner of the mouth

Lift the epiglottis indirectly and use external laryngeal pressure


The infant Miller blade was first described in 1946 by RA Miller (NOT RD Miller of Miller’s Anesthesia). Free full text of the original description online. Anesthesiol 1946;7: 205.

4.6.2 The MacIntosh Blade

The adult size 3 MacIntosh blade is suitable for children of all ages, including older infants. In small children, only the thin, distal part of the blade is inserted, leaving plenty of room in the mouth. Small MacIntosh blades are available but are only scaled down adult blades without proper adjustment of their proportions. If these small blades are used for intubation, the thick part of the blade is in the mouth and takes up more space. They also have a significant curve requiring more mouth opening and force to obtain a direct line of vision. The size 1 MacIntosh and Miller blades have been shown to give an equivalent view in infants as young as 3 months. Although the Mac blade is tempting to use because it is familiar, the Miller blade is needed for neonates, so it is best to gain experience with it on larger infants as well.


Most children are easy to intubate. If the cords are not clearly seen, resist pulling harder- use external laryngeal pressure (the ‘three-handed’ intubation technique).

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Nov 27, 2021 | Posted by in ANESTHESIA | Comments Off on Management in Children

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