Pediatric Airway Series: Part 1 – Overview & Equipment

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September 21, 2017 by Agnes Usoro

By: Agnes Usoro


Introduction

Physiologically and anatomically, there are key differences between the adult and pediatric airway. Over a (5) part series, we will present a brief review of the key differences between the adult and pediatric airway, the equipment needed, pre-intubation, intubation and post-intubation processes, and methods for managing the difficult pediatric airway. Our goal is to set you up for successful management of the pediatric airway.


Physiologic Differences

  • Children have a higher relative minute ventilation (tidal volume x respiratory rate) and are vulnerable to rapid desaturation when oxygen or ventilation is reduced. Keep this in mind when pre-oxygenating the child. They cannot tolerate oxygen saturations below 90%
  • Children are more likely to develop gastric distention during bag-mask ventilation, which further compromises functional minute ventilation. Early placement of an orogastric or nasogastric tube can address this
  • Children have larger extracellular fluid compartments and therefore drugs tend to have a faster onset but shorter duration of action. Use higher doses per kilogram to facilitate rapid-sequence intubation (RSI)

Anatomical Differences

  • Newborn and Infants:
    • Have a larger head and occiput in relation to their body. In addition, they have large tongues,  small mandibles, and a narrower trachea putting them at higher risk for airway obstruction
    • The larynx is more superior and anterior which may require more hyperextension of the neck to align the oral, pharyngeal and tracheal axes. To address this, you can place a small roll under the shoulders to help align the axes
    • Use a straight laryngoscope blade (Miller or Wisconsin). This is helpful due to their larger tongues, larger proportion of oral soft tissue and floppy epiglottis
  • All Children:
    • Narrowest part of the trachea is at the cricoid ring. In an agitated, crying child, the slightest reduction in their already narrow trachea can result in significant airway resistance, obstruction and respiratory arrest
    • Airway obstruction in a child is dynamic. Hence, they respond well to positive-pressure ventilation
    • Due to the small cricothyroid membrane, surgical cricothyrotomy is contraindicated in children < 10 years old. Instead, if a subglottic airway is indicated and an endotracheal tube cannot be safely passed, needle cricothyrotomy is recommended.

Peds airway


Equipment: It is best to use a Broselow Tape to estimate equipment size. But generalizations can be inferred from both experience and known airway data.

Laryngeal Mask Airway (LMA) and Endotracheal Tubes (ETT)

  • LMA’s are an excellent rescue airway. Appropriate size is weight-based
  • ETT’s are considered definitive supraglottic airways
  • (Age/4) + 4 is a generic formula used to estimate the size of an uncuffed ETT. Subtract (0.5) from this number for the estimated size of a cuffed ETT
  • Estimation of LMA and ETT size and depth of insertion according to child’s age:

LMA Size

ETT Size (Cuffed)

Depth Insertion

Premature or Small Newborn

1

2.0 – 2.5

6cm

Newborn (up to 1 month)

1

2.5

7cm

Infant (1 – 3 months)

1.5

2.5

7-9cm

Infant (3 – 6 months)

1.5

3.0

9-10cm

Infant (6mo – 2 years)

2-2.5

3.5

10-12cm

Child (2 – 3 years)

2.5

4.0

12cm

Child (4 – 7 years)

2.5

5.0

12-15cm

Child (> 8 years)

3

(Age/4) + 4

(ETT size) x 3


Laryngoscope Blade

  • Straight laryngoscope blades (Miller or Wisconsin) are preferred to curved blades (Macintosh) in younger children because they allow better immobilization of upper airway structures which results in an improved view
  • Estimation of laryngoscope blade size according to child’s age:

Miller

Wisconsin

Macintosh

Premature or Small Newborn

#0

Newborn – Infant (0 – 1 year)

#1

#1

Child (1 – 3 years)

#2

#1.5

#2

Child (3 – 8 years)

#2

#2

Child (8 – 16 years)

#2

#3


Conclusion of Part 1 of 5 in the Pediatric Airway Series

 

References

  • Kempema, J. PediSTAT Application: Airway Intervention Equipment
  • Litman, Ron. Basics of Pediatric Anesthesia: Companion website to the book. Chapter 16: Routine airway management.
  • Image obtained from: Tintinalli, J.E., et al. Tintinalli’s Emergency Medicine: A Comprehensive Study Guide, 8th Edition. Figure 111-1: Alignment of axes.

 

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