Board Review: The Pediatric Airway

Originally Published: Modern Resident, Jun/Jul 2010

Original Author: Karen Serrano, MD
University of Wisconsin Dept. of Emergency Medicine

Submitted by: Saadiyah Bilal, Publications Committee, Co-Chair
 
Managing the pediatric airway poses unique challenges for the emergency physician, requiring a good understanding of pediatric anatomy and familiarity with child-specific tools and approaches for emergency airway.
Children are more susceptible to airway obstruction than adults. One millimeter of edema in a small caliber pediatric airway (4mm diameter in a neonate) leads to dramatically increased airway resistance compared to the same amount of swelling in an adult (d=8mm) due to the effect of radius to the 4th power on rate of flow. The relatively large tongue of children can also collapse against the posterior pharynx, resulting in airway obstruction. Maneuvers such as the chin-lift or
jaw thrust, as well as use of nasopharyngeal or oral airways, can assist in relieving obstruction. Furthermore, the large occiput of infants can cause neck flexion while supine, occluding the airway and a towel may be needed under the shoulders to relieve the obstruction.

The larynx is higher and more anterior in children, which can make visualization of glottic structures difficult. Because of the large and floppy epiglottis, straight largyngoscopy blades are traditionally advocated in young children to lift this distensible tissue out of the way.
Uncuffed endotracheal tubes are recommended for children less than age eight, due to the fact that the narrowest portion of the trachea is the subglottic area, and inflation of a cuff could cause glottic injury. In contrast, in older children and adults, the narrowest portion of the airway is the cords, making cuffed endotracheal tubes the standard.

Several methods are available for selecting proper endotracheal tube size. Aides such as the Broselow tape predict tube size based on body length. Tube size can also be estimated by matching the tube diameter to the child's pinky finger. For children over age one, the formula (age/4) + 4 can be used to calculate tube diameter in millimeters.

For the difficult or failed airway, the laryngeal mask airway is an effective rescue option. In the rare event of a "can't intubate, can't ventilate" situation, needle cricothyrotomy with jet insuflation is the procedure of choice in children. Surgical cricothyrotomy is contraindicated in children less than age 10 due to a tiny, underdeveloped cricothyroid membrane.

References:

1. Marx John A, Ed, et al. Rosen's Emergency Medicine: Concepts and Clinical Practice, 6th Ed. Philadelphia: Mosby Elsevier, 2006.
2. Walls, Ron M and Murphy, Michael F. Manual of Emergency Airway Management, 3rd Ed. Philadelphia: Lippincott Williams & Williams, 2008.