Oct. 11, 2016
Head trauma — often from a fall or motor vehicle crash — is the leading cause of childhood traumatic death in the United States. For pediatric patients with serious head injuries, appropriate and timely airway management is critical for improved survival and outcomes. Yet managing a child's airway can be challenging in both the pre-hospital and hospital setting, in part because many providers lack experience with pediatric patients — only about 10 percent of emergency calls involve kids and of those, just 1 percent are serious injuries. A child's smaller size and the anatomical differences between children and adults also make managing the airway more difficult.
According to D. Dean Potter Jr., M.D., a pediatric surgeon at Mayo Clinic's campus in Rochester, Minnesota, anatomical differences to consider in kids include:
"Infants and younger children have large heads relative to their body," he explains. "This is important because when a child with a traumatic head injury is placed on a backboard with a neck brace by pre-hospital providers, the cervical spine isn't in a neutral position; the occiput is so big, the head rolls forward. This flexes the neck and compromises the airway."
Some but not all ambulances carry pediatric backboards that have a cut-out for a child's large occiput. When these aren't available, laying a rolled towel or blanket under the child's shoulders and hips elevates the body, protecting the cervical spine in the neutral position and opening the airway.
Kids have relatively large tongues and small mouths; the tongue falling back against the pharynx is one of the most common causes of airway obstruction.
Located at the level of the first or second cervical vertebra, the pharynx is higher and more anterior in infants and children than in adults. This can worsen airway obstruction when the neck is hyperextended.
Children have smaller airways in general — about the diameter of their small finger — which are harder to visualize and more prone to obstruction from relatively small amounts of blood or mucus.
Managing the airway
The steps in managing the airway of a child with serious head trauma include:
Jaw thrust and suction
The most basic technique to ensure a patent airway in traumatic injury is the jaw thrust, which is performed by grasping the lower jaw on both sides and lifting it straight forward. This opens the airway by moving the tongue away from the pharynx. Gentle suctioning of the mouth and upper airway helps clear away blood, vomit and other secretions.
Blow by or bag-valve-mask (BVM)
Every child with significant traumatic injuries should receive oxygen in the pre-hospital setting, which may first be administered by blow by or bag-valve-mask (BVM). Both provide ventilation and oxygenation until a more-definitive airway can be established or when a definitive airway isn't possible.
Masks are sized for newborns, infants and children; choosing the appropriate size and applying it properly are essential to create a better seal and more effective ventilation as well as to reduce the risk of aspiration.
Comparison studies have consistently shown that a two-person BVM technique, in which one rescuer squeezes the bag while the other uses both hands to hold the mask, provides better ventilation than when the mask is placed by a single provider.
If ventilation is inadequate with the BVM, an adjunct oral airway device can help keep the airway open. The Broselow tape — a universal weight-based measure — can be used to calculate the right-size oral airway in kids up to 12 years old. But the size of the device can also be determined simply by measuring from the corner of the patient's mouth to the mandible. It's critically important to select the appropriate device — inserting a too-large oral airway can cause more obstruction.
The vast majority of patients with a severe head injury who have a Glasgow Coma Score of eight or less or are in shock will need endotracheal intubation.
At one time, uncuffed endotracheal (ET) tubes were recommended for infants and small children to avoid pressure-induced damage to the trachea. Unlike the adult airway, which is narrowest at the vocal cords, a child's airway is narrowest at the subglottis, which can create an effective seal without the need for a cuffed tube. But newer, kid-friendly ET tubes with low-pressure cuffs have been shown to provide a better seal and help prevent aspiration.
ET tubes are measured by the internal diameter and range in size from 2.5 to 7.0 millimeters. A tube should be small enough to pass the vocal cords easily but large enough to minimize airflow resistance. The Broselow tape is a good way to size a pediatric ET tube, but the age-based formula 4 + (age in years/4) has also been shown to be accurate in children. Newer, cuffed tubes should be one-half size smaller than the age-based calculations suggest. The tube is inserted at a depth three times its size — for example, a 4-millimeter tube would be inserted 12 centimeters.
Despite improved equipment and techniques, laryngoscopy and intubation are skills that require extensive training and practice. In some studies, practitioners achieved a 90 percent success rate only after performing more than 50 intubations — a number many emergency providers, especially in smaller hospitals, aren't likely to achieve. When a child has a difficult airway or a provider doesn't feel comfortable with tracheal intubation, a rescue device such as a laryngeal mask airway or supraglottic tube may be easier to insert. Dr. Potter also recommends providers call for early assistance from an anesthesiologist or local pediatric transport team to help with tracheal intubation.
"If expert help isn't available, transferring to a higher level of care with a BVM is appropriate, as long as the child is receiving adequate ventilation," he says.