Friday, November 6, 2015
By Cengiz Karsli, BSc, MD, FRCP(C) There is a saying in the pediatric anesthesia world, that “children are not just small adults”. This adage is particularly true when it comes to difficult airway management. What works for the adult airway often does not in the upset, uncooperative child or infant. High metabolic oxygen consumption, a propensity to upper airway obstruction and the sheer range of anatomic abnormalities and patient sizes are just a few of the factors that need to be considered when managing the pediatric difficult airway.
Maintaining a patent airway and oxygenation prior to and between intubation attempts is essential, and the technique of two-handed jaw thrust in children differs from that in adults. Instead of applying anterior pressure at the angle of the mandible, the middle and/or index fingers should be placed at the head of the mandible, behind the ear lobes. This not only provides anterior movement of the mandible, lifting the base of the tongue off the posterior pharyngeal wall, but also opens the mandible, pulling the tongue off the hard and soft palates. A two-person bag-mask ventilation technique or high flow nasal prongs can maintain oxygenation in the apneic infant or child. See Video: Difficult airway management in children 1: Mask ventilation.
A small tracheal tube placed in the nasopharynx can be used to deliver oxygen (and anesthetic gases) to the spontaneously breathing child during intubation attempts. The two-person technique of tracheal intubation using direct laryngoscopy is one of the most important pediatric difficult airway management skills to master. One person performs laryngoscopy and manipulates the larynx into the best view possible. A second person then intubates the trachea using a styletted tracheal tube. As with any device or technique, this maneuver should be practiced regularly on normal airways to maintain proficiency. See Video: Difficult airway management in children 2: Direct laryngoscopy.
Although not initially designed as a conduit for positive pressure ventilation, the supraglottic airway (SGA) plays a vital role in the difficult airway algorithm. There should be a low threshold to insert a SGA in the unconscious child with a difficult airway if bag-mask ventilation is unsatisfactory. This allows the practitioner time to arrange for another method of intubation, to consider using the SGA for the case, to intubate the trachea through the SGA or to abort intubation attempts and awaken the child. If a SGA is chosen as first-line airway device, a back-up plan should be in place in the event the SGA fails to maintain airway patency.
Videolaryngoscopes have influenced the approach to the pediatric difficult airway. Increasingly, first responders and other non-anesthesiologists are reaching for a videolaryngoscope as a first-line intubating device. The superior glottic view afforded by these devices has given anesthesiologists the confidence to render the child apneic for tracheal intubation. Inserting the styletted tracheal tube (in a hockey stick configuration) prior to videolaryngoscope blade insertion may increase the success rate and reduce the time to tracheal intubation. See Video: Difficult airway management in children 3: Video laryngoscopy.
The technique of videolaryngoscope-assisted flexible fiberscope intubation has been used with a high degree of success in pediatric patients with a known difficult airway. In this case both the light source and view come from the videolaryngoscope unit and the flexible fiberscope merely acts as an adjustable stylet. Video 4 demonstrates the technique of videolaryngoscope-assisted flexible fiberscope intubation in the child. See video: Difficult airway management in children 4: Video laryngoscopy-assisted flexible fiberscope intubation.
Although the flexible fiberscope seems to have taken a back seat to videolaryngoscopy in children, there will be instances when only a flexible fiberscope intubation will do. The obvious example is in the case of severely limited or no mouth opening. Because of the child’s propensity to rapid oxygen desaturation, the key to fiberscope intubation is to get the tip of the scope from nose (or mouth) to vocal cords as quickly as possible. Video 5 demonstrates the technique of pre-measuring fiberscope insertion depth at the side of the child’s face in order to minimize the time to tracheal intubation. Using this approach the fiberscope is inserted rapidly down the oro- or nasopharynx and the operator only looks at the viewing screen when his/her fingers touch the patient’s mouth or nose. See video: Difficult airway management in children 5: Pre-measuring fiberscope insertion depth.
The ever-increasing volume of intubating devices available on the market has undoubtedly influenced our approach to the pediatric difficult airway. Despite this, maintaining the skills of bag-mask vent ilation and direct laryngoscopy specific to pediatrics is vital for those of us who are entrusted with advanced management of the child’s airway.
Cengiz Karsli, MD
The Hospital for Sick Children
University of Toronto
Difficult airway management in children: Factors to consider when managing the pediatric difficult airway