Clinical Scenario
You are working an overnight shift at a single-coverage emergency department, when EMS calls ahead with a pediatric medical alert. They are three minutes out with a two-year old female found in respiratory distress. Her initial oxygen saturation was 78%, but it improved with bag-valve mask (BVM) ventilation. EMS unsuccessfully attempted to intubate the patient twice, and she remains in respiratory distress without effective spontaneous breathing. The panic level rises in the ancillary staff around you, and questions begin to race through your head. What challenges did the paramedics have attempting to secure an advanced airway? What equipment should I get ready prior to this 2-year-old girl's arrival? What is my plan B if she is a difficult airway?
Pediatric Airway Challenges
While cliché, nowhere is the old adage “kids aren't just little adults” more true than in the management of emergent pediatric airways. Both anatomically and physiologically unique, not only from adults, but also from age to age, pediatric airways require forethought and planning in order to provide appropriate care.
The first challenge in pediatric airways is overcoming the anatomic challenges associated with younger pediatric patients. A more anteriorly positioned larynx and a large head-to-body ratio result in more acute angles between the oropharynx and the larynx. The tongue and epiglottis tend to be more prominent and soft, making displacement visualizing the vocal cords more difficult. The cricoid cartilage is the narrowest part of the airway, so the tube may pass the cords but may be difficult to advance beyond that. Finally, the relatively small size of the cricothyroid membrane serves as a relative contraindication to traditional cricothyrotomy in the event that airway management from above the vocal cords is unsuccessful.1
Pediatric patients also present several unique physiologic challenges when considering emergent airway management. A relatively small oxygen reserve results in more rapid desaturation than in adults.2 Common medications used in rapid sequence intubation have different volumes of distribution and metabolism than for adults, resulting in shorter duration and the potential need for re-dosing.3
Due to these challenges, forethought must be given to the child's positioning and having properly sized primary and adjunct equipment to minimize the stress associated with managing an emergent pediatric airway.
Pediatric Airway Pearls
Positioning
Placing a towel roll under the patient's shoulders helps facilitate neck extension and better alignment of the oropharynx and trachea, making anatomic obstruction of the airway less likely and improving success of visualizing the vocal cords on direct laryngoscopy. Gentle thyroid cartilage manipulation may additionally help to bring more anteriorly positioned airways into view.4-6
Primary Equipment
An appropriately sized BVM may be the single most important piece of equipment to have available. Masks should be large enough to cover the entire mouth and nose, but not so large as to slide off the face and prevent an appropriate seal. Effective BVM is often sufficient to provide adequate oxygenation and ventilation in the case when an advanced airway is unable to be obtained.7,8 Use a Broselow tape, or equivalent, to estimate weight- and age-based equipment if needed. To estimate the appropriate size of an endotracheal tube (ETT), use the equation (Age/4) + 3.5 mm for cuffed ETT, and consider potentially using an uncuffed tube in for children requiring less than a 5.5 mm tube.9 Miller blades are generally used over Mac blades, as they assist in maneuvering the epiglottis out of the way.5 When selecting blade size, error on the side of too large as opposed to too small. When the age is not known, the child's pinkie diameter can be used to approximate the size of the ETT.
Adjunct Equipment
Laryngeal mask airway (LMA) sizes range from infant to adult, and are based on the patient's weight in kilograms. In the case of failed intubation with direct laryngoscopy, LMAs can be inserted and do not require direct visualization.10 Video laryngoscopy often negates the anatomic differences between pediatrics and adults, making its use in pediatrics similar to that in adult populations.11 Double-balloon devices, such as the King or Combitube should not be used in children less than 48 inches.
Conclusion
An emergent pediatric airway can be a stressful event, so having a systematic approach to appropriate patient positioning and the primary equipment can increase the likelihood of success. Weight-based or length-based estimating tools are useful to identify correct doses and equipment size. Finally, being familiar with adjunct equipment can often be used to successfully manage difficult pediatric airways.
References
- American College of Surgeons Committee on Trauma. Advanced Trauma Life Support (ATLS) Student Course Manual, 9th ed, American College of Surgeons, Chicago 2012.
- Gerhardt T, Reifenberg L, Bancalari E, et al. Functional residual capacity in normal neonates and children up to 5 years of age determined by a N2 washout method. Pediatr Res. 1986;20(7):668.
- Luten R, Wears R, Broselow J, et al: Managing the unique size related issues of pediatric resuscitation: reducing cognitive load with resuscitation aids. Acad Emerg Med 9: 840, 2002.
- Ludwig S, Lavelle JM. Resuscitation - Pediatric basic and advanced life support. In: Textbook of Pediatric Emergency Medicine, 5th, Fleisher GR, Ludwig S, Henretig FM. (Eds), Lippincott, Williams & Wilkins, Philadelphia 2006
- Murphy, MF, Barker, TD, Schneider, RE. Endotracheal intubation. In: Manual of Emergency Airway Management, 3rd, Walls, RM, Murphy, MF (Eds), Lippincott Williams & Wilkins, Philadelphia 2000. p.62.
- Sagarin MJ, Chiang V, Sakles JC, et al. Rapid sequence intubation for pediatric emergency airway management. Pediatr Emerg Care 2002; 18:417.
- Berg MD, Schexnayder SM, Chameides L, et al. Part 13: pediatric basic life support: 2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation 2010
- Mondolfi AA, Grenier BM, Thompson JE, Bachur RG. Comparison of self-inflating bags with anesthesia bags for bag-mask ventilation in the pediatric emergency department. Pediatr Emerg Care 1997; 13:312.
- Luten RC, Wears RL, Broselow J, et al. Length-based endotracheal tube and emergency equipment in pediatrics. Ann Emerg Med 1992; 21:900.
- Selim M, Mowafi H, Al-Ghamdi A, et al: Intubation via LMA in pediatric patients with difficult airways. Can J Anesth46: 891, 1999.
- Doherty JS1, Froom SR, Gildersleve CD. Pediatric laryngoscopes and intubation aids old and new. Paediatr Anaesth. 2009 Jul;19 Suppl 1:30-7.