Pediatric Difficult Airway

Pediatric Difficult AirwayRespiratory illness, sepsis, and trauma are three important entities afflicting children that may lead to needing to manage a child’s airway. Airway management in the ED is a complex interplay of patient factors, clinical illness status, and provider factors that, through our thorough training we become proficient at navigating. We have discussed many airway concepts previously (ex, ETT Depth, Cuffed ETTs, Apneic Oxygenation, Delayed Sequence Intubation, Noninvasive Ventilation, Heliox, and Transtracheal Ventilation) but one topic that deserves specific attention is the notion of a Difficult Airway:

 

Difficult Airway: Basics

  • Defining “Difficult Airway” is challenging, so studies are not strictly comparable (we all know it after we have dealt with it though).
  • Some separate “Difficult Airway” from “Difficult Intubation.” [Belanger, 2015]
    • Difficult Airway – unable to provide adequate gas exchange despite BVM, airway adjuncts, or combination of the two.
    • Difficult Intubation – 3 or more attempts by an experienced clinician
  • The incidence of difficult intubations in children vary from <0.1% to 9% [Graciano, 2014; Heinrich, 2012]
  • Difficult intubations is associated with higher incidence of oxygen desaturations below 80% and adverse events. [Graciano, 2014]

 

Difficult Airway: Important Differences

Anatomic and physiologic differences influence how the oral, pharyngeal, and tracheal axes align as well as how the respiratory mechanics function and how the child compensates to physiologic stress.

The differences are most prominent in children < 2 years of age and more adult anatomy evolves as children progress to 8 years of age.

Anatomic Differences:

  • Relatively larger head (particularly occiput)
    • Need for shoulder roll instead of head elevation to align external auditory meatus with sternal notch (which helps align the three axes).
  • Smaller and compressible nasal passages
    • More easily occluded by mucous
    • Easily obstructed by poorly positioned facemask.
  • Relatively larger tongue
    • More difficult to control with laryngoscope blade.
    • Occupies more mouth and posterior pharyngeal space.
  • Larynx location is more cranial
    • Adult’s larynx located around C4-5
    • Child’s larynx located around C3-4, but can be even higher (C2-3).
    • Makes for more of an “anterior” airway and acute angle from pharyngeal axis to tracheal axis.
  • Epiglottis is longer and more floppy
    • Softer cartilage and more pliable tissues
    • Can be more difficult to retract away from glottic opening.
  • Trachea is more compressible
    • Softer cartilage and more pliable tissues
    • Can be easily compressed by a “helpful” person performing cricoid pressure (don’t let this happen).
  • Ribs are horizontal
    • Contribute less to the work of breathing
    • Diaphragm does most of the work of breathing.
  • Low functional residual capacity
    • Due to smaller airways and less dead space
    • Smaller reservoir from which the apneic child can draw oxygen
  • Smaller number of alveoli
    • Less oxygen absorption surface area.

 

Physiologic Differences:

  • Higher metabolic rate
    • Consumes oxygen at more than twice the adult rate
    • Combined with low functional residual capacity, leads to rapid desaturations.
  • Low glycogen stores

 

Difficult Airway: Predictive Factors

  • Adult-based tools (ex, LEMON, Mallampati, thyromental distance) are not predictive in young children. [Belanger, 2015]
  • There are patient factors that are associated with difficult intubation. [Karsli, 2015; Belanger, 2015]
    • History of difficult airway (duh) [Graciano, 2014]
    • Less than 1 year of age
    • Signs of Upper Airway Obstruction (duh) [Graciano, 2014]
    • Congenital/Genetic Syndromes w/ altered anatomy
    • Physiologic stress [Graciano, 2014]
      • Hypotension, ventilation failure, etc

 

Difficult Airway: Assume the Worst

  • Most pediatric airways can be secured by experienced clinicians, but the potential for discovering a difficult airway after meds have been pushed is a perilous position to be in. [Belanger, 2015]
  • Absence of predictive factors for difficult airway does not mean it will be an easy airway. [Karsli, 2016; Graciano, 2014]
    • One study found 1 in 5 Difficult Airway cases were NOT anticipated. [Karsli, 2016]

 

Moral of the Morsel

  • Pediatric patients are a special population and warrant special considerations.
  • Anatomy and Physiology matter! There are numerous differences that need to be considered… even when it is “easy.”
  • Anticipate the Worst! 1 out of 5 is a concerning number – All pediatric patients should be considered to have a Difficult Airway until you successfully intubate them… then you can hit the “easy” button.
  • There are no “easy airways” in the ED, regardless of age. Patients that require intubation in the ED have, be definition, stressed physiologic systems and, as such, should be considered difficult until proven otherwise.

 

References

Karsli C1, Pehora C2, Al-Izzi A2, Mathew P2. A retrospective review of pediatric difficult airways: once easy, not always easy. Can J Anaesth. 2016 Jun;63(6):776-7. PMID: 26767657. [PubMed] [Read by QxMD]
Karsli C1. Managing the challenging pediatric airway: Continuing Professional Development. Can J Anaesth. 2015 Sep;62(9):1000-16. PMID: 26243378. [PubMed] [Read by QxMD]

Belanger J, Kossick M. Methods of identifying and managing the difficult airway in the pediatric population. AANA J. 2015 Feb;83(1):35-41. PMID: 25842632. [PubMed] [Read by QxMD]

Black AE1, Flynn PE, Smith HL, Thomas ML, Wilkinson KA; Association of Pediatric Anaesthetists of Great Britain and Ireland. Development of a guideline for the management of the unanticipated difficult airway in pediatric practice. Paediatr Anaesth. 2015 Apr;25(4):346-62. PMID: 25684039. [PubMed] [Read by QxMD]

Graciano AL1, Tamburro R, Thompson AE, Fiadjoe J, Nadkarni VM, Nishisaki A. Incidence and associated factors of difficult tracheal intubations in pediatric ICUs: a report from National Emergency Airway Registry for Children: NEAR4KIDS. Intensive Care Med. 2014 Nov;40(11):1659-69. PMID: 25160031. [PubMed] [Read by QxMD]

Heinrich S1, Birkholz T, Ihmsen H, Irouschek A, Ackermann A, Schmidt J. Incidence and predictors of difficult laryngoscopy in 11,219 pediatric anesthesia procedures. Paediatr Anaesth. 2012 Aug;22(8):729-36. PMID: 22340664. [PubMed] [Read by QxMD]

Sean Fox

I enjoy taking care of patients and I finding it endlessly rewarding to help train others to do the same. I trained at the Combined Emergency Medicine and Pediatrics residency program at University of Maryland, where I had the tremendous fortune of learning from world renown educators and clinicians. Now I have the unbelievable honor of working with an unbelievably gifted group of practitioners at Carolinas Medical Center. I strive every day to inspire my residents as much as they inspire me.

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2 Responses

  1. Juanica says:

    My son is 16 and he had his appendix taken out when he was 11 but no medical issues prior except common cold and took a round of antibiotics and after is the same. No bad medical history. My son has always set in front of the tv or game, and has never played sports but one summer of his whole life. I am starting to have some heart trouble and my dad does and my brother died at 26 from cornarial artery disease but he has a different dad and my mom only has lung problems so i dont understand all that but is my son going to have to have surgery for a blockage or a pacemaker this is what im reading or understanding. Im a cna so i know you cant give me a yes or no but in your opinion what is the out come of patients like my sons just for a little in site to what we r looking forward to

  2. Brisson Muia says:

    I like your bloggs for they are very insightful and resourceful…keep it up

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