List  the  ways  in  which  the  paediatric  airway differs  from the  adult   airway. Outline  how these influence your management.

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College Answer

Anatomic paediatric airways offer significant potential challenges to the critical care practitioner. Factors to consider include:

•    Absolute size of airway (including trachea), small mandible, large tongue (use of chart, formula [age/4 + 4 mm if > 1 yr] or Braselow measurement tape to allow sizing of ETT, and depth estimates essential [age/2 + 12 cm from  lower  lip]; often  need  smaller  blade [narrower,  shorter];  concern about tracheostomy)
•    Large  head  (neck  already  flexed,  not  need  pillow  or  as  much  head extension for intubation and airway management)
•    Epiglottis  long  and  stiff  and  may obscure  view  (may  need  to  include epiglottis under laryngoscope blade, or consider using straight blade)
•    Larynx  high,  anterior  and  the narrowest  point  is usually  the laryngeal outlet/cricoid cartilage (often use uncuffed tubes, increased concern about laryngeal stenosis)

Other specific management concerns related to the small size of the artificial airways  include:  importance   of  fixation  (ease  of  dislodgement),   increased likelihood of blockage, circuit/mechanics to minimise work of breathing.

Discussion

Anatomical Peculiarities of the Paediatric Airway
And strategies that may be used to overcome these.
Anatomical problem How this is a problem Strategy to overcome this problem
Prominent occiput Neck is flexed in the supine poistion. 
Laryngoscopy will be difficult in this position.
  • Placing a towel roll under the shoulders can improve airway alignment.
  • There is no need for a pillow under the head. 
    The best position is a neutral position
Small mandible Less anterior excursion; smaller mouth opening
  • Narrow small laryngoscope blade
Large tongue Large tongue relative to the size of the oral cavity. Causes airway obstruction and interferes with laryngoscopy.
  • Earlier use of oropharyngeal airways is called for.
  • Mouth should be kept open during bag ventilation (it keeps the tongue from causing an obstruction). No pressure should be applied against the floor of the mouth.
Larger tonsils and adenoids Can cause airway obstruction. Nasopharyngeal airways may cause bleeding and aspiration.
  • Spray with co-phenylcaine; use copious amounts of lubricant
  • Use CPAP, 10-15cm to overcome the obstruction
Superior laryngeal position Located opposite the C3 to C4 vertebrae, compared with the C4 to C5 in adults. Laryngoscpy is made more difficult.
  • "Sniffing position" is of no benefit
  • External manipulation may be required, i.e. a BURP manoeuvre
Large, floppy epiglottis The epiglottis projects further into the airway and covers more of the glottis (until the age of 4)
  • A straight blade is needed to directly lift the epiglottis f during direct laryngoscopy.
Short trachea Easy to intubate the right main bronchus.
Easy to inadvertently  extubate the child.
  • Use the formula (age/2 +12 cm from lower lip) to estimate tube length.
  • Pay special attention to tube fixation.
  • Carefully monitor tube depth markers
Narrow trachea  More predisposed to obstruction: small decreases in the airway size will cause obstruction.
The needle or surgical cricothyroidotomy is more difficult, as the target is smaller. 
One should also be concerned about the risk of tracheal stenosis following prolonged intubation or tracheostomy.
  • Use a small diameter bougie.
  • Defer surgical airways to ENT staff
Soft trachea and cricoid Cricoid pressure may collapse the airway
  • Don't use cricoid pressure.
    Or use less pressure.
Anatomic subglottic narrowing An effective anatomic seal can be expected without the need for a cuffed ETT. Foreign bodies can become lodged below the cords. This resolves by age 10-12.
  • Use an uncuffed ETT

The difficult paediatric airway 

References

Heard, A. M. B., R. J. Green, and P. Eakins. "The formulation and introduction of a ‘can't intubate, can't ventilate’algorithm into clinical practice." Anaesthesia64.6 (2009): 601-608.

Stacey, Jonathan, et al. "The ‘Can't Intubate Can't Oxygenate’scenario in Pediatric Anesthesia: a comparison of different devices for needle cricothyroidotomy.Pediatric Anesthesia 22.12 (2012): 1155-1158.

Weathers E., "The Anatomy of the Pediatric Airway" 2010 -RC EDUCATIONAL CONSULTING SERVICES, INC.

Santillanes, Genevieve, and Marianne Gausche-Hill. "Pediatric airway management." Emergency medicine clinics of North America 26.4 (2008): 961-975.

HOLM‐KNUDSEN, R. J., and L. S. Rasmussen. "Paediatric airway management: basic aspects." Acta Anaesthesiologica Scandinavica 53.1 (2009): 1-9.

Cardwell, Mary, and Robert WM Walker. "Management of the difficult paediatric airway." BJA CEPD Reviews 3.6 (2003): 167-170.