Neonatal Airway

ANATOMY OF AIRWAY IN NEONATE
  • The anatomy of the upper airway predisposes to obstruction. Its characteristic features are
  • Proportionately larger head and tongue, the tongue is often pushed against the palate
  • Narrow nasal passages
  • Anterior and cephalad larynx (the larynx is anteriorly inclined)
  • Epiglottis is soft, large and patulous, Omega shaped and inclined at 45°.
  • It is situated high up (C2 - C4). (in adults = C3 - C6)
  • Of equal size in both sexes (in adults it is larger in males)
  • Larynx is funnel shaped
  • The narrowest part of the infantile larynx is the junction of subglottic larynx with trachea( rather than the rima glottidis ) and this is because cricoid cartilage is very small Laryngeal cartilages are soft and collapse easily
  • Short trachea and short neck.
  • Vocal cords are angled and lie at level of C4
  • Trachea bifurcates at level of T2
  • Thyroid cartilage is flat. The cricothyroid and thyrohyoid spaces are narrow.
CLINICAL SIGNIFICANCE
  • A child able to breathe and suckle at the same time due to high placed larynx.
  1. Infant's larynx is positioned high in the neck level of glottis being opposite to C3 or C4 at rest and reaches Cl or C2 during swal­lowing. This high position allows the epiglottis to meet soft palate and make a nasopharyngeal channel for nasal breathing during suckling.The milk feed passes separately over the dorsum of tongue and the side of epiglottis, thus allowing breathing and feeding to go on simultaneously.
  • During intubation- passing of Endotracheal tube :
  1. Tube may impinge upon the cricoid cartilage( the cricoid cartilage is the narrowest point of the airway in children younger than 5 years of age)
  2. Mucosal trama can cause post operative edema, stridor, croup & airway obstruction.
  3. The relatively large size of the infant's tongue in relation to the oropharynx increases the likelihood of airway obstruction and technical difficulties during laryngoscopy; The larynx is located higher (more cephalic) in the neck, thus making straight blades more useful than curved blades;
  4. The epiglottis is shaped differently, being short, stubby, omega shaped, and angled over the laryngeal inlet; control with the laryngoscope blade is therefore more difficult; The vocal cords are angled, so a “blindly” passed endotracheal tube may easily lodge in the anterior commissure rather than slide into the trachea; and
  • Tracheostomy in Infants and Children 
  1. Trachea of infants and children is soft and compressible and its identification may become difficult and the surgeon may easily displace it and go deep or lateral to it injuring recurrent laryngeal nerve or even the carotid.
  2. During positioning, do not extend too much as this pulls structures from chest into the neck and thus injury may occur to pleura, innominate vessels and thymus or the tracheostomy opening may be made twoo low near suprasternal notc 
  3. The incision is a short transverse one, midway between lower border of thyroid cartilage and the suprasternal notch. The neck must be well extended.
  4. A incision is made through two tracheal rings, preferably the third or fourth.
Exam Question
  • A child able to breathe and suckle at the same time due to high placed larynx.
  • Infant airway compared to adult airway is relatively large size of the tongue ,Epiglottis is omega shaped , Larynx is funnel shaped.
  • The narrowest part of trachea in a newborn is at the level of cricoidl cartilage.
  • In administering anesthesia in infants, this may lead to Trauma to the subglottic region ,Post operative stridor,Laryngeal oedema.
  • Larynx extends from C2 to C4 in neonates.
  • Subglottic region is the narrowest part of infantile larynx.

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