Developmental anatomy of the airway

Abstract

A thorough understanding of the airway anatomy, as well as the differences that exist between the paediatric and the adult airway is crucial for one to safely manage it. The human airway originates from the primitive foregut at 4 weeks' gestation and fully matures at 36 weeks’ gestation. At birth, the term neonate has a relatively large head, flat occiput, short neck, small mouth opening and a small mandible; features which make them prone to upper airway obstruction as well as a difficult laryngoscopy. Neonates are obligate nasal breathers; allowing them to breathe and suckle simultaneously. The Hagen–Poiseuille equation explains how nasal congestion causes obstruction in neonates which can lead to the development of significant respiratory distress.

The subglottic area of the airway is the most susceptible area to damage from intubation or instrumentation of the airway resulting in subglottic stenosis. Correct endotracheal tube sizing and meticulous attention to detail with respect to cuff pressure are essential to prevent damage to the airway.