Pediatric Airway shape; What has changed, and the implications?

Abstract

Airway shape in infants and children has been defined as “funnel-shaped with the cricoid cartilage as the narrowest point in the airway.”The funnel shape of the pediatric airway was cited from an article by Eckenhoff.1 Eckenhoff’s description of the pediatric larynx was based on cadaveric airway research by Bayeux,(1897),2 which was quoted only partially by Eckenhoff. Eckenhoff did caution that “the measurements so derived may not be completely applicable to the living.”Bayeux used calibrated cylinders separately at three points in the airway, cricoid trachea, and glottis, and concluded that the cricoid was the narrowest part of the airway, this part of his research was reported by Eckenhoff. Bayeux also obtained airway castings, which showed that on an anteroposterior section, the narrowest part of the larynx is the cricoid and whereas in lateral view (transverse sections) these relations are inverse with glottis narrower than the cricoid. This important observation that the airway dimensions in anteroposterior and transverse sections looked different, with airway conical or funnel-shaped in the sagittal sections and reverse of it in the anteroposterior sections has been continuously overlooked in the literature and was not reported by Eckenhoff.