Analysis of the functionally-narrowest portion of the pediatric upper airway in sedated children

Abstract

The narrowest portions of the pediatric larynx are the glottis and subglottic region. However, the pliable and paralyzed subglottic region, acting like a curtain, is no resistance when passing an endotracheal tube. Therefore, the 'functionally' portion of the pediatric upper airway, which may be the most vulnerable to damage during intubation, is the unyielding portion below the cricoid cartilage. We investigated the functionally-narrowest portion below the cricoid cartilage. Computed tomography (CT) was performed under deep sedation. CT images were used for measurement of dimensions and cross-sectional area (CSA) of the larynx at the level of the cricoid, subcricoid, and trachea. We analyzed the anteriorposterior (AP) diameter, transverse diameter, and CSA below the cricoid cartilage (at the cricoid, subcricoid, and tracheal levels). CT images of 46 children from 8 months to 96 months were reviewed from electric medical record (EMR). The mean±SD of AP diameter was the shortest at the subcricoid level (cricoid, 105.7±15.8mm; subcricoid, 94.6±15.3mm; and trachea, 101.5±15.7mm; P