Spatial relationship of i-gel® and Ambu® AuraOnceTM on pediatric airway: a randomized comparison based on three dimensional magnetic resonance imaging

Abstract

Background: Gross morphological differences exist among different brands of pediatric supraglottic devices (SGDs). The aim of this study is to compare the spatial relationship of i-gel® and Ambu® AuraOnce (AO)TM on pediatric airway based on three dimensional (3-D) magnetic resonance imaging (MRI) measurements.

Methods: Sixty patients up to 12 years of age were enrolled and assigned in two groups, i-gel® or Ambu® AOTM. After confirmation of proper placement of these SGDs, 3-D MRI scans of head and neck were performed. Another native scan was also obtained after removal of the SGD for comparison.

Results: i-gel® produced significant degree of compression of the tongue (P<0.001) while Ambu® AOTM significantly reduced the axial diameter of glottis (P=0.033) compared to their native values. Both i-gel® and Ambu® AOTM significantly reduced the area of the glottic opening (P<0.001 for each device) and the distance between the arytenoids (P<0.001 and P=0.007 respectively); and increased the distance between the hyoid bone and cervical spine (P<0.001 and P=0.001 respectively) in comparison to their corresponding native values. Bowl of i-gel® produced greater dilation of the upper esophageal sphincter at all levels of measurement- upper (P<0.001), middle (P=0.001) and lower (P=0.015) in comparison to Ambu® AOTM.

Conclusions: Based on 3-D MRI measurements done on living patients, both SGDs distorted the anatomy of pediatric airway compared to their respective native values to variable extent. The relevance of these effects needs further studies on larger patient group in order to reduce morbidity on pediatric airway.