Ultrasonographic assessment of altered anatomical relationship between internal jugular vein and common carotid artery with supraglottic airway in children: LMA vs i-gel™

BACKGROUND AND AIMS: Use of ultrasound (US) during internal jugular vein (IJV) cannulation reduces the risk of associated complications in children under general anaesthesia. We studied the effect of two varieties of supraglottic airway device (SGAD), the Ambu AuraOnce™ LMA (Ambu LMA), and i-gel™ on the anatomical relationship between IJV and common carotid artery (CCA). Both these SGAD are known to have similar safety profile in paediatric age group. METHODS: A total of 62 children were randomly allocated into 2 groups. In group L: Ambu AuraOnce™ LMA (Ambu LMA) and in group I: i-gel™ was inserted. After induction of GA, US images were taken with head in neutral and 30 degrees rotated to the opposite side both before and after insertion of SGAD. The relationship between IJV and CCA was noted as lateral, anterolateral, and anterior. Degree of overlap between the two vessels was also noted. RESULTS: Lateral rotation of the head significantly alters the relationship between the IJV and CCA and also increases the degree of overlap between them. Though these changes were noted to be similar with both varieties of SGAD, but between the two varieties of SGAD, these changes were significantly higher in group I. CONCLUSION: Higher oesophageal sealing pressure exerted by i-gel™ as compared to other SGAD might cause increased distortion of the surrounding soft tissue leading to altered anatomical relationship between IJV and CCA, which makes the CCA vulnerable to puncture during IJV cannulation using landmark technique.